OFFSHORE LOGISTICS INC
10-Q, 1997-02-14
AIR TRANSPORTATION, NONSCHEDULED
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<PAGE>
============================================================================== 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, DC  20549

                                   FORM 10-Q

           [x]  Quarterly Report Pursuant to  Section 13 or 15(d) of
                      the Securities Exchange Act of 1934
                For the quarterly period ended December 31, 1996

           [ ]   Transition Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934
                   For the transition period  _____ to  _____

                         Commission File Number 0-5232

                           OFFSHORE LOGISTICS, INC.
            (Exact name of registrant as specified in its charter)
 
                DELAWARE                              72-0679819
   (State or other jurisdiction of         (IRS Employer Identification Number)
    incorporation or organization)
 
               224 RUE DE JEAN
      P. O. BOX 5C, LAFAYETTE, LOUISIANA                       70505
   (Address of principal executive offices)                 (Zip Code)
 
Registrant's telephone number, including area code:  (318) 233-1221
 

- -----------------------------------------------------------------------------
  (Former name, former address and former fiscal year, if changed since last
                                    report)

          Indicate by check mark whether the registrant: (1) has filed all
reports required to be filed by Section 13 or 15(d) of the Securities Exchange
Act of  1934 during the preceding 12 months, and (2) has been subject to such
filing requirements for the past 90 days.            Yes [x]     No [ ]

 
                Indicate the number of shares outstanding of each of the
issuer's classes of Common Stock, as of December 31, 1996.

               21,040,989 shares of Common Stock, $.01 par value

==============================================================================
<PAGE>
 
                   OFFSHORE LOGISTICS, INC. AND SUBSIDIARIES
                        CONSOLIDATED STATEMENT OF INCOME
                (thousands of dollars, except per share amounts)

<TABLE>
<CAPTION>
                                               THREE MONTHS ENDED           SIX MONTHS ENDED 
                                                  DECEMBER 31,                DECEMBER 31,  
                                            -------------------------   --------------------------     
                                              1996          1995          1996          1995
                                            ------------  -----------   ------------  ------------
<S>                                         <C>           <C>            <C>           <C>
GROSS REVENUE
Operating revenue.........................  $    49,614   $    39,878   $    91,600   $    78,869
Gain (loss) on disposal of equipment......          492            66           723          (158)
                                            -----------   -----------   -----------   -----------
                                                 50,106        39,944        92,323        78,711
 
OPERATING EXPENSES
Direct cost...............................       36,789        31,608        67,006        61,480
Depreciation and amortization.............        3,137         2,184         5,572         4,337
General and administrative................        3,324         3,152         6,514         6,252
                                            -----------   -----------   -----------   -----------
                                                 43,250        36,944        79,092        72,069
                                            -----------   -----------   -----------   -----------
 
OPERATING INCOME..........................        6,856         3,000        13,231         6,642
Earnings from unconsolidated entities.....        1,019         1,109         2,274         1,734
Interest income...........................        1,246         1,050         2,348         2,051
Interest expense..........................          831           192           970           400
                                            -----------   -----------   -----------   -----------
 
INCOME BEFORE PROVISION FOR INCOME TAXES..        8,290         4,967        16,883        10,027
Provision for income taxes................        2,653         1,436         5,403         2,908
(Income) loss of minority interest........          (29)          (75)          (17)           (4)
                                            -----------   -----------   -----------   -----------
NET INCOME................................  $     5,608   $     3,456   $    11,463   $     7,115
                                            ===========   ===========   ===========   ===========
Earnings per common share and
common equivalent share...................        $0.28         $0.18         $0.57         $0.36
                                            ===========   ===========   ===========   ===========
Common shares and common
equivalent shares outstanding.............   20,174,104    19,728,422    19,969,343    19,748,084
                                            ===========   ===========   ===========   ===========
 
</TABLE>

                                       2
<PAGE>
 
                   OFFSHORE LOGISTICS, INC. AND SUBSIDIARIES
                           CONSOLIDATED BALANCE SHEET
                             (thousands of dollars)

 <TABLE>
<CAPTION>
                                                         DECEMBER 31,   JUNE 30,
                                                            1996          1996
                                                         ------------    -------
ASSETS
- ------
<S>                                                        <C>         <C>
Current Assets:
 Cash and cash equivalents...............................   $ 27,971    $ 57,072
 Investment in marketable securities.....................          -      19,967
 Accounts receivable.....................................     82,601      29,743
 Inventories.............................................     72,832      26,724
 Prepaid expenses........................................        769         694
                                                            --------    --------
      Total current assets...............................    184,173     134,200
 
Investments in unconsolidated entities...................     10,929       8,792
Property and equipment - at cost:
 Land and buildings......................................     15,927       2,977
 Aircraft and equipment..................................    505,692     135,613
                                                            --------    --------
                                                             521,619     138,590
Less: accumulated depreciation and amortization..........    (68,661)    (64,401)
                                                            --------    --------
                                                             452,958      74,189
Other assets.............................................     37,310      24,329
                                                            --------    --------
                                                            $685,370    $241,510
                                                            ========    ========
 
LIABILITIES AND STOCKHOLDERS' INVESTMENT
- ----------------------------------------
Current Liabilities:
 Accounts payable........................................   $ 32,207    $  4,872
 Accrued liabilities.....................................     38,111       8,542
 Current maturities of long-term debt....................     49,678       4,850
                                                            --------    --------
      Total current liabilities..........................    119,996      18,264
 
 Long-term debt, less current maturities.................    206,151         750
 Deferred credits........................................      1,244       2,487
 Deferred taxes..........................................    111,248      19,271
 Minority interest.......................................      9,819       1,055
 
Stockholders' Investment:
 Common Stock, $.01 par value, authorized
    35,000,000 shares; outstanding 20,040,989 and
    19,498,398 at December 31 and June 30,
    respectively (exclusive of 517,550 treasury shares)..        210         195
 Additional paid-in capital..............................    114,944      95,934
 Retained earnings.......................................    115,017     103,554
 Cumulative translation adjustment.......................      6,741           -
                                                            --------    --------
                                                             236,912     199,683
                                                            --------    --------
                                                            $685,370    $241,510
                                                            ========    ========
</TABLE>

                                       3
<PAGE>
 
                   OFFSHORE LOGISTICS, INC. AND SUBSIDIARIES
                      CONSOLIDATED STATEMENT OF CASH FLOWS
                             (thousands of dollars)

<TABLE>
<CAPTION>
                                                                  SIX MONTHS ENDED 
                                                                    DECEMBER 31,
                                                                   1996       1995
                                                                ----------  ---------
<S>                                                             <C>         <C>
Cash flows from operating activities:
     Net income...............................................  $  11,463   $  7,115
Adjustments to reconcile net income to net cash
provided by operating activities:
     Depreciation and amortization............................      5,572      4,337
     Increase (Decrease) in deferred taxes....................       (695)       428
     Loss (Gain) on asset dispositions........................       (723)       158
     Minority interest in earnings............................         17          4
     Increase in accounts receivable..........................     (4,041)      (445)
     Increase in inventories..................................     (1,748)      (885)
     Increase in prepaid expenses and other...................     (3,241)      (681)
     Increase (Decrease) in accounts payable..................       (487)     2,137
     Increase (Decrease) in accrued liabilities...............     11,910     (2,429)
     Decrease in deferred credits.............................     (1,244)    (1,250)
                                                                ---------   --------
Net cash provided by operating activities.....................     16,783      8,489
                                                                ---------   --------
 
Cash flows from investing activities:
     Capital expenditures.....................................     (3,794)    (4,608)
     Proceeds from asset dispositions.........................      1,012        150
     Investment in marketable securities......................        ---    (11,952)
     Proceeds from sale or maturity of marketable securities..     20,001     11,988
     Cash used in Bristow transaction, net of cash received...   (153,029)       ---
                                                                ---------   --------
Net cash used in investing activities.........................   (135,810)    (4,422)
                                                                ---------   --------
 
Cash flows from financing activities:
     Proceeds from borrowings.................................     88,418        150
     Issuance of common stock.................................      1,501        447
                                                                ---------   --------
Net cash provided by financing activities.....................     89,919        597
                                                                ---------   --------
Effect of exchange rate changes in cash.......................          7         --
                                                                ---------   --------
 
Net increase (decrease) in cash...............................    (29,101)     4,664
Cash and cash equivalents at beginning of year................     57,072     47,973
                                                                ---------   --------
 
Cash and cash equivalents at end of quarter...................  $  27,971   $ 52,637
                                                                =========   ========
Supplemental disclosure of cash flow information
Cash paid during the period for:
  Interest....................................................  $   2,654   $    319
  Income taxes................................................      5,235      4,148
 
</TABLE> 

                                       4
<PAGE>
 
                   OFFSHORE LOGISTICS, INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                               DECEMBER 31, 1996

NOTE A - BASIS OF PRESENTATION

     The accompanying unaudited consolidated financial statements have been
prepared in accordance with the instructions to Form 10-Q and do not include all
information and footnotes necessary for a fair presentation of financial
position, results of operations, and cash flows in conformity with generally
accepted accounting principles.  In the opinion of management, any adjustments
considered necessary for a fair presentation have been included.  Operating
results for the six months ended December 31, 1996, are not necessarily
indicative of the results that may be expected for the year ending June 30,
1997.  For further information, refer to the consolidated financial statements
and footnotes included in the Company's Annual Report on Form 10-K for the year
ended June 30, 1996.

NOTE B - BRISTOW HELICOPTERS

     On December 19, 1996, the Company completed its previously announced
transaction to acquire a significant economic interest in Bristow Aviation
Holdings, Ltd. ("BAHL"), a newly incorporated company in England.  BAHL was
formed to acquire all of the outstanding shares of Bristow Helicopter Group,
Ltd. ("Bristow").  Bristow has conducted helicopter operations for more than 30
years and currently operates 121 aircraft in the North Sea, Nigeria, China,
South America, Australia, Cambodia, and Brunei.

     Under the terms of the transaction, the Company will own 49% of BAHL,
(Pounds) 5.0 million of Bristow's subordinated debt and (Pounds) 91 million of
subordinated debt of BAHL. The subordinated debt of BAHL will bear interest at
an annual rate of 13.5%. In addition, the Company has entered into put/call
agreements with the other two shareholders of BAHL whereby the Company will have
the right to buy all BAHL shares held by the shareholders and who, in turn, will
have the right to sell their shares to the Company at a fixed price of (Pounds)
5.1 million, plus an additional amount equal to a 10% or 12% return depending on
which party elects to buy/sell under the agreement. Under current U.K. law,
voting control of BAHL must reside with European citizens and accordingly, the
Company would be required to find a qualified European investor or investors to
own 51% of the outstanding shares of BAHL if it bought out the original
shareholders.

     The Company financed the purchase price of $169.4 million with a
combination of $56.5 million of existing cash, $98 million of 6% convertible
subordinated notes and 1,374,389 shares of common stock.  The 6% convertible
notes ("notes") pay interest semi-annually on June 15 and December 15 and are
due December 15, 2003.  The notes are convertible 60 days after issuance, at the
option of the holder, into shares of common stock of the Company at a conversion
price of $22.86 per share.  The notes are redeemable, in whole or in part after
December 15, 1999, at the option of the Company at the following redemption
prices:

          YEAR                            REDEMPTION PRICE
          ----                            ----------------

          1999.............................    103.43%
          2000.............................    102.57%
          2001.............................    101.71%
          2002.............................    100.86%

                                       5
<PAGE>
 
          The transaction was treated as a purchase for accounting purposes.
The purchase price has been allocated to the assets and liabilities based on
estimated fair value.  The purchase price allocation is preliminary and subject
to final review.

          The operating results of BAHL have been consolidated in the Company's
statement of income since December 19, 1996. The following summarized unaudited
income statement data reflects the impact the transaction would have had on the
Company's results of operations for the six months ended December 31, 1996 and
1995 had the transaction occurred on July 1, 1995:

                                PROFORMA RESULTS FOR THE
                              SIX MONTHS ENDED DECEMBER 31,
                              -----------------------------
                    (thousands of dollars, except per share amounts)
 
                                   1996      1995
                                 --------  --------
                                    (unaudited)
 
Gross revenue..................  $211,904  $198,924
                                 ========  ========
 
Net Income.....................  $ 13,078  $  9,864
                                 ========  ========
 
Earnings per common share and
common equivalent share:
 Primary.......................  $   0.62  $   0.47
                                 ========  ========
 Fully diluted.................  $   0.59  $   0.47
                                 ========  ========

NOTE C - FOREIGN CURRENCY TRANSACTION

          The functional currency of Bristow is the British pound sterling. The
December 31, 1996 balance sheet of Bristow was translated using the period end
exchange rate. The operating results of Bristow from December 19, 1996 through
December 31, 1996 were translated using the weighted average exchange rate for
the period. There were no material foreign transaction gains or losses for the
period from December 19, 1996 through December 31, 1996.

NOTE D - NEW ACCOUNTING PRONOUNCEMENTS

          Effective July 1, 1996, the Company adopted Statement of Accounting
Standards ("SFAS") No. 121 - "Accounting for the Impairment of Long-Lived Assets
and for Long-Lived Assets to be Disposed of."  The adoption had no impact on the
Company's results of operations or financial position.

          On July 1, 1996, the Company elected to continue to account for its
employee stock options in accordance with the provisions of Accounting
Principles Board Opinion 25 and, accordingly, adopted the disclosure provisions
of SFAS No. 123 - "Accounting for Stock-Based Compensation."

                                       6
<PAGE>
 
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS


          The Company's most significant operation is supplying helicopter
transportation services to the worldwide offshore oil and gas industry.  This
area of operation was enhanced by the Company's completion of its investment in
Bristow Aviation Holdings, Ltd. ("BAHL") on December 19, 1996.  BAHL was formed
to acquire all of the outstanding shares of Bristow Helicopter Group, Ltd.
("Bristow").  Bristow is also a leading supplier of helicopter transportation
services to the worldwide offshore oil and gas industry.  With the addition of
the assets and the operations of Bristow, the Company will conduct operations in
the two largest oil and gas producing regions, the North Sea and the Gulf of
Mexico, and more than 15 other countries around the world with a fleet of 320
aircraft.  The Company, through its investment in Bristow, provides pilot and
engineering training services for both governmental agencies and private
industry, technical engineering and design services, search and rescue
operations, and repair and overhaul services.  The Company also provides
production personnel and medical support services to the worldwide oil and gas
industry and manufactures, installs and maintains cathodic protection systems to
arrest corrosion in oil and gas drilling and production facilities and other
metal structures.

          A summary of operating results for the applicable periods is as
follows:

<TABLE>
<CAPTION>

                                           THREE MONTHS ENDED      SIX MONTHS ENDED 
                                               DECEMBER 31,          DECEMBER 31,
                                           ---------------------  --------------------      
                                              1996       1995       1996       1995
                                            ---------  ---------  ---------  ---------
<S>                                         <C>        <C>        <C>        <C>
 
Gross revenue.............................   $50,106    $39,944    $92,323    $78,711
Operating expenses........................    43,250     36,944     79,092     72,069
                                             -------    -------    -------    -------
 
Operating income..........................     6,856      3,000     13,231      6,642
 
Earnings from unconsolidated entities.....     1,019      1,109      2,274      1,734
Interest income, net......................       415        858      1,378      1,651
                                             -------    -------    -------    -------
 
Income before provision for income taxes..     8,290      4,967     16,883     10,027
 
Provision for income taxes................     2,653      1,436      5,403      2,908
(Income) loss of minority interest........       (29)       (75)       (17)        (4)
                                             -------    -------    -------    -------
 
Net income................................   $ 5,608    $ 3,456    $11,463    $ 7,115
                                             =======    =======    =======    =======
</TABLE>

RESULTS OF OPERATIONS
- ---------------------

CONSOLIDATED
          Consolidated operating revenues for the three months ended December
31, 1996 were $49.6 million compared to $39.9 million in the prior year, a 24%
increase, and for the six months ended December 31, 1996 were $91.6 million
compared to $78.9 million in the prior year, a 16% increase.  The increase in
revenue is attributable to the completion of the Bristow transaction on December
19, 1996

                                       7
<PAGE>
 
($8.2 million) , as well as the improved activity levels in helicopter
activities. Consolidated operating expenses for the three months ended December
31, 1996 were $43.3 million compared to $36.9 million in the prior year, a 17%
increase, and for the six months ended December 31, 1996 were $79.1 million
compared to $72.1 million in the prior year, a 10% increase. The increase in
expenses is primarily related to the additional expenses of Bristow since
December 19, 1996. Operating income (excluding gains on disposal of equipment)
for the three months and six months ended December 31, 1996 were $6.4 million
and $12.5 million, respectively, representing an increase of over 100% and over
80%, respectively from the prior year. Net income for the three months and six
months ended December 31, 1996 was $5.6 million and $11.5 million, respectively,
a 60% increase over prior year net income.

HELICOPTER ACTIVITIES

          Consolidated flight hours were approximately 31,400 and 61,800 for the
three months and six months ended December 31, 1996, respectively, a 19% and 14%
increase compared to the same period in the prior year. The increase is related
to the combined effect of improved Gulf of Mexico activity and the transaction
with Bristow outlined previously, as well as increased activity of existing
international operations.

          Operating revenues from helicopter activities for the three months and
six months ended December 31, 1996 were approximately $33.8 million and $59.5
million, respectively, compared to $22.1 million and $43.8 million in the prior
year. Strong drilling activity in the Gulf of Mexico increased the demand for
the Company's larger crew change aircraft prompting an increase in helicopter
rates and resulting in significantly higher operating revenues compared to the
prior year. Operating revenues from the Gulf of Mexico activity were
approximately $21.9 million and $43.0 million for the three months and six
months ended December 31, 1996, a 17% and 16% increase over the prior year.
Operating revenues from Bristow for the period from the transaction (December
19, 1996) through December 31, 1996 were $8.2 million. Operating revenues from
existing International operations were $4.8 million and $9.6 million for the
three months and six months ended December 31, 1996, respectively, an 18% and
30% increase from the prior year. Operating revenues from Alaska operations were
$1.6 million and $4.1 million for the three months and six months ended December
31, 1996, respectively.

          Operating expenses for helicopter activities for the three months and
six months ended December 31, 1996 were approximately $27.4 million and $46.3
million, respectively, compared to $18.8 million and $35.9 million in the prior
year.  Operating expenses for the Gulf of Mexico were approximately $17.9
million and $32.4 million for the three months and six months ended December 31,
1996, a 6% increase from the prior year.  Operating expenses for Bristow for the
period from the transaction (December 19, 1996) through December 31, 1996 were
$7.5 million. Operating expenses for existing International operations were $3.3
million and $6.6 million for the three months and six months ended December 31,
1996, respectively.

          Operating income for helicopter activities (excluding gains on
disposal of equipment) for the three months and six months ended December 31,
1996 were $6.5 million and $13.2 million, respectively, compared to $3.3 million
and $7.9 million in the prior year.  The $3.2 million and $5.3 million increase
in operating income is primarily attributable to the Gulf of Mexico operations.
Operating income in the Gulf of Mexico  increased 125% and 84% for the three
months and six months ended December 31, 1996, compared to the same period in
the prior year.   Consolidated gross margins for helicopter activities were 19%
and 22% for the three months and six months ended December 31, 1996,
respectively, compared to 15% and 18% in the prior year.

                                       8
<PAGE>
 
PRODUCTION MANAGEMENT SERVICES

          Operating revenues from GPM were approximately $7.9 million for the
three months ended December 31, 1996, equal to prior year revenues, and were
$15.5 million for the six months ended December 31, 1996, a 7% decrease from the
prior year.  Operating expenses for GPM were approximately $7.4 million and
$14.6 million for the three months and six months ended December 31, 1996,
respectively, a 6% and an 11% decrease from the prior year.  Gross margins for
the three and six months ended December 31, 1996 were nearly 6%, prior year
operations were close to breakeven.  Improved gross margins were the result of
improved pricing policies and several cost containment measures.

CATHODIC PROTECTION SERVICES

          Operating revenues from CPS were approximately $8.7 million and $18.0
million for the three months and six months ended December 31, 1996,
respectively, a decrease of 20% and 13% from the comparable periods in the prior
year.  Operating expenses for CPS were approximately $8.5 million and $17.8
million for the three months and six months ended December 31, 1996,
respectively, an 18% and a 13% decrease from the prior year.  Operating income
from CPS was $0.1 million and $0.2 million for the three months and six months
ended December 31, 1996.

LIQUIDITY AND CAPITAL RESOURCES

          Cash, cash equivalents, and marketable securities were $28.0 million
and $77.0 million as of December 31, 1996 and June 30, 1996, respectively. The
Company used existing cash of $56.5 million together with the proceeds from
issuing $98.0 million of 6% convertible subordinated debt to finance the Bristow
transaction. Total debt was $255.8 million as of December 31, 1996, including
$98.0 million of subordinated notes, (Pounds) 88.9 million of acquired Bristow
debt ($152 million at December 31, 1996) with recourse to Bristow only, and $5.6
million related to CPS with recourse to CPS only. The convertible subordinated
notes require semi-annual interest payments with principal due on December 15,
2003. The notes are convertible at the option of the holder and can be redeemed
by the Company after December 15, 1999. The acquired Bristow debt has scheduled
repayments through 2001 in British pounds sterling with (Pounds) 26.1 million
repayable over the next 12 months. Certain portions of the debt can be repaid or
acquired by the Company prior to maturity or on November 7, 1997, with no
repayment penalty.

          As of December 31, 1996, the Company had $10 million of credit
available under an unsecured working capital line of credit from a bank.
Management believes that normal operations will provide sufficient working
capital and cash flow to meet debt service for the foreseeable future.

          The effective income tax rates were 32% and 29% for the six months
ended December 31, 1996 and 1995, and is based on the Company's projected
effective tax rate for the fiscal year then ended.  The increase in the
projected tax rate for fiscal 1997 is primarily the result of higher projected
domestic income for the year.

          The Company has received notices  from the United States Environmental
Protection Agency that it is one of approximately 160 potentially responsible
parties ("PRP") at one Superfund site in Texas, one of over 300 PRPs at two
sites in Louisiana, and a PRP at one site in Rhode Island.  The Company
believes, based on presently available information, that its potential liability
for clean up and other response costs in connection with these sites is not
likely to have a material adverse effect on the Company's business or financial
condition.

                                       9
<PAGE>
 
FORWARD LOOKING STATEMENTS

          The Company cannot predict the future prices of crude oil or natural
gas nor the future level of drilling activity.  However, if current drilling
activity levels continue in the Gulf of Mexico, management is optimistic that
the high demand for the Company's helicopter activities will continue. In
addition, management is optimistic about the increase in the Company's worldwide
helicopter operations through its investment in Bristow.

          There are statements contained herein that are forward-looking and are
based on factors including, among other things, the prices of crude oil and
natural gas, the level of offshore drilling activity, and the worldwide oil and
gas market, which could cause actual results to differ materially from such
expectations.

                                       10
<PAGE>
 
                                    PART II

Item 2.  Changes in Securities.
- ------   ---------------------

         On December 17, 1996, the Registrant sold $80,000,000 in aggregate 
principal amount of its 6% Convertible Subordinated Notes Due 2003 (the "Notes")
to Jefferies & Company, Inc., Simmons & Company International, and Johnson Rice 
& Company L.L.C. (the "Initial Purchasers") at an aggregate offering price of 
$80,000,000. The aggregate underwriting discounts were $1,840,000. On December 
27, 1996, the Registrant sold $10,500,000 in aggregate principal amount of the 
Notes to the Initial Purchasers at an aggregate offering price of $10,500,000 
pursuant to the exercise by such purchasers of an over-allotment option. The 
aggregate underwriting discounts were $241,500.

         The Notes were resold by the Initial Purchasers to persons believed by 
them to be "qualified institutional buyers" as defined in Rule 144A under the 
Securities Act of 1933 (the "Act"). The sale of the Notes to the Initial 
Purchasers was exempt from registration pursuant to the provisions of Section 
4(2) of the Act and the resales by the Initial Purchasers were exempt pursuant 
to Rule 144A under the Act.

         The Notes are convertible at any time on or after February 25, 1997 and
prior to maturity at a conversion price of $22.86 per share, subject to 
adjustment in certain events.

Item 6.  Exhibits and Reports on Form 8-K
- ------   --------------------------------

(a)      Listed below are the documents filed as exhibits to this report:

         Exhibit
         -------

             4.    Instruments defining the rights of security holders,
                   including indentures

                   (1)  Indenture dated as of December 15, 1996, between Fleet
                        National Bank and the Company

                   (2)  Registration Rights Agreement dated December 17, 1996,
                        between the Company and Jefferies & Company, Inc.,
                        Simmons & Company International, and Johnson Rice &
                        Company L.L.C.

                   (3)  Registration Rights Agreement dated December 19, 1996,
                        between the Company and Caledonia Industrial and
                        Services Limited

             11.   Computation of earnings per share

             27.   Financial data schedule
 
(b)      Reports on Form 8-K

         On January 3, 1997, the Company filed a Form 8-K dated December 19,
         1996. Information reported was under Item 2 - Acquisition or
         Disposition of Assets and Item 9 - Sales of Equity Securities Pursuant
         to Regulation S.

                                       11
<PAGE>
 
                                   SIGNATURES


          Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                        OFFSHORE LOGISTICS, INC.



                                        BY: /s/ James B. Clement
                                           -----------------------------
                                           JAMES B. CLEMENT
                                           Chairman of the Board, President,
                                           and Chief Executive Officer,
 
                                        DATE:   February  14, 1997



 
 


                                        BY: /s/ George M. Small
                                           -----------------------------      
                                           GEORGE M. SMALL
                                           Vice President and Chief Financial
                                           Officer

                                        DATE: February 14, 1997

                                       12

<PAGE>
 
                                                                    EXHIBIT 4(1)

                            OFFSHORE LOGISTICS, INC.



                                       TO



                              FLEET NATIONAL BANK
                                               TRUSTEE



                              ___________________


                                   INDENTURE

                         Dated as of December 15, 1996

                              ___________________



                   6% CONVERTIBLE SUBORDINATED NOTES DUE 2003



                  ___________________________________________
<PAGE>
 
                            OFFSHORE LOGISTICS, INC.
                 RECONCILIATION AND TIE BETWEEN TRUST INDENTURE
            ACT OF 1939 AND INDENTURE, DATED AS OF DECEMBER 15, 1996


Trust Indenture
  Act Section                                             Indenture Section
 
310(a)(1)...........................................         609
   (a)(2)...........................................         609
   (a)(3)...........................................         Not Applicable
   (a)(4)...........................................         Not Applicable
   (a)(5)...........................................         609
   (b)..............................................         608
   .................................................         610
   (c)..............................................         Not Applicable
 
311(a)..............................................         613
   (b)..............................................         613
   (c)..............................................         Not Applicable
 
312(a)..............................................         701
   (b)..............................................         702
   (c)..............................................         702
 
313(a)..............................................         703
   (b)(1)...........................................         Not Applicable
   (b)(2)...........................................         703
   (c)..............................................         703
   (d)..............................................         703
 
314(a)..............................................         704
   (a)(4)...........................................         102
                                                             1005
   (b)..............................................         Not Applicable
   (c)(1)...........................................         102
   (c)(2)...........................................         102
   (c)(3)...........................................         Not Applicable
   (d)..............................................         Not Applicable
   (e)..............................................         102
   (f)..............................................         102
                                                             1005
 
315(a)..............................................         601
   (b)..............................................         602
 

                                       i
<PAGE>
 
   (c)..............................................         601
   (d)..............................................         601
   (e)..............................................         514
 
316(a) (last sentence)..............................         101
   (a)(1)(A)........................................         512
   (a)(1)(B)........................................         513
   (a)(2)...........................................         Not Applicable
   (b)..............................................         508
   (c)..............................................         104
 
317(a)(1)...........................................         503
   (a)(2)...........................................         504
   (b)..............................................         1003
 
318(a)..............................................         107
   (b)..............................................         Not Applicable
   (c)..............................................         107

____________________

  Note:  This reconciliation and tie shall not, for any purpose, be deemed to be
         a part of the Indenture.

                                       ii
<PAGE>
 
                               TABLE OF CONTENTS
                                                                Page

 
PARTIES.......................................................... 1
 
RECITALS OF THE COMPANY.......................................... 1
 
ARTICLE ONE

   DEFINITIONS AND OTHER PROVISIONS 
   OF GENERAL APPLICATION........................................  1
   Section 101.  Definitions.....................................  1
                 Act.............................................  2
                 Affiliate.......................................  2
                 Agent Member....................................  2
                 Applicable Procedures...........................  2
                 Authenticating Agent............................  2
                 Board of Directors..............................  2
                 Board Resolution................................  2
                 Business Day....................................  3
                 Change of Control...............................  3
                 Commission......................................  3
                 Common Stock....................................  3
                 Company.........................................  3
                 Company Notice..................................  3
                 Company Request or Company Order................  3
                 Consolidated Net Tangible Assets................  3
                 Corporate Trust Office..........................  4
                 Corporation.....................................  4
                 Defaulted Interest..............................  4
                 Depositary......................................  4
                 Dollar, U.S.$ or $..............................  4
                 DTC.............................................  4
                 Effectiveness Period............................  4
                 Event of Default................................  4
                 Exchange Act....................................  4
                 Global Security.................................  4
                 Holder..........................................  5
                 Indenture.......................................  5
                 Initial Purchasers..............................  5
                 Interest Payment Date...........................  5
                 Issue Date......................................  5
                 Liquidated Damages..............................  5
                 Maturity........................................  5
                 Officers' Certificate...........................  5


                                      iii

                                    
<PAGE>
 
                                                                Page

                 Opinion of Counsel..............................  5
                 Outstanding.....................................  5
                 Paying Agent....................................  6
                 Person..........................................  6
                 Predecessor Security............................  6
                 Purchase Agreement..............................  6 
                 Record Date.....................................  6 
                 Redemption Date.................................  6
                 Redemption Price................................  7
                 Registrable Securities..........................  7 
                 Registration Default............................  7
                 Registration Rights Agreement...................  7
                 Regular Record Date.............................  7
                 Regulation D Securities.........................  7
                 Regulation S....................................  7
                 Repurchase Date.................................  7
                 Repurchase Price................................  7
                 Responsible Officer.............................  7
                 Restricted Global Security......................  7
                 Restricted Securities...........................  8
                 Restricted Securities Certificate...............  8
                 Restricted Securities Legend....................  8
                 Rule 144A.......................................  8
                 Rule 144A Information...........................  8
                 Rule 144A Securities............................  8
                 Securities......................................  8
                 Securities Act..................................  8
                 Security........................................  8
                 Security Register and Security Registrar........  8
                 Senior Indebtedness.............................  8
                 Shelf Registration Statement....................  9
                 Special Record Date.............................  9
                 Stated Maturity.................................  9
                 Subsidiary......................................  9
                 Successor Security..............................  9
                 Surrender Certificate...........................  9
                 Trust Indenture Act.............................  10
                 Trustee.........................................  10
                 Unrestricted Securities Certificate.............  10
                 Vice President..................................  10
   Section 102.  Compliance Certificates and Opinions............  10
   Section 103.  Form of Documents Delivered to Trustee..........  11
   Section 104.  Acts of Holders.................................  11
   Section 105.  Notices, Etc., to Trustee and Company...........  12
   Section 106.  Notice to Holders; Waiver.......................  12
   Section 107.  Conflict with Trust Indenture Act...............  13
 

                                      iv

                                      
<PAGE>
 
                                                                Page
                                                                
   Section 108.  Effect of Headings and Table of Contents........  13
   Section 109.  Successors and Assigns..........................  13
   Section 110.  Separability Clause.............................  13
   Section 111.  Benefits of Indenture...........................  13
   Section 112.  Governing Law...................................  14
   Section 113.  Legal Holidays..................................  14
   Section 114.  No Recourse Against Others......................  14
   Section 115.  Duplicate Originals.............................  14
 
ARTICLE TWO

   SECURITY FORMS................................................  15
   Section 201.  Forms Generally.................................  15
   Section 202.  Form of Face of Security........................  16
   Section 203.  Form of Reverse of Security.....................  22
   Section 204.  Form of Trustee's Certificate of Authentication.  29
   Section 205.  Form of Election to Convert.....................  29
   Section 206.  Form of Assignment..............................  30
 
ARTICLE THREE

   THE SECURITIES................................................  31
   Section 301.  Title and Terms.................................  31
   Section 302.  Denominations...................................  32
   Section 303.  Execution, Authentication, Delivery and Dating..  32
   Section 304.  Global Securities; Physical Securities..........  32
   Section 305.  Registration, Registration of Transfer and 
                 Exchange; Restrictions on Transfer..............  34
   Section 306.  Mutilated, Destroyed, Lost and Stolen Securities  39
   Section 307.  Payment of Interest; Interest Rights Preserved..  39
   Section 308.  Persons Deemed Owners...........................  41
   Section 309.  Cancellation....................................  41
   Section 310.  Computation of Interest.........................  41
   Section 311.  CUSIP Numbers...................................  41
 
ARTICLE FOUR

   SATISFACTION AND DISCHARGE..................................... 42
   Section 401.  Satisfaction and Discharge of Indenture.......... 42
   Section 402.  Application of Trust Money....................... 43
   Section 403.  Reinstatement.................................... 43
 
ARTICLE FIVE

   REMEDIES......................................................  44
   Section 501.  Events of Default...............................  44
 


                                       v

                                       
<PAGE>
 
                                                                Page

   Section 502.  Acceleration of Maturity; Rescission and  
                 Annulment.......................................  46
   Section 503.  Collection of Indebtedness and Suits for
                 Enforcement by Trustee..........................  47
   Section 504.  Trustee May File Proofs of Claim................  47
   Section 505.  Trustee May Enforce Claims Without Possession of  
                 Securities......................................  48  
   Section 506.  Application of Money Collected..................  48
   Section 507.  Limitation on Suits.............................  49
   Section 508.  Unconditional Right of Holders to Receive 
                 Principal, Premium and Interest and to Convert..  50
   Section 509.  Restoration of Rights and Remedies..............  50
   Section 510.  Rights and Remedies Cumulative..................  50
   Section 511.  Delay or Omission Not Waiver....................  50
   Section 512.  Control by Holders..............................  51
   Section 513.  Waiver of Past Defaults.........................  51
   Section 514.  Undertaking for Costs...........................  52
   Section 515.  Waiver of Stay or Extension Laws................  52
 
ARTICLE SIX

   THE TRUSTEE.................................................... 52
   Section 601.  Certain Duties and Responsibilities.............. 52
   Section 602.  Notice of Defaults............................... 53
   Section 603.  Certain Rights of Trustee........................ 53
   Section 604.  Not Responsible for Recitals or Issuance of 
                 Securities....................................... 54
   Section 605.  May Hold Securities.............................. 54
   Section 606.  Money Held in Trust.............................. 54
   Section 607.  Compensation and Reimbursement................... 54
   Section 608.  Disqualification; Conflicting Interests.......... 55
   Section 609.  Institutional Trustee Required; Eligibility...... 55
   Section 610.  Resignation and Removal; Appointment of Successor 56
   Section 611.  Acceptance of Appointment by Successor........... 57
   Section 612.  Merger, Conversion, Consolidation or Succession
                 to Business...................................... 57
   Section 613.  Preferential Collection of Claims Against Company 57
   Section 614.  Appointment of Authenticating Agent.............. 58
 
ARTICLE SEVEN

   HOLDERS' LISTS AND REPORTS
   BY TRUSTEE AND COMPANY........................................  59
   Section 701.  Company to Furnish Trustee Names and Addresses 
                 of Holders......................................  59
   Section 702.  Preservation of Information; Communications to 
                 Holders.........................................  60
   Section 703.  Reports by Trustee..............................  60
   Section 704.  Reports by Company..............................  60


                                      vi

                                       
<PAGE>
 
                                                                Page

ARTICLE EIGHT

   CONSOLIDATION, MERGER, CONVEYANCE,
   TRANSFER OR LEASE.............................................  61
   Section 801.  Company May Consolidate, Etc., Only on Certain
                 Terms...........................................  61
   Section 802.  Successor Legal Entity Substituted..............  62
 
ARTICLE NINE

   SUPPLEMENTAL INDENTURES.......................................  62
   Section 901.  Supplemental Indentures Without Consent 
                 of Holders......................................  62
   Section 902.  Supplemental Indentures with Consent 
                 of Holders......................................  63
   Section 903.  Execution of Supplemental Indentures............  64
   Section 904.  Effect of Supplemental Indentures...............  64
   Section 905.  Conformity with Trust Indenture Act.............  64
   Section 906.  Reference in Securities to Supplemental 
                 Indentures......................................  64
   Section 907.  Notice of Supplemental Indentures 
                 and Waivers.....................................  65
 
ARTICLE TEN

   COVENANTS.....................................................  65
   Section 1001. Payment of Principal, Premium and Interest......  65
   Section 1002. Maintenance of Office or Agency.................  65
   Section 1003. Money for Security Payments to Be Held in Trust.  66
   Section 1004. Existence.......................................  67
   Section 1005. Statement by Officers as to Default.............  67
   Section 1006. Waiver of Certain Covenants.....................  67
   Section 1007. Registration Rights.............................  68
   Section 1008. Resale of Certain Securities; Reporting Issuer..  69
   Section 1009. Payment of Certain Duties.......................  69
 
ARTICLE ELEVEN

   REDEMPTION OF SECURITIES......................................  69
   Section 1101. Right of Redemption.............................  69
   Section 1102. Applicability of Article........................  70
   Section 1103. Election to Redeem; Notice to Trustee...........  70
   Section 1104. Selection by Trustee of Securities 
                 to Be Redeemed..................................  70
   Section 1105. Notice of Redemption............................  71
   Section 1106. Deposit of Redemption Price.....................  71
   Section 1107. Securities Payable on Redemption Date...........  72
   Section 1108. Securities Redeemed in Part.....................  72
   Section 1109. Mandatory Redemption............................  72
  

                                      vii

                                      
<PAGE>
 
                                                                Page


 ARTICLE TWELVE

 RIGHT TO REQUIRE REPURCHASE.....................................  73
   Section 1201. Right to Require Repurchase.....................  73
   Section 1202. Notice; Method of Exercising Repurchase Right.... 73
   Section 1203. Deposit of Repurchase Price.....................  74
   Section 1204. Securities Not Repurchased on Repurchase Date...  74
   Section 1205. Securities Repurchased in Part..................  75
   Section 1206. "Change of Control" and "Termination 
                 of Trading" Defined.............................  75
 
ARTICLE THIRTEEN

CONVERSION OF SECURITIES.........................................  76
   Section 1301. Right of Conversion.............................  76
   Section 1302. Issuance of Common Stock; Time of Conversion....  76
   Section 1303. No Adjustments in Respect of 
                 Interest or Dividends...........................  78
   Section 1304. Adjustment of Conversion Price..................  78
   Section 1305. No Fractional Shares............................  81
   Section 1306. Reclassification, Consolidation, 
                 Merger or Sale of Assets........................  81
   Section 1307. Prior Notice of Certain Events..................  83
   Section 1308. Shares to be Reserved; Accounting 
                 Treatment of Consideration......................  83
                 
   Section 1309. Listing of Shares...............................  84
   Section 1310. Taxes and Charges...............................  84
   Section 1311. Trustee and Conversion Agents Not Liable........  84
 
ARTICLE FOURTEEN

SUBORDINATION OF SECURITIES......................................  85
   Section 1401. Securities Subordinate to Senior Indebtedness...  85
   Section 1402. Payment Over of Proceeds Upon 
                 Dissolution, Etc................................  85
   Section 1403. Prior Payment to Senior Indebtedness 
                 Upon Acceleration Securities....................  86
   Section 1404. No Payment When Senior Indebtedness 
                 in Default......................................  87
   Section 1405. Acknowledgment of Reliance......................  87
   Section 1406. Subrogation to Rights of Holders of 
                 Senior Indebtedness.............................  87
   Section 1407. Provisions Solely to Define 
                 Relative Rights.................................  88
   Section 1408. Trustee to Effectuate Subordination.............  88
   Section 1409. No Waiver of Subordination Provisions...........  88
   Section 1410. Notice to Trustee...............................  89
   Section 1411. Reliance on Judicial Order or 
                 Certificate of Liquidating Agent................  90
                 
   Section 1412. Trustee Not Fiduciary for Holders 
                 of Senior Indebtedness..........................  90
   Section 1413. Rights of Trustee as Holder of 
                 Senior Indebtedness; Preservation 
                 of Trustee's Rights.............................  90
   Section 1414. Article Applicable to Paying Agents.............  90
   Section 1415. Certain Conversions Deemed Payment..............  91



                                     viii

<PAGE>
 
     THIS INDENTURE, dated as of December 15, 1996, is between OFFSHORE
LOGISTICS, INC., a corporation duly organized and validly existing under the
laws of the State of Delaware (herein called the "Company"), having its
principal office at 224 Rue de Jean, Lafayette, Louisiana 70508, and FLEET
NATIONAL BANK, a national banking association, as Trustee (herein called the
"Trustee"), having its corporate trust office at 777 Main Street, Hartford,
Connecticut 06115.

                            RECITALS OF THE COMPANY

     The Company has duly authorized the creation of an issue of its 6%
Convertible Subordinated Notes due 2003 (herein called the "Securities") of
substantially the tenor and amount hereinafter set forth, and to provide
therefor the Company has duly authorized the execution and delivery of this
Indenture.

     All things necessary to make the Securities, when issued and executed by
the Company and authenticated and delivered by the Trustee as herein provided,
the valid obligations of the Company, and to make this Indenture a valid
agreement of the Company and the Trustee, in accordance with their and its
terms, have been done.

     NOW, THEREFORE, THIS INDENTURE WITNESSETH:

     For and in consideration of the premises and the purchase of the Securities
by the Holders thereof, it is mutually covenanted and agreed, for the equal and
proportionate benefit of all Holders of the Securities, as follows:

                                  ARTICLE ONE

                        DEFINITIONS AND OTHER PROVISIONS
                             OF GENERAL APPLICATION

 Section 101.  Definitions.

     For all purposes of this Indenture, except as otherwise expressly provided
or unless the context otherwise requires:

     (1) the terms defined in this Article have the meanings assigned to them in
this Article and include the plural as well as the singular;

     (2) all other terms used herein which are defined in the Trust Indenture
Act, either directly or by reference therein, or defined by Commission rule
under the Trust Indenture Act, have the meanings assigned to them therein;
<PAGE>
 
     (3) all accounting terms not otherwise defined herein have the meanings
assigned to them in accordance with generally accepted accounting principles;

     (4) the words "Article" and "Section" refer to an Article and Section,
respectively, of this Indenture;

     (5) the words "herein", "hereof" and "hereunder" and other words of similar
import refer to this Indenture as a whole and not to any particular Article,
Section or other subdivision; and

     (6) the masculine gender includes the feminine and the neuter.

     Certain terms, used principally in Article Twelve, are defined in that
Article.

     "Act", when used with respect to any Holder, has the meaning specified in
Section 104.

     "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any specified Person means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

     "Agent Member" means any member of, or participant in, the Depositary.

     "Applicable Procedures" means, with respect to any transfer or transaction
involving a Global Security or beneficial interest therein, the rules and
procedures of Euroclear and CEDEL, and of the Depositary for such Security, in
each case to the extent applicable to such transaction and as in effect from
time to time.

     "Authenticating Agent" means any Person authorized by the Trustee to act
on behalf of the Trustee to authenticate Securities.

     "Board of Directors" means either the board of directors of the Company or
any duly authorized committee of that board.

     "Board Resolution" means a copy of a resolution certified by the Secretary
or an Assistant Secretary of the Company to have been duly adopted by the Board
of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

     "Bristow Transaction" has the meaning specified in the Offering Circular
dated December 11, 1996 relating to the sale of the Securities by the Initial
Purchasers.

                                      -2-
<PAGE>
 
     "Business Day" means each Monday, Tuesday, Wednesday, Thursday and Friday
that is not a day on which banking institutions in New York, New York, Hartford,
Connecticut or Lafayette, Louisiana are authorized or obligated by law or
executive order to close.

     "Caledonia" means Caledonia Industrial & Services Limited, a company
incorporated in England and Wales with registered number 3143101.

     "Caledonia Security" means the Regulation S Security to be issued on the
Issue Date to Caledonia (or its nominee) in the original principal amount of
$7,500,000.

     "CEDEL" means Cedel Bank, S.A. (or any successor securities clearing
agency).

     "Change of Control" has the meaning specified in Section 1206.

     "Commission" means the Securities and Exchange Commission, as from time to
time constituted, created under the Exchange Act, or, if at any time after the
execution of this instrument such Commission is not existing and performing the
duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

     "Common Stock" initially means the class designated as Common Stock, par
value $.01 per share, of the Company as of the date hereof and includes any
other class of capital stock of the Company into which such Common Stock may be
reclassified.

     "Company" means the Person named as the "Company" in the first paragraph
of this instrument until a successor Person shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Company" shall mean
such successor Person, and in each case shall include any other obligor upon the
Securities.

     "Company Notice" has the meaning specified in Section 1202.

     "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by its Chairman of the Board, its President or
a Vice President, and by its Treasurer, an Assistant Treasurer, its Secretary or
an Assistant Secretary, and delivered to the Trustee.

     "Consolidated Net Tangible Assets" means the total of all  assets included
in a consolidated balance sheet of the Company and its Subsidiaries, prepared in
accordance with generally accepted accounting principles (and as of a date not
more than 90 days prior to the date as of which Consolidated Net Tangible Assets
are to be determined), less the sum of the following items each as included in
such balance sheet:

     (i)  all current liabilities;

                                      -3-
<PAGE>
 
     (ii)   all depreciation, valuation and other reserves;

     (iii)  all goodwill, trade names, trademarks, patents, unamortized debt
discount and expense and other like intangibles; and

     (iv)   minority interests in the equity of Subsidiaries.

     "Corporate Trust Office" means the principal office of the Trustee at
which its corporate trust business shall be administered.  As of the date of
this Indenture, the address of such office is 777 Main Street, Hartford,
Connecticut 06115.

     "Corporation" means a corporation, partnership, association, company,
joint-stock company, limited liability company or business trust.

     "Defaulted Interest" has the meaning specified in Section 307.

     "Depositary" means, with respect to any Securities, a clearing agency that
is registered as such under the Exchange Act and is designated by the Company to
act as Depositary for such Securities (or any successor securities clearing
agency so registered).  The initial Depositary for the Securities shall be DTC.

     "Designated Event" means either a Change of Control or a Termination of
Trading.

     "Dollar", "U.S.$" or "$" means a dollar or other equivalent unit in such
coin or currency of the United States as at the time shall be legal tender for
the payment of public and private debts.

     "DTC" means The Depository Trust Company, a New York corporation.

     "Effectiveness Period" has the meaning specified in Section 203.

     "Euroclear" means the Euroclear Clearance System (or any successor
securities clearing agency).

     "Event of Default" has the meaning specified in Section 501.

     "Exchange Act" means the Securities Exchange Act of 1934, as amended, and
any successor statute.

     "Global Security" means a Security that is registered in the Security
Register in the name of a Depositary or a nominee thereof.

                                      -4-
<PAGE>
 
     "Holder" means a Person in whose name a Security is registered in the
Security Register.

     "Indenture" means this instrument as originally executed or as it may from
time to time be supplemented or amended by one or more indentures supplemental
hereto entered into pursuant to the applicable provisions hereof.

     "Initial Purchasers" means Jefferies & Company, Inc., Simmons & Company
International and Johnson Rice & Company L.L.C., as initial purchasers in the
offering of the Securities.

     "Interest Payment Date" means the Stated Maturity of an installment of
interest on the Securities.

     "Issue Date" means the initial date on which the Securities are originally
issued under this Indenture.

     "Liquidated Damages" has the meaning specified in Section 1007.

     "Maturity", when used with respect to any Security, means the date on
which the principal of such Security becomes due and payable as therein or
herein provided, whether at the Stated Maturity or by declaration of
acceleration, call for redemption, exercise of the repurchase right set forth in
Article Twelve or otherwise.

     "Officers' Certificate" means a certificate signed by the principal
executive officer and the principal financial officer or principal accounting
officer of the Company and delivered to the Trustee.

     "Opinion of Counsel" means a written opinion of counsel, who may be
counsel for the Company (including the General Counsel of the Company), and who
shall be acceptable to the Trustee.

     "Outstanding", when used with respect to Securities, means, as of the date
of determination, all Securities theretofore authenticated and delivered under
this Indenture, except:

     (i) Securities theretofore canceled by the Trustee or delivered to the
Trustee for cancellation;

     (ii) Securities for whose payment or redemption money in the necessary
amount has been theretofore deposited with the Trustee or any Paying Agent
(other than the Company) in trust or set aside and segregated in trust by the
Company (if the Company shall act as its own Paying Agent) for the Holders of
such Securities in accordance with the terms of this Indenture; provided that,
if such Securities are to be redeemed, notice of such

                                      -5-
<PAGE>
 
redemption has been duly given pursuant to this Indenture or provision therefor
satisfactory to the Trustee has been made; and

     (iii)  Securities in exchange for or in lieu of which other Securities have
been authenticated and delivered pursuant to this Indenture, other than any such
Securities in respect of which there shall have been presented to the Trustee
proof satisfactory to it that such Securities are held by a bona fide purchaser
in whose hands such Securities are valid obligations of the Company;

provided, however, that in determining whether the Holders of the requisite
principal amount of the Outstanding Securities have given any request, demand,
authorization, direction, notice, consent or waiver hereunder, Securities owned
by the Company or any other obligor upon the Securities or any Affiliate of the
Company or of such other obligor shall be disregarded and deemed not to be
Outstanding, except that, in determining whether the Trustee shall be protected
in relying upon any such request, demand, authorization, direction, notice,
consent or waiver, only Securities which the Trustee knows to be so owned shall
be so disregarded.  Securities so owned which have been pledged in good faith
may be regarded as Outstanding if the pledgee establishes to the satisfaction of
the Trustee the pledgee's right so to act with respect to such Securities and
that the pledgee is not the Company or any other obligor upon the Securities or
any Affiliate of the Company or of such other obligor.

     "Paying Agent" means any Person authorized by the Company to pay the
principal of (and premium, if any) or interest on any Securities on behalf of
the Company.

     "Person" means any individual, Corporation or government or any agency or
political subdivision thereof.

     "Physical Securities" has the meaning specified in Section 201.

     "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 306 in exchange for or in lieu of a
mutilated, destroyed, lost or stolen Security shall be deemed to evidence the
same debt as the mutilated, destroyed, lost or stolen Security.

     "Purchase Agreement" has the meaning specified in Section 301.

     "Record Date" means any Regular Record Date or Special Record Date.

     "Redemption Date", when used with respect to any Security to be redeemed,
means the date fixed for such redemption by or pursuant to this Indenture.

                                      -6-
<PAGE>
 
     "Redemption Price", when used with respect to any Security to be redeemed,
means the price at which it is to be redeemed pursuant to this Indenture.

     "Registrable Securities" has the meaning specified in Section 1007.

     "Registration Default" has the meaning specified in Section 1007.

     "Registration Rights Agreement" has the meaning specified in Section 1007.

     "Regular Record Date" for the interest payable on any Interest Payment
Date means the 1st of June or 1st of December (whether or not a Business Day),
as the case may be, next preceding such Interest Payment Date.

     "Regulation D Securities" means the Securities sold by the Initial
Purchasers in the initial offering contemplated by the Purchase Agreement in
reliance on an exemption from the registration requirements of the Securities
Act other than Rule 144A and Regulation S.

     "Regulation S" means Regulation S under the Securities Act (or any
successor provision), as it may be amended from time to time.

     "Regulation S Certificate" means a certificate substantially in the form
set forth in Annex A.

     "Regulation S Global Security" has the meaning specified in Section 201.

     "Regulation S Legend" means a legend substantially in the form of the
legend required in the form of Security set forth in Section 202 to be placed
upon a Regulation S Security.

     "Regulation S Securities" means all Securities required pursuant to Section
305(c) to bear a Regulation S Legend.  Such term includes the Regulation S
Global Security and the Caledonia Security.

     "Repurchase Date" has the meaning specified in Section 1201.

     "Repurchase Price" has the meaning specified in Section 1201.

     "Responsible Officer", when used with respect to the Trustee, means any
person in the Corporate Trust Administration Department of the Trustee familiar
with corporate trust matters.

     "Restricted Global Security" has the meaning specified in Section 201.

     "Restricted Period" means the period of 41 consecutive days beginning on
and including the later of (i) the day on which Securities are first offered to
Persons other than

                                      -7-
<PAGE>
 
distributors (as defined in Regulation S) in reliance on Regulation S and (ii)
the last original issuance date of the Securities.

     "Restricted Securities" means all Securities required pursuant to Section
305(c) to bear any Restricted Securities Legend.  Such term includes the
Restricted Global Security but excludes any Regulation S Security.

     "Restricted Securities Certificate" means a certificate substantially in
the form set forth in Annex B.

     "Restricted Securities Legend" means, collectively, the legends
substantially in the forms of the legends required in the form of Security set
forth in Section 202 to be placed upon each Restricted Security.

     "Rule 144A" means Rule 144A under the Securities Act (or any successor
provisions), as it may be amended from time to time.

     "Rule 144A Information" has the meaning specified in Section 704.

     "Rule 144A Securities" means the Securities purchased by the Initial
Purchasers from the Company pursuant to the Purchase Agreement and resold by the
Initial Purchasers, other than the Regulation D Securities and Regulation S
Securities.

     "Securities" has the meaning set forth in the recitals of this indenture.

     "Securities Act" means the Securities Act of 1933, as amended, and any
successor statute.

     "Securities Act Legend" means a Restricted Securities Legend or a
Regulation S Legend.

     "Security" means any of the Securities.

     "Security Register" and "Security Registrar" have the respective meanings
specified in Section 305(a).

     "Senior Indebtedness" means the principal of, premium, if any, and unpaid
interest (including, without limitation, any interest accruing subsequent to the
commencement of a case or other proceeding under any bankruptcy or other similar
law with respect to the Company) on, and other obligations in respect of, the
following, whether outstanding at the date hereof or thereafter incurred or
created:  (a) indebtedness of the Company for money borrowed (including
purchase-money obligations) evidenced by notes or other written obligations, (b)
indebtedness of the Company evidenced by notes, debentures, bonds or other
securities issued under the provisions of

                                      -8-
<PAGE>
 
an indenture or similar instrument, (c) indebtedness secured by any mortgage,
pledge, lien or other encumbrance existing on property which is owned or held by
the Company subject to such mortgage, pledge or encumbrance, whether or not
indebtedness secured thereby shall have been assumed by the Company, (d)
obligations of the Company as lessee under capitalized leases and under leases
of property made as part of any sale and leaseback transactions, (e) obligations
of the Company in respect of letters of credit issued for its account and
"swaps" of interest rates, commodity prices or foreign currencies (and other
interest rate, commodity price or foreign currency hedging agreements) to which
the Company is a party, (f) indebtedness of others of any of the kinds described
in the preceding clauses (a) through (e) assumed or guaranteed by the Company
and (g) renewals, extensions and refundings of, and indebtedness and obligations
of a successor Person issued in exchange for or in replacement of, indebtedness
or obligations of the kinds described in the preceding clauses (a) through (f);
provided, however, that the following shall not constitute Senior Indebtedness:
(i) any indebtedness or obligation which by its terms refers explicitly to the
Securities and states that such indebtedness or obligation shall not be senior
in right of payment thereto, (ii) any indebtedness or obligation of the Company
in respect of the Securities and (iii) any indebtedness or obligation of the
Company to any Subsidiary.

     "Shelf Registration Statement" has the meaning specified in Section 1007.

     "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Trustee pursuant to Section 307.

     "Stated Maturity", when used with respect to any Security or any
installment of interest thereon, means the date specified in such Security as
the fixed date on which the principal of such Security or such installment of
interest is due and payable.

     "Subsidiary" means a Corporation more than 50% of the outstanding voting
stock or other voting or managing ownership interest of which is owned, directly
or indirectly, by the Company or by one or more other Subsidiaries, or by the
Company and one or more other Subsidiaries.  For the purposes of this
definition, "voting stock" means stock which ordinarily has voting power for the
election of directors, whether at all times or only so long as no senior class
of stock has such voting power by reason of any contingency.

     "Successor Security" of any particular Security means every Security
issued after, and evidencing all or a portion of the same debt as that evidenced
by, such particular Security; and, for the purposes of this definition, any
Security authenticated and delivered under Section 306 in exchange for or in
lieu of a mutilated, destroyed, lost or stolen Security shall be deemed to
evidence the same debt as the mutilated, destroyed, lost or stolen Security.

     "Surrender Certificate" means a certificate substantially in the form set
forth in Annex D.

     "Termination of Trading" has the meaning specified in Section 1206.

                                      -9-
<PAGE>
 
     "Trust Indenture Act" means the Trust Indenture Act of 1939 as in force at
the date as of which this instrument was executed, except as provided in Section
905; provided, however, that in the event the Trust Indenture Act is amended
after such date, Trust Indenture Act means, to the extent required by any such
amendment, the Trust Indenture Act as so amended.

     "Trustee" means the Person named as the "Trustee" in the first paragraph
of this instrument until a successor Trustee shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Trustee" shall mean
such successor Trustee.

     "Unrestricted Securities Certificate" means a certificate substantially in
the form set forth in Annex C.

     "Vice President", when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title "vice president".

 Section 102.  Compliance Certificates and Opinions.

     Upon any application or request by the Company to the Trustee to take any
action under any provision of this Indenture, the Company shall furnish to the
Trustee an Officers' Certificate stating that all conditions precedent, if any,
provided for in this Indenture relating to the proposed action have been
complied with and an Opinion of Counsel stating that in the opinion of such
counsel all such conditions precedent, if any, have been complied with, except
that in the case of any such application or request as to which the furnishing
of such documents is specifically required by any provision of this Indenture
relating to such particular application or request, no additional certificate or
opinion need be furnished.

     Every certificate or opinion with respect to compliance with a condition or
covenant provided for in this Indenture shall include:

     (1) a statement that each individual signing such certificate or opinion
has read such covenant or condition and the definitions herein relating thereto;

     (2) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

     (3) a statement that, in the opinion of each such individual, he has made
such examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with; and

     (4) a statement as to whether, in the opinion of each such individual, such
condition or covenant has been complied with.

                                      -10-
<PAGE>
 
 Section 103.  Form of Documents Delivered to Trustee.

     In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

     Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows that the certificate or
opinion or representations with respect to the matters upon which his
certificate or opinion is based are erroneous.  Any such certificate or Opinion
of Counsel may be based, insofar as it relates to factual matters, upon a
certificate or opinion of, or representations by, an officer or officers of the
Company stating that the information with respect to such factual matters is in
the possession of the Company, unless such counsel knows that the certificate or
opinion or representations with respect to such matters are erroneous.

     Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

 Section 104.  Acts of Holders.

     (a) Any request, demand, authorization, direction, notice, consent, waiver
or other action provided by this Indenture to be given or taken by Holders may
be embodied in and evidenced by one or more instruments of substantially similar
tenor signed by such Holders in person or by agent duly appointed in writing;
and, except as herein otherwise expressly provided, such action shall become
effective when such instrument or instruments are delivered to the Trustee and,
where it is hereby expressly required, to the Company.  Such instrument or
instruments (and the action embodied therein and evidenced thereby) are herein
sometimes referred to as the "Act" of the Holders signing such instrument or
instruments.  Proof of execution of any such instrument or of a writing
appointing any such agent shall be sufficient for any purpose of this Indenture
and (subject to Section 601) conclusive in favor of the Trustee and the Company,
if made in the manner provided in this Section.

     (b) The fact and date of the execution by any Person of any such instrument
or writing may be proved by the affidavit of a witness of such execution or by a
certificate of a notary public or other officer authorized by law to take
acknowledgments of deeds, certifying that the individual signing such instrument
or writing acknowledged to him the execution thereof.  Where such execution is
by a signer acting in a capacity other than his individual capacity, such
certificate or affidavit shall also constitute sufficient proof of his
authority.  The fact and date of the execution

                                      -11-
<PAGE>
 
of any such instrument or writing, or the authority of the Person executing the
same, may also be proved in any other manner which the Trustee deems sufficient.

     (c) The ownership of Securities shall be proved by the Security Register.

     (d) Any request, demand, authorization, direction, notice, consent, waiver
or other Act of the Holder of any Security shall bind every future Holder of the
same Security and the Holder of every Security issued upon the registration of
transfer thereof or in exchange therefor or in lieu thereof in respect of
anything done, omitted or suffered to be done by the Trustee or the Company in
reliance thereon, whether or not notation of such action is made upon such
Security.

 Section 105.  Notices, Etc., to Trustee and Company.

     Any request, demand, authorization, direction, notice, consent, waiver or
Act of Holders or other document provided or permitted by this Indenture to be
made upon, given or furnished to, or filed with,

     (1) the Trustee by any Holder or by the Company shall be sufficient for
every purpose hereunder (unless otherwise herein expressly provided) if made,
given, furnished or filed in writing to or with the Trustee at its Corporate
Trust Office, Attention:  Corporate Trust Administration Department, or

     (2) the Company by the Trustee or by any Holder shall be sufficient for
every purpose hereunder (unless otherwise herein expressly provided) if in
writing and mailed, first-class postage prepaid, to the Company addressed to it
at the address of its principal office specified in the first paragraph of this
instrument or at any other address previously furnished in writing to the
Trustee by the Company.  If a notice or communication is mailed in the manner
provided above, it is duly given, whether or not received by the addressee.

 Section 106.  Notice to Holders; Waiver.

     Where this Indenture provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if in writing and mailed, first-class postage prepaid, to each Holder affected
by such event, at his address as it appears in the Security Register, not later
than the latest date, and not earlier than the earliest date, prescribed for the
giving of such notice.  In any case where notice to Holders is given by mail,
neither the failure to mail such notice, nor any defect in any notice so mailed,
to any particular Holder shall affect the sufficiency of such notice with
respect to other Holders.  Where this Indenture provides for notice in any
manner, such notice may be waived in writing by the Person entitled to receive
such notice, either before or after the event, and such waiver shall be the
equivalent of such notice.  Waivers of notice by Holders shall be filed with the
Trustee, but such filing shall not be a condition precedent to the validity of
any action taken in reliance upon such waiver.  If the Company mails a notice or
communication to the Holders, it shall mail a copy to the Trustee and each
Security Registrar, Paying

                                      -12-
<PAGE>
 
Agent and other agent designated by it under Article Ten.  If a notice or
communication is mailed in the manner provided above, it is duly given on the
date of such mailing, whether or not received by the addressee.

     In case by reason of the suspension of regular mail service or by reason of
any other cause it shall be impracticable to give such notice by mail, then such
notification as shall be made with the approval of the Trustee shall constitute
a sufficient notification for every purpose hereunder.

 Section 107.  Conflict with Trust Indenture Act.

     If any provision hereof limits, qualifies or conflicts with another
provision hereof which is required to be included in this Indenture by any of
the provisions of the Trust Indenture Act, such required provision shall
control.  If any provision of this Indenture modifies or excludes any provision
of the Trust Indenture Act that may be so modified or excluded, the latter
provision shall be deemed to apply to this Indenture as so modified or to be
excluded, as the case may be.  Until such time as this Indenture shall be
qualified under the Trust Indenture Act, this Indenture, the Company and the
Trustee shall be deemed for all purposes hereof to be subject to and governed by
the Trust Indenture Act to the same extent as would be the case if this
Indenture were so qualified on the date hereof.

 Section 108.  Effect of Headings and Table of Contents.

     The Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.

 Section 109.  Successors and Assigns.

     All covenants and agreements in this Indenture by the Company shall bind
its successors and assigns, whether so expressed or not.

 Section 110.  Separability Clause.

     In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

 Section 111.  Benefits of Indenture.

     Nothing in this Indenture or in the Securities, express or implied, shall
give to any Person, other than the parties hereto and their successors
hereunder, the holders of Senior Indebtedness and the Holders of Securities, any
benefit or any legal or equitable right, remedy or claim under this Indenture.

                                      -13-
<PAGE>
 
 Section 112.  Governing Law; Consent to Jurisdiction.

     This Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York.

     The Company irrevocably submits to the non-exclusive jurisdiction of any
United States Federal or New York State court sitting in the Burough of
Manhattan, The City of New York, in any action or proceeding arising out of or
relating to this Indenture or the Securities, and the Company irrevocably agrees
that all claims in respect of such action or proceeding may be heard and
determined by any such court.

 Section 113.  Legal Holidays.

     In any case where any Interest Payment Date, Redemption Date, Repurchase
Date or Stated Maturity of any Security or the last date on which a Holder has
the right to convert his Securities shall not be a Business Day, then
(notwithstanding any other provision of this Indenture or of the Securities)
payment of interest or principal (and premium, if any) or payment of the
Repurchase Price with respect to, or delivery for conversion of,  the Securities
need not be made on such date, but may be made on the next succeeding Business
Day with the same force and effect as if made on the Interest Payment Date,
Redemption Date or Repurchase Date, or at the Stated Maturity, or on such last
day for conversion, provided that no interest shall accrue for the period from
and after such Interest Payment Date, Redemption Date, Repurchase Date or Stated
Maturity, as the case may be.

 Section 114.  No Recourse Against Others.

     A director, officer, employee, stockholder, incorporator or Affiliate, as
such, past, present or future, of the Company shall not have any personal
liability under the Securities or this Indenture by reason of his or its status
as a director, officer, employee, stockholder, incorporator or Affiliate or any
liability for any obligations of the Company under the Securities or this
Indenture or for any claim based on, in respect of or by reason of such
obligations or their creation.  Each Holder, by accepting any of the Securities,
waives and releases all such liability to the extent permitted by applicable
law.

 Section 115.  Duplicate Originals.

     The parties may sign any number of copies or counterparts of this
Indenture.  Each signed copy shall be an original, but all of them together
shall represent the same agreement.

                                      -14-
<PAGE>
 
                                  ARTICLE TWO

                                 SECURITY FORMS

 Section 201.  Forms Generally.

          The Securities shall be in substantially the form set forth in this
Article, with such appropriate insertions, omissions, substitutions and other
variations as are required or permitted by this Indenture, and may have such
letters, numbers or other marks of identification and such legends or
endorsements placed thereon as may be required to comply with the rules of any
securities exchange, the Internal Revenue Code of 1986, as amended, and
regulations thereunder, or as may, consistently herewith, be determined by the
officers executing such Securities, as evidenced by their execution thereof.

          Repurchase notices shall be substantially in the form set forth in
Section 203.

          The Trustee's certificates of authentication shall be in substantially
the form set forth in Section 204.

          Conversion notices shall be in substantially the form set forth in
Section 205.

          Assignments of Securities shall be made in substantially the form set
forth in Section 206.

          The Securities shall be printed, lithographed, typewritten or engraved
or produced by any combination of these methods on steel engraved borders if so
required by any securities exchange upon which the Securities may be listed, or
may be produced in any other manner permitted by the rules of any such
securities exchange, or, if the Securities are not listed on a securities
exchange, in any other manner approved by the Company all as determined by the
officers executing such Securities, as evidenced by their execution thereof.

          Upon their original issuance, Rule 144A Securities shall be issued in
the form of one or more Global Securities without interest coupons and shall be
registered in the name of DTC, as Depositary, or its nominee and deposited with
the Trustee, as custodian for DTC, for credit by DTC to the respective accounts
of beneficial owners of the Securities represented thereby (or such other
accounts as the Initial Purchasers may direct).  Such Global Securities,
together with their Successor Securities which are Global Securities (other than
the Regulation S Global Security) that are required to bear a Restricted
Securities Legend pursuant to Section 305(c), are collectively herein called the
"Restricted Global Security".

          Upon their original issuance, Regulation S Securities (other than the
Caledonia Security) shall be issued in the form of one or more Global Securities
without interest coupons and shall be registered in the name of DTC, as
Depositary, or its nominee and deposited with the Trustee,

                                      -15-
<PAGE>
 
as custodian for DTC for credit to the respective accounts at DTC of the
depositaries for Morgan Guaranty Trust Company of New York, Brussels office, as
operator of Euroclear, or CEDEL.  Such Global Security, together with its
Successor Securities which are Global Securities other than the Restricted
Global Security, are collectively herein called the "Regulation S Global
Security".

          Upon their original issuance, the Caledonia Security and all
Regulation D Securities shall be issued as definitive securities in fully
registered form without interest coupons ("Physical Securities") but not in the
form of a Global Security or in any other form intended to facilitate book-entry
trading in beneficial interests in such Securities.

 Section 202.  Form of Face of Security.

[THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH RESTRICTED SECURITY OTHER
THAN ANY GLOBAL SECURITY:

          THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), AND THIS SECURITY AND ANY SHARES OF
COMMON STOCK ISSUABLE UPON ITS CONVERSION MAY NOT BE SOLD OR OTHERWISE
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
THEREFROM.  THIS SECURITY MAY ONLY BE SOLD IN ACCORDANCE WITH THE INDENTURE,
COPIES OF WHICH ARE AVAILABLE FOR INSPECTION AT THE CORPORATE TRUST OFFICE OF
THE TRUSTEE. EACH PURCHASER OF THIS SECURITY WHICH IS A QUALIFIED INSTITUTIONAL
BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IS HEREBY NOTIFIED THAT
THE SELLER OF THIS SECURITY MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS
OF SECTION 5 OF THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

          THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF OFFSHORE
LOGISTICS, INC. (THE "COMPANY") THAT (A) THIS SECURITY AND ANY SHARES OF COMMON
STOCK ISSUABLE UPON ITS CONVERSION MAY BE RESOLD, PLEDGED OR OTHERWISE
TRANSFERRED ONLY (I) TO A PERSON WHO THE SELLER REASONABLY BELIEVES IS A
QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT)
IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (II) IN AN OFFSHORE
TRANSACTION COMPLYING WITH THE PROVISIONS OF RULE 904 OF REGULATION S UNDER THE
SECURITIES ACT, (III) IN THE CASE OF ANY PURCHASER, OTHER THAN A PURCHASER WHO
HAS OTHERWISE AGREED WITH THE COMPANY IN WRITING, TO AN INSTITUTION THAT IS AN
"ACCREDITED INVESTOR" WITHIN THE MEANING OF RULE 501(A)(1), (2), (3) OR (7)
UNDER THE SECURITIES ACT IN A TRANSACTION EXEMPT FROM THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT, (IV) PURSUANT TO AN EXEMPTION FROM
REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE

                                      -16-
<PAGE>
 
144 THEREUNDER (IF AVAILABLE), OR (V) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT AND IN EACH OF CASES (I) THROUGH (V) IN
ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF THE STATES AND OTHER
JURISDICTIONS OF THE UNITED STATES, AND (B) SUCH HOLDER WILL, AND EACH
SUBSEQUENT HOLDER OF THIS SECURITY OR ANY SHARES OF COMMON STOCK ISSUABLE UPON
ITS CONVERSION IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS SECURITY AND ANY
COMMON STOCK ISSUABLE UPON ITS CONVERSION FROM IT OF THE RESALE RESTRICTIONS
REFERRED TO IN (A) ABOVE.

          THIS SECURITY, ANY SHARES OF COMMON STOCK ISSUABLE UPON ITS CONVERSION
AND ANY RELATED DOCUMENTATION MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME
TO MODIFY THE RESTRICTIONS ON AND PROCEDURES FOR RESALES AND OTHER TRANSFERS OF
THIS SECURITY AND ANY SUCH SHARES TO REFLECT ANY CHANGE IN APPLICABLE LAW OR
REGULATION (OR THE INTERPRETATION THEREOF) OR IN PRACTICES RELATING TO THE
RESALE OR TRANSFER OF RESTRICTED SECURITIES GENERALLY.  THE HOLDER OF THIS
SECURITY AND ANY SUCH SHARES SHALL BE DEEMED BY THE ACCEPTANCE OF THIS SECURITY
AND ANY SUCH SHARES TO HAVE AGREED TO ANY SUCH AMENDMENT OR SUPPLEMENT.]

[THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH RESTRICTED GLOBAL
SECURITY:

          THE SECURITIES EVIDENCED BY THIS GLOBAL SECURITY (OR ITS PREDECESSOR)
WERE ORIGINALLY ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION UNDER THE
UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND
SUCH SECURITIES AND ANY SHARES OF COMMON STOCK ISSUABLE UPON THEIR CONVERSION
MAY NOT BE SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR
AN APPLICABLE EXEMPTION THEREFROM.  SUCH SECURITIES MAY ONLY BE SOLD IN
ACCORDANCE WITH THE INDENTURE, COPIES OF WHICH ARE AVAILABLE FOR INSPECTION AT
THE CORPORATE TRUST OFFICE OF THE TRUSTEE.  EACH PURCHASER OF ANY BENEFICIAL
INTEREST IN THE SECURITIES WHICH IS A QUALIFIED INSTITUTIONAL BUYER (AS DEFINED
IN RULE 144A UNDER THE SECURITIES ACT) IS HEREBY NOTIFIED THAT THE SELLER OF
SUCH BENEFICIAL INTEREST IN THE SECURITIES MAY BE RELYING ON THE EXEMPTION FROM
THE PROVISIONS OF SECTION 5 OF THE SECURITIES ACT PROVIDED BY RULE 144A
THEREUNDER.

          EACH BENEFICIAL OWNER OF AN INTEREST IN ANY OF THE SECURITIES
EVIDENCED BY THIS GLOBAL SECURITY (INCLUDING ANY PARTICIPANT IN THE DEPOSITARY
HOLDING THE GLOBAL SECURITY THAT IS SHOWN AS HOLDING SUCH AN INTEREST ON THE
RECORDS OF SUCH DEPOSITARY AND EACH BENEFICIAL OWNER THAT HOLDS THROUGH ANY SUCH
PARTICIPANT) AGREES FOR THE

                                      -17-
<PAGE>
 
BENEFIT OF OFFSHORE LOGISTICS, INC. (THE "COMPANY") THAT (A) ANY BENEFICIAL
INTEREST IN THE SECURITIES AND ANY SHARES OF COMMON STOCK ISSUABLE UPON THEIR
CONVERSION MAY BE RESOLD, PLEDGED OR OTHERWISE TRANSFERRED ONLY (I) TO A PERSON
WHO THE SELLER REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER (AS
DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN A TRANSACTION MEETING THE
REQUIREMENTS OF RULE 144A, (II) IN AN OFFSHORE TRANSACTION COMPLYING WITH THE
PROVISIONS OF RULE 904 OF REGULATION S UNDER THE SECURITIES ACT, (III) IN THE
CASE OF ANY PURCHASER, OTHER THAN A PURCHASER WHO HAS OTHERWISE AGREED WITH THE
COMPANY IN WRITING, TO AN INSTITUTION THAT IS AN "ACCREDITED INVESTOR" WITHIN
THE MEANING OF RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT IN A
TRANSACTION EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT,
(IV) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT
PROVIDED BY RULE 144 THEREUNDER (IF AVAILABLE), OR (V) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND IN EACH OF CASES (I) THROUGH
(V) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF THE STATES AND OTHER
JURISDICTIONS OF THE UNITED STATES, AND (B) SUCH BENEFICIAL OWNER WILL, AND EACH
SUBSEQUENT BENEFICIAL OWNER OF THIS SECURITY OR ANY SHARES OF COMMON STOCK
ISSUABLE UPON ITS CONVERSION IS REQUIRED TO, NOTIFY ANY PURCHASER OF ANY
BENEFICIAL INTEREST IN THE SECURITIES AND ANY COMMON STOCK ISSUABLE UPON ITS
CONVERSION FROM IT OF THE RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

          THIS SECURITY, ANY SHARES OF COMMON STOCK ISSUABLE UPON ITS CONVERSION
AND ANY RELATED DOCUMENTATION MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME
TO MODIFY THE RESTRICTIONS ON AND PROCEDURES FOR RESALES AND OTHER TRANSFERS OF
THIS SECURITY AND ANY SUCH SHARES TO REFLECT ANY CHANGE IN APPLICABLE LAW OR
REGULATION (OR THE INTERPRETATION THEREOF) OR IN PRACTICES RELATING TO THE
RESALE OR TRANSFER OF RESTRICTED SECURITIES GENERALLY.  THE HOLDER AND
BENEFICIAL OWNERS OF AN INTEREST IN ANY OF THE SECURITIES EVIDENCED BY THIS
GLOBAL SECURITY AND ANY SUCH SHARES SHALL BE DEEMED BY THE ACCEPTANCE OF THIS
GLOBAL SECURITY AND THE BENEFICIAL INTERESTS THEREIN AND ANY SUCH SHARES TO HAVE
AGREED TO ANY SUCH AMENDMENT OR SUPPLEMENT.]

[THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH GLOBAL SECURITY:

          THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF THE DEPOSITARY OR A
NOMINEE OF THE DEPOSITARY, WHICH MAY BE TREATED BY THE

                                      -18-
<PAGE>
 
COMPANY, THE TRUSTEE AND ANY AGENT THEREOF AS OWNER AND HOLDER OF THIS SECURITY
FOR ALL PURPOSES.

          UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR PHYSICAL
SECURITIES IN DEFINITIVE REGISTERED FORM IN THE LIMITED CIRCUMSTANCES REFERRED
TO IN THE INDENTURE, THIS GLOBAL SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY.]

[THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH GLOBAL SECURITY FOR WHICH
THE DEPOSITORY TRUST COMPANY IS TO BE THE DEPOSITARY:

          UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

[THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH REGULATION S SECURITY:

          THE SECURITIES EVIDENCED BY THIS SECURITY (OR ITS PREDECESSOR) WERE
ORIGINALLY ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED
STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND MAY NOT BE
OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED IN THE UNITED STATES OR TO, OR
FOR THE ACCOUNT OR BENEFIT OF, ANY U.S. PERSON EXCEPT PURSUANT TO AN AVAILABLE
EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND ALL
APPLICABLE STATE SECURITIES LAWS.  TERMS USED ABOVE HAVE THE MEANINGS GIVEN THEM
IN REGULATION S UNDER THE SECURITIES ACT.]

                                      -19-
<PAGE>
 
                                 OFFSHORE LOGISTICS, INC.
                          6% Convertible Subordinated
                                 Note due 2003

No. _________________                              $______________

[IF CALEDONIA SECURITY -- WITHOUT A CUSIP NO.]

[IF RESTRICTED GLOBAL SECURITY - CUSIP NO. 676255 AD 4]
[IF REGULATION S GLOBAL SECURITY -- CUSIP NO. U67530 AA 0]
[IF REGULATION D SECURITY - CUSIP NO. 676255 AE 2]

          OFFSHORE LOGISTICS, INC., a corporation duly organized and existing
under the laws of the State of Delaware (herein called the "Company", which term
includes any successor Person under the Indenture referred to on the reverse
hereof), for value received, hereby promises to pay to _______________, or
registered assigns, the principal sum of ____________________ Dollars [IF THIS
SECURITY IS A GLOBAL SECURITY, THEN INSERT -(which principal amount may from
time to time be increased or decreased to such other principal amounts (which,
taken together with the principal amounts of all other Outstanding Securities,
shall not exceed $98,000,000 in the aggregate at any time) by adjustments made
on the records of the Trustee hereinafter referred to in accordance with the
Indenture)] on December 15, 2003 and to pay interest thereon, from December 17,
1996, or from the most recent Interest Payment Date (as defined below) to which
interest has been paid or duly provided for, semi-annually on June 15 and
December 15 in each year (each , an "Interest Payment Date"), commencing June
15, 1997, at the rate of 6% per annum, until the principal hereof is due, and at
the rate of 6% per annum on any overdue principal and premium, if any, and, to
the extent permitted by law, on any overdue interest.  The interest so payable,
and punctually paid or duly provided for, on any Interest Payment Date will, as
provided in the Indenture, be paid to the Person in whose name this Security (or
one or more Predecessor Securities) is registered at the close of business on
the Regular Record Date for such interest, which shall be the June 1st or
December 1st (whether or not a Business Day), as the case may be, next preceding
such Interest Payment Date.  Any such interest not so punctually paid or duly
provided for will forthwith cease to be payable to the Holder on such Regular
Record Date and may either be paid to the Person in whose name this Security (or
one or more Predecessor Securities) is registered at the close of business on a
Special Record Date for the payment of such Defaulted Interest to be fixed by
the Trustee, notice whereof shall be given to Holders of Securities not less
than 10 days prior to such Special Record Date, or be paid at any time in any
other lawful manner not inconsistent with the requirements of any securities
exchange on which the Securities may be listed, and upon such notice as may be
required by such exchange, all as more fully provided in the Indenture.
Payments of principal shall be made upon the surrender of this Security to the
Company at the office or agency of the Company in New York, New York designated
by the Company for such purpose pursuant to the terms of the Indenture in such
coin or currency of the United States of America as at the time of payment shall
be legal tender for the payment of public and private debts, by United States
Dollar check drawn on, or transfer to, a United States Dollar account (such a
transfer to be made only to a

                                      -20-
<PAGE>
 
Holder of an aggregate principal amount of Securities in excess of U.S.
$2,000,000, and only if such Holder shall have furnished wire instructions in
writing to the Trustee no later than 15 days prior to the relevant payment date)
maintained by the payee with a bank in New York, New York.  Payment of interest
on this Security may be made by United States Dollar check drawn on a bank in
New York, New York mailed to the address of the Person entitled thereto as such
address shall appear in the Security Register, or, upon written application by
the Holder to the Security Registrar setting forth wire instructions not later
than the relevant Record Date, by transfer to a United States Dollar account
(such a transfer to be made only to a Holder of an aggregate principal amount of
Securities in excess of U.S. $2,000,000 and only if such Holder shall have
furnished wire instructions in writing to the Trustee no later than 15 days
prior to the relevant payment date) maintained by the payee with a bank in  New
York, New York.

          Except as specifically provided herein and in the Indenture, the
Company shall not be required to make any payment with respect to any tax,
assessment or other governmental charge imposed by any government or any
political subdivision or taxing authority thereof or therein.

          Reference is hereby made to the further provisions of this Security
set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

          Unless the certificate of authentication hereon has been executed by
the Trustee referred to on the reverse hereof or an Authenticating Agent by the
manual signature of one of their respective authorized signatories, this
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated:
                                                 OFFSHORE LOGISTICS,
INC.


                                                 By:
                                                    --------------------------
Attest:                                             President


______________________________
         Secretary

 Section 203.  Form of Reverse of Security.

          This Security is one of a duly authorized issue of securities of the
Company designated as its 6% Convertible Subordinated Notes due 2003 (herein
called the "Securities"),

                                      -21-
<PAGE>
 
limited in aggregate principal amount to $87,500,000 (subject to increase to up
to $98,000,000 aggregate principal amount), issued and to be issued under an
Indenture, dated as of December 15, 1996 (herein called the "Indenture"),
between the Company and Fleet National Bank, as Trustee (herein called the
"Trustee", which term includes any successor trustee under the Indenture), to
which Indenture and all indentures supplemental thereto reference is hereby made
for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee, the holders of Senior
Indebtedness and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered.

          Subject to the provisions of the Indenture, the Holder hereof has the
right, at his option, at any time on or after the 60th day following the last
original issue date of the Securities and prior to the close of business on the
maturity date, to convert the principal amount of this Security (or any portion
of the principal amount hereof which is an integral multiple of $1,000) into
fully paid and nonassessable shares of Common Stock of the Company at the
conversion price of $22.86 of principal amount of this Security per share of
Common Stock, subject to such adjustment, if any, of the conversion price and
the securities or other property issuable upon conversion as may be required by
the provisions of the Indenture (except that, in case this Security (or any
portion hereof) shall be called for redemption before maturity, such right shall
terminate at the close of business on the Business Day immediately preceding the
Redemption Date for this Security (or such portion hereof), unless in any such
case the Company shall default in payment due upon such redemption), but only
upon surrender of this Security for the purpose of such conversion to the
Company at the office or agency designated by the Company for such purpose
pursuant to the provisions of the Indenture, accompanied by written notice that
the Holder elects to convert this Security or any portion hereof and specifying
the name or names (with address or addresses) in which a certificate or
certificates for shares of Common Stock are to be issued and (if so required by
the Company or the Trustee) by a written instrument or instruments of transfer
in form satisfactory to the Company and the Trustee duly executed by the
registered Holder or his duly authorized legal representative and transfer tax
stamps or funds therefor, if required pursuant to the provisions of the
Indenture and, in case such surrender shall be made during the period from the
close of business on any Regular Record Date to the opening of business on the
next succeeding Interest Payment Date (unless this Security or the portion
thereof being converted has been called for redemption), also accompanied by
payment in funds acceptable to the Company of an amount equal to the interest
payable on such Interest Payment Date on the principal amount of this Security
then being converted.  Subject to the aforesaid requirement with respect to
payment in the event of conversion after the close of business on a Regular
Record Date, no adjustment is to be made on conversion for interest accrued
hereon or for dividends on shares of Common Stock issued on conversion;
provided, however, that upon a call for redemption by the Company, accrued and
unpaid interest to the Redemption Date shall be payable with respect to Notes
converted after the redemption call and prior to the Redemption Date. No
fractional shares are issuable upon any conversion, but in lieu thereof the
Company shall pay therefor in cash as provided in the Indenture.

          The Securities are subject to redemption upon not less than 30 nor
more than 60 days' notice by first-class mail, postage prepaid, at any time on
or after December 15, 1999, as a whole

                                      -22-
<PAGE>
 
or in part, at the election of the Company, at the following Redemption Prices
(expressed as percentages of the principal amount), if redeemed during the 12-
month period beginning December 15 of the years indicated,

          Year                                    Redemption Price
          ----                                    ----------------
          1999....................................    103.43%
          2000....................................    102.57%
          2001....................................    101.71%
          2002....................................    100.86%


together with, in each case,  accrued and unpaid interest to the Redemption
Date, but interest installments whose Stated Maturity is on or prior to such
Redemption Date will be payable to the Holders of such Securities, or one or
more Predecessor Securities, of record at the close of business on the relevant
Record Dates referred to on the face hereof, all as provided in the Indenture.

          In the event the Company fails to consummate the Bristow Transaction
within 15 days of the Issue Date, then the Company will mandatorily redeem, upon
not less than 30 days' notice by first-class mail, postage prepaid, the
Securities as a whole on February 5, 1997, at a Redemption Price equal to 100%
of their principal amount, plus accrued and unpaid interest to the Redemption
Date.

          At any time when the Company is not subject to Section 13 or 15(d) of
the U.S. Securities Exchange Act of 1934, as amended, upon the request of a
Holder of a Restricted Security or the holder of shares of Common Stock issued
upon conversion thereof, the Company will promptly furnish or cause to be
furnished Rule 144A Information (as defined below) to such Holder of Restricted
Securities or such holder of shares of Common Stock issued upon conversion of
Restricted Securities, or to a prospective purchaser of any security designated
by any such Holder or holder, as the case may be, to the extent required to
permit compliance by such Holder or holder with Rule 144A under the Securities
Act of 1933, as amended (the "Securities Act"), in connection with the resale of
any such security.  "Rule 144A Information" shall be such information as is
specified pursuant to Rule 144A(d)(4) under the Securities Act (or any successor
provision thereto).

          If this Security is a Registrable Security, then the Holder of this
Security [IF THIS SECURITY IS A GLOBAL SECURITY, THEN INSERT - (including any
Person that has a beneficial interest in this Security)] and the Common Stock
issuable upon conversion hereof is entitled to the benefits of a Registration
Rights Agreement, dated as of December 17, 1996 (the "Registration Rights
Agreement"), executed by the Company.  Pursuant to the Registration Rights
Agreement, the Company has agreed for the benefit of the Holders from time to
time of Securities and the Common Stock issuable upon conversion thereof, in
each case, that are Registrable Securities, to file a shelf registration
statement (the "Shelf Registration Statement") with the Commission with respect
to resales of the Registrable Securities.

                                      -23-
<PAGE>
 
          If (i) on or prior to 90 days following the initial date of original
issuance of the Securities, a Shelf Registration Statement has not been filed
with the Commission, or (ii) on or prior to 180 days following such date, such
Shelf Registration Statement is not declared effective (each, a "Registration
Default"), additional interest ("Liquidated Damages") will accrue on this
Security from and including the day following such Registration Default to but
excluding the day on which such Registration Default has been cured.  Liquidated
Damages will be paid semi-annually in arrears, with the first semi-annual
payment due on the first Interest Payment Date following the date on which such
Liquidated Damages begin to accrue, and will accrue at a rate per annum equal to
an additional one-quarter of one percent (.25%) of the principal amount hereof
to and including the 90th day following such Registration Default and at a rate
per annum equal to one-half of one percent (.5%) thereof from and after the 91st
day following such Registration Default.  In the event that the Shelf
Registration Statement ceases to be effective during the period (the
"Effectiveness Period") beginning on the initial effective date of the Shelf
Registration Statement and ending on the earliest of, (i) three years after such
effective date, (ii) when there are no outstanding Registrable Securities, or
(iii) when all outstanding Registrable Securities, subject to certain limited
exceptions, may be resold without registration under the Securities Act pursuant
to Rule 144(k) (or any successor provision to such Rule), or the Company
suspends the use of the prospectus which is a part thereof for a period in
excess of 60 days, whether or not consecutive, during any 12-month period, then
the interest rate borne by this Security shall increase by an additional one-
half of one percent (.5%) per annum from the 61st day of the applicable 12-month
period such Shelf Registration Statement ceases to be effective or the Company
suspends the use of the prospectus which is a part thereof, as the case may be,
to but excluding the day on which (i) the Shelf Registration Statement again
becomes effective, (ii) the use of the related prospectus ceases to be suspended
or (iii) the Effectiveness Period expires.

          Whenever in this Security there is mentioned, in any context, the
payment of the principal of, premium, if any, or interest on, or in respect of,
this Security, such mention shall be deemed to include mention of the payment of
Liquidated Damages payable as described in the preceding paragraph to the extent
that, in such context, Liquidated Damages are, were or would be payable in
respect of this Security pursuant to such paragraph, and an express mention of
the payment of Liquidated Damages (if applicable) in any provisions of this
Security shall not be construed as excluding Liquidated Damages in those
provisions of this Security where such express mention is not made.

          [If this Security is a Registrable Security and the Holder of this
Security [IF THIS SECURITY IS A GLOBAL SECURITY, THEN INSERT - (including any
Person that has a beneficial interest in this Security)] elects to sell this
Security pursuant to the Shelf Registration Statement then, by his acceptance
hereof, such Holder of this Security agrees to be bound by the terms of the
Registration Rights Agreement relating to the Registrable Securities which are
the subject of such election.]

          Upon the occurrence of a Designated Event (as defined in the
Indenture), the Company is required to offer to purchase the Securities at a
purchase price equal to 100% of the

                                      -24-
<PAGE>
 
principal amount of such Securities, together with accrued and unpaid interest
to the Repurchase Date.

  [THE FOLLOWING PARAGRAPH SHALL APPEAR IN EACH SECURITY THAT IS NOT A GLOBAL
SECURITY:

          In the event of redemption, repurchase or conversion of this Security
in part only, a new Security or Securities for the unredeemed, unrepurchased or
unconverted portion hereof will be issued in the name of the Holder hereof.]

        [THE FOLLOWING PARAGRAPH SHALL APPEAR IN EACH GLOBAL SECURITY:

          In the event of a deposit or withdrawal of an interest in this
Security, including an exchange, transfer, redemption, repurchase or conversion
of this Security in part only, the Trustee, as custodian of the Depositary,
shall make an adjustment on its records to reflect such deposit or withdrawal in
accordance with the Applicable Procedures.]

          The indebtedness evidenced by the Securities is, to the extent and in
the manner provided in the Indenture, expressly subordinate and subject in right
of payment to the prior payment in full of any Senior Indebtedness of the
Company or provision for such payment, whether outstanding at the date of the
Indenture or thereafter incurred, and this Security is issued subject to the
provisions of the Indenture with respect thereto.  Each Holder of this Security,
by his acceptance hereof, agrees to and shall be bound by such provisions of the
Indenture and authorizes and directs the Trustee on his behalf to take such
action as may be necessary or appropriate to effectuate  such subordination and
appoints the Trustee his attorney-in-fact for any and all such purposes.

          If an Event of Default, as defined in the Indenture, shall occur and
be continuing, the principal of all the Securities may be declared due and
payable in the manner and with the effect provided in the Indenture.

          The Indenture permits, with certain exceptions as therein provided,
the amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities under the Indenture at
any time by the Company and the Trustee with the consent of the Holders of at
least a majority in aggregate principal amount of the Securities at the time
Outstanding.  The Indenture also contains provisions permitting the Holders of
at least a majority in aggregate principal amount of the Securities at the time
Outstanding, on behalf of the Holders of all the Securities, to waive compliance
by the Company with certain provisions of the Indenture and certain past
defaults under the Indenture and their consequences.  Any such consent or waiver
by the Holder of this Security shall be conclusive and binding upon such Holder
and upon all future Holders of this Security and of any Security issued upon the
registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.

                                      -25-
<PAGE>
 
          The Indenture provides that no Holder of any Security may enforce any
remedy under the Indenture except in the case of failure of the Trustee to act
after notice of default and after request by the Holders of not less than 25% in
aggregate principal amount of the Outstanding Securities and the offer and, if
requested, provision to the Trustee of reasonable indemnity satisfactory to the
Trustee; provided, however, that such provision shall not prevent the Holder
hereof from enforcing payment of the principal of (and premium, if any) or
interest on this Security after the same shall have become due.

          Initially, the Trustee will act as Paying Agent, Security Registrar,
conversion agent and as the agent where notices and demands to or upon the
Company in respect of the Securities may be served.  The Company may appoint and
change any Paying Agent, Security Registrar, conversion agent or agent for
notices; provided, however, that no such appointment or change shall relieve the
Company of its obligation to maintain an office or agency in New York, New York
where the Securities may be presented or surrendered for payment.

          No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, subject to the subordination provisions, to pay
the principal of (and premium, if any) and interest on (including Liquidated
Damages and additional interest) this Security at the times, place and rate, and
in the coin or currency, herein prescribed or to convert this Security as
provided in the Indenture.

          As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company designated under the Indenture, duly endorsed
by, or accompanied by a written instrument of transfer in form satisfactory to
the Company and the Security Registrar and duly executed by the Holder hereof or
his attorney duly authorized in writing, and thereupon one or more new
Securities, of authorized denominations and for the same aggregate principal
amount, will be issued to the designated transferee or transferees.

          The Securities are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof.  As provided in the
Indenture and subject to certain limitations therein set forth, Securities are
exchangeable for a like aggregate principal amount of Securities of a different
authorized denomination, as requested by the Holder surrendering the same.

          No service charge shall be made to the Holder for any such
registration of transfer or exchange, but the Company may require payment of a
sum sufficient to cover any tax or other governmental charge payable in
connection therewith.

          Prior to due presentment of this Security for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Security is registered as the owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

                                      -26-
<PAGE>
 
          THE COMPANY WILL FURNISH TO ANY HOLDER UPON WRITTEN REQUEST AND
WITHOUT CHARGE A COPY OF THE INDENTURE.  REQUESTS MAY BE MADE TO:

          OFFSHORE LOGISTICS, INC.
          224 RUE DE JEAN
          LAFAYETTE, LOUISIANA  70508
          ATTENTION:  TREASURER

          This Security and the rights of the Holder hereof shall be governed by
and construed in accordance with the laws of the State of New York.

          All terms used in this Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

                                      -27-
<PAGE>
 
                       OPTION OF HOLDER TO ELECT PURCHASE

          If you want to elect to have this Security purchased by the Company
pursuant to Article Twelve of the Indenture, check the box:  [  ]

          If you want to elect to have only part of this Security purchased by
the Company pursuant to Article Twelve of the Indenture, state the amount (in
integral multiples of $1,000): $___________

          You hereby direct the Trustee or the Company to pay you, unless a
different name has been indicated in the assignment below, an amount in cash
equal to 100% of the principal amount to be repurchased (as set forth above),
plus interest accrued to the Repurchase Date, as provided in the Indenture.


Date:_______________________         Your Signature:________________________
                                                   (Sign exactly as your name
                                                    appears on this Security)

Your Social Security or
Tax Identification Number:___________________________________________________

Signature Guarantee:_________________________________________________________

Note:     Signature(s) must be guaranteed by an eligible guarantor institution
          which is a member of one of the following recognized signature
          guarantee programs: (1) The Securities Transfer Agents Medallion
          Program (STAMP); (2) The New York Stock Exchange Medallion Signature
          Program (MSP); or (3) The Stock Exchange Medallion Program (SEMP).

                                      -28-
<PAGE>
 
 Section 204.   Form of Trustee's Certificate of Authentication.

          This is one of the Securities referred to in the within-mentioned
Indenture.

                                         FLEET NATIONAL BANK,
                                         as Trustee



                                         By
                                           ----------------------------------- 
                                               Authorized Signatory

 Section 205.  Form of Election to Convert.

To Offshore Logistics, Inc.:

          The undersigned owner of this Security hereby irrevocably exercises
the option to convert this Security, or the portion below designated, into
shares of Common Stock of Offshore Logistics, Inc. in accordance with the terms
of the Indenture referred to in this Security, and directs that the shares
issuable and deliverable upon conversion, together with any check in payment for
fractional shares, be issued in the name of and delivered to the undersigned,
unless a different name has been indicated in the assignment below.  If shares
are to be issued in the name of a Person other than the undersigned, the
undersigned will pay all transfer taxes payable with respect thereto.

Date:

Portion of Security to be converted
($1,000 or an integral multiple thereof):
$_______________________                     -------------------------------
                                             Signature (for conversion only)
                                             Please Print or Type Name and 
                                             Address, Including Zip Code,
                                             and Social Security or Other 
                                             Identifying Number:

                                             ______________________________
                                             ______________________________
                                             ______________________________

                                      -29-
<PAGE>
 
 Section 206.  Form of Assignment.

                                   ASSIGNMENT

For value received _______________________________________________ hereby
sell(s), assign(s) and transfer(s) unto
_____________________________________________________,
__________________________________ [Please insert social security or other
identifying number of assignee], the within Security, hereby irrevocably
constituting and appointing ______________________________ attorney to transfer
the said Security on the books of the Company, with full power of substitution
in the premises.

Date:________________                               ---------------------------
                                                            Signature(s)

                                           Note:  The signature(s) to this
                                                  assignment must correspond
                                                  with the name as it appears
                                                  upon the face of the within
                                                  Security in every particular,
                                                  without alteration, or
                                                  enlargement or any change
                                                  whatever.


- ------------------------------------ 
Signature Guarantee

Note:     Signature(s) must be guaranteed by an eligible guarantor institution
          which is a member of one of the following recognized signature
          guarantee programs: (1) The Securities Transfer Agents Medallion
          Program (STAMP); (2) The New York Stock Exchange Medallion Signature
          Program (MSP); or (3) The Stock Exchange Medallion Program (SEMP).

                                      -30-
<PAGE>
 
                                 ARTICLE THREE

                                 THE SECURITIES

 Section 301.  Title and Terms.

          The aggregate principal amount of Securities which may be
authenticated and delivered under this Indenture is limited to the sum of (a)
$87,500,000 and (b) such aggregate principal amount (which may not exceed
$10,500,000 aggregate principal amount) of Securities, if any, as shall be
purchased by the Initial Purchasers at the "Second Closing Time" (as defined in
the Purchase Agreement) pursuant to and in accordance with the terms and
provisions of the Purchase Agreement, dated December 11, 1996 (the "Purchase
Agreement"), between the Company and each Initial Purchaser, except for
Securities authenticated and delivered upon registration of transfer of, or in
exchange for, or in lieu of, other Securities pursuant to Section 304, 305, 306,
906, 1108, 1205 or 1301.

          The Securities shall be known and designated as the "6% Convertible
Subordinated Notes due 2003" of the Company.  Their Stated Maturity shall be
December 15, 2003 and they shall bear interest at the rate of 6% per annum, from
December 17, 1996 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, as the case may be, payable
semiannually in arrears on June 15 and December 15,  commencing June 15, 1997,
until the principal thereof is due, and at the rate of 6% per annum on any
overdue principal and premium, if any, and, to the extent permitted by law, on
any overdue interest.

          The principal of (and premium, if any) and interest on the Securities
shall be payable in the manner provided in the form of Securities set forth in
Section 202 and at the office or agency of the Company in New York, New York,
maintained for such purpose and at any other office or agency maintained by the
Company for such purpose.

          The Registrable Securities are entitled to the benefits of a
Registration Rights Agreement as provided by Sections 203 and 1007.  The
Securities are entitled to the payment of Liquidated Damages as provided by
Section 1007.

          The Securities shall be redeemable as provided in Article Eleven.

          The Securities shall be subject to repurchase at the option of the
Holders as provided in Article Twelve.

          The Securities shall be convertible as provided in Article Thirteen.

          The Securities shall be subordinated in right of payment to Senior
Indebtedness as provided in Article Fourteen.

                                      -31-
<PAGE>
 
 Section 302.  Denominations.

          The Securities shall be issuable only in registered form without
coupons and only in denominations of $1,000 and any integral multiple thereof.

 Section 303.  Execution, Authentication, Delivery and Dating.

          The Securities shall be executed on behalf of the Company by its
Chairman of the Board, its President or one of its Vice Presidents, under its
corporate seal affixed or reproduced thereon attested by its Secretary or one of
its Assistant Secretaries.  The signature of any of these officers on the
Securities may be manual or facsimile.

          Securities bearing the manual or facsimile signatures of individuals
who were at the time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals have ceased to hold such offices prior to
the authentication and delivery of such Securities or did not hold such offices
at the date of such Securities.

          At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities executed by the Company to
the Trustee for authentication, together with a Company Order for the
authentication and delivery of such Securities; and the Trustee in accordance
with such Company Order shall authenticate and deliver such Securities as in
this Indenture provided and not otherwise.

          Each Security shall be dated the date of its authentication.

          No Security shall be entitled to any benefit under this Indenture or
be valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature, and such certificate upon any
Security shall be conclusive evidence, and the only evidence, that such Security
has been duly authenticated and delivered hereunder.  Notwithstanding the
foregoing, if the Caledonia Security or any other Security shall have been
authenticated and delivered hereunder but never issued and sold by the Company,
and the Company shall deliver such Security to the Trustee for cancellation as
provided in Section 309, for all purposes of this Indenture such Security shall
be deemed never to have been authenticated and delivered hereunder and shall
never be entitled to the benefits of this Indenture.

 Section 304.  Global Securities; Physical Securities.

     (A)  Global Securities

          (a) Each Global Security authenticated under this Indenture shall be
registered in the name of the Depositary designated by the Company for such
Global Security or a nominee

                                      -32-
<PAGE>
 
thereof and delivered to such Depositary or a nominee thereof or custodian
therefor, and each such Global Security shall constitute a single Security for
all purposes of this Indenture.

          (b) Notwithstanding any other provision in this Indenture, no Global
Security may be exchanged in whole or in part for Securities registered, and no
transfer of a Global Security in whole or in part may be registered, in the name
of any Person other than the Depositary for such Global Security or a nominee
thereof unless (i) such Depositary (A) has notified the Company that it is
unwilling or unable to continue as Depositary for such Global Security or (B)
has ceased to be a clearing agency registered as such under the Exchange Act or
announces an intention permanently to cease business or does in fact do so or
(ii) there shall have occurred and be continuing an Event of Default; provided,
however, a Global Security may be exchanged or transferred as a whole by the
Depositary for such Global Security to its nominee or by its nominee to such
Depositary or to another nominee of such Depositary or by such Depositary or any
such nominee to a successor Depositary or a nominee of such successor
Depositary.

          (c) If any Global Security is to be exchanged for other Securities or
canceled in whole, it shall be surrendered by or on behalf of the Depositary or
its nominee to the Trustee, as Security Registrar, for exchange or cancellation,
as provided in this Article Three.  If any Global Security is to be exchanged
for other Securities or canceled in part, or if another Security is to be
exchanged in whole or in part for a beneficial interest in any Global Security,
in each case, as provided in Section 305, then either (i) such Global Security
shall be so surrendered for exchange or cancellation, as provided in this
Article Three, or (ii) the principal amount thereof shall be reduced or
increased by an amount equal to the portion thereof to be so exchanged or
canceled, or equal to the principal amount of such other Security to be so
exchanged for a beneficial interest therein, as the case may be, by means of an
appropriate adjustment made on the records of the Trustee, as Security
Registrar, whereupon the Trustee, in accordance with the Applicable Procedures,
shall instruct the Depositary or its authorized representative to make a
corresponding adjustment to its records.  Upon any such surrender or adjustment
of a Global Security, the Trustee shall, subject to Section 305(c) and as
otherwise provided in this Article Three, authenticate and deliver any
Securities issuable in exchange for such Global Security (or any portion
thereof) to or upon the order of, and registered in such names as may be
directed by, the Depositary or its authorized representative.  Upon the request
of the Trustee in connection with the occurrence of any of the events specified
in the preceding paragraph, the Company shall promptly make available to the
Trustee a reasonable supply of Securities that are not in the form of Global
Securities.  The Trustee shall be entitled to rely upon any order, direction or
request of the Depositary or its authorized representative which is given or
made pursuant to this Article Three if such order, direction or request is given
or made in accordance with the Applicable Procedures.

          (d) Every Security authenticated and delivered upon registration of
transfer of, or in exchange for or in lieu of, a Global Security or any portion
thereof, whether pursuant to this Article Three or otherwise, shall be
authenticated and delivered in the form of, and shall be, a registered Global
Security, unless such Security is registered in the name of a Person other than
the

                                      -33-
<PAGE>
 
Depositary for such Global Security or a nominee thereof, in which case such
Security shall be authenticated and delivered in the form of one or more
Physical Securities.

          (e) The Depositary or its nominee, as registered owner of a Global
Security, shall be the Holder of such Global Security for all purposes under the
Indenture and the Securities, and owners of beneficial interests in a Global
Security shall hold such interests pursuant to the Applicable Procedures.
Accordingly, any such owner's beneficial interest in a Global Security will be
shown only on, and the transfer of such interest shall be effected only through,
records maintained by the Depositary or its nominee or its Agent Members and
such owners of beneficial interests in a Global Security will not be considered
the owners or holders thereof.

     (B)  Physical Securities

          Regulation D Securities and the Caledonia Security shall be initially
issued in the form of Physical Securities, which, in the case of the Regulation
D Securities, shall initially be registered in such names and be in such
authorized denominations as the Initial Purchasers shall designate and shall
bear the legends required hereunder.  The Company will make available to the
Trustee a reasonable supply of Physical Securities.

          Pending the preparation of  definitive Physical Securities, the
Company may execute, and upon Company Order the Trustee shall authenticate and
make available for delivery, temporary Physical Securities which are printed,
lithographed, typewritten, mimeographed or otherwise produced, in any authorized
denomination, substantially of the tenor of the definitive Physical Securities
in lieu of which they are issued and with such appropriate insertions,
omissions, substitutions and other variations as the officers executing such
temporary Physical Securities may determine, as evidenced by their execution of
such temporary Physical Securities.

          If temporary Physical Securities are issued, the Company will cause
definitive Physical Securities to be prepared without unreasonable delay.  After
the preparation of the definitive Physical Securities, the temporary Physical
Securities shall be exchangeable for definitive Physical Securities upon
surrender of the temporary Physical Securities at any office or agency of the
Company designated pursuant to Section 1002, without charge to the Holder.  Upon
surrender for cancellation of any one or more temporary Physical Securities, the
Company shall execute and the Trustee shall authenticate and make available for
delivery in exchange therefor a like principal amount of definitive Physical
Securities of authorized denominations.  Until so exchanged the temporary
Physical Securities shall in all respects be entitled to the same benefits under
this Indenture as definitive Physical Securities.

  Section 305. Registration, Registration of Transfer and Exchange; Restrictions
on Transfer.

          (a) The Company shall cause to be kept at the office of the Security
Registrar a register (the register maintained in such office and in any other
office or agency of the Company designated pursuant to Section 1002 being herein
sometimes collectively referred to as the "Security

                                      -34-
<PAGE>
 
Register') in which, subject to such reasonable regulations as it may prescribe,
the Company shall provide for the registration of Securities and of transfers of
Securities.  The Trustee is hereby initially appointed "Security Registrar" for
the purpose of registering Securities and transfers and exchanges of Securities
as herein provided.

          Upon surrender for registration of transfer of any Security at an
office or agency of the Company designated pursuant to Section 1002 for such
purpose, the Company shall execute, and the Trustee shall authenticate and
deliver, in the name of the designated transferee or transferees, one or more
new Securities of any authorized denominations and of a like aggregate principal
amount and bearing such restrictive legends as may be required by this
Indenture.

          At the option of the Holder, and subject to the other provisions of
this Section 305, Securities may be exchanged for other Securities of any
authorized denomination and of a like aggregate principal amount, upon surrender
of the Securities to be exchanged at any such office or agency.  Whenever any
Securities are so surrendered for exchange, and subject to the other provisions
of this Section 305, the Company shall execute, and the Trustee shall
authenticate and deliver, the Securities which the Holder making the exchange is
entitled to receive.  Every Security presented or surrendered for registration
of transfer or for exchange shall (if so required by the Company or the Security
Registrar) be duly endorsed, or be accompanied by a written instrument of
transfer in form satisfactory to the Company and the Security Registrar duly
executed, by the Holder thereof or his attorney duly authorized in writing.

          All Securities issued upon any registration of transfer or exchange of
Securities shall be the valid obligations of the Company, evidencing the same
debt, and subject to the other provisions of this Section 305, entitled to the
same benefits under this Indenture, as the Securities surrendered upon such
registration of transfer or exchange.

          No service charge shall be made for any registration of transfer or
exchange of Securities except as provided in Section 306, but the Company may
require payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in connection with any registration of transfer or
exchange of Securities, other than exchanges pursuant to Section 304, 906, 1108,
1205, or 1301 not involving any transfer.

          In the event of a redemption of the Securities, the Company will not
be required (a) to register the transfer of or exchange Physical Securities for
a period of 15 days immediately preceding the date notice is given identifying
the serial numbers of the Physical Securities called for such redemption or (b)
to register the transfer of or exchange any Physical Security, or portion
thereof, called for redemption.

          (b) Certain Transfers and Exchanges.  Notwithstanding any other
provision of this Indenture or the Securities, transfers and exchanges of
Securities and beneficial interests in a Global Security of the kinds specified
in this Section 305(b) shall be made only in accordance with this Section
305(b).

                                      -35-
<PAGE>
 
          (i) Restricted Global Security to Regulation S Global Security.  If
the owner of a beneficial interest in the Restricted Global Security wishes at
any time to transfer such interest to a Person who wishes to acquire the same in
the form of a beneficial interest in the Regulation S Global Security, such
transfer may be effected only in accordance with the provisions of this clause
(b)(i) and clause (b)(v) below and subject to the Applicable Procedures.  Upon
receipt by the Trustee, as Security Registrar, of (A) an order given by the
Depositary or its authorized representative directing that a beneficial interest
in the Regulation S Global Security in a specified principal amount be credited
to a specified Agent Member's account and that a beneficial interest in the
Restricted Global Security in an equal principal amount be debited from another
specified Agent Member's account and (B) a Regulation S Certificate,
satisfactory to the Trustee and duly executed by the owner of such beneficial
interest in the Restricted Global Security or his attorney duly authorized in
writing, then the Trustee, as Security Registrar but subject to Clause (b)(v)
below, shall reduce the principal amount of the Restricted Global Security and
increase the principal amount of the Regulation S Global Security by such
specified principal amount as provided in Section 304(A)(c).

     (ii) Regulation S Global Security to Restricted Global Security.  If the
owner of a beneficial interest in the Regulation S Global Security wishes at any
time to transfer such interest to a Person who wishes to acquire the same in the
form of a beneficial interest in the Restricted Global Security, such transfer
may be effected only in accordance with this clause (b)(ii) and subject to the
Applicable Procedures.  Upon receipt by the Trustee, as Security Registrar, of
(A) an order given by the Depositary or its authorized representative directing
that a beneficial interest in the Restricted Global Security in a specified
principal amount be credited to a specified Agent Member's account and that a
beneficial interest in the Regulation S Global Security in an equal principal
amount be debited from another specified Agent Member's account and (B) if such
transfer is to occur during the Restricted Period, a Restricted Securities
Certificate, satisfactory to the Trustee and duly executed by the owner of such
beneficial interest in the Regulation S Global Security or his attorney duly
authorized in writing, then the Trustee, as Security Registrar, shall reduce the
principal amount of the Regulation S Global Security and increase the principal
amount of the Restricted Global Security by such specified principal amount as
provided in Section 304(A)(c).

     (iii)     Restricted Physical Security to Restricted Global Security or
Regulation S Global Security.  If the Holder of a Restricted Security (other
than a Global Security) wishes at any time to transfer all or any portion of
such Restricted Security to a Person who wishes to take delivery thereof in the
form of a beneficial interest in the Restricted Global Security or Regulation S
Global Security, such transfer may be effected only in accordance with the
provisions of this clause (b)(iii) and clause (b)(v) and subject to the
Applicable Procedures. Upon receipt by the Trustee, as Security Registrar, of
(A) such Restricted Security as provided in Section 305(a) and instructions
satisfactory to the Trustee directing that a beneficial interest in the
Restricted Global Security or Regulation S Global Security in a

                                      -36-
<PAGE>
 
specified principal amount not greater than the principal amount of such
Restricted Security be credited to a specified Agent Member's account and (B) a
Restricted Securities Certificate, if the specified account is to be credited
with a beneficial interest in the Restricted Global Security, or a Regulation S
Certificate, if the specified account is to be credited with a beneficial
interest in the Regulation S Security, in either case satisfactory to the
Trustee and duly executed by such Holder or his attorney duly authorized in
writing, then the Trustee, as Security Registrar but subject to clause (b)(v)
below, shall cancel such Restricted Security (and issue a new Restricted
Security the form of one or more Physical Securities in respect of any
untransferred portion thereof) as provided in Section 305(a) and increase the
principal amount of the Restricted Global Security or Regulation S Global
Security, as the case may be, by the specified principal amount as provided in
Section 304(A)(c).

     (iv) Exchanges between Global Security and Physical Security.  A beneficial
interest in a Global Security may be exchanged for a Security that is not a
Global Security as provided in Section 304, provided that, if such interest is a
beneficial interest in the Restricted Global Security, or if such interest is a
beneficial interest in the Regulation S Global Security and such exchange is to
occur during the Restricted Period, then such interest shall be exchanged for a
Restricted Security (subject in each case to Section 305(c)). A Security that is
not a Global Security may be exchanged for a beneficial interest in a Global
Security only if such exchange occurs in connection with a transfer effected in
accordance with clause (b)(iii) above.

     (v) Regulation S Global Security to be Held Through Euroclear or CEDEL
during Restricted Period.  The Company shall use its reasonable best efforts to
cause the Depositary to ensure that, until the expiration of the Restricted
Period, beneficial interests in the Regulation S Global Security may be held
only in or through accounts maintained at the Depositary by Euroclear or CEDEL
(or by Agent Members acting for the account thereof), and no Person shall be
entitled to effect any transfer or exchange that would result in any such
interest being held otherwise than in or through such an account; provided that
this clause (b)(v) shall not prohibit any transfer or exchange of such an
interest in accordance with clause (b)(ii) or (iv) above.

          (c) Securities Act Legends.  Rule 144A Securities, Regulation D
Securities and their respective Successor Securities shall bear the applicable
Restricted Securities Legend, and the Regulation S Securities and their
Successor Securities shall bear a Regulation S Legend, subject to the following:

     (i) subject to the following clauses of this Section 305(c), a Security or
any portion thereof which is exchanged, upon transfer or otherwise, for a Global
Security or any portion thereof shall bear the Securities Act Legend borne by
such Global Security while represented thereby;

                                      -37-
<PAGE>
 
          (ii) subject to the following clauses of this Section 305(c), a new
Physical Security which is issued in exchange for another Security (including a
Global Security) or any portion thereof, upon transfer or otherwise, shall bear
the Securities Act Legend borne by such other Security, provided that, if such
new Security is required pursuant to Section 305(b)(iv) to be issued in the form
of a Restricted Security, it shall bear a Restricted Securities Legend and, if
such new Security is so required to be issued in the form of a Regulation S
Security, it shall bear a Regulation S Legend;

     (iii)     any Securities which are sold or otherwise disposed of pursuant
to an effective registration statement under the Securities Act (including the
Shelf Registration Statement), together with their Successor Securities shall
not bear a Securities Act Legend; the Company shall inform the Trustee in
writing of the effective date of any such registration statement registering the
Securities under the Securities Act and shall notify the Trustee at any time
when prospectuses may not be delivered with respect to Securities to be sold
pursuant to such registration statement; and the Trustee shall not be liable for
any action taken or omitted to be taken by it in good faith pursuant to
instructions from the Company contemplated by the aforementioned registration
statement;

     (iv) at any time after the Securities may be freely transferred without
registration under the Securities Act or without being subject to transfer
restrictions pursuant to the Securities Act, a new Security which does not bear
a Securities Act Legend may be issued in exchange for or in lieu of a Security
(other than a Global Security) or any portion thereof which bears such a legend
if the Trustee has received an Unrestricted Securities Certificate, satisfactory
to the Trustee and duly executed by the Holder of such legended Security or his
attorney duly authorized in writing, and after such date and receipt of such
certificate, the Trustee shall authenticate and deliver such a new Security in
exchange for or in lieu of such other Security as provided in this Article
Three;

     (v) a new Security which does not bear a Securities Act Legend may be
issued in exchange for or in lieu of a Security (other than a Global Security)
or any portion thereof which bears such a legend if, in the Company's judgment,
placing such a legend upon such new Security is not necessary to ensure
compliance with the registration requirements of the Securities Act, and the
Trustee, at the direction of the Company, shall authenticate and deliver such a
new Security as provided in this Article Three; and

     (vi) notwithstanding the foregoing provisions of this Section 305(c), a
Successor Security of a Security that does not bear a particular form of
Securities Act Legend shall not bear such form of legend unless the Company has
reasonable cause to believe that such Successor Security is a "restricted
security" within the meaning of Rule 144, in which case the Trustee, at the
direction of the Company, shall authenticate and deliver a new Security bearing
a Restricted Securities Legend in exchange for such Successor Security as
provided in this Article Three.

                                      -38-
<PAGE>
 
          (d) Neither the Trustee, the Paying Agent nor any of their agents
shall (1) have any duty to monitor compliance with or with respect to any
federal or state or other securities or tax laws or (2) have any duty to obtain
documentation on any transfers or exchanges other than as specifically required
hereunder.

 Section 306.  Mutilated, Destroyed, Lost and Stolen Securities.

          If any mutilated Security is surrendered to the Trustee, the Company
shall execute and the Trustee shall authenticate and deliver in exchange
therefor a new Security of like tenor and principal amount and bearing a number
not contemporaneously outstanding.

          If there shall be delivered to the Company and the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any Security
and (ii) such security or indemnity as may be required by them to save each of
them and any agent of either of them harmless, then, in the absence of actual
notice to the Company or the Trustee that such Security has been acquired by a
bona fide purchaser, the Company shall execute and upon a Company Request the
Trustee shall authenticate and deliver, in lieu of any such destroyed, lost or
stolen Security, a new Security of like tenor and principal amount and bearing a
number not contemporaneously outstanding.

          In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in its discretion, but
subject to any conversion rights, may, instead of issuing a new Security, pay
such Security.

          Upon the issuance of any new Security under this Section, the Company
may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
reasonable expenses (including the expenses of the Trustee) connected therewith.

          Every new Security issued pursuant to this Section in lieu of any
mutilated, destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the mutilated,
destroyed, lost or stolen Security shall be at any time enforceable by anyone,
and shall be entitled to all the benefits of this Indenture equally and
proportionately with any and all other Securities duly issued hereunder.

          The provisions of this Section are exclusive and shall preclude (to
the extent lawful) all other rights and remedies with respect to the replacement
or payment of mutilated, destroyed, lost or stolen Securities.

 Section 307.  Payment of Interest; Interest Rights Preserved.

          Interest on any Security which is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the Person in
whose name that Security (or one or

                                      -39-
<PAGE>
 
more Predecessor Securities) is registered at the close of business on the
Regular Record Date for such interest.

          Any interest on any Security which is payable, but is not punctually
paid or duly provided for, on any Interest Payment Date (herein called
"Defaulted Interest") shall forthwith cease to be payable to the Holder on the
relevant Regular Record Date by virtue of having been such Holder, and such
Defaulted Interest may be paid by the Company, at its election in each case, as
provided in clause (a) or (b) below:

     (a) The Company may elect to make payment of any Defaulted Interest to the
Persons in whose names the Securities (or their respective Predecessor
Securities) are registered at the close of business on a Special Record Date for
the payment of such Defaulted Interest, which shall be fixed in the following
manner.  The Company shall notify the Trustee in writing of the amount of
Defaulted Interest proposed to be paid on each Security and the date of the
proposed payment, and at the same time the Company shall deposit with the
Trustee an amount of money equal to the aggregate amount proposed to be paid in
respect of such Defaulted Interest or shall make arrangements satisfactory to
the Trustee for such deposit prior to the date of the proposed payment, such
money when deposited to be held in trust for the benefit of the Persons entitled
to such Defaulted Interest as in this clause provided.  Thereupon the Trustee
shall fix a Special Record Date for the payment of such Defaulted Interest which
shall be not more than 15 days and not less than 10 days prior to the date of
the proposed payment and not less than 10 days after the receipt by the Trustee
of the notice of the proposed payment.  The Trustee shall promptly notify the
Company of such Special Record Date and, in the name and at the expense of the
Company, shall cause notice of the proposed payment of such Defaulted Interest
and the Special Record Date therefor to be mailed, first-class postage prepaid,
to each Holder at his address as it appears in the Security Register, not less
than 10 days prior to such Special Record Date. Notice of the proposed payment
of such Defaulted Interest and the Special Record Date therefor having been so
mailed, such Defaulted Interest shall be paid to the Persons in whose names the
Securities (or their respective Predecessor Securities) are registered at the
close of business on such Special Record Date and shall no longer be payable
pursuant to the following clause (b).

     (b) The Company may make payment of any Defaulted Interest in any other
lawful manner not inconsistent with the requirements of any securities exchange
on which the Securities may be listed, and upon such notice as may be required
by such exchange, if, after notice given by the Company to the Trustee of the
proposed payment pursuant to this clause, such manner of payment shall be deemed
practicable by the Trustee.

          Subject to the foregoing provisions of this Section, each Security
delivered under this Indenture upon registration of transfer of or in exchange
for or in lieu of any other Security shall carry the rights to interest accrued
and unpaid, and to accrue, which were carried by such other Security.

                                      -40-
<PAGE>
 
          In the case of any Security which is converted after any Regular
Record Date and on or prior to the next succeeding Interest Payment Date (other
than any Security whose Maturity is prior to such Interest Payment Date),
interest whose Stated Maturity is on such Interest Payment Date shall be payable
on such Interest Payment Date notwithstanding such conversion, and such interest
(whether or not punctually paid or duly provided for) shall be paid to the
Person in whose name that Security (or one or more Predecessor Securities) is
registered at the close of business on such Regular Record Date.  Upon a call
for redemption by the Company, accrued and unpaid interest to the Redemption
Date shall be payable with respect to Securities converted after the notice of
redemption has been mailed and prior to the Redemption Date.  Except as
otherwise expressly provided in this paragraph, in the case of any Security
which is converted, interest whose Stated Maturity is after the date of
conversion of such Security shall not be payable.

 Section 308.  Persons Deemed Owners.

          Prior to due presentment of a Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name such Security is registered as the owner of such
Security for the purpose of receiving payment of and principal of (and premium,
if any) and (subject to Section 307) interest on such Security and for all other
purposes whatsoever, whether or not such Security be overdue, and neither the
Company, the Trustee nor any agent of the Company or the Trustee shall be
affected by notice to the contrary.

 Section 309.  Cancellation.

          All Securities surrendered for payment, redemption, repurchase,
registration of transfer or exchange or conversion shall, if surrendered to any
Person other than the Trustee, be delivered to the Trustee and shall be promptly
cancelled by it.  The Company may at any time deliver to the Trustee for
cancellation any Securities previously authenticated and delivered hereunder
which the Company may have acquired in any manner whatsoever, and all Securities
so delivered shall be promptly cancelled by the Trustee.  No Securities shall be
authenticated in lieu of or in exchange for any Securities cancelled as provided
in this Section, except as expressly permitted by this Indenture.  All cancelled
Securities held by the Trustee shall be disposed of as directed by a Company
Order or in accordance with the Trustee's usual practice; provided, however,
that the Trustee shall not be required to destroy cancelled Securities.

 Section 310.  Computation of Interest.

          Interest on the Securities (including any Liquidated Damages and
additional interest) shall be computed on the basis of a 360-day year consisting
of twelve 30-day months.

 Section 311.  CUSIP Numbers.

          The Company in issuing Securities may use "CUSIP" numbers (if then
generally in use) in addition to serial numbers, and, if so, the Trustee shall
use such CUSIP numbers in addition

                                      -41-
<PAGE>
 
to serial numbers in notices of redemption and repurchase as a convenience to
Holders; provided, however, that any such notice may state that no
representation is made as to the correctness of such CUSIP numbers either as
printed on the Securities or as contained in any notice of a redemption or
repurchase and that reliance may be placed only on the serial or other
identification numbers printed on the Securities, and any such redemption or
repurchase shall not be affected by any defect in or omission of such CUSIP
numbers.

                                  ARTICLE FOUR

                           SATISFACTION AND DISCHARGE

 Section 401.  Satisfaction and Discharge of Indenture.

          This Indenture shall cease to be of further effect (except as to any
surviving rights of conversion, registration of transfer, exchange or
replacement of Securities herein expressly provided for and any right to receive
Liquidated Damages as provided in the form of Securities herein), and the
Trustee, on demand of and at the expense of the Company, shall execute proper
instruments acknowledging satisfaction and discharge of this Indenture, when

     (1)  either

     (A) all Securities theretofore authenticated and delivered (other than (i)
Securities which have been destroyed, lost or stolen and which have been
replaced or paid as provided in Section 306 and (ii) Securities for whose
payment money has theretofore been deposited in trust or segregated and held in
trust by the Company and thereafter repaid to the Company or discharged from
such trust, as provided in Section 1003) have been delivered to the Trustee for
cancellation; or

     (B) all such Securities not theretofore delivered to the Trustee for
cancellation

        (i)  have become due and payable, or

        (ii) will become due and payable at their Stated Maturity within one
year, or

        (iii)     are to be called for redemption within one year under
arrangements satisfactory to the Trustee for the giving of notice of redemption
by the Trustee in the name, and at the expense, of the Company,

and the Company, in the case of (i), (ii) or (iii) above, has irrevocably
deposited or caused to be irrevocably deposited with the Trustee as trust funds
in trust for the purpose an amount sufficient to pay and discharge the entire
indebtedness on such

                                      -42-
<PAGE>
 
     Securities not theretofore delivered to the Trustee for cancellation, for
     principal (and premium, if any) and interest (including any Liquidated
     Damages) to the date of such deposit (in the case of Securities which have
     become due and payable) or to the Stated Maturity or Redemption Date, as
     the case may be, together with instructions from the Company irrevocably
     directing the Trustee to apply such funds to the payment thereof at
     Maturity;

     (2) the Company has paid or caused to be paid all other sums payable
hereunder by the Company; and

     (3) the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel, each stating that all conditions precedent herein
provided for relating to the satisfaction and discharge of this Indenture have
been complied with.

Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 607, the obligations of
the Trustee to any Authenticating Agent under Section 614 and, if money shall
have been deposited with the Trustee pursuant to subclause (B) of clause (1) of
this Section, the obligations of the Trustee under Section 402 and the last
paragraph of Section 1003 shall survive.

 Section 402.  Application of Trust Money.

          Subject to the provisions of the last paragraph of Section 1003, all
money deposited with the Trustee pursuant to Section 401 shall be held in trust
and applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if
any) and interest for whose payment such money has been deposited with the
Trustee.  All money deposited with the Trustee pursuant to Section 401 (and held
by it or any Paying Agent) for the payment of Securities subsequently converted
shall be returned to the Company upon Company Request.

 Section 403.  Reinstatement.

          If the Trustee or Paying Agent is unable to apply any money deposited
with respect to the Securities in accordance with Section 401 by reason of any
legal proceeding or by reason of any order or judgment of any court or
governmental authority enjoining, restraining or otherwise prohibiting such
application, the Company's obligations under this Indenture and the Securities
shall be revived and reinstated as though no deposit had occurred pursuant to
Section 401 until such time as the Trustee or Paying Agent is permitted to apply
all such money in accordance with Section 401; provided, however, that if the
Company has made any payment of principal of (or premium, if any) or interest on
any Securities because of the reinstatement of its obligations, the Company
shall be subrogated to the rights of the Holders of such Securities to receive
such payment from the money held by the Trustee or Paying Agent.

                                      -43-
<PAGE>
 
                                  ARTICLE FIVE

                                    REMEDIES

 Section 501.  Events of Default.

          "Event of Default", wherever used herein, means any one of the
following events (whatever the reason for such Event of Default and whether it
shall be occasioned by the provisions of Article Fourteen or be voluntary or
involuntary or be effected by operation of law or pursuant to any judgment,
decree or order of any court or any order, rule or regulation of any
administrative or governmental body):

     (1) default in the payment of any interest (including any Liquidated
Damages) upon any Security when it becomes due and payable, whether or not such
payment is prohibited by the provisions of Article Fourteen, and continuance of
such default for a period of 30 days; or

     (2) default in the payment of the principal of (or premium, if any, on) any
Security at its Maturity, whether or not such payment is prohibited by the
provisions of Article Fourteen; or

     (3) default in the performance, or breach, of the provisions of Article
Eight or failure by the Company (A) to give the Company Notice in accordance
with Section 1202 or (B) to effect a mandatory redemption of the Securities if
and when so required in Section 1109; or

     (4) default in the performance, or breach, of any covenant or warranty of
the Company in this Indenture (other than a covenant or warranty, a default in
whose performance or whose breach is elsewhere in this Section specifically
dealt with), and continuance of such default or breach for a period of 60 days
after there has been given, by registered or certified mail, to the Company by
the Trustee or to the Company and the Trustee by the Holders of at least 25% in
aggregate principal amount of the Outstanding Securities a written notice
specifying such default or breach and requiring it to be remedied and stating
that such notice is a "Notice of Default" hereunder; or

     (5) default under any bond, debenture, note or other evidence of
indebtedness for money borrowed or under any mortgage, indenture or other
instrument under which there may be issued or by which there may be secured or
evidenced any indebtedness for money borrowed by the Company or under any
guarantee of payment by the Company of indebtedness for money borrowed, whether
such indebtedness or guarantee now exists or shall hereafter be created, which
default extends beyond any period of grace provided with respect thereto and
which default relates to (a) the obligation to pay the principal of or interest
on any such indebtedness or guarantee or (b) an obligation other than the
obligation

                                      -44-
<PAGE>
 
to pay the principal of or interest on any such indebtedness, if the effect of
such event of default is to cause the acceleration of a principal amount of such
indebtedness and such other indebtedness or guarantee shall not have been paid
within ten days after there has been given to the Company by the Trustee or to
the Company and the Trustee by the Holders of at least 25% in aggregate
principal amount of the Outstanding Securities a written notice specifying such
event of default and stating that such notice is a "Notice of Default"
hereunder; provided, however, that no default under this Section 501(5) shall
exist if all such defaults do not relate to such indebtedness or such guarantees
with an aggregate principal amount in excess of 5% of Consolidated Net Tangible
Assets; and provided further, that if any such event of default has been cured
or waived and any acceleration with respect thereto rescinded, or if such other
indebtedness has been repaid or otherwise discharged, the Event of Default
arising under this Section 501(5) by virtue thereof shall not be deemed to have
occurred and any acceleration under this Section 501(5) pursuant to Section 502
hereof shall ipso facto be rescinded so long as such rescission does not
conflict with any judgment or decree; or

     (6) the entry by a court having jurisdiction in the premises of (a) a
decree or order for relief in respect of the Company in an involuntary case or
proceeding under any applicable federal or state bankruptcy, insolvency,
reorganization or other similar law or (b) a decree or order adjudging the
Company a bankrupt or insolvent, or approving as properly filed a petition
seeking reorganization, arrangement, adjustment or composition of or in respect
of the Company under any applicable federal or state law, or appointing a
custodian, receiver, liquidator, assignee, trustee, sequestrator or other
similar official of the Company or of any substantial part of its property, or
ordering the winding up or liquidation of its affairs, and the continuance of
any such decree or order for relief or any such other decree or order unstayed
and in effect for a period of 60 consecutive days; or

     (7) the commencement by the Company of a voluntary case or proceeding under
any applicable federal or state bankruptcy, insolvency, reorganization or other
similar law or of any other case or proceeding to be adjudicated a bankrupt or
insolvent, or the consent by it to the entry of a decree or order for relief in
respect of the Company in an involuntary case or proceeding under any applicable
federal or state bankruptcy, insolvency, reorganization or other similar law or
to the commencement of any bankruptcy or insolvency case or proceeding against
it, or the filing by it of a petition or answer or consent seeking
reorganization or relief under any applicable federal or state law, or the
consent by it to the filing of such petition or to the appointment of or taking
possession by a custodian, receiver, liquidator, assignee, trustee, sequestrator
or similar official of the Company or of any substantial part of its property,
or the making by it of an assignment for the benefit of creditors, or the
admission by it in writing of its inability to pay its debts generally as they
become due, or the taking of corporate action by the Company in furtherance of
any such action.

                                      -45-
<PAGE>
 
 Section 502.  Acceleration of Maturity; Rescission and Annulment.

          If an Event of Default occurs and is continuing, then and in every
such case the Trustee or the Holders of not less than 25% in aggregate principal
amount of the Outstanding Securities may declare the principal of all the
Securities and the interest accrued thereon to be due and payable immediately,
by a notice in writing to the Company (and to the Trustee if given by Holders)
and upon any such declaration such principal and interest shall become
immediately due and payable.

          At any time after such a declaration of acceleration has been made and
before a judgment or decree for payment of the money due has been obtained by
the Trustee as hereinafter in this Article provided, the Holders of a majority
in aggregate principal amount of the Outstanding Securities, by written notice
to the Company and the Trustee, may rescind and annul such declaration and its
consequences if

     (1) the Company has paid or deposited with the Trustee a sum sufficient to
pay

         (A) all overdue interest on all Securities,

         (B) the principal of (and premium, if any, on) any Securities which
    have become due otherwise than by such declaration of acceleration and
    interest thereon at the rate borne by the Securities,

         (C) to the extent that payment of such interest is lawful, interest
    upon overdue interest at the rate borne by the Securities (without
    duplication of any amount paid or deposited pursuant to clause (A) or (B)
    above, and

         (D) all sums paid or advanced or liabilities incurred by the Trustee
    hereunder and the reasonable compensation, expenses, disbursements and
    advances of the Trustee, its agents and counsel;

    and

    (2)  all Events of Default, other than the nonpayment of the principal of
Securities which have become due solely by such declaration of acceleration,
have been cured or waived as provided in Section 513.

No such rescission shall affect any subsequent default or impair any right
consequent thereon.

                                      -46-
<PAGE>
 
 Section 503.  Collection of Indebtedness and Suits for Enforcement by Trustee.

          The Company covenants that if

     (1) default is made in the payment of any interest (including any
Liquidated Damages) on any Security when such interest becomes due and payable
and such default continues for a period of 30 days, or

     (2) default is made in the payment of the principal of (or premium, if any,
on) any Security at the Maturity thereof,

the Company will, upon demand of the Trustee, pay to it, for the benefit of the
Holders of such Securities, the whole amount then due and payable on such
Securities for principal (and premium, if any) and interest, and, to the extent
that payment of such interest shall be legally enforceable, interest (including
any Liquidated Damages), on any overdue principal (and premium, if any) and on
any overdue interest (including any Liquidated Damages), at the rate borne by
the Securities, and, in addition thereto, such further amount as shall be
sufficient to cover the costs and expenses of collection, including the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel.

          If the Company fails to pay such amounts forthwith upon such demand,
the Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree and may enforce the same
against the Company or any other obligor upon the Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon the Securities, wherever
situated.

          If an Event of Default occurs and is continuing, the Trustee may in
its discretion proceed to protect and enforce its rights and the rights of the
Holders by such appropriate judicial proceedings as the Trustee, being advised
by counsel, shall deem most effectual to protect and enforce any such rights,
whether for the specific enforcement of any covenant or agreement in this
Indenture or in aid of the exercise of any power granted herein, or to enforce
any other proper remedy.

 Section 504.  Trustee May File Proofs of Claim.

          In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors, the Trustee (irrespective of whether the principal of the Securities
shall then be due and payable as therein expressed or by declaration or
otherwise and irrespective of whether the Trustee shall have made any demand on
the Company for the payment of overdue

                                      -47-
<PAGE>
 
principal or interest) shall be entitled and empowered, by intervention in such
proceeding or otherwise,

     (i) to file and prove a claim for the whole amount of principal (and
premium, if any) and interest owing and unpaid in respect of the Securities,
subject to the provisions of Article Fourteen, and to file such other papers or
documents as may be necessary or advisable in order to have the claims of the
Trustee (including any claim for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel) and of the
Holders allowed in such judicial proceeding, subject to the provisions of
Article Fourteen, and

     (ii) subject to the provisions of Article Fourteen, to collect and receive
any money or other property payable or deliverable on any such claims and to
distribute the same;

and any custodian, receiver, assignee, trustee, liquidator, sequestrator or
other similar official in any such judicial proceeding is hereby authorized by
each Holder to make such payments to the Trustee and, in the event that the
Trustee shall consent to the making of such payments directly to the Holders, to
pay to the Trustee any amount due it for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, and any other
amounts due the Trustee under Section 607.

          Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceeding.

 Section 505.  Trustee May Enforce Claims Without Possession of Securities.

          All rights of action and claims under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without the possession of any of
the Securities or the production thereof in any proceeding relating thereto, and
any such proceeding instituted by the Trustee shall be brought in its own name
as trustee of an express trust, and any recovery of judgment shall, after
provision for the payment of the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, be for the
ratable benefit of the Holders of the Securities in respect of which such
judgment has been recovered.  In any such proceeding brought by the Trustee, the
Trustee shall be deemed to represent all Holders without the necessity of
joining any Holders as parties.

 Section 506.  Application of Money Collected.

          Subject to Article Fourteen, any money collected by the Trustee
pursuant to this Article shall be applied in the following order, at the date or
dates fixed by the Trustee and, in the case of the distribution of such money on
account of principal (or premium, if any) or interest, upon

                                      -48-
<PAGE>
 
presentation of the Securities and the notation thereon of the payment if only
partially paid and upon surrender thereof if fully paid:

     FIRST:  To the payment of all costs and expenses in connection with the
collection of such money and to the payment of all amounts due the Trustee under
Section 607;

     SECOND:  To the payment of the amounts then due and unpaid for principal of
(and premium, if any) and interest on the Securities in respect of which or for
the benefit of which such money has been collected, ratably, without preference
or priority of any kind, according to the amounts due and payable on such
Securities for principal (and premium, if any) and interest, respectively; and

     THIRD:  Any remaining amounts shall be repaid to the Company.

 Section 507.  Limitation on Suits.

          No Holder of any Security shall have any right to institute any
proceeding, judicial or otherwise, with respect to this Indenture or for the
appointment of a receiver or trustee or for any other remedy hereunder, unless

     (1) such Holder has previously given written notice to the Trustee of a
continuing Event of Default;

     (2) the Holders of not less than 25% in aggregate principal amount of the
Outstanding Securities shall have made written request to the Trustee to
institute proceedings in respect of such Event of Default in its own name as
Trustee hereunder;

     (3) such Holder or Holders offer and, if requested, provide to the Trustee
indemnity satisfactory to the Trustee against the costs, expenses and
liabilities to be incurred in compliance with such request;

     (4) the Trustee for 60 days after its receipt of such notice, request and
offer and, if requested, provision of indemnity has failed to institute any such
proceeding; and

     (5) no direction inconsistent with such written request has been given to
the Trustee during such 60-day period by the Holders of a majority in aggregate
principal amount of the Outstanding Securities;

it being understood and intended that no one or more Holders shall have any
right in any manner whatever by virtue of, or by availing of, any provision of
this Indenture to affect, disturb or prejudice the rights of any other Holders,
or to obtain or to seek to obtain priority or preference over any other Holders
or to enforce any right under this Indenture, except in the manner herein
provided and for the equal and ratable benefit of all the Holders.

                                      -49-
<PAGE>
 
  Section 508. Unconditional Right of Holders to Receive Principal, Premium and
Interest and to Convert.

          Notwithstanding any other provision in this Indenture, the Holder of
any Security shall have the right, which is absolute and unconditional, subject
to the subordination provisions in Article Fourteen, to receive payment of the
principal of (and premium, if any) and (subject to Section 307) interest on such
Security on the respective Stated Maturities expressed in such Security (or, in
the case of redemption or repurchase, on the Redemption Date or Repurchase Date,
as the case may be) and to institute suit for the enforcement of any such
payment and the right to convert, and such rights shall not be impaired without
the consent of such Holder.

 Section 509.  Restoration of Rights and Remedies.

          If the Trustee or any Holder has instituted any proceeding to enforce
any right or remedy under this Indenture and such proceeding has been
discontinued or abandoned for any reason, or has been determined adversely to
the Trustee or to such Holder, then and in every such case, subject to any
determination in such proceeding, the Company, the Trustee and the Holders shall
be restored severally and respectively to their former positions hereunder and
thereafter all rights and remedies of the Trustee and the Holders shall continue
as though no such proceeding had been instituted.

 Section 510.  Rights and Remedies Cumulative.

          Except as otherwise provided with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities in the last paragraph
of Section 306, no right or remedy herein conferred upon or reserved to the
Trustee or to the Holders is intended to be exclusive of any other right or
remedy, and every right and remedy shall, to the extent permitted by law, be
cumulative and in addition to every other right and remedy given hereunder or
now or hereafter existing at law or in equity or otherwise.  The assertion or
employment of any right or remedy hereunder, or otherwise, shall not prevent the
concurrent assertion or employment of any other appropriate right or remedy.

 Section 511.  Delay or Omission Not Waiver.

          No delay or omission of the Trustee or of any Holder of any Security
to exercise any right or remedy accruing upon any Event of Default shall impair
any such right or remedy or constitute a waiver of any such Event of Default or
an acquiescence therein.  Every right and remedy given by this Article or by law
to the Trustee or to the Holders may be exercised from time to time, and as
often as may be deemed expedient, by the Trustee or by the Holders, as the case
may be.

                                      -50-
<PAGE>
 
 Section 512.  Control by Holders.

          The Holders of not less than a majority in aggregate principal amount
of the Outstanding Securities shall have the right to direct in writing the
time, method and place of conducting any proceeding for any remedy available to
the Trustee or exercising any trust or power conferred on the Trustee, provided
that

     (1) such direction shall not be in conflict with any rule of law or with
this Indenture,

     (2) the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction, and

     (3) subject to the provisions of Section 601, the Trustee shall have the
right to decline to follow any such direction if the Trustee in good faith shall
determine that the action so directed would involve the Trustee in personal
liability or would be unduly prejudicial to Holders not joining in such
direction.

          This Section 512 shall be in lieu of Section 316(a)(1)(A) of the Trust
Indenture Act and said Section 316(a)(1)(A) is hereby expressly excluded from
this Indenture, as permitted by the Trust Indenture Act.

 Section 513.  Waiver of Past Defaults.

          The Holders of not less than a majority in aggregate principal amount
of the Outstanding Securities may on behalf of the Holders of all the Securities
waive any past default hereunder and its consequences, except a default

     (1) in the payment of the principal of (or premium, if any) or interest on
any Security, or

     (2) in respect of a covenant or provision hereof which under Article Nine
cannot be modified or amended without the consent of the Holder of each
Outstanding Security affected.

          Upon any such waiver, such default shall cease to exist, and any Event
of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon. This Section 513 shall be
in lieu of Section 316(a)(1)(B) of the Trust Indenture Act and said Section
316(a)(1)(B) is hereby expressly excluded from this Indenture, as permitted by
the Trust Indenture Act.

                                      -51-
<PAGE>
 
 Section 514.  Undertaking for Costs.

          All parties to this Indenture agree, and each Holder of any Security
by his acceptance thereof shall be deemed to have agreed, that any court may in
its discretion require, in any suit for the enforcement of any right or remedy
under this Indenture, or in any suit against the Trustee for any action taken,
suffered or omitted by it as Trustee, the filing by any party litigant in such
suit of an undertaking to pay the costs of such suit, and that such court may in
its discretion assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in such suit, having due regard to the merits and
good faith of the claims or defenses made by such party litigant; but the
provisions of this Section shall not apply to any suit instituted by the
Company, to any suit instituted by the Trustee, to any suit instituted by any
Holder, or group of Holders, holding more than 10% in aggregate principal amount
of the Outstanding Securities, or to any suit instituted by any Holder for the
enforcement of the payment of the principal of (or premium, if any) or interest
on any Security on or after the respective Stated Maturities expressed in such
Security (or, in the case of redemption or repurchase, on or after the
Redemption Date or Repurchase Date, as the case may be) or for the enforcement
of the right to convert any Security in accordance with Article Thirteen.  This
Section 514 shall be in lieu of Section 315(e) of the Trust Indenture Act and
said Section 315(e) is hereby expressly excluded from this Indenture, as
permitted by the Trust Indenture Act.

 Section 515.  Waiver of Stay or Extension Laws.

          The Company covenants (to the extent that it may lawfully do so) that
it will not at any time insist upon, or plead, or in any manner whatsoever claim
or take the benefit or advantage of, any stay or extension law wherever enacted,
now or at any time hereafter in force, which may affect the covenants or the
performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such law
and covenants that it will not hinder, delay or impede the execution of any
power herein granted to the Trustee, but will suffer and permit the execution of
every such power as though no such law had been enacted.


                                  ARTICLE SIX

                                  THE TRUSTEE

 Section 601.  Certain Duties and Responsibilities.

          The duties and responsibilities of the Trustee shall be as provided by
the Trust Indenture Act.  Notwithstanding the foregoing, no provision of this
Indenture shall require the Trustee to expend or risk its own funds or otherwise
incur any financial liability in the performance of any of its duties hereunder,
or in the exercise of any of its rights or powers, if it shall have reasonable
grounds for believing that repayment of such funds or adequate indemnity against
such risk or liability is not reasonably assured to it.  Whether or not therein
expressly so provided, every

                                      -52-
<PAGE>
 
provision of this Indenture relating to the conduct or affecting the liability
of or affording protection to the Trustee shall be subject to the provisions of
this Section.

 Section 602.  Notice of Defaults.

          The Trustee shall give the Holders notice of any default hereunder as
and to the extent provided by the Trust Indenture Act; provided, however, that
in the case of any default of the character specified in Section 501(4), no such
notice to Holders shall be given until at least 30 days after the occurrence
thereof.  For the purpose of this Section, the term "default" means any event
which is, or after notice or lapse of time or both would become, an Event of
Default.

 Section 603.  Certain Rights of Trustee.

          Subject to the provisions of Section 601:

     (a) the Trustee may rely and shall be protected in acting or refraining
from acting upon any resolution, certificate, statement, instrument, opinion,
report, notice, request, direction, consent, order, bond, debenture, note, other
evidence of indebtedness or other paper or document believed by it to be genuine
and to have been signed or presented by the proper party or parties;

     (b) any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or Company Order and any resolution
of the Board of Directors may be sufficiently evidenced by a Board Resolution;

     (c) whenever in the administration of this Indenture the Trustee shall deem
it desirable that a matter be proved or established prior to taking, suffering
or omitting any action hereunder, the Trustee (unless other evidence be herein
specifically prescribed) may, in the absence of bad faith on its part, rely upon
an Officers' Certificate;

     (d) the Trustee may consult with counsel and the written advice of such
counsel or any Opinion of Counsel shall be full and complete authorization and
protection in respect of any action taken, suffered or omitted by it hereunder
in good faith and in reliance thereon;

     (e) the Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request, order or direction of
any of the Holders pursuant to this Indenture, unless such Holders shall have
offered to the Trustee security or indemnity satisfactory to the Trustee against
the costs, expenses and liabilities which might be incurred by it in compliance
with such request or direction;

     (f) the Trustee shall not be bound to make any investigation into the facts
or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture,
note, other evidence of indebtedness or

                                      -53-
<PAGE>
 
other paper or document, but the Trustee, in its discretion, may make such
further inquiry or investigation into such facts or matters as it may see fit,
and, if the Trustee shall determine to make such further inquiry or
investigation, it shall be entitled to examine the books, records and premises
of the Company personally or by agent or attorney; and

     (g) the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys, and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder.

 Section 604.  Not Responsible for Recitals or Issuance of Securities.

          The recitals contained herein and in the Securities, except the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and the Trustee assumes no responsibility for their correctness.
The Trustee makes no representations as to the validity or sufficiency of this
Indenture, or of any supplemental indenture or of the Securities.  The Trustee
shall not be accountable for the use or application by the Company of Securities
or the proceeds thereof.

 Section 605.  May Hold Securities.

          The Trustee, any Authenticating Agent, any Paying Agent, any Security
Registrar or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to Sections
608 and 613, may otherwise deal with the Company with the same rights it would
have if it were not Trustee, Authenticating Agent, Paying Agent, Security
Registrar or such other agent.

 Section 606.  Money Held in Trust.

          Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law.  The Trustee shall be
under no liability for interest on any money received by it hereunder except as
otherwise agreed with the Company.

 Section 607.  Compensation and Reimbursement.

          The Company agrees

     (1) to pay to the Trustee from time to time reasonable compensation for all
services rendered by it hereunder (which compensation shall not be limited by
any provision of law in regard to the compensation of a trustee of an express
trust);

     (2) except as otherwise expressly provided herein, to reimburse the Trustee
upon its request for all reasonable expenses, disbursements and advances
incurred or made by the Trustee in accordance with any provision of this
Indenture (including the reasonable

                                      -54-
<PAGE>
 
compensation and the expenses and disbursements of its agents and counsel),
except any such expense, disbursement or advance as may be attributable to its
negligence or bad faith; and

     (3) to indemnify the Trustee, its agents, employees, officers, directors
and shareholders for, and to hold each of them harmless against, any loss,
liability or expense incurred without negligence or bad faith on its part,
arising out of or in connection with the acceptance or administration of this
trust, including the costs and expenses of defending itself against any claim or
liability in connection with the exercise or performance of any of its powers or
duties hereunder.

          As security for the performance of the obligations of the Company
under this Section the Trustee shall have a lien prior to the Securities upon
all property and funds held or collected by the Trustee as such, except funds
held in trust for the payment of principal of, premium, if any, or interest on
particular Securities.

          When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 501(6) or (7) occurs, the expenses (including the
reasonable charges and expenses of its agents, attorneys and counsel) and the
compensation for services shall be preferred over the status of the Holders in
any reorganization or similar proceeding and are intended to constitute expenses
of administration under any reorganization, bankruptcy or similar law.

 Section 608.  Disqualification; Conflicting Interests.

          If the Trustee has or shall acquire a conflicting interest within the
meaning of the Trust Indenture Act, the Trustee shall either eliminate such
interest or resign, to the extent and in the manner provided by, and subject to
the provisions of, the Trust Indenture Act and this Indenture.

 Section 609.  Institutional Trustee Required; Eligibility.

          There shall at all times be a Trustee hereunder which shall be an
institution that is eligible pursuant to the Trust Indenture Act to act as such
and shall have a combined capital and surplus of at least $50,000,000.  If such
institution publishes reports of condition at least annually, pursuant to law or
to the requirements of federal or state supervising or examining authority, then
for the purposes of this Section, the combined capital and surplus of such
institution shall be deemed to be its combined capital and surplus as set forth
in its most recent report of condition so published. If at any time the Trustee
shall cease to be eligible in accordance with the provisions of this Section, it
shall resign immediately in the manner and with the effect hereinafter specified
in this Article.  No obligor upon any Securities issued under this Indenture or
Person directly or indirectly controlling, controlled by or under common control
with such obligor shall serve as Trustee under this Indenture.

                                      -55-
<PAGE>
 
 Section 610.  Resignation and Removal; Appointment of Successor.

          (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 611.

          (b) The Trustee may resign at any time by giving written notice
thereof to the Company.  If an instrument of acceptance by a successor Trustee
shall not have been delivered to the Trustee within 30 days after the giving of
such notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee.

          (c) The Trustee may be removed at any time by Act of the Holders of a
majority in aggregate principal amount of the Outstanding Securities specifying
such removal, delivered to the Trustee and to the Company.

          (d)  If at any time:

     (1) the Trustee shall fail to comply with Section 608 after written request
therefor by the Company or by any Holder who has been a bona fide Holder of a
Security for at least six months, or

     (2) the Trustee shall cease to be eligible under Section 609 and shall fail
to resign after written request therefor by the Company or by any such bona fide
Holder described in (d)(1) above, or

     (3) the Trustee shall become incapable of acting or shall be adjudged a
bankrupt or insolvent or a receiver of the Trustee or of its property shall be
appointed or any public officer shall take charge or control of the Trustee or
of its property or affairs for the purpose of rehabilitation, conservation or
liquidation,

then, in any such case, (i) the Company by a Board Resolution may remove the
Trustee, or (ii) subject to Section 514, any Holder who has been a bona fide
Holder of a Security for at least six months may, on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
removal of the Trustee and the appointment of a successor Trustee.

          (e) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, the
Company, by a Board Resolution, shall promptly appoint a successor Trustee.  If,
within one year after such resignation, removal or incapability, or the
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority in aggregate principal amount of the Outstanding
Securities delivered to the Company and the retiring Trustee, the successor
Trustee so appointed shall, forthwith upon its acceptance of such appointment,
become the successor Trustee and supersede the successor Trustee appointed by
the Company.  If no successor Trustee shall have been so appointed by the
Company or the Holders and accepted appointment in the manner hereinafter
provided, any Holder who has

                                      -56-
<PAGE>
 
been a bona fide Holder of a Security for at least six months may, on behalf of
himself and all others similarly situated, petition any court of competent
jurisdiction for the appointment of a successor Trustee.

          (f) The Company shall give notice of each resignation and each removal
of the Trustee and each appointment of a successor Trustee by mailing written
notice of such event by first-class mail, postage prepaid, to all Holders as
their names and addresses appear in the Security Register.  Each notice shall
include the name of the successor Trustee and the address of its Corporate Trust
Office.

 Section 611.  Acceptance of Appointment by Successor.

          Every successor Trustee appointed hereunder shall execute, acknowledge
and deliver to the Company and to the retiring Trustee an instrument accepting
such appointment, and thereupon the resignation or removal of the retiring
Trustee shall become effective and such successor Trustee, without any further
act, deed or conveyance, shall become vested with all the rights, powers, trusts
and duties of the retiring Trustee; but, on request of the Company or the
successor Trustee, such retiring Trustee shall, upon payment of its charges,
execute and deliver an instrument transferring to such successor Trustee all the
rights, powers and trusts of the retiring Trustee and shall duly assign,
transfer and deliver to such successor Trustee all money and other property held
by such retiring Trustee hereunder.  Upon request of any such successor Trustee,
the Company shall execute any and all instruments for more fully and certainly
vesting in and confirming to such successor Trustee all such rights, powers and
trusts.

          No successor Trustee shall accept its appointment unless at the time
of such acceptance such successor Trustee shall be qualified and eligible under
this Article.

 Section 612.  Merger, Conversion, Consolidation or Succession to Business.

          Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all the corporate trust business
of the Trustee, shall be the successor of the Trustee hereunder, provided such
corporation shall be otherwise qualified and eligible under this Article,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto.  In case any Securities shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the Securities so authenticated with the same
effect as if such successor Trustee had itself authenticated such Securities.

 Section 613.  Preferential Collection of Claims Against Company.

          If and when the Trustee shall be or become a creditor of the Company
(or any other obligor upon the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor).

                                      -57-
<PAGE>
 
 Section 614.  Appointment of Authenticating Agent.

          The Trustee may appoint an Authenticating Agent or Agents which shall
be authorized to act on behalf of the Trustee to authenticate Securities issued
upon original issue and upon exchange, registration of transfer or partial
conversion, repurchase or redemption or pursuant to Section 306, and Securities
so authenticated shall be entitled to the benefits of this Indenture and shall
be valid and obligatory for all purposes as if authenticated by the Trustee
hereunder.  Wherever reference is made in this Indenture to the authentication
and delivery of Securities by the Trustee or the Trustee's certificate of
authentication, such reference shall be deemed to include authentication and
delivery on behalf of the Trustee by an Authenticating Agent and a certificate
of authentication executed on behalf of the Trustee by an Authenticating Agent.
Each Authenticating Agent shall be acceptable to the Company and shall at all
times be a corporation organized and doing business under the laws of the United
States of America, any state thereof or the District of Columbia, authorized
under such laws to act as Authenticating Agent, having a combined capital and
surplus of not less than $50,000,000 and subject to supervision or examination
by federal or state authority. If such Authenticating Agent publishes reports of
condition at least annually, pursuant to law or to the requirements of said
supervising or examining authority, then for the purposes of this Section, the
combined capital and surplus of such Authenticating Agent shall be deemed to be
its combined capital and surplus as set forth in its most recent report of
condition so published.  If at any time an Authenticating Agent shall cease to
be eligible in accordance with the provisions of this Section, such
Authenticating Agent shall resign immediately in the manner and with the effect
specified in this Section.

          Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
under this Section, without the execution or filing of any paper or any further
act on the part of the Trustee or the Authenticating Agent.

          An Authenticating Agent may resign at any time by giving 30 days'
written notice thereof to the Trustee and to the Company.  The Trustee may at
any time terminate the agency of an Authenticating Agent by giving 30 days'
written notice thereof to such Authenticating Agent and to the Company.  Upon
receiving such a notice of resignation or upon such a termination, or in case at
any time such Authenticating Agent shall cease to be eligible in accordance with
the provisions of this Section, the Trustee may appoint a successor
Authenticating Agent which shall be acceptable to the Company and shall mail
written notice of such appointment by first-class mail, postage prepaid, to all
Holders as their names and addresses appear in the Security Register.  Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section.

                                      -58-
<PAGE>
 
          The Trustee agrees to pay to each Authenticating Agent from time to
time reasonable compensation for its services under this Section, and the
Trustee shall be entitled to be reimbursed for such payments, subject to the
provisions of Section 607.

          If an appointment is made pursuant to this Section, the Securities may
have endorsed thereon, in addition to the Trustee's certificate of
authentication, an alternate certificate of authentication in the following
form:

          This is one of the Securities described in the within-mentioned
Indenture.

                                           FLEET NATIONAL BANK,
                                           As Trustee


                                           By
                                             ----------------------------
                                                As Authenticating Agent


                                           By
                                             ----------------------------
                                                Authorized Signatory


                                 ARTICLE SEVEN

                           HOLDERS' LISTS AND REPORTS
                             BY TRUSTEE AND COMPANY

 Section 701.  Company to Furnish Trustee Names and Addresses of Holders.

          The Company will furnish or cause the Security Registrar to furnish to
the Trustee:

     (a) semiannually, not more than 15 days after each Regular Record Date, a
list, in such form as the Trustee may reasonably require, of the names and
addresses of the Holders as of such Regular Record Date, and

     (b) at such other times as the Trustee may request in writing, within 30
days after the receipt by the Company of any such request, a list of similar
form and content as of a date not more than 15 days prior to the time such list
is furnished;

excluding from any such list names and addresses received by the Trustee in its
capacity as Security Registrar.

                                      -59-
<PAGE>
 
 Section 702.  Preservation of Information; Communications to Holders.

          (a) The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 701 and the names and
addresses of Holders received by the Trustee in its capacity as Security
Registrar.  The Trustee may destroy any list furnished to it as provided in
Section 701 upon receipt of a new list so furnished.

          (b) The rights of Holders to communicate with other Holders with
respect to their rights under this Indenture or under the Securities, and the
corresponding rights and duties of the Trustee, shall be as provided by the
Trust Indenture Act.

          (c) Every Holder of Securities, by receiving and holding the same,
agrees with the Company and the Trustee that neither the Company nor the Trustee
nor any agent of either of them shall be held accountable by reason of any
disclosure of information as to names and addresses of Holders made pursuant to
the Trust Indenture Act.

 Section 703.  Reports by Trustee.

          (a) The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act at the times and in the manner provided pursuant thereto.
Reports so required to be transmitted at stated intervals of not more than 12
months shall be transmitted no later than May 15 of each year, commencing with
the May 15 first following the Issue Date.

          (b) A copy of each such report shall, at the time of such transmission
to Holders, be filed by the Trustee with each stock exchange upon which the
Securities are listed, with the Commission and with the Company.  The Company
will notify the Trustee when the Securities are listed on any stock exchange and
of any delisting thereof.

 Section 704.  Reports by Company.

          (a) The Company shall file with the Trustee and the Commission, and
transmit to Holders, such information, documents and other reports, and such
summaries thereof, as may be required pursuant to the Trust Indenture Act at the
times and in the manner provided pursuant to such Act; provided, however, that
any such information, documents or reports required to be filed with the
Commission pursuant to Section 13 or 15(d) of the Exchange Act shall be filed
with the Trustee within 15 days after the same is so required to be filed with
the Commission.  In the event the Company is not subject to the requirements of
Section 13 or 15(d) of the Exchange Act, the Company shall file with the Trustee
(a) within 60 days after the end of each of the Company's first three fiscal
quarters in each fiscal year, a report containing unaudited financial statements
with respect to such fiscal quarter and (b) within 105 days after the end of the
Company's fiscal year, a report containing audited financial statements with
respect to such fiscal year.

                                      -60-
<PAGE>
 
          (b) At any time when the Company is not subject to Section 13 or 15(d)
of the Exchange Act, upon the request of a Holder of a Restricted Security or
the holder of shares of Common Stock issued upon conversion thereof, the Company
will promptly furnish or cause to be furnished Rule 144A Information (as defined
below) to such Holder of Restricted Securities or such holder of shares of
Common Stock issued upon conversion of Restricted Securities, or to a
prospective purchaser of any security designated by any such Holder or holder,
as the case may be, to the extent required to permit compliance by such Holder
or holder with Rule 144A under the Securities Act in connection with the resale
of any such security.  "Rule 144A Information" shall be such information as is
specified pursuant to Rule 144A(d)(4) under the Securities Act (or any successor
provision thereto).


                                 ARTICLE EIGHT

                       CONSOLIDATION, MERGER, CONVEYANCE,
                               TRANSFER OR LEASE

 Section 801.  Company May Consolidate, Etc., Only on Certain Terms.

          The Company shall not consolidate with or merge into any other Person
or convey, transfer, lease or otherwise dispose of its properties and assets
substantially as an entirety to any Person, and the Company shall not permit any
Person to consolidate with or merge into the Company or convey, transfer, lease
or otherwise dispose of its properties and assets substantially as an entirety
to the Company, unless:

     (1) in case the Company shall consolidate with or merge into another Person
or convey, transfer, lease or otherwise dispose of its properties and assets
substantially as an entirety to any Person, the Person formed by such
consolidation or into which the Company is merged or the Person which acquires
by conveyance or transfer or otherwise, or which leases, the properties and
assets of the Company substantially as an entirety shall be a Corporation, shall
be organized and validly existing under the laws of the United States of
America, any state thereof or the District of Columbia and shall expressly
assume, by an indenture supplemental hereto, executed and delivered to the
Trustee, in form satisfactory to the Trustee, the due and punctual payment of
the principal of (and premium, if any) and interest (including Liquidated
Damages, if any, payable pursuant to Section 1007) on all the Securities and the
performance of every covenant of this Indenture on the part of the Company to be
performed or observed and shall have provided for conversion rights in
accordance with Section 1306;

     (2) immediately after giving effect to such transaction, no Event of
Default, and no event which, after notice or lapse of time or both, would become
an Event of Default, shall have happened and be continuing; and

     (3) the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel, each stating that such consolidation, merger, conveyance,
transfer, lease

                                      -61-
<PAGE>
 
or other disposition and, if a supplemental indenture is required in connection
with such transaction, such supplemental indenture comply with this Article and
that all conditions precedent herein provided for relating to such transaction
have been complied with.

 Section 802.  Successor Legal Entity Substituted.

          Upon any consolidation of the Company with, or merger of the Company
into, any other Person or any conveyance, transfer, lease or other disposition
of the properties and assets of the Company substantially as an entirety in
accordance with Section 801, the successor Person formed by such consolidation
or into which the Company is merged or to which such conveyance, transfer, lease
or other disposition is made shall succeed to, and be substituted for, and may
exercise every right and power of, the Company under this Indenture with the
same effect as if such successor Person had been named as the Company herein,
and thereafter, except in the case of a lease, the predecessor Person shall be
relieved of all obligations and covenants under this Indenture and the
Securities and may liquidate and dissolve.


                                  ARTICLE NINE

                            SUPPLEMENTAL INDENTURES

 Section 901.  Supplemental Indentures Without Consent of Holders.

          Without the consent of any Holders, the Company, when authorized by a
Board Resolution, and the Trustee upon Company Request, at  any time and from
time to time, may enter into one or more indentures supplemental hereto, in form
satisfactory to the Trustee, for any of the following purposes:

     (1) to evidence the succession of another Person to the Company and the
assumption by any such successor of the covenants of the Company herein and in
the Securities; or

     (2) to add to the covenants of the Company for the benefit of the Holders
or to surrender any right or power herein conferred upon the Company; or

     (3)  to secure the Securities; or

     (4) to make provision with respect to the conversion rights of Holders
pursuant to the requirements of Section 1306; or

     (5) to make any changes or modifications to this Indenture necessary in
connection with the registration of any Registrable Securities under the
Securities Act as contemplated by Section 1007, provided, however, such action
pursuant to this clause (5) shall not adversely affect the interests of the
Holders of Securities in any material respect; or

                                      -62-
<PAGE>
 
     (6) to comply with the requirements of the Trust Indenture Act or the rules
and regulations of the Commission thereunder in order to effect or maintain the
qualification of this Indenture under the Trust Indenture Act, as contemplated
by this Indenture or otherwise; or

     (7) to evidence and provide for the acceptance of appointment hereunder by
a successor Trustee; or

     (8) to make any change in Article Fourteen that would limit or terminate
the benefits available to any holder of Senior Indebtedness under such Article;
or

     (9) to cure any ambiguity, to correct or supplement any provision herein
which may be inconsistent with any other provision herein or to make any other
provisions with respect to matters or questions arising under this Indenture,
provided such action pursuant to this clause (9) shall not adversely affect the
interests of the Holders in any material respect.

 Section 902.  Supplemental Indentures with Consent of Holders.

          With the consent of the Holders of not less than a majority in
aggregate principal amount of the Outstanding Securities, by Act of said Holders
delivered to the Company and the Trustee, the Company, when authorized by a
Board Resolution, and the Trustee upon Company Request may enter into an
indenture or indentures supplemental hereto for the purpose of adding any
provisions to or changing in any manner or eliminating any of the provisions of
this Indenture or of modifying in any manner the rights of the Holders under
this Indenture; provided, however, that no such supplemental indenture shall,
without the consent of the Holder of each Outstanding Security affected thereby,

     (1) change the Stated Maturity of the principal of, or any installment of
interest on, any Security, or reduce the principal amount thereof or the rate of
interest thereon or any premium payable upon the redemption thereof, or change
the obligation of the Company to pay Liquidated Damages pursuant to Section 1007
in a manner adverse to the Holders, or change the place of payment where, or the
coin or currency in which, any Security or any premium or the interest thereon
is payable, or impair the right to institute suit for the enforcement of (A) any
such payment on or after the Stated Maturity thereof (or, in the case of
redemption or repurchase, on or after the Redemption Date or Repurchase Date, as
the case may be), or (B) the right to convert any Security, or adversely affect
the right to convert any Security as provided in Article Thirteen (except as
permitted by Section 901(4)), or modify the provisions of this Indenture with
respect to the subordination of the Securities in a manner adverse to the
Holders of Securities, or

     (2) reduce the percentage in principal amount of the Outstanding
Securities, the consent of whose Holders is required for any such supplemental
indenture, or the consent of whose Holders is required for any waiver (of
compliance with certain provisions of this

                                      -63-
<PAGE>
 
Indenture or certain defaults hereunder and their consequences) provided for in
this Indenture, or

          (3) modify any of the provisions of this Section, Section 513 or
Section 1006, except to increase any such percentage or to provide that certain
other provisions of this Indenture cannot be modified or waived without the
consent of the Holder of each Outstanding Security affected thereby.

          It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed supplemental Indenture, but it shall
be sufficient if such Act shall approve the substance thereof.

          The Company may, but shall not be obligated to, fix a record date for
the purpose of determining the Holders entitled to consent to any indenture
supplemental hereto.  If a record date is fixed, then those Persons who were
Holders at such record date (or their duly designated proxies), and only those
Persons, shall be entitled to consent to such supplemental Indenture or to
revoke any consent previously given, whether or not such Persons continue to be
Holders after such record date. No such consent shall be valid or effective for
more than 90 days after such record date.

 Section 903.  Execution of Supplemental Indentures.

          In executing, or accepting any additional trusts created by, any
supplemental indenture permitted by this  Article or the modifications thereby
of the trusts created by this Indenture, the Trustee shall be entitled to
receive, and (subject to Section 601) shall be fully protected in relying upon,
an Opinion of Counsel stating that the execution of such supplemental indenture
is authorized or permitted by this Indenture.  The Trustee may, but shall not be
obligated to, enter into any such supplemental indenture which affects the
Trustee's own rights, duties or immunities under this Indenture or otherwise.

 Section 904.  Effect of Supplemental Indentures.

          Upon the execution of any supplemental indenture under this Article,
this Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

 Section 905.  Conformity with Trust Indenture Act.

          Every supplemental indenture executed pursuant to this Article shall
conform to the requirements of the Trust Indenture Act as then in effect.

 Section 906.  Reference in Securities to Supplemental Indentures.

          Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to this  Article may, and shall if required by
the Trustee, bear a notation in form

                                      -64-
<PAGE>
 
approved by the Trustee as to any matter provided for in such supplemental
indenture.  If the Company shall so determine, new Securities so modified as to
conform, in the opinion of the Trustee and the Company, to any such supplemental
indenture may be prepared and executed by the Company and authenticated and
delivered by the Trustee in exchange for Outstanding Securities.

 Section 907.  Notice of Supplemental Indentures and Waivers.

          Promptly after (i) the execution by the Company and the Trustee of any
supplemental indenture pursuant to the provisions of Section 902 or (ii) a
waiver under Section 513 or 1006 becomes effective, the Company shall give
notice thereof to the Holders of each Outstanding Security affected, in the
manner provided for in Section 106, setting forth in general terms the substance
of such supplemental indenture or waiver, as the case may be.


                                  ARTICLE TEN

                                   COVENANTS

 Section 1001. Payment of Principal, Premium and Interest.

          The Company will duly and punctually pay the principal of (and
premium, if any) and interest on the Securities in accordance with the terms of
the Securities and this Indenture.

 Section 1002. Maintenance of Office or Agency.

          The Company will maintain in New York, New York an office or agency
where Securities may be presented or surrendered for payment, and the Company
hereby initially designates the office of the Trustee at Fleet National Bank,
c/o First Chicago Trust Company of New York, 14 Wall Street, 8th Floor -- Window
No. 2, New York, New York 10005, Attention: Corporate Trust Operations, as its
office or agency for such purpose.  Furthermore, the Company will maintain an
office or agency where Securities may be surrendered for registration of
transfer or exchange, where Securities may be surrendered for conversion and
where notices and demands to or upon the Company in respect of the Securities
and this Indenture may be served.  The Company initially designates the
Corporate Trust Office of the Trustee as its office or agency for such purposes.
The Company will give prompt written notice to the Trustee of the location, and
any change in the location, of any such office or agency.  If at any time the
Company shall fail to maintain any such required office or agency or shall fail
to furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office of the
Trustee, and the Company hereby appoints the Trustee as its agent to receive all
such presentations, surrenders, notices and demands.

          The Company may also from time to time designate one or more other
offices or agencies (in or outside New York, New York) where the Securities may
be presented or surrendered for any or all such purposes and may from time to
time rescind such designations; provided, however, that no such designation or
rescission shall in any manner relieve the Company of its

                                      -65-
<PAGE>
 
obligation to maintain an office or agency in New York, New York where the
Securities may be presented or surrendered for payment.  The Company will give
prompt written notice to the Trustee and the Holders of any such designation or
rescission and of any change in the location of any such office or agency.

 Section 1003. Money for Security Payments to Be Held in Trust.

          If the Company shall at any time act as its own Paying Agent, it will,
on or before each due date of the  principal of (and premium, if any) or
interest on any of the Securities, segregate and hold in trust for the benefit
of the Persons entitled thereto a sum sufficient to pay the principal (and
premium, if any) or interest so becoming due until such sums shall be paid to
such Persons or otherwise disposed of as herein provided and will promptly
notify the Trustee of its action or failure so to act.

          Whenever the Company shall have one or more Paying Agents, it will,
prior to 11:00 a.m., Eastern time, on each due date of the principal of (and
premium, if any) or interest on any Securities, deposit in immediately available
funds with a Paying Agent a sum sufficient to pay the principal (and premium, if
any) or interest so becoming due, such sum to be held in trust for the benefit
of the Persons entitled to such principal, premium or interest, and (unless such
Paying Agent is the Trustee) the Company will promptly notify the Trustee of its
action or failure so to act.

          The Company will cause each Paying Agent other than the Trustee to
execute and deliver to the Trustee an instrument in which such Paying Agent
shall agree with the Trustee, subject to the provisions of this Section, that
such Paying Agent will:

     (1) comply with the provisions of the Trust Indenture Act applicable to it
as a Paying Agent; and

     (2) at any time during the continuance of any default, upon the written
request of the Trustee, forthwith pay to the Trustee all sums so held in trust
by such Paying Agent.

          The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent, such sums to be held by the Trustee
upon the same trusts as those upon which such sums were held by the Company or
such Paying Agent; and, upon such payment by any Paying Agent to the Trustee,
such Paying Agent shall be released from all further liability with respect to
such money.

          Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of (and premium, if
any) or interest on any Security and remaining unclaimed for two years (or such
shorter period as required by applicable abandonment law with respect to the
Holder entitled to payment thereof) after such principal (and premium, if any)
or interest has become due and payable shall be paid to the Company on Company
Request, or (if then held by the Company) shall be discharged from such trust;
and the Holder of such Security shall thereafter, as an unsecured general
creditor, look only to the Company for

                                      -66-
<PAGE>
 
payment thereof, unless an applicable abandonment statute designates another
Person, and all liability of the Trustee or such Paying Agent with respect to
such trust money, and all liability of the Company as trustee thereof, shall
thereupon cease; provided, however, that the Trustee or such Paying Agent,
before being required to make any such repayment, may at the expense of the
Company cause to be published once, in a newspaper published in the English
language, customarily published on each Business Day and of general circulation
in New York, New York, notice that such money remains unclaimed and that, after
a date specified therein, which shall not be less than 30 days from the date of
such publication, any unclaimed balance of such money then remaining will be
repaid to the Company.

 Section 1004. Existence.

          Except as permitted by Article Eight, the Company will do or cause to
be done all things necessary to preserve and keep in full force and effect its
corporate existence, rights (charter and statutory) and franchises; provided,
however, that the Company shall not be required to preserve any such right or
franchise if the Board of Directors shall determine that the preservation
thereof is no longer desirable in the conduct of the business of the Company and
that the loss thereof is not disadvantageous in any material respect to the
Holders.

 Section 1005. Statement by Officers as to Default.

          The Company will deliver to the Trustee, within 120 days after the end
of each fiscal year of the Company, in each case ending after the date hereof,
an Officers' Certificate, stating that a review of the activities of the Company
during the preceding fiscal year has been made under the supervision of the
signing officers with a view to determining whether the Company has kept,
observed, performed and fulfilled its obligations under this Indenture, and
further stating, as to each such officer signing such certificate, that to the
best of his knowledge the Company is not in default in the performance or
observance of any of the terms, provisions and conditions hereof or, if a
default or Event of Default shall have occurred, describing all such defaults or
Events of Default of which he may have knowledge and that to the best of his
knowledge no event has occurred and remains in existence by reason of which
payments on account of the principal of or interest, if any, on the Securities
are prohibited or if such event has occurred, a description of the event.

 Section 1006. Waiver of Certain Covenants.

          The Company may omit in any particular instance to comply with any
covenant or condition set forth in Section 1004, if before the time for such
compliance the Holders of at least a majority in aggregate principal amount of
the Outstanding Securities shall, by Act of such Holders, either waive such
compliance in such instance or generally waive compliance with such covenant or
condition, but no such waiver shall extend to or affect such covenant or
condition except to the extent so expressly waived, and, until such waiver shall
become effective, the obligations of the Company and the duties of the Trustee
in respect of any such covenant or condition shall remain in full force and
effect.

                                      -67-
<PAGE>
 
 Section 1007.        Registration Rights.

          The Company agrees that the Holders from time to time of Registrable
Securities (as defined below) are entitled to the benefits of a Registration
Rights Agreement, dated as of December 17, 1996 (the "Registration Rights
Agreement"), executed by the Company and each Initial Purchaser.  Pursuant to
the Registration Rights Agreement, the Company has agreed for the benefit of the
Holders from time to time of Registrable Securities to file a shelf registration
statement (the "Shelf Registration Statement") with the Commission with respect
to resales of the Registrable Securities.

          If (i) on or prior to 90 days following the Issue Date, a Shelf
Registration Statement has not been filed with the Commission, or (ii) on or
prior to 180 days following the Issue Date, such Shelf Registration Statement is
not declared effective (each, a "Registration Default"), additional interest
("Liquidated Damages") will accrue on the Securities from and including the day
following such Registration Default to but excluding the day on which such
Registration Default has been cured.  Liquidated Damages will be paid semi-
annually in arrears, with the first semi-annual payment due on the first
Interest Payment Date following the date on which such Liquidated Damages begin
to accrue, and will accrue at a rate per annum equal to an additional one-
quarter of one percent (.25%) of the principal amount of the Securities to and
including the 90th day following such Registration Default and at a rate per
annum equal to one-half of one percent (.5%) thereof from and after the 91st day
following such Registration Default.  In the event that the Shelf Registration
Statement ceases to be effective during the Effectiveness Period or the Company
suspends the use of the prospectus which is a part thereof for a period in
excess of 60 days, whether or not consecutive, during any 12-month period, then
the interest rate borne by the Securities shall increase by an additional one-
half of one percent (.5%) per annum on the 61st day of the applicable 12-month
period such Shelf Registration Statement ceases to be effective or the Company
suspends the use of the prospectus which is a part thereof, as the case may be,
to but excluding the day on which (i) the Shelf Registration Statement again
becomes effective, (ii) the use of the related prospectus ceases to be suspended
or (iii) the Effectiveness Period expires.

          Whenever in this Indenture there is mentioned, in any context, the
payment of the principal of, premium, if any, or interest on, or in respect of,
any Security, such mention shall be deemed to include mention of the payment of
Liquidated Damages provided for in this Section to the extent that, in such
context, Liquidated Damages are, were or would be payable in respect thereof
pursuant to the provisions of this Section, and express mention of the payment
of Liquidated Damages (if applicable) in any provisions hereof shall not be
construed as excluding Liquidated Damages in those provisions hereof where such
express mention is not made.

          For the purposes of the Registration Rights Agreement, "Registrable
Securities" means all or any portion of the Securities issued from time to time
under this Indenture and the shares of Common Stock issuable upon conversion of
such Securities; provided, however, that a Security or the shares of Common
Stock issuable upon conversion of a Security ceases to be a Registrable Security
when it (i) has been effectively registered under the Securities Act and sold in
a manner contemplated by the Shelf Registration Statement, (ii) has been
transferred in compliance with Rule 144 under the Securities Act (or any
successor provisions thereto) or (iii) otherwise has

                                      -68-
<PAGE>
 
been transferred and a new Security or share of Common Stock not subject to
transfer restrictions under the Securities Act has been delivered by or on
behalf of the Company in accordance with Section 305.

          If a Security, or the shares of Common Stock issuable upon conversion
of a Security, is a Registrable Security, and the Holder thereof elects to sell
such Registrable Security pursuant to the Shelf Registration Statement then, by
its acceptance thereof, the Holder of such Registrable Security will have agreed
to be bound by the terms of the Registration Rights Agreement relating to the
Registrable Securities which are the subject of such election.

          For the purposes of the Registration Rights Agreement, the term
"Holder" includes any Person that has a beneficial interest in any Global
Security or any beneficial interest in a global security representing shares of
Common Stock issuable upon conversion of a Security.

 Section 1008. Resale of Certain Securities; Reporting Issuer.

          During the period beginning on the last date of original issuance of
the Securities and ending on the date that is three years from such date, the
Company will not, and will not permit any of its subsidiaries or other
"affiliates" (as defined under Rule 144 under the Securities Act or any
successor provision thereto) controlled by the Company to, resell (x) any
Securities which constitute "restricted securities" under Rule 144 or (y) any
securities into which the Securities have been converted under this Indenture
which constitute "restricted securities" under Rule 144, that in either case
have been reacquired by any of them.  The Trustee shall have no responsibility
in respect of the Company's performance of its agreement in the preceding
sentence.

 Section 1009.  Payment of Certain Duties.

          The Company will pay or discharge, or cause to be paid or discharged,
before the same may become delinquent, all stamp and other duties, if any, which
may be imposed by the United States or United Kingdom or any political
subdivision thereof or taxing authority thereof or therein with respect to the
issuance or conversion of any Securities or with respect to this Indenture.


                                 ARTICLE ELEVEN

                            REDEMPTION OF SECURITIES

 Section 1101. Right of Redemption.

          The Securities may be redeemed at the election of the Company, as a
whole or from time to time in part, at any time on or after December 15, 1999,
at the Redemption Prices specified in the form of Security hereinbefore set
forth, together with accrued interest to the Redemption Date.

                                      -69-
<PAGE>
 
 Section 1102.        Applicability of Article.

          Redemption of Securities at the election of the Company or otherwise,
as permitted or required by any provision of this Indenture, shall be made in
accordance with such provision and this Article.

 Section 1103. Election to Redeem; Notice to Trustee.

          The election of the Company to redeem any Securities pursuant to
Section 1101 shall be evidenced by a Board Resolution.  In case of any
redemption at the election of the Company of less than all the Securities, the
Company shall, at least 45 days prior to the Redemption Date fixed by the
Company (unless a shorter notice shall be satisfactory to the Trustee), notify
the Trustee of such Redemption Date and of the principal amount of Securities to
be redeemed and whether the Trustee is to give the notice of redemption.

 Section 1104. Selection by Trustee of Securities to Be Redeemed.

          If less than all the Securities are to be redeemed pursuant to Section
1101, the particular Securities to be redeemed shall be selected not more than
45 days prior to the Redemption Date by the Trustee, from the Outstanding
Securities not previously called for redemption, by such method (including pro
rata or by lot) as the Trustee shall deem fair and appropriate and which may
provide for the selection for redemption of portions (equal to $1,000 or any
integral multiple thereof) of the principal amount of Securities of a
denomination larger than $1,000.

          If any Security selected for partial redemption is converted in part
before termination of the conversion right with respect to the portion of the
Security so selected, the converted portion of such Security shall be deemed (so
far as may be) to be the portion selected for redemption. Securities which have
been converted during a selection of Securities to be redeemed shall be treated
by the Trustee as Outstanding for the purpose of such selection.

          The Trustee shall promptly notify the Company and each Security
Registrar in writing of the Securities selected for redemption and, in the case
of any Securities selected for partial redemption, the principal amount thereof
to be redeemed.

          The provisions of the preceding paragraphs of this Section 1104 shall
not apply with respect to any redemption affecting only a Global Security,
whether such Global Security is to be redeemed in whole or in part.  In the case
of any such redemption in part, the unredeemed portion of the principal amount
of the Global Security shall be in an authorized denomination.

          For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Securities redeemed or to be redeemed only in part, to the
portion of the principal amount of such Securities which has been or is to be
redeemed.

                                      -70-
<PAGE>
 
 Section 1105.        Notice of Redemption.

          Notice of redemption shall be given by first-class mail, postage
prepaid, mailed not less than 30 nor more than 60 days prior to the Redemption
Date, to each Holder of Securities to be redeemed, at his address appearing in
the Security Register.  Once given, notice of redemption shall be irrevocable.

           All notices of redemption shall state:

     (1)   the Redemption Date;

     (2)   the Redemption Price;

     (3) in the case of a partial redemption of Physical Securities, the
identification of the particular Securities to be redeemed, and, if any Global
Security or Physical Security is to be redeemed in part, the portion of the
principal amount thereof to be redeemed;

     (4) that on the Redemption Date the Redemption Price will become due and
payable upon each such Security to be redeemed and that interest thereon will
cease to accrue on and after said date;

     (5) the conversion price, the date on which the right to convert the
principal of the Securities to be redeemed will terminate and the place or
places where such Securities may be surrendered for conversion; and

     (6) the place or places where such Securities are to be surrendered for
payment of the Redemption Price and accrued interest, if any.

     Notice of redemption of Securities to be redeemed at the election of
the Company shall be given by the Company or, at Company Request, by the Trustee
in the name and at the expense of the Company.

 Section 1106. Deposit of Redemption Price.

          Prior to 11:00 a.m., Eastern time, on any Redemption Date, the Company
shall deposit with the Trustee or with a Paying Agent (or, if the  Company is
acting as its own Paying Agent, segregate and hold in trust as provided in
Section 1003) an amount of money in immediately available funds sufficient to
pay the Redemption Price of, and (except if the Redemption Date shall be an
Interest Payment Date) accrued interest on, all the Securities which are to be
redeemed on that date other than any Securities called for redemption on that
date which have been converted prior to the date of such deposit, in which case
only accrued interest payable on such Securities pursuant to Section 307 or 1303
need be so deposited.

          If any Security called for redemption is converted, any money
deposited with the Trustee or with any Paying Agent or so segregated and held in
trust for the redemption of such

                                      -71-
<PAGE>
 
Security shall (subject to the right of the Holder of such Security or any
Predecessor Security to receive interest as provided in the last paragraph of
Section 307 or in Section 1303) be paid to the Company upon Company Request or,
if then held by the Company, shall be discharged from such trust.

 Section 1107. Securities Payable on Redemption Date.

          Notice of redemption having been given as aforesaid, the Securities so
to be redeemed shall, on the Redemption Date, become due and payable at the
Redemption Price therein specified, and from and after such date (unless the
Company shall default in the payment of the Redemption Price and accrued
interest) such Securities shall cease to bear interest.  Upon surrender of any
such Security for redemption in accordance with said notice, such Security shall
be paid by the Company at the Redemption Price, together with accrued interest
to the Redemption Date; provided, however, that installments of interest whose
Stated Maturity is on or prior to the Redemption Date shall be payable to the
Holders of such Securities, or one or more Predecessor Securities, registered as
such at the close of business on the relevant Record Dates according to their
terms and the provisions of Section 307.

          If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal (and premium, if any) and, to
the extent permitted by applicable law, any overdue interest thereon shall,
until paid, bear interest from the Redemption Date at the rate borne by the
Security, and such Security shall remain convertible until the principal thereof
shall have been paid or duly provided for.

 Section 1108. Securities Redeemed in Part.

          Any Security which is to be redeemed only in part shall be surrendered
at an office or agency of the Company designated for that purpose pursuant to
Section 1002 (with, if the Company or Trustee so requires, due endorsement by,
or a written instrument of transfer in form satisfactory to the Company and the
Trustee duly executed by, the Holder thereof or his attorney duly authorized in
writing), and the Company shall execute, and the Trustee shall authenticate and
deliver to the Holder of such Security without service charge, a new Security or
Securities, of any authorized denomination as requested by such Holder, in
aggregate principal amount equal to and in exchange for the unredeemed portion
of the principal of the Security so surrendered.


 Section 1109. Mandatory Redemption.

          In the event that the Company fails to consummate the Bristow
Transaction within 15 days of the Issue Date, then the Company shall redeem the
Securities as a whole on February 5, 1997, at the Redemption Price specified in
the form of Security hereinbefore set forth, together with accrued interest to
the Redemption Date.

                                      -72-
<PAGE>
 
                                 ARTICLE TWELVE

                          RIGHT TO REQUIRE REPURCHASE

 Section 1201. Right to Require Repurchase.

          (a) In the event that any Designated Event shall occur after the Issue
Date,  then each Holder shall have the right, at such Holder's option, to
require the Company to purchase, and upon the exercise of such right, the
Company shall, subject to the provisions of Article Fourteen, purchase, all or
any part of such Holder's Securities on a date (the "Repurchase Date") selected
by the Company that is not more than 75 days after the date the Company gives
notice of the Designated Event as contemplated in Section 1202(a) at a price
(the "Repurchase Price") equal to 100% of the principal amount thereof, together
with accrued and unpaid interest to the Repurchase Date.

          (b) The Repurchase Price shall be paid only in cash.

 Section 1202. Notice; Method of Exercising Repurchase Right.

          (a) On or before the 15th day after the occurrence of the Designated
Event, the Company, or at Company Request, the Trustee (in the name and at the
expense of the Company), shall give notice (the "Company Notice") of the
occurrence of such Designated Event and of the repurchase right set forth herein
arising as a result thereof by first-class mail, postage prepaid, to each Holder
of the Securities at such Holder's address appearing in the Security Register.
The Company shall also deliver a copy of such notice of a repurchase right to
the Trustee.

           Each notice of a repurchase right shall state:

               (1) the event constituting the Designated Event and the date
thereof,

               (2) the Repurchase Date,

               (3) the date by which the repurchase right must be exercised,

               (4) the Repurchase Price, and

               (5) the instructions a Holder must follow to exercise a
repurchase right.

          No failure of the Company to give the foregoing notice shall limit any
Holder's right to exercise a repurchase right.  The Trustee shall have no
affirmative obligation to determine if there shall have occurred a Designated
Event.

          (b) To exercise a repurchase right, a Holder shall deliver to the
Company (or an agent designated by the Company for such purpose in the notice
referred to in (a) above) and to the

                                      -73-
<PAGE>
 
Trustee on or before the close of business on the Business Day immediately
preceding the Repurchase Date (i) written notice of the Holder's exercise of
such right, which notice shall set forth the name of the Holder, the principal
amount of the Security or Securities (or portion of a Security) to be
repurchased, and a statement that an election to exercise the repurchase right
is being made thereby, and (ii), subject to the Applicable Procedures, the
Security or Securities with respect to which the repurchase right is being
exercised.  Such written notice shall be irrevocable.  If the Repurchase Date
falls between any Regular Record Date and the next succeeding Interest Payment
Date, Securities to be repurchased must be accompanied by payment from the
Holder in New York Clearing House or other funds acceptable to the Company of an
amount equal to the interest thereon which the registered thereof is to receive
on such Interest Payment Date.

          (c) In the event a repurchase right shall be exercised in accordance
with the terms hereof, then, subject to Article Fourteen, the Company shall pay
or cause to be paid to the Trustee the Repurchase Price as provided in Section
1203, for payment to the Holder on the Repurchase Date, together with accrued
and unpaid interest to the Repurchase Date payable with respect to the
Securities as to which the purchase right has been exercised; provided, however,
that installments of interest that mature on or prior to the Repurchase Date
shall be payable to the Holders of such Securities, or one or more Predecessor
Securities, registered as such at the close of business on the relevant Regular
Record Date.

          (d) The Company shall comply with Rules 13e-4 and 14e-1 under the
Exchange Act and any other securities laws and regulations thereunder to the
extent such laws and regulations are applicable, in the event that a Designated
Event occurs and the Company is required to purchase Securities as described in
this Article Twelve.

 Section 1203. Deposit of Repurchase Price.

          Prior to 11:00 a.m., Eastern time, on the Repurchase Date and subject
to Article Fourteen, the Company shall deposit with the Trustee or with a Paying
Agent (or, if the Company is acting as its own Paying Agent, segregate and hold
in trust as provided in Section 1003) an amount of money, in immediately
available funds, sufficient to pay the Repurchase Price of the Securities which
are payable on the Repurchase Date, plus (unless the Repurchase Date shall be an
Interest Payment Date) accrued interest thereon.

 Section 1204. Securities Not Repurchased on Repurchase Date.

          If any Security surrendered for repurchase shall not be paid on the
Repurchase Date, the principal and any overdue interest thereon shall, until
paid, bear interest to the extent permitted by applicable law from the
Repurchase Date at a rate per annum borne by such Security, and such Security
shall remain convertible until the principal thereof shall have been paid or
duly provided for.

                                      -74-
<PAGE>
 
 Section 1205.        Securities Repurchased in Part.

          Any Security which is to be repurchased only in part shall be
surrendered at any office or agency of the Company designated for that purpose
pursuant to Section 1002 (with, if the Company or the Trustee so requires, due
endorsement by, or written instrument of transfer in form satisfactory to the
Company and the Trustee duly executed by, the Holder thereof or his attorney
duly authorized in writing), and the Company shall execute, and the Trustee
shall authenticate and deliver to the Holder of such Security without service
charge, a new Security or Securities of any authorized denomination as requested
by such Holder, in aggregate principal amount equal to and in exchange for the
repurchased portion of the principal of the Security so surrendered.

 Section 1206. "Change of Control" and "Termination of Trading" Defined.

           For purposes of this Article, a "Change of Control" means any of the
following events shall have occurred:

          (1) the Company's assets are sold or otherwise disposed of
substantially as an entirety to any Person or related group of Persons in any
one transaction or a series of related transactions;

          (2) there shall be consummated any consolidation or merger of the
Company (A) in which the Company is not the continuing or surviving corporation
(other than a consolidation or merger with a wholly-owned Subsidiary of the
Company in which all shares of Common Stock outstanding immediately prior to the
effectiveness thereof are changed into or exchanged for the same number of
shares of common stock of such Subsidiary) or (B) pursuant to which the Common
Stock is converted into cash, securities or other property, in each case other
than a consolidation or merger of the Company in which the holders of the Common
Stock immediately prior to the consolidation or merger have, directly or
indirectly, at least a majority of the common stock of the continuing or
surviving Corporation immediately after such consolidation or merger; or

          (3) any Person, or any Persons acting together which would constitute
a "group" for purposes of Section 13(d) of the Exchange Act (a "Group") (other
than the Company, any Subsidiary, any employee stock purchase plan, stock option
plan or other stock incentive plan or program, retirement plan or automatic
dividend reinvestment plan or any substantially similar plan of the Company or
any Subsidiary or any Person holding securities of the Company for or pursuant
to the terms of any such employee benefit plan, which may file or become
obligated to file a report under or in response to Schedule 13D or Schedule 14D-
1 (or any successor schedule, form or report) under the Exchange Act), together
with any Affiliates thereof, shall acquire beneficial ownership (as defined in
Rule 13d-3 of the Exchange Act) of at least 50% of the total voting power of all
classes of capital stock of the Company entitled to vote generally in the
election of directors of the Company.

          For purposes of this Article, a "Termination of Trading" shall have
occurred if the Common Stock (or other common stock into which the Securities
are then convertible) is neither

                                      -75-
<PAGE>
 
listed for trading on a United States national securities exchange nor approved
for trading on an established over-the-counter trading market in the United
States.


                                ARTICLE THIRTEEN

                            CONVERSION OF SECURITIES

 Section 1301. Right of Conversion.

          The Holder of any Security or Securities shall have the right at any
time on or after 60 days from the last original issuance date of the Securities
and prior to the close of business on the maturity date, subject, in the case of
conversion of any Global Security, to any Applicable Procedures, at his option,
to convert, subject to the terms and provisions of this Article Thirteen, the
principal of any such Security or Securities (or any portion of the principal
thereof which is $1,000 or an integral multiple of $1,000) into fully paid and
nonassessable shares of Common Stock of the Company at the conversion price of
$22.86 of principal amount of Securities per share of Common Stock or, in case
an adjustment therein has taken place pursuant to the provisions of Section
1304, then at the price as so adjusted (except that with respect to any Security
or Securities, or any such portion, which shall be called for redemption, such
right shall terminate, except as provided in the last paragraph of Section 1302,
at the close of business on the Business Day immediately preceding the
Redemption Date for such Security or Securities or portion unless the Company
shall default in payment due upon redemption thereof).  Such right shall be
exercised by the surrender of the Security or Securities, the principal of which
is so to be converted, to the Company at any time during usual business hours at
any office or agency to be maintained by it in accordance with the provisions of
Section 1002, accompanied by written notice that the Holder elects to convert
such Security or Securities or any portion thereof and specifying the name or
names (with address) in which a certificate or certificates for Common Stock are
to be issued and (if so required by the Company or the Trustee) by a written
instrument or instruments of transfer in form satisfactory to the Company and
the Trustee, duly executed by the Holder or his attorney duly authorized in
writing, and transfer tax stamps or funds therefor, if required pursuant to
Section 1310.  For convenience, the conversion of all or a portion, as the case
may be, of the principal of any Security into the Common Stock of the Company is
hereinafter sometimes referred to as the conversion of such Security.  All
Securities surrendered for conversion shall, if surrendered to the Company or
any conversion agent, be delivered to the Trustee for cancellation and cancelled
by it or, if surrendered to the Trustee, shall be cancelled by it; and, subject
to the next succeeding sentence, no Securities shall be issued in lieu thereof.
In the case of any Security which is converted in part only, upon such
conversion the Company shall execute and the Trustee shall authenticate and
deliver to the Holder thereof, at the expense of the Company, a new Security or
Securities of authorized denominations in an aggregate principal amount equal to
the unconverted portion of the principal amount of such Security.

 Section 1302. Issuance of Common Stock; Time of Conversion.

          As promptly as practicable after the surrender, as herein provided, of
any Security or Securities for conversion, the Company shall deliver or cause to
be delivered at any office or

                                      -76-
<PAGE>
 
agency to be maintained by it in accordance with the provisions of Section 1002
to or upon the written order of the Holder of the Security or Securities so
surrendered a certificate or certificates representing the number of fully paid
and nonassessable shares of Common Stock of the Company into which such Security
or Securities (or portion thereof) may be converted in accordance with the
provisions of this Article Thirteen.  Subject to the following provisions of
this paragraph and of Section 1304, such conversion shall be deemed to have been
made immediately prior to the close of business on the date that such Security
or Securities shall have been surrendered in satisfactory form for conversion,
so that the rights of the Holder as a Holder shall cease with respect to such
Security or Securities (or the portion thereof being converted) at such time,
and the Person or Persons entitled to receive the shares of Common Stock
deliverable upon conversion of such Security or Securities shall be treated for
all purposes as having become the record holder or holders of such shares of
Common Stock at such time, and such conversion shall be at the conversion price
in effect at such time; provided, however, that no such surrender on any date
when the stock transfer books of the Company shall be closed shall be effective
to constitute the Person or Persons entitled to receive the shares of Common
Stock deliverable upon such conversion as the record holder or holders of such
shares of Common Stock on such date, but such surrender shall be effective to
constitute the Person or Persons entitled to receive such shares of Common Stock
as the record holder or holders thereof for all purposes immediately prior to
the close of business on the next succeeding day on which such stock transfer
books are open, and such conversion shall be deemed to have been made at, and
shall be made at the conversion rate in effect at, such time on such next
succeeding day.

          All shares of Common Stock delivered upon conversion of Restricted
Securities shall bear restrictive legends substantially in the form of the
legends required to be set forth on the Restricted Securities pursuant to
Section 305(c) and shall be subject to the restrictions on transfer provided in
such legends.  Neither the Trustee nor any agent maintained for the purpose of
such conversion shall have any responsibility for the inclusion or content of
any such restrictive legends on such Common Stock; provided, however, that the
Trustee or any agent maintained for the purpose of such conversion shall
provided, to the Company or to the Company's transfer agent for such Common
Stock, prior to or concurrently with a request to the Company to deliver such
Common Stock, written notice that the Securities delivered for conversion are
Restricted Securities.

          If shares of Common Stock to be issued upon conversion of a Restricted
Security, or Securities to be issued upon conversion of a Restricted Security in
part only, are to be registered in a name other than that of the beneficial
owner of such Restricted Security, then such Holder must deliver to the
conversion agent designated by the Company a Surrender Certificate, dated the
date of surrender of such Restricted Security and signed by such beneficial
owner, as to compliance with the restrictions on transfer applicable to such
Restricted Security.  Neither the Trustee nor any conversion agent designated by
the Company or the Security Registrar shall be required to register in a name
other than that of the beneficial owner, shares of Common Stock or Securities
issued upon conversion of any such Restricted Security not so accompanied by a
properly completed Surrender Certificate.

          If the last day for the exercise of the conversion right shall not be
a Business Day, then such conversion right may be exercised on the next
succeeding Business Day.

                                      -77-
<PAGE>
 
 Section 1303. No Adjustments in Respect of Interest or Dividends.

          Securities surrendered for conversion during the period from the close
of business on any Regular Record Date to the opening of business on the next
succeeding Interest Payment Date shall (except in the case of Securities or
portions thereof which have been called for redemption) be accompanied by
payment in New York Clearing House funds or other funds acceptable to the
Company of an amount equal to the interest payable on such Interest Payment Date
on the principal amount of Securities being surrendered for conversion.  Upon a
call for redemption by the Company, accrued and unpaid interest to the
Redemption Date shall be payable with respect to Securities converted after the
redemption notice has been mailed and prior to the Redemption Date.  Except as
provided in this Section 1303 and subject to the last paragraph of Section 307,
no payment or adjustment shall be made upon any conversion on account of any
interest accrued on the Securities surrendered for conversion or on account of
any dividends on the shares of Common Stock issued upon conversion.

 Section 1304. Adjustment of Conversion Price.

          The conversion price, and consequently the number of shares of Common
Stock into which a Security is convertible, shall be subject to adjustment from
time to time as follows:

     (a) In case the Company shall (i) pay a dividend on Common Stock or make a
distribution on its Common Stock that is paid or made (1) in shares of any class
of capital stock of the Company or (2) in rights to purchase any stock or other
securities if such rights are not separable from the Common Stock except upon
the occurrence of a contingency, (ii) subdivide its outstanding shares of Common
Stock into a greater number of shares or (iii) combine its outstanding shares of
Common Stock into a smaller number of shares, then in each such case the
conversion price in effect immediately prior thereto shall be adjusted
retroactively as provided below so that the Holder of any Security thereafter
surrendered for conversion shall be entitled to receive the number of shares of
Common Stock and other shares and rights to purchase stock or other securities
(or, in the event of the redemption of any such shares or rights, any cash,
property or securities paid in respect of such redemption) which such Holder
would have owned or have been entitled to receive after the happening of any of
the events described above had such Security been converted immediately prior to
the happening of such event.  An adjustment made pursuant to this Subsection (a)
shall become effective immediately after the record date in the case of a
dividend or distribution and shall become effective immediately after the
effective date in the case of a subdivision or combination.

     (b) In case the Company shall issue rights or warrants to all holders of
its Common Stock entitling them (for a period expiring within 45 days after the
date fixed for determination mentioned below) to subscribe for or purchase
shares of Common Stock at a price per share less than the current market price
per share (determined as provided in paragraph (d) of this Section) of the
Common Stock on the date fixed for the determination of stockholders entitled to
receive such rights or warrants, then the conversion price in effect at the
opening of business on the day following the date fixed for such determination
shall

                                      -78-
<PAGE>
 
be decreased by multiplying such conversion price by a fraction of which the
denominator shall be the number of shares of Common Stock outstanding at the
close of business on the date fixed for such determination plus the number of
shares of Common Stock so offered for subscription or purchase, and the
numerator shall be the number of shares of Common Stock outstanding at the close
of business on the date fixed for such determination plus the number of shares
of Common Stock which the aggregate of the offering price of the total number of
shares of Common Stock so offered for subscription or purchase would purchase at
such current market price, such reduction to become effective immediately after
the opening of business on the day following the date fixed for such
determination; provided, however, in the event that all the shares of Common
Stock offered for subscription or purchase are not delivered upon the exercise
of such rights or warrants, upon the expiration of such rights or warrants the
conversion price shall be readjusted to the conversion price which would have
been in effect had the numerator and the denominator of the foregoing fraction
and the resulting adjustment been made based upon the number of shares of Common
Stock actually delivered upon the exercise of such rights or warrants rather
than upon the number of shares of Common Stock offered for subscription or
purchase.  For the purposes of this paragraph (b), the number of shares of
Common Stock at any time outstanding shall not include shares held in the
treasury of the Company.

     (c) In case the Company shall, by dividend or otherwise, distribute to
substantially all holders of its Common Stock evidences of its indebtedness,
cash (excluding quarterly cash dividends paid or to be paid on a regular basis),
other assets or rights or warrants to subscribe for or purchase any securities
(excluding those referred to in paragraphs (a) and (b) above), then in each such
case, the conversion price shall be adjusted retroactively so that the same
shall equal the price determined by multiplying the conversion price in effect
immediately prior to the close of business on the date fixed for the
determination of stockholders entitled to receive such distribution by a
fraction of which the denominator shall be the current market price per share
(determined as provided in paragraph (d) of this Section) of the Common Stock on
the date fixed for such determination and the numerator shall be such current
market price per share of the Common Stock less the amount of cash and the then
fair market value (as determined by the Board of Directors, whose determination
shall be conclusive and described in a Board Resolution filed with the Trustee)
of the portion of the assets, rights, warrants or evidences of indebtedness so
distributed applicable to one share of Common Stock, such adjustment to become
effective immediately prior to the opening of business on the day following the
date fixed for the determination of stockholders entitled to receive such
distribution.

     (d) For the purpose of any computation under paragraphs (b) and (c) of this
Section, the current market price per share of Common Stock on any date shall be
deemed to be the average of the daily closing prices for the 30 consecutive
trading days commencing with the 45th trading day before the day in question.
The closing price for each day shall be the last reported sales price regular
way or, in case no such reported sale takes place on such day, the average of
the reported closing bid and asked prices regular way, in either case on the
composite tape of the principal national securities exchange upon which the
Common Stock is listed or on the Nasdaq National Market (based on the aggregate
dollar value of all

                                      -79-
<PAGE>
 
securities listed or admitted to trading) or, if the Common Stock is not listed
or admitted to trading on any national securities exchange or quoted on the
Nasdaq National Market, the average of the closing bid and asked prices in the
over-the-counter market as furnished by any New York Stock Exchange member firm
selected from time to time by the Company for that purpose, or, if such prices
are not available, the fair market value set by, or in a manner established by,
the Board of Directors of the Company in good faith.  "Trading day" shall mean a
day on which the national securities exchange or the Nasdaq National Market used
to determine the closing price is open for the transaction of business or the
reporting of trades or, if the closing price is not so determined, a day on
which the New York Stock Exchange is open for the transaction of business.

     (e) No adjustment in the conversion price shall be required unless such
adjustment would require an increase or decrease of at least 1% in such price;
provided, however, that the Company may make any such adjustment at its
election; and provided, further, that any adjustments which by reason of this
paragraph (e) are not required to be made shall be carried forward and taken
into account in any subsequent adjustment.  All calculations under this Article
Thirteen shall be made to the nearest cent or to the nearest one-hundredth of a
share, as the case may be, and in no case shall any adjustment in the conversion
price result in a conversion price of less than $.01.

     (f) Whenever the conversion price is adjusted as provided in any provision
of this Article Thirteen:

             (i) the Company shall compute the adjusted conversion price in
        accordance with paragraph (d) and shall prepare a certificate signed by
        the principal financial officer of the Company setting forth the
        adjusted conversion price and showing in reasonable detail the facts and
        calculations upon which such adjustment is based, and such certificate
        shall forthwith be filed with the Trustee and at each office or agency
        maintained for the purpose of conversion of Securities; and

             (ii) a notice stating that the conversion price has been adjusted
        and setting forth the adjusted conversion price shall forthwith be
        required, and as soon as practicable after it is required, such notice
        shall be mailed by the Company to all Holders at their last addresses as
        they shall appear in the Security Register.

     (g)  In the event that at any time, as a result of any adjustment made
pursuant to this Article Thirteen, the Holder of any Security thereafter
surrendered for conversion shall become entitled to receive any shares of the
Company other than shares of Common Stock or to receive any other securities,
the number of such other shares or securities so receivable upon conversion of
any Security shall be subject to adjustment from time to time in a manner and on
terms as nearly equivalent as practicable to the provisions contained in this
Article Thirteen with respect to the Common Stock.

     (h) The Company from time to time may, by Board Resolution delivered to the
Trustee, decrease the conversion price by any amount for any period of time if
the period is

                                      -80-
<PAGE>
 
at least 20 days and if the decrease is irrevocable during the period.  Whenever
the conversion price is so decreased, the Company shall mail to the Holders a
notice of the decrease at least 15 days before the date the decreased conversion
price takes effect, and such notice shall state the decreased conversion price
and the period it will be in effect.

     (i) The Company may make such decreases in the conversion price, in
addition to those required or allowed by this Article Thirteen, as shall be
determined by it, as evidenced by a Board Resolution delivered to the Trustee,
to be advisable in order to avoid or diminish any income tax to holders of
Common Stock resulting from any dividend or distribution of stock or issuance of
rights or warrants to purchase or subscribe for stock or from any event treated
as such for income tax purposes.

     (j) In any case in which this Section 1304 provides that an adjustment
shall become effective immediately after a record date for an event, the Company
may defer until the occurrence of such event (i) issuing to the holder of any
Security converted after such record date and before the occurrence of such
event the additional shares of Common Stock issuable upon such conversion by
reason of the adjustment required by such event over and above the Common Stock
issuable upon such conversion before giving effect to such adjustment and (ii)
paying to such holder any amount in cash in lieu of any fraction pursuant to
Section 1305.

 Section 1305. No Fractional Shares.

          No fractional shares or scrip representing fractional shares of Common
Stock shall be issued upon conversion of Securities.  If more than one Security
shall be surrendered for conversion at one time by the same Holder, the number
of full shares issuable upon conversion thereof shall be computed on the basis
of the aggregate principal amount of the Securities (or specified portions
thereof) so surrendered.  Instead of any fractional share of Common Stock which
would otherwise be issuable upon conversion of any Security or Securities (or
specified portions thereof), the Company shall pay a cash adjustment in respect
of such fraction in an amount equal to the same fraction of the closing price
per share of Common Stock as quoted on the composite tape of the principal
national securities exchange upon which the Common Stock is listed or the Nasdaq
National Market or, in case no such reported sale takes place on such day, the
average of the reported closing bid and asked prices regular way, in either case
on the Nasdaq National Market or, if the Common Stock is not listed or admitted
to trading on any national securities exchange or quoted on the Nasdaq National
Market, the average of the closing bid and asked prices in the over-the-counter
market as furnished by any New York Stock Exchange member firm selected from
time to time by the Company for that purpose, or, if such prices are not
available, the fair market value set by, or in a manner established by, the
Board of Directors of the Company in good faith, all of the above to be
determined as of the close of business on the day of conversion.

 Section 1306. Reclassification, Consolidation, Merger or Sale of Assets.

          In case of any reclassification of the Common Stock, any consolidation
of the Company with, or merger of  the Company into, any other Person, any
merger of another Person into

                                      -81-
<PAGE>
 
the Company (other than a merger which does not result in any reclassification,
conversion, exchange or cancellation of outstanding shares of Common Stock of
the Company), any sale or other disposition of the assets of the Company
substantially as an entirety or any compulsory share exchange pursuant to which
share exchange the Common Stock is converted into other securities, cash or
other property, then the Holder of each Security then outstanding shall have the
right thereafter, during the period such Security shall be convertible, pursuant
to Section 1301, to convert such Security only into the kind and amount of
securities, cash and other property receivable upon such reclassification,
consolidation, merger, sale, other disposition or share exchange by a holder of
the number of shares of Common Stock of the Company into which such Security
might have been converted immediately prior to such reclassification,
consolidation, merger, sale, other disposition or share exchange assuming such
holder of Common Stock (i) is not a Person with which the Company consolidated
or into which the Company merged or which merged into the Company, to which such
sale or other disposition was made or a party to such share exchange, as the
case may be ("constituent Person"), or an Affiliate of a constituent Person and
(ii) failed to exercise his rights of election, if any, as to the kind or amount
of securities, cash and other property receivable upon such reclassification,
consolidation, merger, sale, other disposition or share exchange (provided that
if the kind or amount of securities, cash and other property receivable upon
such reclassification, consolidation, merger, sale, other disposition or share
exchange is not the same for each share of Common Stock held immediately prior
to such reclassification, consolidation, merger, sale, other disposition or
share exchange by others than a constituent Person or an Affiliate thereof and
in respect of which such rights of election shall not have been exercised ("non-
electing share"), then for the purpose of this Article the kind and amount of
securities, cash and other property receivable upon such reclassification,
consolidation, merger, sale, other disposition or share exchange by each non-
electing share shall be deemed to be the kind and amount so receivable per share
by a plurality of the non-electing shares).  The Company or the Person formed by
such consolidation or resulting from such merger or which acquires such assets
or which acquires the Company's shares, as the case may be, shall execute and
deliver to the Trustee a supplemental indenture to establish such right. Such
supplemental indenture shall provide for adjustments which, for events
subsequent to the effective date of such supplemental indenture, shall be as
nearly equivalent as may be practicable to the adjustments provided for in this
Article.  The above provisions of this Section shall similarly apply to
successive reclassifications, consolidations, mergers, sales, other dispositions
or share exchanges.

          Notice of the execution of such a supplemental indenture shall be
given by the Company to each Holder by mailing such notice to his last address
appearing on the Security Register.

          Neither the Trustee nor any conversion agent shall be under any
responsibility to determine the correctness of any provisions contained in any
such supplemental indenture relating either to the kind or amount of securities,
cash or other property receivable by Holders of Securities upon the conversion
of their Securities after any such reclassification, change, consolidation,
merger, sale, other disposition or share exchange or to any such adjustment,
but, subject to the provisions of Section 601, may accept as conclusive evidence
of the correctness of any such provisions, and shall be protected in relying
upon, an Opinion of Counsel with respect thereto, which the Company shall cause
to be furnished to the Trustee upon request.

                                      -82-
<PAGE>
 
 Section 1307. Prior Notice of Certain Events.

           In case:

     (a) the Company shall (i) declare any dividend (or any other distribution)
on its Common Stock other than (1) a dividend payable in shares of Common Stock
or (2) a quarterly cash dividend paid or to be paid on a regular basis or (ii)
declare or authorize a redemption or repurchase of in excess of 10% of the then
outstanding shares of Common Stock; or

     (b) the Company shall authorize the granting to the holders of its Common
Stock of rights or warrants to subscribe for or purchase any shares of stock of
any class or of any other rights or warrants; or

     (c) of any reclassification of the Common Stock of the Company (other than
a subdivision or combination of its outstanding Common Stock, or a change in par
value, or from par value to no par value, or from no par value to par value), or
of any consolidation or merger to which the Company is a party and for which
approval of any stockholders of the Company is required, or of the sale or other
disposition of the assets of the Company substantially as an entirety or of any
compulsory share exchange whereby the Common Stock is converted into other
securities, cash or other property; or

     (d) of the voluntary or involuntary dissolution, liquidation or winding up
of the Company;

then the Company shall cause to be filed with the Trustee and to be mailed to
each Holder of Securities at his last address appearing on the Security
Register, as promptly as possible but in any event at least 15 days prior to the
applicable date hereinafter specified, a notice stating (x) the date on which a
record is to be taken for the purpose of such dividend, distribution or granting
of rights or warrants or, if a record is not to be taken, the date as of which
the holders of Common Stock of record to be entitled to such dividend,
distribution, rights or warrants are to be determined, or (y) the date on which
such reclassification, consolidation, merger, sale, other disposition, share
exchange, dissolution, liquidation or winding up is expected to become
effective, and the date as of which it is expected that holders of Common Stock
of record shall be entitled to exchange their shares of Common Stock for
securities or other property deliverable upon such reclassification,
consolidation, merger, sale, other disposition, share exchange, dissolution,
liquidation or winding up.

 Section 1308. Shares to be Reserved; Accounting Treatment of Consideration.

          The Company covenants that it will at all times reserve and keep
available out of its authorized but unissued Common Stock, free from preemptive
rights solely for the purpose of issue upon conversion of Securities as herein
provided, such number of shares of Common Stock as shall then be issuable upon
the conversion of all outstanding Securities.  The Company covenants that all
shares of Common Stock which shall be so issuable shall, when issued, be duly
and validly issued and fully paid and nonassessable.

                                      -83-
<PAGE>
 
          The Company covenants that, upon conversion of Securities as herein
provided, there will be credited to the Common Stock capital account from the
consideration for which the shares of Common Stock issuable upon such conversion
are issued an amount per share of Common Stock so issued as determined by the
Board of Directors, which amount shall not be less than the amount required by
law and by the Company's certificate of incorporation, as amended, as in effect
on the date of such conversion.  For the purposes of this covenant the principal
amount of the Securities converted, less any cash paid in respect of fractional
share interests upon such conversion, shall be deemed to be the amount of
consideration for which the shares of Common Stock issuable upon such conversion
are issued.

 Section 1309. Listing of Shares.

          The Company covenants that so long as the Common Stock of the Company
is listed on any national securities exchange or quoted on the Nasdaq National
Market, the Company will, if permitted by the rules thereof, list and keep
listed or quoted thereon, upon official notice of issuance, all shares of Common
Stock issuable upon conversion of Securities.

 Section 1310. Taxes and Charges.

          The issuance of certificates for shares of Common Stock upon the
conversion of Securities shall be made without charge to the converting Holder
of Securities for such certificates or for any tax in respect of the issuance of
such certificates or the securities represented thereby, and such certificates
shall be issued in the respective names of, or in such names as may be directed
by, the Holders of the Securities converted; provided, however, that the Company
shall not be required to pay any tax which may be payable in respect of any
transfer involved in the issuance and delivery of any such certificate in a name
other than that of the Holder of the Security converted, and the Company shall
not be required to issue or deliver such certificates unless or until the Person
or Persons requesting the issuance thereof shall have paid to the Company the
amount of such tax or shall have established to the satisfaction of the Company
that such tax has been paid.

 Section 1311. Trustee and Conversion Agents Not Liable.

          Neither the Trustee nor any conversion agent shall at any time be
under any duty or responsibility to any Holder of Securities to determine
whether any facts exist which may require any adjustment of the conversion rate,
or with respect to the nature or extent of any such adjustment when made, or
with respect to the method employed, or herein or in any supplemental indenture
provided to be employed, in making the same.  Neither the Trustee nor any
conversion agent shall be accountable with respect to the validity or value (or
the kind or amount) of any shares of Common Stock or of any securities or cash
or other property which may at any time be issued or delivered upon the
conversion of any Security, or makes any representation with respect thereto.
Neither the Trustee nor any conversion agent shall be responsible for any
failure of the Company to make any cash payment or to issue, transfer or deliver
any shares of Common Stock or stock certificates or other securities or property
upon the surrender of any Security for the purpose of conversion, or, subject to
Section 601, with any of the covenants of the Company contained in this Article
Thirteen.

                                      -84-
<PAGE>
 
                                ARTICLE FOURTEEN

                          SUBORDINATION OF SECURITIES

 Section 1401. Securities Subordinate to Senior Indebtedness.

          The Company covenants and agrees, and each Holder of a Security by his
acceptance thereof likewise covenants and agrees that, to the extent and in the
manner hereinafter set forth in this Article, the indebtedness represented by
the Securities and the payment of the principal of (and premium, if any) and
interest (including any Liquidated Damages) on each and all of the Securities
are hereby expressly made subordinate and subject in right of payment to the
prior payment in full of all Senior Indebtedness.

 Section 1402. Payment Over of Proceeds Upon Dissolution, Etc.

          Upon any distribution of assets of the Company in the event of (a) any
insolvency or bankruptcy case or proceeding, or any receivership, liquidation,
reorganization or other similar case or proceeding in connection therewith,
relative to the Company or to its creditors, as such, or to its assets, or (b)
any liquidation, dissolution or other winding up of the Company, whether
voluntary or involuntary and whether or not involving insolvency or bankruptcy,
or (c) any assignment for the benefit of creditors or any other marshaling of
assets and liabilities of the Company, then and in any such event the holders of
Senior Indebtedness shall be entitled to receive payment in full of all amounts
due or to become due on or in respect of all Senior Indebtedness, or provision
shall be made for such payment in money or money's worth, before the Holders of
the Securities are entitled to receive any payment on account of principal of
(or premium, if any) or interest (including any Liquidated Damages) on the
Securities, and to that end the holders of Senior Indebtedness shall be entitled
to receive, for application to the payment thereof, any payment or distribution
of any kind or character, whether in cash, securities or other property,
including any such payment or distribution which may be payable or deliverable
by reason of the payment of any other indebtedness of the Company being
subordinated to the payment of the Securities, which may be payable or
deliverable in respect of the Securities in any such case, proceeding,
dissolution, liquidation or other winding up or event. In furtherance of the
foregoing, but not by way of limitation thereof, in the event of any case or
proceeding described in clause (a) above with the result that the Company is
excused from the obligation to pay all or any part of the interest otherwise
payable in respect of any Senior Indebtedness during the period subsequent to
the commencement of any such case or proceeding, all or such part, as the case
may be, of such interest shall be payable out of, and to that extent shall
diminish and be at the expense of, reorganization dividends or other
distributions in respect of the Notes.

          In the event that, notwithstanding the foregoing provisions of this
Section, the Trustee or the Holder of any Security shall have received any
payment or distribution of assets of the Company of any kind or character,
whether in cash, securities or other property, including any such payment or
distribution which may be payable or deliverable by reason of the payment of any
other indebtedness of the Company being subordinated to the payment of the
Securities, before all Senior Indebtedness is paid in full or payment thereof
provided for, and if such fact shall then have

                                      -85-
<PAGE>
 
been made known to the Trustee, or, as the case may be, such Holder, then and in
such event such payment or distribution shall be paid over or delivered
forthwith to the trustee in bankruptcy, receiver, liquidating trustee,
custodian, assignee, agent or other Person making payment or distribution of
assets of the Company for application to the payment of all Senior Indebtedness
remaining unpaid, to the extent necessary to pay all Senior Indebtedness in
full, after giving effect to any concurrent payment or distribution to or for
the holders of Senior Indebtedness.

          For purposes of this Article only, the words "cash, securities or
other property" shall not be deemed to include shares of stock of the Company as
reorganized or readjusted, or securities of the Company or any other corporation
provided for by a plan of reorganization or readjustment the payment of which is
subordinated at least to the extent provided in this Article with respect to the
Securities to the payment of all Senior Indebtedness which may at the time be
outstanding; provided, however, that (i) such Senior Indebtedness is assumed by
the new corporation, if any, resulting from any such reorganization or
readjustment, and (ii) the rights of the holders of the Senior Indebtedness are
not, without the consent of such holders, altered by such reorganization or
readjustment.  The consolidation of the Company with, or the merger of the
Company into, another Person or the liquidation or dissolution of the Company
following the conveyance or other disposition of its properties and assets
substantially as an entirety to another Person upon the terms and conditions set
forth in Article Eight shall not be deemed a dissolution, winding up,
liquidation, reorganization, assignment for the benefit of creditors or
marshaling of assets and liabilities of the Company for the purposes of this
Section if the Person formed by such consolidation or into which the Company is
merged or the Person which acquires by conveyance or other disposition such
properties and assets substantially as an entirety, as the case may be, shall,
as a part of such consolidation, merger, conveyance or other disposition, comply
with the conditions set forth in Article Eight.

 Section 1403. Prior Payment to Senior Indebtedness Upon Acceleration of
Securities.

          In the event that any Securities are declared due and payable before
their Stated Maturity, then and in such event the holders of Senior Indebtedness
outstanding at the time such Securities so become due and payable shall be
entitled to receive payment in full of all amounts due or to become due on or in
respect of all such Senior Indebtedness, or provision shall be made for such
payment in money or money's worth, before the Holders of the Securities are
entitled to receive any payment (including any payment which may be payable by
reason of the payment of any other indebtedness of the Company being
subordinated to the payment of the Securities) by the Company on account of the
principal of (or premium, if any) or interest (including any Liquidated Damages)
on the Securities or on account of the purchase or other acquisition of
Securities.

          In the event that, notwithstanding the foregoing, the Company shall
make any payment to the Trustee or the Holder of any Securities prohibited by
the foregoing provisions of this Section, and if such facts shall then have been
made known to the Trustee or, as the case may be, such Holder, then and in such
event such payment shall be paid over and delivered forthwith to the Company for
the benefit of the holders of Senior Indebtedness.

                                      -86-
<PAGE>
 
           The provisions of this Section shall not apply to any payment with
respect to which Section 1402 would be applicable.

 Section 1404. No Payment When Senior Indebtedness in Default.

          (a) In the event and during the continuation of any default in the
payment of principal (or premium, if any) or interest on any Senior
Indebtedness, or in the payment of any commitment or other fees in respect
thereof, or in the event that any event of default with respect to any Senior
Indebtedness shall have occurred and be continuing permitting the holders of
such Senior Indebtedness (or a trustee on behalf of the holders thereof) to
declare such Senior Indebtedness due and payable prior to the date on which it
would otherwise have become due and payable, unless and until such event of
default shall have been cured or waived or shall have ceased to exist and such
acceleration shall have been rescinded or annulled, or (b) in the event any
judicial proceeding shall be pending with respect to any such default in payment
or event of default, then no payment (including any payment which may be payable
by reason of the payment of any other indebtedness of the Company being
subordinated to the payment of the Securities) shall be made by the Company on
account of principal of (or premium, if any) or interest (including any
Liquidated Damages) on the Securities or on account of the purchase or other
acquisition of Securities.

          In the event that, notwithstanding the foregoing, the Company shall
make any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions of this Section, and if such fact shall then have been made
known to the Trustee or, as the case may be, such Holder, then and in such event
such payment shall be paid over and delivered forthwith to the Company for the
benefit of the holders of Senior Indebtedness.

           The provisions of this Section shall not apply to any payment with
respect to which Section 1402 would be applicable.

 Section 1405. Acknowledgment of Reliance.

          Each Holder of Notes by his acceptance thereof acknowledges and agrees
that the subordination provisions included herein are, and are intended to be,
an inducement and a consideration to each holder of any Senior Indebtedness,
whether such Senior Indebtedness was created or acquired before or after the
issuance of Notes, to acquire and/or continue to hold such Senior Indebtedness,
and such holder of Senior Indebtedness shall be deemed conclusively to have
relied on such subordination provisions in acquiring and/or continuing to hold
such Senior Indebtedness.

 Section 1406. Subrogation to Rights of Holders of Senior Indebtedness.

          Subject to the payment in full of all Senior Indebtedness, the Holders
of the Securities shall be subrogated to the extent of the payments or
distributions made to the holders of such Senior Indebtedness pursuant to the
provisions of this Article to the rights of the holders of such Senior
Indebtedness to receive payments or distributions of cash, securities or other
property applicable to the Senior Indebtedness until the principal of (and
premium, if any) and interest on the

                                      -87-
<PAGE>
 
Securities shall be paid in full.  For purposes of such subrogation, no payments
or distributions to the holders of the Senior Indebtedness of any cash,
securities or other property to which the Holders of the Securities or the
Trustee would be entitled except for the provisions of this Article, and no
payments over pursuant to the provisions of this Article to the Company or to
the holders of Senior Indebtedness by Holders of the Securities or the Trustee
shall, as between the Company, its creditors other than holders of Senior
Indebtedness and the Holders of the Securities, be deemed to be a payment or
distribution by the Company to or on account of the Securities.

 Section 1407. Provisions Solely to Define Relative Rights.

          The provisions of this Article are and are intended solely for the
purpose of defining the relative rights of the Holders of the Securities, on the
one hand, and the holders of Senior Indebtedness, on the other hand.  Nothing
contained in this Article or elsewhere in this Indenture or in the Securities is
intended to or shall (a) impair, as among the Company, its creditors and the
Holders of the Securities, the obligation of the Company, which is absolute and
unconditional, and which, subject to the rights under this Article of the
holders of Senior Indebtedness, is intended to rank equally with all other
general obligations of the Company, to pay to the Holders of the Securities the
principal of (and premium, if any) and interest on the Securities as and when
the same shall become due and payable in accordance with their terms, or (b)
affect the relative rights against the Company of the Holders of the Securities
and creditors of the Company other than the holders of Senior Indebtedness, or
(c) prevent the Trustee or the Holder of any Security from exercising all
remedies otherwise permitted by applicable law upon default under this
Indenture, subject to the rights, if any, under this Article of the holders of
Senior Indebtedness to receive cash, securities or other property otherwise
payable or deliverable to the Trustee or such Holder.

 Section 1408. Trustee to Effectuate Subordination.

          Each Holder of a Security by his acceptance thereof authorizes and
directs the Trustee on his behalf to take such action as may be necessary or
appropriate to effectuate the subordination provided in this Article and
appoints the Trustee his attorney-in-fact for any and all such purposes.

 Section 1409. No Waiver of Subordination Provisions.

          No right of any present or future holder of any Senior Indebtedness to
enforce subordination as herein provided shall at any time in any way be
prejudiced or impaired by any act or failure to act on the part of the Company
or by any act or failure to act in good faith by any such holder, or by any
noncompliance by the Company with the terms, provisions and covenants of this
Indenture, regardless of any knowledge thereof any such holder may have or be
otherwise charged with.

          Without in any way limiting the generality of the foregoing paragraph,
the holders of Senior Indebtedness may, at any time and from time to time,
without the consent of or notice to the Trustee or the Holders of the
Securities, without incurring responsibility to the Holders of the Securities
and without impairing or releasing the subordination provided in this Article or
the

                                      -88-
<PAGE>
 
obligations hereunder of the Holders of the Securities to the holders of Senior
Indebtedness, do any one or more of the following: (i) change the manner, place
or terms of payment or extend the time of payment of, or renew or alter, Senior
Indebtedness, or otherwise amend or supplement in any manner Senior Indebtedness
or any instrument evidencing the same or any agreement under which Senior
Indebtedness is outstanding; (ii) sell, exchange, release or otherwise deal with
any property pledged, mortgaged or otherwise securing Senior Indebtedness; (iii)
release any Person liable in any manner for the collection of Senior
Indebtedness; and (iv) exercise or refrain from exercising any rights against
the Company and any other Person.

 Section 1410. Notice to Trustee.

          The Company shall give prompt written notice to the Trustee of any
fact known to the Company which would prohibit the making of any payment to or
by the Trustee in respect of the Securities.  Failure to give such notice shall
not affect the subordination of the Securities to Senior Indebtedness.
Notwithstanding the provisions of this Article or any other provision of this
Indenture, the Trustee shall not be charged with knowledge of the existence of
any facts which would prohibit the making of any payment to or by the Trustee in
respect of the Securities, unless and until a Responsible Officer of the Trustee
shall have received written notice thereof from the Company or a holder of
Senior Indebtedness or from any trustee therefor; and, prior to the receipt of
any such written notice, the Trustee, subject to the provisions of Section 601,
shall be entitled in all respects to assume that no such facts exist; provided,
however, that if the Trustee shall not have received, at least three Business
Days prior to the date upon which by the terms hereof any such money may become
payable for any purpose (including without limitation, the payment of the
principal of, and premium, if any, or interest on any Security), the notice with
respect to such money provided for in this Section, then, anything herein
contained to the contrary notwithstanding, the Trustee shall have full power and
authority to receive such money and to apply the same to the purpose for which
such money was received and shall not be affected by any notice to the contrary
which may be received by it within three Business Days prior to such date.

          Subject to the provisions of Section 601, the Trustee shall be
entitled to rely on the delivery to it of a written notice by a Person
representing himself to be a holder of Senior Indebtedness (or a trustee on
behalf of such holder) to establish that such notice has been given by a holder
of Senior Indebtedness (or a trustee on behalf of any such holder).  In the
event that the Trustee determines in good faith that further evidence is
required with respect to the right of any Person as a holder of Senior
Indebtedness to participate in any payment or distribution pursuant to this
Article, the Trustee may request such Person to furnish evidence to the
reasonable satisfaction of the Trustee as to the amount of Senior Indebtedness
held by such Person, the extent to which such Person is entitled to participate
in such payment or distribution and any other facts pertinent to the rights of
such Person under this Article, and if such evidence is not furnished, the
Trustee may defer any payment to such Person pending judicial determination as
to the right of such Person to receive such payment.

                                      -89-
<PAGE>
 
 Section 1411. Reliance on Judicial Order or Certificate of Liquidating
Agent.

          Upon any payment or distribution of assets of the Company referred to
in this Article, the Trustee, subject to the provisions of Section 601, and the
Holders of the Securities shall be entitled to rely upon any order or decree
entered by any court of competent jurisdiction in which such insolvency,
bankruptcy, receivership, liquidation, reorganization, dissolution, winding up
or similar case or proceeding is pending, or a certificate of the trustee in
bankruptcy, liquidating trustee, custodian, receiver, assignee for the benefit
of creditors, agent or other Person making such payment or distribution,
delivered to the Trustee or to the Holders of Securities, for the purpose of
ascertaining the Persons entitled to participate in such payment or
distribution, the holders of Senior Indebtedness and other indebtedness of the
Company, the amount thereof or payable thereon, the amount or amounts paid or
distributed thereon and all other facts pursuant thereto or to this Article.

 Section 1412. Trustee Not Fiduciary for Holders of Senior Indebtedness.

          The Trustee shall not be deemed to owe any fiduciary duty to the
holders of Senior Indebtedness and shall not be liable to any such holders if it
shall in good faith mistakenly pay over or distribute to Holders of Securities
or to the Company or to any other Person cash, securities or other property to
which any holders of Senior Indebtedness shall be entitled by virtue of this
Article or otherwise.

  Section 1413.  Rights of Trustee as Holder of Senior Indebtedness;
Preservation of Trustee's Rights.

          The Trustee in its individual capacity shall be entitled to all the
rights set forth in this Article with respect to any Senior Indebtedness which
may at any time be held by it, to the same extent as any other holder of Senior
Indebtedness, and nothing in this Indenture shall deprive the Trustee of any of
its rights as such holder.

          Nothing in this Article shall apply to claims of, or payments to, the
Trustee or any predecessor Trustee under or pursuant to Section 607.

 Section 1414. Article Applicable to Paying Agents.

          In case at any time any Paying Agent other than the Trustee shall have
been appointed by the Company and be then acting hereunder, the term "Trustee"
as used in this Article shall in such case (unless the context otherwise
requires) be construed as extending to and including such Paying Agent within
its meaning as fully for all intents and purposes as if such Paying Agent were
named in this Article in addition to or in place of the Trustee; provided,
however, that Section 1413 shall not apply to the Company or any Affiliate of
the Company if it or such Affiliate acts as Paying Agent.

                                      -90-
<PAGE>
 
 Section 1415. Certain Conversions Deemed Payment.

          For the purposes of this Article only, (1) the issuance and delivery
of junior securities upon conversion of Securities in accordance with Article
Thirteen shall not be deemed to constitute a payment or distribution on account
of the principal of or premium or interest on Securities or on account of the
purchase or other acquisition of Securities, and (2)  the payment, issuance or
delivery of cash, securities or other property (other than junior securities)
upon conversion of a Security shall be deemed to constitute payment on account
of the principal of such Security.  For the purposes of this Section, the term
"junior securities" means (a) shares of any stock of any class of the Company
and (b) securities of the Company which are subordinated in right of payment to
all Senior Indebtedness which may be outstanding at the time of issuance or
delivery of such securities to substantially the same extent as, or to a greater
extent than, the Securities are so subordinated as provided in this Article.
Nothing contained in this Article or elsewhere in this Indenture or in the
Securities is intended to or shall impair, as among the Company, its creditors,
other than holders of Senior Indebtedness and the Holders of the Securities, the
right, which is absolute and unconditional, of the Holder of any Security to
convert such Security in accordance with Article Thirteen.


                                    * * * *


          This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.

                                      -91-
<PAGE>
 
          IN WITNESS WHEREOF, the parties hereto have caused this Indenture to
be duly executed, all as of the day and year first above written.

                                       OFFSHORE LOGISTICS, INC.



                                       By
                                         ------------------------------


                                       FLEET NATIONAL BANK
 


                                       By
                                         -------------------------------

                                      -92-
<PAGE>
 
                                                              ANNEX A -- Form of
                                                        Regulation S Certificate


                            REGULATION S CERTIFICATE

          (For transfers pursuant to Section 305(b)(i), (iii) and (v)
                               of the Indenture)


Fleet National Bank
  as Trustee
777 Main Street
Hartford, Connecticut  06115

     Re:   6% Convertible Subordinated Notes due
           2003 of Offshore Logistics, Inc. (the "Securities")
           ---------------------------------------------------

     Reference is made to the Indenture, dated as of December 15, 1996 (the
"Indenture"), from Offshore Logistics, Inc. (the "Company") to Fleet National
Bank, as Trustee.  Terms used herein and defined in the Indenture or in
Regulation S or Rule 144 under the U.S. Securities Act of 1933 (the "Securities
Act") are used herein as so defined.

     This certificate relates to U.S. $____________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

     CUSIP No(s). _____________________

     CERTIFICATE No(s). ___________________

The person in whose name this certificate is executed below (the "Undersigned")
hereby certifies that either (i) it is the sole beneficial owner of the
Specified Securities or (ii) it is acting on behalf of all the beneficial owners
of the Specified Securities and is duly authorized by them to do so.  Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner.  If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

     The Owner has requested that the Specified Securities be transferred to a
person (the "Transferee") who will take delivery in the form of a Regulation S
Security.  In connection with such transfer, the Owner hereby certifies that,
unless such transfer is being effected pursuant to an effective registration
statement under the Securities Act, it is being effected in accordance with Rule
904 or Rule 144 under the Securities Act and with all applicable securities laws
of the states

                                      A-1
<PAGE>
 
of the United States and other jurisdictions.  Accordingly, the Owner hereby
further certifies as follows:

     (1) Rule 904 Transfers.  If the transfer is being effected in accordance
with Rule 904:

         (A) the Owner is not a distributor of the Securities, an affiliate of
     the Company or any such distributor or a person acting on behalf of any of
     the foregoing;

         (B) the offer of the Specified Securities was not made to a person in
     the United States;

         (C) either:

                (i) at the time the buy order was originated, the Transferee was
         outside the United States or the Owner and any person acting on its
         behalf reasonably believed that the Transferee was outside the United
         States, or

                (ii) the transaction is being executed in, on or through the
         facilities of the Eurobond market, as regulated by the Association of
         International Bond Dealers, or another designated offshore securities
         market and neither the Owner nor any person acting on its behalf knows
         that the transaction has been prearranged with a buyer in the United
         States;

         (D) no directed selling efforts have been made in the United States by
or on behalf of the Owner or any affiliate thereof;

         (E) if the Owner is a dealer in securities or has received a selling
concession, fee or other remuneration in respect of the Specified Securities,
and the transfer is to occur during the Restricted Period, then the requirements
of Rule 904(c)(1) have been satisfied; and

         (F) the transaction is not part of a plan or scheme to evade the
registration requirements of the Securities Act.

(2) Rule 144 Transfers. If the transfer is being effected pursuant to Rule 144:

         (A) the transfer is occurring after a holding period of at least two
years (computed in accordance with paragraph (d) of Rule 144) has elapsed since
the date the Specified Securities were acquired from the Company or from an
affiliate (as such term is defined in Rule 144) of the Company, whichever is
later, and is being effected in accordance with the applicable amount, manner of
sale and notice requirements of paragraphs (e), (f) and (h) of Rule 144; or

         (B) the transfer is occurring after a period of at least three years
has elapsed since the date the Specified Securities were acquired from the
Company or from an affiliate (as

                                      A-2
<PAGE>
 
         such term is defined in Rule 144) of the Company, whichever is later,
         and the Owner is not, and during the preceding three months has not
         been, an affiliate of the Company.

         This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Initial Purchasers.


Dated:
      -----------------------------------------------------------------------  
      (Print the name of the Undersigned, as such term is defined in the
       second paragraph of this certificate.)



      By:
         --------------------------------------------------------------------
         Name:
         Title:

      (If the Undersigned is a corporation, partnership or fiduciary, the title
      of the person signing on behalf of the Undersigned must be stated.)

                                      A-3
<PAGE>
 
                                                   ANNEX B -- Form of Restricted
                                                          Securities Certificate


                       RESTRICTED SECURITIES CERTIFICATE

       (For transfers pursuant to Section 305(b)(ii), (iii), (iv) and (v)
                               of the Indenture)


Fleet National Bank
  as Trustee
777 Main Street
Hartford, Connecticut  06115

     Re:   6% Convertible Subordinated Notes due
           2003 of Offshore Logistics, Inc. (the "Securities")
           ---------------------------------------------------

     Reference is made to the Indenture, dated as of December 15, 1996 (the
"Indenture"), from Offshore Logistics, Inc. (the "Company") to Fleet National
Bank, as Trustee.  Terms used herein and defined in the Indenture or in Rule 144
under the U.S. Securities Act of 1933 (the "Securities Act") are used herein as
so defined.

     This certificate relates to U.S.$______________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

     CUSIP No(s). _____________________

     CERTIFICATE No(s). ___________________

The person in whose name this certificate is executed below (the "Undersigned")
hereby certifies that either (i) it is the sole beneficial owner of the
Specified Securities or (ii) it is acting on behalf of all the beneficial owners
of the Specified Securities and is duly authorized by them to do so.  Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner.  If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

     The Owner has requested that the Specified Securities be transferred to a
person (the "Transferee") who will take delivery in the form of a Restricted
Security.  In connection with such transfer, the Owner hereby certifies that,
unless such transfer is being effected pursuant to an effective registration
statement under the Securities Act, it is being effected in accordance with Rule
144A or Rule 144 under the Securities Act and all applicable securities laws of
the states of the United States and other jurisdictions.  Accordingly, the Owner
hereby further certifies as:

                                      B-1
<PAGE>
 
(1)  Rule 144A Transfers.  If the transfer is being effected in accordance with
     Rule 144A:

     (A) the Specified Securities are being transferred to a person that the
Owner and any person acting on its behalf reasonably believe is a "qualified
institutional buyer" within the meaning of Rule 144A, acquiring for its own
account or for the account of a qualified institutional buyer; and

     (B) the Owner and any person acting on its behalf have taken reasonable
steps to ensure that the Transferee is aware that the Owner may be relying on
Rule 144A in connection with the transfer; and

(2)  Rule 144 Transfers.  If the transfer is being effected pursuant to Rule
     144:

     (A) the transfer is occurring after a holding period of at least two years
(computed in accordance with paragraph (d) of Rule 144) has elapsed since the
date the Specified Securities were acquired from the Company or from an
affiliate (as such term is defined in Rule 144) of the Company, whichever is
later, and is being effected in accordance with the applicable amount, manner of
sale and notice requirements of paragraphs (e), (f) and (h) of Rule 144; or

     (B) the transfer is occurring after a period of at least three years has
elapsed since the date the Specified Securities were acquired from the Company
or from an affiliate (as such term is defined in Rule 144) of the Company,
whichever is later, and the Owner is not, and during the preceding three months
has not been, an affiliate of the Company.

     This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Initial Purchasers.



Dated:
      -----------------------------------------------------------------------  
      (Print the name of the Undersigned, as such term is defined in the
      second paragraph of this certificate.)



      By:
         ---------------------------------------------------------------------
         Name:
         Title:

      (If the Undersigned is a corporation, partnership or fiduciary, the
      title of the person signing on behalf of the Undersigned must be stated.)

                                      B-2
<PAGE>
 
                                                 ANNEX C -- Form of Unrestricted
                                                          Securities Certificate


                      UNRESTRICTED SECURITIES CERTIFICATE

       (For removal of Securities Act Legend pursuant to Section 305(c))


Fleet National Bank
  as Trustee
777 Main Street
Hartford, Connecticut  06115

     Re:   6% Convertible Subordinated Notes due
           2003 of Offshore Logistics, Inc. (the "Securities")
           ---------------------------------------------------

     Reference is made to the Indenture, dated as of December 15, 1996 (the
"Indenture"), from Offshore Logistics, Inc. (the "Company") to Fleet National
Bank, as Trustee.  Terms used herein and defined in the Indenture or in
Regulation S or Rule 144 under the U.S. Securities Act of 1933 (the "Securities
Act") are used herein as so defined.

     This certificate relates to U.S.$_______________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

     CUSIP No(s). _____________________

     CERTIFICATE No(s). ___________________

The person in whose name this certificate is executed below (the "Undersigned")
hereby certifies that either (i) it is the sole beneficial owner of the
Specified Securities or (ii) it is acting on behalf of all the beneficial owners
of the Specified Securities and is duly authorized by them to do so.  Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner.  If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

     The Owner has requested that the Specified Securities be exchanged for
Securities bearing no Securities Act Legend pursuant to Section 305(c) of the
Indenture.  In connection with such exchange, the Owner hereby certifies that
the exchange is occurring after a period of at least three years has elapsed
since the date the Specified Securities were acquired from the Company or from
an affiliate (as such term is defined in Rule 144) of the Company, whichever is
later, and the Owner is not, and during the preceding three months has not been,
an affiliate of the Company.  The Owner

                                      C-1
<PAGE>
 
also acknowledges that any future transfers of the Specified Securities must
comply with all applicable securities laws of the states of the United States
and other jurisdictions.

     This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Initial Purchasers.



Dated:
      -----------------------------------------------------------------------  
      (Print the name of the Undersigned, as such term is defined in the
      second paragraph of this certificate.)



      By:
         ---------------------------------------------------------------------
         Name:
         Title:

      (If the Undersigned is a corporation, partnership or fiduciary, the
      title of the person signing on behalf of the Undersigned must be stated.)

                                      C-2
<PAGE>
 
                                                              ANNEX D -- Form of
                                                           Surrender Certificate

     In connection with the certification contemplated by Section 1302 relating
to compliance with certain restrictions relating to transfers of Restricted
Securities, such certification shall be provided substantially in the form of
the following certificate, with only such changes thereto as shall be approved
by the Company and the Initial Purchasers:

                                  CERTIFICATE

                            OFFSHORE LOGISTICS, INC.

                         6% CONVERTIBLE NOTES DUE 2003

     This is to certify that as of the date hereof with respect to
U.S.$__________ principal amount (as defined in the Indenture) of the above-
captioned securities surrendered on the date hereof (the "Surrendered
Securities") for registration of transfer, or for conversion where the
securities issuable upon such conversion are to be registered in a name other
than that of the undersigned Holder (each such transaction being a "transfer"),
the undersigned Holder (as defined in the Indenture) certifies that the transfer
of Surrendered Securities associated with such transfer complies with the
restrictive legend set forth on the face of the Surrendered Securities for the
reason checked below:

    ------         The transfer of the Surrendered Securities complies with Rule
                   144 under the U.S. Securities Act of 1933, as amended (the
                   "Securities Act"); or

    ------         The transfer of the Surrendered Securities complies with Rule
                   144A under the Securities Act; or
 
    ------         The transfer of the Surrendered Securities complies with Rule
                   904 of Regulation S under the Securities Act; or
 
    ------         The transfer of the Surrendered Securities has been made to
                   an institution that is an "accredited investor" within the
                   meaning of Rule 501(a)(1), (2), (3) or (7) under the
                   Securities Act in a transaction exempt from the registration
                   requirements of the Securities Act.
 
                            [Name of Holder]


                            ---------------------------

Dated __________________ *
     *To be dated the date
       of surrender

                                      D-1
<PAGE>
 
                IN WITNESS WHEREOF, the parties hereto have caused this 
Indenture to be duly executed, all as of the day and year first above written.

                                   OFFSHORE LOGISTICS, INC.



                                   By: /s/ J.B. Clement
                                       ------------------------------- 
                                       J.B. Clement
                                       Chairman of the Board, President & CEO


                                   FLEET NATIONAL BANK       

              

                                   By: /s/ Susan C. Merker
                                      --------------------------------         
                                      Susan C. Merker
                                      Assistant Vice President

                                      D-2

<PAGE>
 
                                                                    EXHIBIT 4(2)

     THIS REGISTRATION RIGHTS AGREEMENT, dated as of December 17, 1996 (this
"Agreement"), is by and among Offshore Logistics, Inc., a Delaware corporation
(the "Company"), Jefferies & Company, Inc. ("Jefferies"), Simmons & Company
International ("SCI") and Johnson Rice & Company L.L.C. ("JRC" and, together
with Jefferies and SCI, the "Purchasers").

                                    RECITALS

     WHEREAS, the Company and the Purchasers have entered into a Purchase
Agreement, dated December 11, 1996 (the "Purchase Agreement"), providing for,
among other things, the sale by the Company and the purchase by the Purchasers
of an aggregate of $80,000,000 principal amount, and, at the election of the
Purchasers, up to an aggregate of $10,500,000 additional principal amount, of
the Company's 6% Convertible Subordinated Notes due 2003, convertible into
shares of Common Stock (as defined herein) of the Company as provided in the
Indenture (as defined herein); and

     WHEREAS, this Agreement is being entered into pursuant to the Purchase
Agreement as a condition to the closing of the sale of the Securities (as
defined herein) pursuant thereto;

     NOW, THEREFORE, in consideration of the premises, and of the mutual
covenants, representations, warranties and agreements herein contained, the
parties hereto agree as follows:

1.  CERTAIN DEFINITIONS.
    ------------------- 

     As used in this Agreement, the following terms shall have the following
respective meanings:

     (a) "Closing Date" shall mean (i) the First Time of Delivery as defined in
the Purchase Agreement and (ii) the Issue Date as defined in the Indenture.

     (b) "Commission" shall mean the Securities and Exchange Commission, or any
other federal agency at the time administering the Exchange Act or the
Securities Act, whichever is the relevant statute for the particular purpose.

     (c) "Common Stock" means the Common Stock, par value $.01 per share, of the
Company, and any securities of the Company or any successor which may be
issuable upon conversion of the Securities pursuant to Article Thirteen of the
Indenture.

     (d) "Effective Time" shall mean the date on which the Commission declares
the Registration Statement effective or on which the Registration Statement
otherwise becomes effective.

     (e) "Exchange Act" shall mean the Securities Exchange Act of 1934, or any
successor thereto, as the same shall be amended from time to time.

     (f) The term "holder" shall mean any person that is the record owner of
Registrable Securities or any person that has a beneficial interest in a global
security representing Registerable Securities.
<PAGE>
 
     (g) "Indenture" shall mean the Indenture, dated as of December 15, 1996,
between the Company and Fleet National Bank, as Trustee, as amended and
supplemented from time to time in accordance with its terms.

     (h) The term "managing underwriter or underwriters" shall mean the person
or persons selected pursuant to Section 7(a) of this Agreement to manage an
underwritten offering of Registrable Securities.

     (i) The term "person" shall have the meaning specified in the Indenture.

     (j) "Prospectus" shall mean the prospectus (including any preliminary
prospectus and any final prospectus) included in any Registration Statement, as
amended or supplemented by any prospectus supplement with respect to the terms
of the offering of any portion of the Registrable Securities covered by the
Registration Statement and by all other amendments and supplements to such
prospectus, including all material incorporated by reference in such prospectus
and all documents filed after the date of such prospectus by the Company under
the Exchange Act and incorporated by reference therein.

     (k) "Registrable Securities" shall mean all or any portion of the
Securities issued under the Indenture and the shares of Common Stock issuable
upon conversion of such Securities; provided, however, that a security ceases to
be a Registrable Security when it is no longer a Restricted Security.

     (l) "Registration Expenses" shall have the meaning assigned thereto in
Section 4 of this Agreement.

     (m) "Registration Statement" shall mean a "shelf" registration statement
filed under the Securities Act providing for the registration of, and the sale
on a continuous or delayed basis by the holders of, all of the Registrable
Securities pursuant to Rule 415 under the Securities Act and/or any similar rule
that may be adopted by the Commission, filed by the Company pursuant to the
provisions of Section 2 of this Agreement, including the Prospectus contained
therein, any amendments and supplements to such registration statement,
including post-effective amendments, and all exhibits and all material
incorporated by reference in such registration statement.

     (n) "Restricted Security" shall mean any Security or share of Common Stock
issuable upon conversion thereof unless or until (i) it has been effectively
registered under the Securities Act and sold in a manner contemplated by the
Registration Statement, (ii) it has been transferred in compliance with Rule 144
under the Securities Act (or any successor provision thereto) or (iii) it has
otherwise been transferred and a new Security or share of Common Stock not
subject to transfer restrictions under the Securities Act has been delivered by
or on behalf of the Company in accordance with Section 305 of the Indenture.

     (o) "Rules and Regulations" shall mean the published rules and regulations
of the Commission promulgated under the Securities Act or the Exchange Act, as
in effect at any relevant time.

                                      -2-
<PAGE>
 
     (p) "Security" or "Securities" shall mean the Company's 6% Convertible
Subordinated Notes due 2003, to be issued pursuant to the Indenture and sold,
either pursuant to the Purchase Agreement or to Caledonia Industrial & Services
Limited in connection with the Bristow Transaction (as defined in the Offering
Circular, which, in turn, is defined in the Purchase Agreement) and any
securities issued in exchange therefor or in lieu thereof pursuant to the
Indenture.

     (q) "Securities Act" shall mean the Securities Act of 1933, as amended, or
any successor thereto, as the same shall be amended from time to time.

     (r) "Trust Indenture Act" shall mean the Trust Indenture Act of 1939, as
amended, or any successor thereto, and the rules, regulations and forms
promulgated thereunder, all as the same shall be amended from time to time.

     (s) The term "underwriter" shall hereinafter mean any underwriter of an
underwritten offering of Registrable Securities.

     (t) Wherever there is a reference in this Agreement to a percentage of the
"principal amount" of the Registrable Securities or to a percentage of
Registrable Securities, Common Stock that constitutes a Registrable Security
shall be treated as representing the principal amount of Securities which was
surrendered for conversion in order to receive such number of shares of Common
Stock.

2.  REGISTRATION UNDER THE SECURITIES ACT.
    ------------------------------------- 

     (a) The Company shall, at its expense, within 90 calendar days following
the Closing Date, file with the Commission a Registration Statement with respect
to the Registrable Securities as to which the Company has obtained the
information contemplated by Section 3(d) and thereafter shall use its reasonable
best efforts to cause such Registration Statement to be declared effective by
the Commission under the Securities Act within 180 calendar days after the
Closing Date.

     (b) Subject to Section 2(c) hereof, the Company shall use its reasonable
best efforts, and will file such supplements or amendments to the Registration
Statement as may be necessary or appropriate, to keep the Registration Statement
continuously effective under the Securities Act and usable by holders for
resales of Registrable Securities for a period of three years from the Effective
Time or, such shorter period that will terminate upon the earlier of the
following: (i) when there are no outstanding Registrable Securities and (ii)
when, in the written opinion of Fulbright & Jaworski L.L.P. or other independent
counsel to the Company, all outstanding Registrable Securities held by persons
that are not "affiliates" of the Company (as defined in Rule 144(a)(1) under the
Securities Act) may be resold without registration under the Securities Act
pursuant to Rule 144(k) under the Securities Act (or any successor provision to
such Rule) (and thereupon the Company shall remove all legends from the
Registrable Securities restricting the transfer thereof (other than any
Registrable Securities held by an affiliate)).

     (c)  (i)  If the Company determines in its good faith judgment that the
filing of any supplement or amendment to the Registration Statement to keep such
Registration Statement continuously effective under the Securities Act during
the Effectiveness Period and usable by holders for resales of Registrable
Securities, would require the disclosure of material information that the
Company has a bona fide business purpose for preserving as confidential or the
disclosure of which would materially adversely affect the Company's

                                      -3-
<PAGE>
 
ability to consummate a significant transaction, upon written notice of such
determination by the Company to the holders of the Registrable Securities, the
obligation of the Company to supplement or amend the Registration Statement
(including any action contemplated by Section 3 hereof) will be suspended until
the Company notifies the holders in writing that the reasons for suspension of
such obligations on the part of the Company as set forth in this Section 2(c)(i)
no longer exist; provided, however, that no such suspension shall last more than
60 consecutive days.

     (ii) If the Company initiates and is in good faith pursuing an underwritten
primary offering of equity securities (as defined in Rule 405 under the
Securities Act) (which primary offering may also include secondary sales of
securities of the Company) on a registration statement (other than any
registration by the Company on Form S-8, or a successor or substantially similar
form, of an employee stock option, stock purchase or compensation plan or of
securities issued or issuable pursuant to any such plan), upon written notice
thereof by the Company to the holders the obligation of the Company to
supplement or amend the Registration Statement shall be suspended during the
registration period of such underwritten primary offering.

     (d) Notwithstanding the provisions of Section 2(c) hereof, the aggregate
number of days (whether or not consecutive) during which the Company may delay
the filing of any such supplement or amendment shall in no event exceed 90 days
during any period of 12 consecutive months and the right of the Company to
suspend its obligation to supplement or amend the Registration Statement under
Section 2(c) shall not limit any obligation the Company may have to pay
additional interest pursuant to Section 1007 of the Indenture.

3.  REGISTRATION PROCEDURES.
    ----------------------- 

     (a) Prior to or at the Effective Time the Company shall use its reasonable
best efforts to qualify the Indenture under the Trust Indenture Act; in
connection with such qualification, the Company shall cooperate with the trustee
under the Indenture and the Holders (as defined in the Indenture) to effect such
changes to the Indenture as may be required for such Indenture to be so
qualified in accordance with the terms of the Trust Indenture Act; and the
Company shall execute, and use all reasonable efforts to cause the trustee under
the Indenture to execute, all documents that may be required to effect such
changes and other forms and documents required to be filed with the Commission
to enable such Indenture to be so qualified in a timely manner.

     (b) In the event that any such amendment or modification referred to in
Section 3(a) hereof involves the appointment of a new trustee under the
Indenture, the Company shall appoint a new trustee thereunder pursuant to the
applicable provisions of the Indenture.

     (c) In connection with the Company's obligations with respect to the
Registration Statement, the Company shall use its reasonable best efforts to
effect or cause the Registration Statement to permit the sale of the Registrable
Securities by the holders thereof in accordance with the intended method or
methods of distribution thereof described in the Registration Statement;
provided, however, that such method or methods of distribution may take the form
of an underwritten offering of the Registrable Securities only as provided in
Section 7 hereof.  In connection therewith, the Company shall, as promptly as
possible:

     (i) before filing a Registration Statement or Prospectus or any amendments
or supplements thereto, including documents incorporated by reference in the
Registration

                                      -4-
<PAGE>
 
Statement, offer to provide, and if requested, furnish to the holders of the
Registrable Securities covered by such Registration Statement and the managing
underwriter or underwriters, if any, of Registrable Securities being sold in an
underwritten offering copies of all such documents proposed to be filed,
together with copies of documents previously filed with the Commission and
proposed to be incorporated by reference in the Registration Statement, which
Registration Statement or Prospectus or any supplement or amendment thereto (but
not any document incorporated by reference therein) will be subject to the
review of such holders and managing underwriter or underwriters, and the Company
will not file the Registration Statement or any amendment thereto or any
Prospectus or any supplement thereto (including documents filed with the
Commission under the Exchange Act after the initial filing of the Registration
Statement and incorporated by reference in the Registration Statement) to which
any of the Purchasers or, if none of the Purchasers is a selling holder, the
holders of at least 20% in aggregate principal amount of the Registrable
Securities covered by such Registration Statement or the managing underwriter or
underwriters, if any, shall reasonably object; provided, however, that the
Company may assume, for the purposes of this subparagraph (i), that objections
to the inclusion of information specifically requested to be included in the
Registration Statement or other documents by the staff of the Commission, or in
the opinion of counsel to the Company required to be in the Registration
Statement or other documents, or specifically required by the Securities Act or
the Rules and Regulations, shall not be deemed to be reasonable;

     (ii) for a reasonable period prior to the filing of the Registration
Statement and throughout the period specified in Section 2(b) hereof, make
available for inspection (solely for the purpose of verifying the accuracy of
information contained in the Registration Statement) by a representative or
representatives of the Purchasers or, if none of the Purchasers is then a
holder, the holders of not less than 20% of the principal amount of the
Registrable Securities, any underwriter participating in any disposition
pursuant to a Registration Statement, and any attorney or accountant retained by
any of the Purchasers or such selling holders or underwriter, all relevant
financial and other records, pertinent corporate documents and properties of the
Company, and cause the Company's officers, directors, employees and agents,
including independent public accounts and counsel, to supply all information
reasonably requested by any such representative, underwriter, attorney or
accountant in connection with such Registration Statement; provided, however,
that any records, information or documents that are designated by the Company in
writing as confidential shall be kept confidential by such persons unless
disclosure of such records, information or documents is required by court or
administrative order;

     (iii)  subject to the provisions of Section 2(c) above, prepare and file
with the Commission such amendments and post-effective amendments to the
Registration Statement, and such supplements to the Prospectus, as may be
required by the Rules and Regulations or the instructions applicable to the
registration form utilized by the Company or by the Securities Act or otherwise
necessary to keep the Registration Statement effective for the period specified
in Section 2(b) and cause the Prospectus as so supplemented to be filed pursuant
to Rule 424 under the Securities Act; and comply with the provisions of the
Securities Act with respect to the disposition of all Registrable Securities
covered by such Registration Statement during the period specified in Section
2(b) in accordance with the intended methods of disposition by the sellers
thereof set forth in such Registration Statement or supplement to the
Prospectus;

                                      -5-
<PAGE>
 
     (iv) notify the selling holders of Registrable Securities and the managing
underwriter or underwriters, if any, promptly, and confirm such advice in
writing,

     (A) when the Registration Statement, any pre-effective amendment thereto,
the Prospectus or any prospectus supplement or post-effective amendment to the
Registration Statement has been filed, and, with respect to the Registration
Statement or any post-effective amendment, when the same has become effective,

     (B) of any comments by the Commission or the "Blue Sky" or securities
commissioners or regulator of any State with respect to the Registration
Statement, the Prospectus or any prospectus supplement or any request by the
Commission or any securities commissioner or regulator for amendments or
supplements to the Registration Statement, the Prospectus or any prospectus
supplement or for additional information,

     (C) of the issuance by the Commission of any stop order suspending the
effectiveness of the Registration Statement or the initiation or threatening of
any proceedings for that purpose,

     (D) if at any time the representations and warranties of the Company
contemplated by subparagraph (xiv) below or Section 5 hereof cease to be true
and correct,

     (E) of the receipt by the Company of any notification with respect to the
suspension of the qualification of the Registrable Securities for sale under the
securities or "Blue Sky" laws of any jurisdiction or the initiation or
threatening of any proceeding for such purpose, and

     (F) of the existence of any fact or the happening of any event during the
period (other than any suspension period referred to in Section 2(c) hereof)
during which the Registration Statement is required hereunder to be effective as
a result of which the Registration Statement, any amendment or post-effective
amendment thereto, the Prospectus, any prospectus supplement, or any document
incorporated therein by reference contain an untrue statement of material fact
or omit to state a material fact required to be stated therein or necessary to
make the statements therein not misleading;

     (v) use its reasonable best efforts to obtain the withdrawal of any order
suspending the effectiveness of the Registration Statement at the earliest
possible moment;

     (vi) if requested by any managing underwriter or underwriters or any holder
of Registrable Securities being sold pursuant to an underwritten offering, as
soon as practicable incorporate in a prospectus supplement or post-effective
amendment to the Registration Statement such information as is required by the
applicable Rules and Regulations and as the managing underwriter or underwriters
or such holder specifies should be included therein relating to the terms of the
sale of the Registrable Securities, including, without limitation, information
with respect to the principal amount or number of shares of Registrable
Securities being sold by such holder to any underwriter or underwriters, the
name and description of such holder or underwriter, the offering price of such
Registrable Securities and any discount, commission or other compensation
payable

                                      -6-
<PAGE>
 
in respect thereof, the purchase price being paid therefor by such underwriter
or underwriters and with respect to any other terms of the underwritten offering
(including whether such underwriting commitment is on a firm commitment or best
efforts basis) of the Registrable Securities to be sold in such offering; and
make all required fillings of such prospectus supplement or post-effective
amendment promptly after being notified of the matters to be incorporated in
such prospectus supplement or post-effective amendment;

     (vii)  furnish to each selling holder of Registrable Securities and each
managing underwriter, if any, without charge, an executed copy of the
Registration Statement, each amendment and supplement thereto (in each case
including all exhibits thereto and documents incorporated by reference therein)
and such number of copies of the Registration Statement (including exhibits
thereto and documents incorporated by reference therein) as such persons may
reasonably request in order to facilitate the offering and disposition of the
Registrable Securities;

     (viii)  deliver to each selling holder of Registrable Securities and each
managing underwriter, if any, without charge, as many copies of the Prospectus
(including each preliminary prospectus) and any amendment or supplement thereto,
and such other documents, as such persons may reasonably request in order to
facilitate the offering and disposition of the Registrable Securities and to
permit any of such persons to satisfy the prospectus delivery requirements of
the Securities Act; the Company hereby consents to the use of the Prospectus or
any amendment or supplement thereto by each of the selling holders of
Registrable Securities and by each underwriter thereof, if any, in connection
with the offering and sale of the Registrable Securities covered by the
Prospectus or any amendment or supplement thereto; and as promptly as
practicable after the filing with the Commission of any document which is
incorporated by reference in the Prospectus (including each preliminary
prospectus) and any amendment or supplement thereto) deliver a copy of such
document to each holder of Registerable Securities covered by the Registration
Statement who requests such documents in writing from the Company;

     (ix) prior to any public offering of Registrable Securities, use reasonable
efforts to (A) register or qualify the Registrable Securities covered by the
Registration Statement for offer and sale under the securities or "Blue Sky"
laws of such jurisdictions as any selling holder or underwriter reasonably shall
request, (B) keep such registrations or qualifications in effect and comply with
such laws so as to permit the continuance of offers, sales and dealings therein
in such jurisdictions for so long as may be necessary (but not to exceed three
years from the Effective Time) to enable any such holder or underwriter to
complete its distribution of Registrable Securities pursuant to the Registration
Statement and (C) take any and all other actions as may be reasonably necessary
or advisable to enable the disposition in such jurisdictions of such Registrable
Securities; provided, however, that the Company shall not be required for any
such purpose to qualify as a foreign corporation in any jurisdiction wherein it
would not otherwise be required to qualify but for the requirements of this
Section 3(c)(ix) or consent to general service of process in any such
jurisdiction;

     (x) cooperate with the selling holders of Registrable Securities and the
managing underwriter or underwriters, if any, to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to
be sold, which certificates shall not bear any restrictive legends and which, if
so required by any securities exchange upon which any Registrable Securities are
listed, shall be penned, lithographed or engraved, or

                                      -7-
<PAGE>
 
produced by any combination of such methods, on steel engraved borders; and
enable such Registrable Securities to be in such denominations and registered in
such names as the selling holder or the managing underwriter or underwriters, if
any, may request at least two business days prior to any delivery of Registrable
Securities;

     (xi) use reasonable efforts to cause the Registrable Securities covered by
the Registration Statement to be registered with or approved by such other
governmental agencies or authorities (federal, state and local) as may be
necessary to enable the seller or sellers thereof or the underwriter or
underwriters, if any, to consummate the disposition of such Registrable
Securities;

     (xii)  if any fact or event contemplated by subparagraph (iv)(F) above
shall exist or occur, prepare a post-effective amendment or supplement to the
Registration Statement or the related Prospectus or any document incorporated
therein by reference or file any other required document so that the Prospectus,
as thereafter delivered to the purchasers of the Registrable Securities, will
not contain an untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein
not misleading;

     (xiii)  use its reasonable best efforts to cause the shares of Common Stock
constituting Registrable Securities covered by the Registration Statement to be
quoted on the Nasdaq National Market or, if the Common Stock is not then quoted
on the Nasdaq National Market, to be listed on such securities exchanges as the
Common Stock of the Company is then listed, upon effectiveness of the Shelf
Registration Statement;

     (xiv)  enter into such customary agreements (including a customary
underwriting agreement with the underwriter or underwriters, if any, which shall
include only such "lock-up arrangements", if any, as shall be agreeable to the
Company and the underwriter or underwriters) and take all such other actions
reasonably necessary in connection therewith in order to expedite or facilitate
the disposition of any Registrable Securities and, in such connection, whether
or not an underwriting agreement is entered into and whether or not the
Registrable Securities are to be sold in an underwritten offering:

     (A) make such representations and warranties to the holders of such
Registrable Securities and the underwriter or underwriters, if any, in form,
substance and scope as are customarily made in connection with primary
underwritten offerings of equity or convertible debt securities;

     (B) cause to be delivered to the sellers of Registrable Securities and the
underwriter or underwriters, if any, opinions of counsel to the Company, dated
the effective date of the Registration Statement and, in the case of an
underwritten offering, the date of delivery of any Registrable Securities sold
pursuant thereto (which counsel and opinions (in form, scope and substance)
shall be reasonably satisfactory to the managing underwriter or underwriters, if
any, and the appointed representative of or counsel to the holders of at least
50% in aggregate principal amount of the Registrable Securities being registered
(or, in the case of an underwritten offering, sold), addressed to each selling
holder and each underwriter, if any, covering the matters customarily covered in
opinions requested in primary underwritten offerings of equity and convertible
debt securities;

                                      -8-
<PAGE>
 
     (C) cause to be delivered on the effective date of the Registration
Statement, the date of the Prospectus and the effective date of the most recent
post-effective amendment to the Registration Statement, and at the time of the
signing of the underwriting or purchase agreement and at the time of delivery of
any Registrable Securities sold pursuant thereto, letters from the Company's
independent public accountants addressed to each selling holder and each
underwriter stating that such accountants are independent public accountants
within the meaning of the Securities Act and the applicable published Rules and
Regulations thereunder, and otherwise in customary form and covering such
financial and accounting matters as are customarily covered by letters of
independent certified public accountants delivered in connection with primary
underwritten public offerings of equity or convertible debt securities;

     (D) if an underwriting agreement is entered into, cause the same to set
forth in full the indemnification provisions and procedures of Section 6 hereof
(or such other provisions and procedures satisfactory to the managing
underwriter or underwriters and the Company) with respect to all parties to be
indemnified pursuant to said Section;

     (E) deliver such documents and certificates as may be reasonably requested
by any holder of Registrable Securities being sold or the managing underwriter
or underwriters, if any, to evidence the accuracy of the representations
contemplated by clause (A) above and compliance with any customary conditions
contained in the underwriting agreement or other agreement entered into by the
Company in connection with such offering;

     (xv) otherwise use its reasonable best efforts to comply with all
applicable Rules and Regulations, and make generally available to its security
holders earnings statements satisfying the provisions of Section 11(a) of the
Securities Act no later than 45 days after the end of any 12-month period (or 90
days, if such period is a fiscal year) (A) commencing at the end of any fiscal
quarter in which the Registrable Securities are sold in an underwritten
offering, or, if not sold in such an offering, (B) commencing with the first
month of the Company's first fiscal quarter commencing after the effective date
of the Registration Statement, which statements shall cover said 12-month
periods;

     (xvi)  notify in writing each holder of Registrable Securities of any
proposal by the Company to amend or waive any provision of this Agreement
pursuant to Section 9(h) hereof and of any amendment or waiver effected pursuant
thereto, each of which notices shall contain the text of the amendment or waiver
proposed or effected, as the case may be; and

     (xvii)  in the event that any broker-dealer registered under the Exchange
Act shall be an "Affiliate" (as defined in Schedule E to the By-Laws of the
National Association of Securities Dealers, Inc. ("NASD")) of the Company or has
a "Conflict of Interest" (as defined in such Schedule) and such broker-dealer
shall underwrite, participate as a member of an underwriting syndicate or
selling group or "assist in the distribution" (within the meaning of such
Schedule) of any Registrable Securities, whether as a holder of such Registrable
Securities or as an underwriter, a placement or sales agent or a broker or
dealer in respect thereof, or otherwise, assist such broker-dealer in complying
with the requirements of such Schedule, including, without limitation, by (A)
engaging a "qualified independent under-

                                      -9-
<PAGE>
 
writer" (as defined in such Schedule) to participate in the preparation of the
registration statement relating to such Registrable Securities, to exercise
usual standards of due diligence in respect thereto and to recommend the public
offering price of such Registrable Securities, (B) indemnifying such qualified
independent underwriter to the extent of the indemnification of underwriters
provided in Section 6 hereof, and (C) providing such information within the
possession of the Company to such broker-dealer as may be reasonably required in
order for such broker-dealer to comply with the requirements of the Rules of
Fair Practice of the NASD.

     (d) The Company may require each selling holder of Registrable Securities
as to which any registration is being effected to furnish to the Company such
information regarding such holder, the Registrable Securities held by such
holder, and the distribution of such Registrable Securities as the Company may
from time to time request in writing, but only to the extent that such
information shall be required by law or by the Commission in connection with any
registration. Each such holder agrees, by the acquisition of Registrable
Securities, to notify the Company as promptly as practicable of any inaccuracy
or change in information previously furnished by such holder to the Company or
of the occurrence of any event in either case as a result of which any
Prospectus relating to such registration contains or would contain an untrue
statement of a material fact regarding such holder or such holder's intended
method of distribution of such Registrable Securities or omits to state any
material fact regarding such holder or such holder's intended method of
distribution of such Registrable Securities necessary to make the statements
therein, in light of the circumstances then existing, not misleading and
promptly to furnish to the Company any additional information required to
correct and update any previously furnished information or required so that such
Prospectus shall not contain, with respect to such holder or the distribution of
such Registrable Securities, an untrue statement of a material fact or omit to
state a material fact necessary to make the statements therein, in light of the
circumstances then existing, not misleading.

     (e) Each holder of Registrable Securities agrees by acquisition of such
Registrable Securities that, upon receipt of any notice from the Company of the
happening of any event of the kind described in Section 3(c)(iv)(F) hereof or of
the commencement of any suspension period referred to in Section 2(c) hereof,
such holder will forthwith discontinue disposition of Registrable Securities
pursuant to the Registration Statement until such holder's receipt of the copies
of the supplemented or amended Prospectus contemplated by Section 3(c)(xii)
hereof, or until it is advised in writing by the Company that the use of the
Prospectus may be resumed, and has received copies of any additional or
supplemental filings which are incorporated by reference in the Prospectus, and,
if so directed by the Company, such holder will deliver to the Company (at the
Company's expense) all copies, other than permanent file copies, then in such
holder's possession of the Prospectus covering such Registrable Securities at
the time of receipt of such notice.

4.  REGISTRATION EXPENSES.
    --------------------- 

     The Company agrees to bear and to pay or cause to be paid promptly upon
request being made therefor all expenses incident to the Company's performance
of or compliance with this Agreement, including, without limitation, (a) all
Commission and any NASD registration and filing fees and expenses, (b) all fees
and expenses in connection with the registration or qualification of the
Registrable Securities for offering and sale under the State securities and blue
sky laws referred to in Section 3(c)(ix) hereof and determines their eligibility
for investment under the laws of such jurisdiction as the managing underwriter
or underwriters, if any, or the holders of such Registrable Securities may
designate, including reasonable fees and disbursements, if any, of

                                      -10-
<PAGE>
 
counsel for the selling holders or underwriters in connection with such
registrations or qualifications and determinations, (c) all expenses relating to
the preparation, printing, distribution and reproduction of the Registration
Statement required to be filed hereunder, each prospectus included therein or
prepared for distribution pursuant hereto, each amendment or supplement to the
foregoing, the expenses of preparing the Registrable Securities for delivery and
the expenses of reproducing any underwriting agreement(s), agreement(s) among
underwriters and "Blue Sky" or legal investment memoranda, any selling
agreements and all other documents in connection with the offering, sale or
delivery of Registrable Securities to be disposed of, (d) fees and expenses of
any Trustee under the Indenture, any Transfer Agent and Registrar with respect
to the Registrable Securities and any escrow agent or custodian, (e) internal
expenses of the Company (including, without limitation, all salaries and
expenses of the Company's officers and employees performing legal or accounting
duties), (f) fees, disbursements and expenses of counsel and independent
certified public accountants of the Company (including the expenses of any
opinions or "cold comfort" letters required by or incident to such performance
and compliance), (g) fees, disbursements and expenses of one counsel for the
holders of Registrable Securities retained in connection with such registration,
as selected by the holders of at least 50% in aggregate principal amount of the
outstanding Registrable Securities being registered, (h) fees, expenses and
disbursements of any other persons, including special experts, retained by the
Company in connection with such registration, (i) disbursements of any managing
underwriter or underwriters in connection with the offering and sale of
Registrable Securities under the Registration Statement (excluding commissions
or fees of underwriters, selling brokers, dealer managers or similar securities
industry professionals) and (j) all fees and expenses incurred in connection
with the qualification of the shares of Common Stock constituting Registrable
Securities for trading on the Nasdaq National Market, or the listing of such
shares on any other securities exchange, pursuant to Section 3(c)(xiii)
(collectively, the "Registration Expenses").  To the extent that any
Registration Expenses are incurred, assumed or paid by any holder of Registrable
Securities or any underwriter thereof, the Company shall reimburse such person
for the full amount of the Registration Expenses so incurred, assumed or paid
promptly after receipt of a request therefor.  Notwithstanding the foregoing,
the holders of the Registrable Securities being registered shall pay all agency
fees and commissions and underwriting discounts and commissions attributable to
the sale of such Registrable Securities and the fees and disbursements of any
counsel or other advisors or experts retained by such holders (severally or
jointly), other than the counsel and experts specifically referred to above, and
all fees, disbursements and expenses of any "qualified independent underwriters"
engaged pursuant to Section 3(c)(xvii).

5.  REPRESENTATIONS AND WARRANTIES.
    ------------------------------ 

     The Company represents and warrants to, and agrees with, the Purchasers and
each of the holders from time to time of Registrable Securities that:

     (a) Each Registration Statement and each Prospectus contained therein or
furnished pursuant to Sections 3(c)(vii) and 3(c)(viii) hereof and any further
amendments or supplements to any such Registration Statement or Prospectus, when
it becomes effective or is filed with the Commission, as the case may be, and,
in the case of an underwritten offering of Registrable Securities, at the time
of the closing under the underwriting agreement relating thereto, will conform
in all material respects to the requirements of the Securities Act and will not
contain an untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading; and at all times subsequent to the Effective Time when a prospectus
would be required to be delivered under the Securities Act, other than from

                                      -11-
<PAGE>
 
(i) such time as a notice has been given to holders of Registrable Securities
pursuant to Section 3(c)(iv)(F) hereof until (ii) such time as the Company
furnishes an amended or supplemented prospectus pursuant to Section 3(c)(xii)
hereof, the Registration Statement, and the Prospectus (including any summary
prospectus) contained therein or furnished pursuant to Section 3(c)(vii) or
3(c)(viii) hereof, as then amended or supplemented, will conform in all material
respects to the requirements of the Securities Act and will not contain an
untrue statement of a material fact or omit to state a material fact necessary
to make the statements therein, in light of the circumstances then existing, not
misleading; provided, however, that this representation and warranty shall not
apply to any statements or omissions made in reliance upon and in conformity
with information furnished in writing to the Company by an underwriter in
connection with an offering or by a holder of Registrable Securities expressly
for use therein.

     (b) Any documents incorporated by reference in any Prospectus referred to
in Section 5(a) hereof, when they become or became effective or are or were
filed with the Commission, as the case may be, will conform or conformed in all
material respects to the requirements of the Securities Act or the Exchange Act,
as applicable, and none of such documents will contain or contained an untrue
statement of a material fact or will omit or omitted to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading.

     (c) The compliance by the Company with all of the provisions of this
Agreement and the consummation of the transactions herein contemplated will not
conflict with or result in a breach of any of the terms or provisions of, or
constitute a default under, any indenture, mortgage, deed of trust, loan
agreement or other agreement or instrument to which the Company or any
subsidiary thereof is a party or by which the Company or any subsidiary thereof
is bound or to which any of the property or assets of the Company or any
subsidiary thereof is subject, nor will such action result in any violation of
the provisions of the Certificate of Incorporation, as amended and restated, or
the Bylaws, as amended, of the Company or any statute or any order, rule or
regulation of any court or governmental agency or body having jurisdiction over
the Company or any subsidiary thereof or any of their properties; and no
consent, approval, authorization, order, registration or qualification of or
with any such court or governmental agency or body is required for the
consummation by the Company of the transactions contemplated by this Agreement,
except the registration under the Securities Act of the Registrable Securities
and such consents, approvals, authorizations, registrations or qualifications as
may be required under State securities or "Blue Sky" laws or foreign laws in
connection with the offering and distribution of the Registrable Securities.

     (d) This Agreement has been duly authorized, executed and delivered by the
Company and, when duly authorized, executed and delivered by the other parties
hereto, will constitute a valid and legally binding obligation of the Company
enforceable in accordance with its terms, subject, as to enforcement, to
bankruptcy, insolvency, reorganization, moratorium and similar laws of general
applicability relating to or affecting creditors' rights and to general equity
principles.

                                      -12-
<PAGE>
 
6.  INDEMNIFICATION.
    --------------- 

     (a) Indemnification by the Company.  Upon the registration of the
Registrable Securities pursuant to Section 2 hereof, and in consideration of the
agreements of the Purchasers contained herein and in the Purchase Agreement, and
as an inducement to the Purchasers to enter into such Agreements, the Company
shall, and it hereby agrees to, indemnify and hold harmless each of the holders
of Registrable Securities to be included in such registration, each underwriter,
selling agent or placement agent with respect to the Registrable Securities and
each of their respective officers, directors, employees and agents and each
person who controls such holder or underwriter, selling agent or placement agent
within the meaning of Section 15 of the Securities Act or Section 20 of the
Exchange Act (each such person being sometimes referred to as an "Indemnified
Person") against any losses, claims, damages or liabilities, joint or several,
to which such Indemnified Person may become subject under the Securities Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon an untrue statement or alleged
untrue statement of a material fact contained in any Registration Statement
under which such Registrable Securities were registered under the Securities
Act, or any Prospectus contained therein or furnished by the Company to any
Indemnified Person, or any amendment or supplement thereto, or arise out of or
are based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and the Company shall, and it hereby agrees to, reimburse such
Indemnified Person for any reasonable legal or other expenses reasonably
incurred by them in connection with investigating or defending any such action
or claim; provided, however, that the Company shall not be liable to any such
Indemnified Person in any such case to the extent that any such loss, claim,
damage or liability arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission made in such
Registration Statement or Prospectus, or amendment or supplement, in reliance
upon and in conformity with written information furnished to the Company by or
on behalf of such Indemnified Person expressly for use therein.

     (b) Indemnification by the Holders and any Agents and Underwriters.  The
Company may require, as a condition to including any Registrable Securities in
any Registration Statement filed pursuant to this Agreement and to entering into
any underwriting agreement with respect thereto, that the Company shall have
received an undertaking reasonably satisfactory to it from the holder of such
Registrable Securities and from each underwriter named in any such underwriting
agreement, severally and not jointly, to (i) indemnify and hold harmless the
Company, its directors, officers who sign any Registration Statement and each
person, if any, who controls the Company within the meaning of either Section 15
of the Securities Act or Section 20 of the Exchange Act, against any losses,
claims, damages or liabilities to which the Company or such other persons may
become subject, under the Securities Act or otherwise, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of or
are based upon an untrue statement or alleged untrue statement of a material
fact contained in such Registration Statement, or any Prospectus contained
therein or furnished by the Company to any such holder or underwriter, or any
amendment or supplement thereto, or arise out of or are based upon the omission
or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, in each case
to the extent, but only to the extent, that such untrue statement or alleged
untrue statement or omission or alleged omission was made in reliance upon and
in conformity with written information furnished in writing to the Company by or
on behalf of such holder or underwriter expressly for use therein, and (ii)
reimburse the Company for any legal or other expenses reasonably incurred by the
Company in connection with investigating or defending any such action or claim;

                                      -13-
<PAGE>
 
     (c) Notices of Claims, Etc.  Promptly after receipt by an indemnified party
under subsection (a) or (b) above of written notice of the commencement of any
action, such indemnified party shall, if a claim in respect thereof is to be
made against an indemnifying party pursuant to the indemnification provisions of
or contemplated by this Section 6, notify such indemnifying party in writing of
the commencement of such action; but the omission so to notify the indemnifying
party shall not relieve it from any liability which it may have to any
indemnified party other than under the indemnification provisions of or
contemplated by Section 6(a) or 6(b) hereof.  In case any such action shall be
brought against any indemnified party and it shall notify an indemnifying party
of the commencement thereof, such indemnifying party shall be entitled to
participate therein and, to the extent that it shall wish, jointly with any
other indemnifying party similarly notified, to assume the defense thereof, with
counsel satisfactory to such indemnified party (who shall not, except with the
consent of the indemnified party, be counsel to the indemnifying party), and,
after notice from the indemnifying party to such indemnified party of its
election so to assume the defense thereof, such indemnifying party shall not be
liable to such indemnified party for any legal expenses of other counsel or any
other expenses, in each case subsequently incurred by such indemnified party, in
connection with the defense thereof.  No indemnifying party shall, without the
written consent of the indemnified party, effect the settlement or compromise
of, or consent to the entry of any judgment with respect to, any pending or
threatened action or claim in respect of which indemnification or contribution
may be sought hereunder (whether or not the indemnified party is an actual or
potential party to such action or claim) unless such settlement, compromise or
judgment (i) includes an unconditional release of the indemnified party from all
liability arising out of such action or claim and (ii) does not include a
statement as to, or an admission of, fault, culpability or a failure to act, by
or on behalf of any indemnified party.

     (d) Contribution.  Each party hereto agrees that, if for any reason the
indemnification provisions contemplated by Section 6(a) or Section 6(b) are
unavailable to or insufficient to hold harmless an indemnified party in respect
of any losses, claims, damages or liabilities (or actions in respect thereof)
referred to therein, then each indemnifying party shall contribute to the amount
paid or payable by such indemnified party as a result of such losses, claims,
damages or liabilities (or actions in respect thereof) in such proportion as is
appropriate to reflect the relative fault of the indemnifying party and the
indemnified party in connection with the statements or omissions which resulted
in such losses, claims, damages or liabilities (or actions in respect thereof),
as well as any other relevant equitable considerations.  The relative fault of
such indemnifying party and indemnified party shall be determined by reference
to, among other things, whether the untrue or alleged untrue statement of a
material fact or omission or alleged omission to state a material fact relates
to information supplied by such indemnifying party or by such indemnified party,
and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.  The parties
hereto agree that it would not be just and equitable if contribution pursuant to
this Section 6(d) were determined by pro rata allocation (even if the holders or
any agents or underwriters or all of them were treated as one entity for such
purpose) or by any other method of allocation which does not take account of the
equitable considerations referred to in this Section 6(d).  The amount paid or
payable by an indemnified party as a result of the losses, claims, damages or
liabilities (or actions in respect thereof) referred to above shall be deemed to
include any legal or other fees or expenses reasonably incurred by such
indemnified party in connection with investigating or defending any such action
or claim.  No person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act) shall be entitled to contribution from
any person who was not guilty of such fraudulent misrepresentation. The holders'
and any underwriters' obligations in this Section 6(d) to contribute shall be
several in proportion to the percentage of principal amount of Registrable
Securities registered or underwritten, as the case may be, by them and not
joint.

                                      -14-
<PAGE>
 
     (e) Notwithstanding any other provision of this Section 6, in no event will
any (i) holder be required to undertake liability to any person under this
Section 6 for any amounts in excess of the dollar amount of the proceeds to be
received by such holder from the sale of such holder's Registrable Securities
(after deducting any fees, discounts and commissions applicable thereto)
pursuant to such registration and (ii) underwriter be required to undertake
liability to any person hereunder for any amounts in excess of the discount,
commission or other compensation payable to such underwriter with respect to the
Registrable Securities underwritten by it and distributed to the public pursuant
to any such underwriting agreement.

     (f) The obligations of the Company under this Section 6 shall be in
addition to any liability which the Company may otherwise have to any
Indemnified Person, including any liability of the Company to the Purchasers
pursuant to Section 8 of the Purchase Agreement.

7.  UNDERWRITTEN OFFERINGS.
    ---------------------- 

     (a) Right to Effect Underwritten Offering.  The holders of Registrable
Securities covered by the Registration Statement may sell such Registrable
Securities in an underwritten offering, provided that the holders of at least
20% in aggregate principal amount of the Registrable Securities initially
outstanding elect to participate in such an offering and except that any such
underwritten offering shall be suspended during the periods specified in Section
2(c) hereof.

     (b) Selection of Underwriters.  If any of the Registrable Securities
covered by the Registration Statement are to be sold pursuant to an underwritten
offering, the managing underwriter or underwriters thereof shall be designated
by the holders of at least 50% in aggregate principal amount of the outstanding
Registrable Securities to be included in such offering, provided that such
designated managing underwriter or underwriters is or are reasonably acceptable
to the Company.

     (c) Participation by Holders.  Each holder of Registrable Securities hereby
agrees with the Company and each other such holder that no such holder may
participate in any underwritten offering hereunder unless such holder (i) agrees
to sell such holder's Registrable Securities on the basis provided in any
underwriting arrangements approved by the persons entitled hereunder to approve
such arrangements and (ii) completes and executes all questionnaires, powers of
attorney, indemnities, underwriting agreements and other documents reasonably
required under the terms of such underwriting arrangements.

8.  RULE 144.
    -------- 

     The Company covenants to the holders of Registrable Securities that to the
extent it shall be required to do so under the Exchange Act, the Company shall
timely file the reports required to be filed by it under the Exchange Act or the
Securities Act (including, but not limited to, the reports under Sections 13 and
15(d) of the Exchange Act referred to in subparagraph (c)(1) of Rule 144 under
the Securities Act) and the Rules and Regulations, and shall take such further
action as shall be necessary to enable such holder to sell Registrable
Securities without registration under the Securities Act within the limitations
of the exemption provided by Rule 144 under the Securities Act, as such Rule may
be amended from time to time, or any similar rule or regulation hereafter
adopted by the Commission.  Upon the request of any holder of Registrable
Securities, the Company shall deliver to such holder a written statement as to
whether it has complied with such requirements.

                                      -15-
<PAGE>
 
9.  MISCELLANEOUS.
    ------------- 

     (a) No Inconsistent Agreements.  The Company will not on or after the date
of this Agreement grant registration rights with respect to Registrable
Securities or any other securities, or enter into any agreement with respect to
its securities, which prevents the exercise of or otherwise conflicts with the
provisions hereof.  The Company is not currently a party to any agreement with
respect to any of its equity or debt securities granting any registration rights
to any person, but, as described in the Offering Circular, it proposes to enter
into such an agreement in connection with the Bristow Transaction.

     (b) Specific Performance.  The parties hereto acknowledge that there may be
no adequate remedy at law if any party fails to perform any of its obligations
hereunder and that each party may be irreparably harmed by any such failure, and
accordingly agree that each party, in addition to any other remedy to which it
may be entitled at law or in equity, shall be entitled to compel specific
performance of the obligations of any other party under this Agreement in
accordance with the terms and conditions of this Agreement, in any court of the
United States or any State thereof having jurisdiction.

     (c) Notices.  All notices, requests, claims, demands, waivers and other
communications hereunder shall be given in the manner provided for in the
Indenture.

     (d) Parties in Interest.  All the terms and provisions of this Agreement
shall be binding upon, shall inure to the benefit of and shall be enforceable by
the respective successors and assigns of the parties hereto.  In the event that
any transferee of any holder of Registrable Securities shall acquire Registrable
Securities, in any manner, whether by gift, bequest, purchase, operation of law
or otherwise, such transferee shall, without any further writing or action of
any kind, be deemed a party hereto for all purposes and such Registrable
Securities shall be held subject to all of the terms of this Agreement, and by
taking and holding such Registrable Securities such transferee shall be entitled
to receive the benefits of and be conclusively deemed to have agreed to be bound
by and to perform all of the terms and provisions of this Agreement.  If the
Company shall so request, any such successor, assign or transferee shall agree
in writing to acquire and hold the Registrable Securities subject to all of the
terms hereof.

     (e) Survival.  The respective indemnities, agreements, representations,
warranties and each other provision set forth in this Agreement or made pursuant
hereto shall remain in full force and effect regardless of any investigation (or
statement as to the results thereof) made by or on behalf of any holder of
Registrable Securities, any director, officer or partner of such holder, any
agent or underwriter or any director, officer or partner thereof, or any
controlling person of any of the foregoing, and shall survive delivery of and
payment for the Registrable Securities pursuant to the Purchase Agreement and
the transfer and registration of Registrable Securities by such holder.

     (f) LAW GOVERNING.  THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

     (g) Headings.  The descriptive headings of the several Sections and
paragraphs of this Agreement are inserted for convenience only, do not
constitute a part of this Agreement and shall not affect in any way the meaning
or interpretation of this Agreement.

     (h) Amendments and Waivers.  This Agreement may be amended and the
observance of any term of this Agreement may be waived (either generally or in a
particular instance and either

                                      -16-
<PAGE>
 
retroactively or prospectively) only by a written instrument duly executed by
the Company and the holders of at least 66-2/3% of the principal amount of the
Registrable Securities at the time outstanding.  Each holder of any Registrable
Securities at the time or thereafter outstanding shall be bound by any amendment
or waiver effected pursuant to this Section 9(h), whether or not any notice,
writing or marking indicating such amendment or waiver appears on such
Registrable Securities or is delivered to such holder.

     (i) Inspection.  For so long as this Agreement shall be in effect, this
Agreement and a complete list of the names and addresses of all the holders of
Registrable Securities shall be made available upon reasonable prior written
notice for inspection and copying on any business day by any holder of
Registrable Securities at the offices of the Company at the address set forth in
the Indenture.

     (j) Counterparts.  This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

     (k) Termination.  If the Company mandatorily redeems the Securities as a
whole in compliance with Section 1109 of the Indenture, thereupon this Agreement
shall terminate automatically and be of no further force or effect.

                                      -17-
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this instrument to be
duly executed as of the date first written above.

                                        OFFSHORE LOGISTICS, INC.
                                
                                
                                
                                        By:  /s/ J. B. CLEMENT
                                           --------------------------------
                                            Name:  J. B. Clement
                                            Title: Chairman of the Board,
                                                   President & CEO
                                
                                
                                        JEFFERIES & COMPANY, INC.
                                
                                
                                
                                        By:  /s/ DAVID E. K. FRISCHKORN, JR.
                                           ---------------------------------
                                            Name: David E. K. Frischkorn, Jr.
                                            Title: Managing Director
                                
                                
                                        SIMMONS & COMPANY INTERNATIONAL
                                
                                
                                
                                        By:  /s/ NICHOLAS L. SWYKA
                                           ----------------------------------
                                            Name:  Nicholas L. Swyka
                                            Title: Managing Director
                                
                                
                                        JOHNSON RICE & COMPANY L.L.C.
                                
                                
                                
                                        By:  /s/ GREGORY S. MINER
                                            ---------------------------------
                                            Name:  Gregory S. Miner
                                            Title: Partner

                                      -18-

<PAGE>
 
                                                                    EXHIBIT 4(3)


                         REGISTRATION RIGHTS AGREEMENT


                                                               December 19, 1996


Caledonia Industrial & Services Limited
Cayzer House
1 Thomas More Street
London E1 9AR
England


Dear Sirs:

     This will confirm that, in connection with the Master Agreement, made on
December 12, 1996 (the "Master Agreement"), among Offshore Logistics, Inc., a
Delaware corporation (the "Company"), Caledonia Industrial & Services Limited
(the "Purchaser") and the other parties named therein, and the issuance to the
Purchaser pursuant to the Master  Agreement of (i) an aggregate 1,300,000 shares
(the "Common Shares") of Common Stock, $.01 par value, of the Company and (ii)
an aggregate $ 7,500,000 principal amount of Notes (as defined herein),
convertible into shares of Common Stock of the Company, and as an inducement to
the Purchaser to consummate the transactions contemplated by the Master
Agreement, the Company hereby covenants and agrees with the Purchaser and with
each subsequent holder of Restricted Securities (as such term is defined
herein), as follows:

     1. Certain Definitions.  As used herein, the following terms shall have the
following respective meanings:

       "Commission" shall mean the Securities and Exchange   Commission, or any
     other federal agency at the time administering the Securities Act.

       "Common Stock" shall mean the Common Stock, $.01 par value, of the
     Company, as constituted as of the date of this Agreement, subject to
     adjustment pursuant to the provisions of Section 10 hereof.

       "Conversion Shares" shall mean shares of Common Stock issued upon
     conversion of the Notes.

       "Exchange Act" shall mean the Securities Exchange Act of 1934 or any
     similar federal statute, and the rules and regulations of the Commission
     thereunder, all as the same shall be in effect at the time.
<PAGE>
 
       "Notes" shall mean the Company's 6% Convertible Subordinated Notes due
     2003. to be issued pursuant to the Indenture, dated as of December 15, 1996
     (the "Indenture"), between the Company and Fleet National Bank, as Trustee,
     as amended and supplemented from time to time.

       "Other Registration Rights Agreement" shall mean the Registration Rights
     Agreement, dated as of December 17, 1996, by and among the Company  and
     Jefferies & Company, Inc., Simmons & Company International and Johnson Rice
     & Company L.L.C.

       "Permitted Registrations" shall mean registrations under the Securities
     Act of securities of the Company for sale pursuant to registration
     statements on Form S-4 or Form S-8 or another form not available for
     registering the Restricted Securities for sale to the public.

       "Registration Expenses" shall mean the expenses so described in Section 8
      hereof.

       "Restricted Securities" shall mean (i) any Common Shares, Conversion
     Shares and Rights Shares (a) the certificates for which (and each
     certificate issued upon exchange, adjustment or transfer thereof) (A) in
     the case of Common Shares, bear the legend set forth in Section 1(K) of
     that certain letter agreement, dated December 19, 1996 (the "Supplemental
     Agreement"), between the Company and the Purchaser supplementing the Master
     Agreement, (B) in the case of Conversion Shares bear the Regulation S
     Legend (as such term is defined in the Indenture) or (C) in the case of
     Rights Shares, bear the legend set forth in Section 2 hereof or (b) in any
     such case, the sale, transfer or other disposition of which is restricted
     under Rule 144 (or any successor regulation) under the Securities Act and
     (ii) those Notes (and any notes issued upon exchange, adjustment or
     transfer thereof) (a) which bear the Regulation S Legend or (b) the sale,
     transfer or other disposition of which is restricted under Rule 144 (or any
     successor regulation) under the Securities Act provided, however, that the
     term Restricted Securities shall not include Conversion Shares and Notes
     which are then covered by a registration statement that was filed by the
     Company pursuant to the Other Registration Rights Agreement, that was
     declared effective by the Commission under the Securities Act and that then
     continues to be effective under the Securities Act for the period and on
     the terms provided for under the Other Registration Rights Agreement.

       "Securities Act" shall mean the Securities Act of 1933   or any similar
     federal statute, and the rules and regula-

                                       2
<PAGE>
 
     tions of the Commission thereunder, all as the same shall be in effect at
     the time.

       "Rights" shall have the meaning given to it in the Rights Agreement,
     dated as of February 29, 1996, between the Company and Chase Mellon
     Shareholders Services, L.L.C.

       "Rights Shares"  shall mean the shares of Common Stock issuable under
     certain circumstances in exchange for any Rights that may be issued from
     time to time in respect of the Common Shares or the Conversion Shares.

       "Selling Expenses" shall mean the expenses so described   in Section 8
     hereof.

     2. Restrictive Legend for Rights Shares. Each certificate representing the
Rights Shares, and each certificate issued upon exchange, adjustment or transfer
thereof, other than in a public sale or as otherwise permitted by the last
paragraph of Section 3 hereof, shall be stamped or otherwise imprinted with a
legend substantially in the following form:

      "THE SHARES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
      THE SECURITIES ACT OF 1933, AND MAY NOT BE SOLD, TRANSFERRED OR
      OTHERWISE DISPOSED OF UNLESS THEY HAVE BEEN REGISTERED UNDER THAT ACT
      OR AN EXEMPTION FROM REGISTRATION IS AVAILABLE."


     3.  Notice of Proposed Transfer.  Prior to any proposed transfer of any
Restricted Securities constituting Rights Shares (other than under the
circumstances described in Sections 4, 5 or 6 hereof), the holder thereof shall
give written notice to the Company of its intention to effect such transfer.
Each such notice shall describe the manner of the proposed transfer and, if
requested by the Company, shall be accompanied by an opinion of counsel
reasonably satisfactory to the Company (it being agreed that Reboul, MacMurray,
Hewitt, Maynard & Kristol shall be satisfactory) to the effect that the proposed
transfer of such Restricted Securities may be effected without registration
under the Securities Act, whereupon the holder of such Restricted Securities
shall be entitled to transfer such Restricted Securities in accordance with the
terms of its notice.  Each certificate for such Restricted Securities
transferred as above provided shall bear the legend set forth in Section 2
hereof unless (i) such transfer is in accordance with the provisions of Rule 144
(or any other rule permitting public sale without registration under the
Securities Act) or (ii) the opinion of counsel referred to above is to the
further effect that the transferee and any subsequent transferee (other than an

                                       3
<PAGE>
 
affiliate of the Company) would be entitled to transfer such securities in a
public sale without registration under the Securities Act.  The foregoing
restrictions on transferability of Restricted Securities constituting Rights
Shares shall terminate as to any particular shares of such Restricted Securities
when such shares shall have been effectively registered under the Securities Act
and sold or otherwise disposed of in accordance with the intended method of
disposition by the seller or sellers thereof set forth in the registration
statement concerning such shares.  Whenever a holder of Restricted Securities
constituting Rights Shares is able to demonstrate to the Company (and its
counsel) that the provisions of Rule 144(k) of the Securities Act are available
to such holder without limitation, or that such Restricted Securities is
otherwise freely transferable without registration under the Securities Act,
such holder of shall be entitled to receive from the Company, without expense, a
new certificate such Restricted Securities not bearing the restrictive legend.

     Matters pertaining to the transfer of Restricted Securities constituting
Common Shares, Conversion Shares and Notes (other than under the circumstances
described in Sections 4, 5 or 6 hereof) shall be governed, to the extent
provided for therein, by the applicable provisions of the Supplemental
Agreement, in the case of Common Shares, and the Indenture, in the case of the
Conversion Shares and the Notes.

     4.  Required Registration.

     (a) At any time that the Company is not entitled to use Form S-3, the
holder or holders of Restricted Securities constituting at least 25% of the
Restricted Securities outstanding at such time (the "Original Requesting
Holders") may request the Company to register under the Securities Act all or
any portion of the Restricted Securities held by such requesting holder or
holders for sale in the manner specified in such notice; provided, however, that
(i) such portion of the Restricted Securities held by such requesting holder or
holders for which registration is requested shall not be less than the greater
of (x) 25% of all the then outstanding Restricted Securities and (y) an amount
which exceeds amounts which can be sold in accordance with the volume limitation
provisions of Rule 144 (e) under the Securities Act applicable to such
requesting holder or holders and (ii) the only securities which the Company
shall be required to register pursuant hereto shall be shares of Common Stock
and Notes.

     (b)  Promptly following receipt of any notice under this Section 4, the
Company shall immediately give written notice to any holders of Restricted
Securities from whom 

                                       4
<PAGE>
 
notice has not been received and shall use its best efforts to register under
the Securities Act, for public sale in accordance with the method of disposition
specified in such notice from the Original Requesting Holders (and in any
notices received from other such holders of Restricted Securities within 20 days
after their receipt of such notice from the Company) provided, however, that if
the proposed method of disposition specified by the requesting holders shall be
an underwritten public offering, the number of shares or principal amount, as
the case may be, of Restricted Securities to be included in such an offering may
be reduced, first, pro rata among any holders of Restricted Securities
requesting registration other than the Original Requesting Holders based upon
the number of shares of Common Stock or principal amount of Notes requested to
be registered by such holders, if and to the extent that the managing
underwriter shall be of the opinion that the inclusion of Restricted Securities
held by such other holders would adversely affect the marketing of the
Restricted Securities to be sold by the Original Requesting Holders (it being
understood that such number of shares or such principal amount of Restricted
Securities shall not be reduced if any shares of Common Stock or any Notes are
to be included in such underwriting for the account of any person other than the
Original Requesting Holders) and second, if the managing underwriter deems such
reduction to be insufficient, pro rata among the Original Requesting Holders
based upon the number of shares or principal amount of Restricted Securities so
requested to be registered by them (it being understood that such number of
shares or principal amount of Restricted Securities shall not be reduced if any
shares of Common Stock or Notes are to be included in such underwriting for the
account of any person other than the holders of Restricted Securities); and
provided, further, however that if (i) in the good faith judgment of a majority
of the members of the Board of Directors of the Company, such registration would
be materially detrimental to the business of the Company or would materially
interfere with preexisting contractual obligations to which the Company is then
subject or financing arrangements or other material transactions involving the
Company or any of its subsidiaries that are pending or are under active
consideration by the Company at the time any notice under this Section is given,
and the Board of Directors of the Company concludes, as a result, that it is
essential to defer the filing of such registration statement at such time, and
(ii) the Company shall furnish to such requesting holders a certificate, dated
no more than ten days after such notice of required registration is given,
signed by the President of the Company to the effect set forth in the preceding
clause (i), then the Company shall have the right,

                                       5
<PAGE>
 
to defer such filing, but only so long as is necessary in order to preclude
adverse impact upon the business of the Company or such preexisting contractual
obligations, such financing or other pending transaction, and in any event for a
period of not more than one hundred eighty (180) days after such notice of
required registration is given. Except for Permitted Registrations, the Company
will not effect any other registration of its Common Stock or Notes, whether for
its own account or that of other holders, from the date of furnishing such
certificate until the end of such deferral period. If such method of disposition
shall be an underwritten public offering, the Company may designate the managing
underwriter of such offering, subject to the approval of the selling holders of
a majority of the Restricted Securities (such majority to be determined on the
basis of the number of shares of Common Stock and the principal amount of Notes
included in the offering, which approval shall not be unreasonably withheld.
Notwithstanding anything to the contrary contained herein, the obligation of the
Company under this Section 4 shall be deemed satisfied only when a registration
statement covering all shares and all principal amounts of Restricted Securities
specified in notices received as aforesaid, for sale in accordance with the
method of disposition specified by the requesting holder, shall have become
effective and, if such method of disposition is a firm commitment underwritten
public offering, all such shares and all such principal amounts shall have been
sold pursuant thereto.

     (c)  The Company and other holders of Common Stock and Notes of the Company
shall be entitled to include in any registration statement referred to in this
Section 4, for sale in accordance with the method of disposition specified by
the requesting holders, shares of Common Stock and principal amounts of Notes to
be sold by the Company or such other holders for their own account, except to
the extent that, in the opinion of the managing underwriter (if such method of
disposition shall be an underwritten public offering), such inclusion would
adversely affect the marketing of the Restricted Securities to be sold.  Except
as provided in this paragraph (c), and except for Permitted Registrations, the
Company will not effect any other registration of its Common Stock and Notes,
whether for its own account or that of other holders, from the date of receipt
of a notice from requesting holders pursuant to this Section 4 until one hundred
and twenty (120) days after the effective date of the registration contemplated
thereby.

     (d) Notwithstanding anything to the contrary contained herein, the Company
shall be obligated to register Restricted Securities pursuant to this Section 4
at the 

                                       6
<PAGE>
 
request of the holders Restricted Securities, on three occasions only.

     5.  Form S-3 Registration.

     (a) If the Company shall receive from any holder or holders of Restricted
Securities a written notice or notices requesting that the Company effect a
registration on Form S-3 (which request may also specify that the Restricted
Securities is to be offered on a delayed or continuous basis by means of a
"shelf" registration pursuant to Rule 415 under the Securities Act) and any
related qualification or compliance with respect to Restricted Securities owned
by such holder or holders, provided that the Company has not effected a
registration under this Section 5 at the request of any holder or holders of
Restricted Securities within the three months immediately preceding the date of
such request, the Company will:

       (i) promptly give written notice of the proposed registration, and any
     related qualification or compliance, to all other holders of Restricted
     Securities; and

       (ii) as soon as practicable, effect such registration (including, without
     limitation, the execution of an undertaking to file post-effective
     amendments, appropriate qualifications under applicable blue sky or other
     state securities laws and appropriate compliance with applicable
     regulations issued under the Securities Act and any other government
     requirements or regulations) as may be so requested and as would permit or
     facilitate the sale and distribution of all or such portion of such
     holder's or holders' Restricted Securities as are specified in such
     request, together with all or such portion of the Restricted Securities of
     any holder or holders joining in such request as are specified in a written
     request given within thirty (30) days after receipt of such written notice
     from the Company; provided, however, that if (i) in the good faith judgment
     of a majority of the members of the Board of Directors of the Company, such
     registration would be materially detrimental to the business of the Company
     or would materially interfere with preexisting contractual obligations to
     which the Company is then subject or financing arrangements or other
     material transactions involving the Company or any of its subsidiaries that
     are pending or are under active consideration by the Company at the time
     any notice under this Section is given, and the Board of Directors of the
     Company concludes, as a result, that it is essential to defer the filing of
     such registration statement at such time, and (ii) the Company shall
     furnish to such requesting holders a certificate, dated no more than ten
     days after such notice of required registration is given, signed by the
     
                                       7
<PAGE>
 
     President of the Company to the effect set forth in the preceding clause
     (i), then the Company shall have the right to defer such filing, but only
     so long as is necessary in order to preclude the adverse impact upon the
     business of the Company or such preexisting contractual obligations,
     financing or other pending transaction, and in any event for a period of
     not more than one hundred eighty (180) days after such notice of required
     registration is given.  Except for Permitted Registrations, the Company
     will not effect any other registration of its Common Stock and Notes,
     whether for its own account or that of other holders, from the date of
     furnishing such certificate until the end of such deferral period.  Subject
     to the foregoing provisions of this paragraph (a) and as set forth in
     paragraphs (b) and (c) below, the Company shall file a registration
     statement covering the Restricted Securities so requested to be registered
     as soon as practicable after receipt of the request or requests of the
     holders of the Restricted Securities.  Except for Permitted Registrations,
     the Company will not effect any other registration of its Common Stock and
     Notes, whether for its own account or that of other holders, from the date
     of receipt of a notice from requesting holders pursuant to this Section 5
     until thirty (30) days after the effective date of the registration
     contemplated thereby.

       (b) The Company shall not be obligated to register Restricted Securities
     pursuant to this Section 5 if the Company is not entitled to use Form S-3.

       (c) The only securities which the Company shall be required to register
     pursuant hereto shall be shares of Common Stock and Notes.

       (d) Registrations effected pursuant to this Section 5 shall not be
     counted as requests for registration pursuant to Section 4.

     6.  Incidental Registration.  If the Company at any time (other than
pursuant to Sections 4 or 5 hereof) proposes to register any of its Common Stock
or Notes under the Securities Act for sale to the public, whether for its own
account or for the account of other security holders ("Requesting Parties") or
both (except in connection with a Permitted Registration), it will give written
notice at such time to all holders of outstanding Restricted Securities of its
intention to do so.  Upon the written request of any such holder, given within
thirty (30) days after receipt of any such notice by the Company, to register
any of its Restricted Securities (which request shall state the intended method
of disposition thereof), the Company will use its best efforts to cause the
Restricted Securities as to which registration shall have been so requested to
be included 

                                       8
<PAGE>
 
in the securities to be covered by the registration statement proposed to be
filed by the Company, all to the extent requisite to permit the sale or other
disposition by the holder (in accordance with its written request) of such
Restricted Securities so registered; provided, however, that nothing herein
shall prevent the Company from abandoning or delaying such registration at any
time. In the event that any registration pursuant to this Section 6 shall be, in
whole or in part, an underwritten public offering of Common Stock, any request
by a holder pursuant to this Section 6 to register Restricted Securities shall
specify that either (i) such Restricted Securities is to be included in the
underwriting on the same terms and conditions as the shares of Common Stock or
Notes otherwise being sold through underwriters under such registration or (ii)
such Restricted Securities is to be sold in the open market without any
underwriting, on terms and conditions comparable to those normally applicable to
offerings of common stock in reasonably similar circumstances. If and to the
extent that the managing underwriter shall be of the opinion that such inclusion
would adversely affect the marketing of the securities to be sold by the Company
or by the Requesting Parties, the number of shares and the principal amount of
Restricted Securities to be included in such an underwriting may be reduced,
first, pro rata among any persons requesting registration other than the
Requesting Parties, the Company and the holders of Restricted Securities, based
upon the number of shares of Common Stock and principal amount of Notes
requested to be registered by such holders, and second, if the managing
underwriter deems such reduction to be insufficient, pro rata among the
requesting holders of Restricted Securities based upon the number of shares and
principal amount of Restricted Securities so requested to be registered; it
being understood that such number of shares and principal amount of Restricted
Securities shall not be reduced if any shares or Notes are to be included in
such underwriting for the account of any person other than the Requesting
Parties, the Company and the holders of Restricted Securities.

     Notwithstanding anything to the contrary contained in this Section 6, in
the event that there is a firm commitment underwritten public offering of
securities of the Company pursuant to a registration covering Restricted
Securities and a holder of Restricted Securities does not elect to sell his
Restricted Securities to the underwriters of the Company's securities in
connection with such offering, such holder shall refrain from selling such
Restricted Securities so registered pursuant to this Section 6 during the period
of distribution of the Company's securities by such underwriters and the period
in which the underwriting syndicate participates in the after market; provided,
however, that such holder shall, in any event, be entitled to sell its
Restricted Securities commencing on the 

                                       9
<PAGE>
 
90th day after the date of the pricing of the securities issued under such
registration statement.

     7. Registration Procedures. If and whenever the Company is required by the
provisions of Section 4, 5 or 6 hereof to use its best efforts to effect the
registration of any of the Restricted Securities under the Securities Act, the
Company will, as expeditiously as possible:

     (a)  prepare (and afford counsel for the selling holders reasonable
opportunity to review and comment thereon) and file with the Commission a
registration statement (which, in the case of an underwritten public offering
pursuant to Section 4 hereof, shall be on Form S-1 or another form of general
applicability satisfactory to the managing underwriter selected as therein
provided) with respect to such securities and use its reasonable best efforts to
cause such registration statement to become and remain effective for the period
of the distribution contemplated thereby (determined as hereinafter provided);

     (b) prepare (and afford counsel for the selling holders reasonable
opportunity to review and comment thereon) and file with the Commission such
amendments and supplements to such registration statement and the prospectus
used in connection therewith as may be necessary to keep such registration
statement effective for the period specified in paragraph (a) above and as
comply with the provisions of the Securities Act with respect to the disposition
of all Restricted Securities covered by such registration statement in
accordance with the sellers' intended method of disposition set forth in such
registration statement for such period;

     (c) furnish to each seller and to each underwriter such number of copies of
the registration statement and the prospectus included therein (including each
preliminary prospectus) as such persons may reasonably request in order to
facilitate the public sale or other disposition of the Restricted Securities as
the case may be, covered by such registration statement;

     (d) use its reasonable best efforts to register or qualify the Restricted
Securities covered by such registration statement under the securities or blue
sky laws of such jurisdictions as the sellers of Restricted Securities or, in
the case of an underwritten public offering, the managing underwriter, shall
reasonably request (provided that the Company will not be required to (i)
qualify generally to do business in any jurisdiction where it would not
otherwise be required to so qualify but for 

                                      10
<PAGE>
 
this paragraph (d), (ii) subject itself to taxation in any such jurisdiction or
(iii) consent to general service of process in any jurisdiction);

     (e) immediately notify each seller under such registration statement and
each underwriter, at any time when a prospectus relating thereto is required to
be delivered under the Securities Act, of the happening of any event as a result
of which the prospectus contained in such registration statement, as then in
effect, includes an untrue statement of a material fact or omits to state any
material fact required to be stated therein or necessary to make the statements
therein not misleading in the light of the circumstances then existing;

     (f) use its reasonable best efforts (if the offering is underwritten) to
furnish, at the request of any seller, on the date that Restricted Securities is
delivered to the underwriters for sale pursuant to such registration:  (i) an
opinion of counsel representing the Company for the purposes of such
registration, addressed to the underwriters and to such seller and dated such
date, stating that such registration statement has become effective under the
Securities Act and that (A) to the best knowledge of such counsel, no stop order
suspending the effectiveness thereof has been issued and no proceedings for that
purpose have been instituted or are pending or contemplated under the Securities
Act, (B) the registration statement, the related prospectus, and each amendment
or supplement thereof, comply as to form in all material respects with the
requirements of the Securities Act and the applicable rules and regulations of
the Commission thereunder (except that such counsel need express no opinion as
to financial statements, the notes thereto, and the financial schedules and
other financial and statistical data contained therein) and (C) to such other
effects as may reasonably be requested by counsel for the underwriters or by
such seller or its counsel, and (ii) a letter dated such date from the
independent public accountants retained by the Company, addressed to the
underwriters, stating that they are independent public accountants within the
meaning of the Securities Act and that, in the opinion of such accountants, the
financial statements of the Company included in the registration statement or
the prospectus, or any amendment or supplement thereof, comply as to form in all
material respects with the applicable accounting requirements of the Securities
Act, and such letter shall additionally cover such other financial matters
(including information as to the period ending no more than five business days
prior to the date of such letter) with respect to the registration in respect of
which

                                      11
<PAGE>
 
such letter is being given as such underwriters or seller may reasonably
request; and

     (g) make available for inspection by each seller, any underwriter
participating in any distribution pursuant to such registration statement, and
any attorney, accountant or other agent retained by such seller or underwriter,
all financial and other records, pertinent corporate documents and properties of
the Company, and cause the Company's officers, directors and employees to supply
all information reasonably requested by any such seller, underwriter, attorney,
accountant or agent in connection with such registration statement and permit
such seller, attorney, accountant or agent to participate in the preparation of
such registration statement.

For purposes of paragraphs (a) and (b) above and of Section 4(c) hereof, the
period of distribution of Restricted Securities in a firm commitment
underwritten public offering shall be deemed to extend until each underwriter
has completed the distribution of all securities purchased by it, and the period
of distribution of Restricted Securities in any other registration shall be
deemed to extend until the earlier of the sale of all Restricted Securities
covered thereby or six months after the effective date thereof.

     In connection with each registration hereunder, the selling holders of
Restricted Securities will furnish to the Company in writing such information
with respect to themselves and the proposed distribution by them as shall be
reasonably necessary in order to assure compliance with federal and applicable
state securities laws.

     In connection with each registration pursuant to Sections 4, 5 and 6 hereof
covering an underwritten public offering, the Company agrees to enter into a
written agreement with the managing underwriter selected in the manner herein
provided in such form and containing such provisions as are customary in the
securities business for such an arrangement between major underwriters and
companies of the Company's size and investment stature, provided, however, that
such agreement shall not contain any such provision applicable to the Company
which is inconsistent with the provisions hereof and provided, further, however,
that the time and place of the closing under said agreement shall be as mutually
agreed upon among the Company,  such managing underwriter and the selling
holders of Restricted Securities.

     8. Expenses.  All expenses incurred by the Company in complying with
Sections 4, 5 and 6 hereof, including without limitation all registration and
filing fees, printing expenses, 

                                      12
<PAGE>
 
fees and disbursements of counsel and independent public accountants for the
Company, fees of the National Association of Securities Dealers, Inc., transfer
taxes, fees of transfer agents and registrars and fees and expenses of one
counsel for the sellers of Restricted Securities, but excluding any Selling
Expenses, are herein called "Registration Expenses". All underwriting discounts
and selling commissions applicable to the sale of Restricted Securities are
herein called "Selling Expenses".

     The Company will pay all Registration Expenses in connection with each
registration statement filed pursuant to Section 4, 5 or 6 hereof.  All Selling
Expenses in connection with any registration statement filed pursuant to Section
4, 5 or 6 hereof shall be borne by the participating sellers in proportion to
the number of shares sold by each, or by such persons other than the Company
(except to the extent the Company shall be a seller) as they may agree.

     9. Indemnification.  In the event of a registration of any of the
Restricted Securities under the Securities Act pursuant to Section 4, 5 or 6
hereof, the Company will indemnify and hold harmless each seller of such
Restricted Securities thereunder and each underwriter of Restricted Securities
thereunder and each other person, if any, who controls such seller or
underwriter within the meaning of the Securities Act, against any losses,
claims, damages or liabilities, joint or several, to which such seller or
underwriter or controlling person may become subject under the Securities Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any untrue statement or alleged
untrue statement of any material fact contained in any registration statement
under which such Restricted Securities was registered under the Securities Act
pursuant to Section 4, 5 or 6, any preliminary prospectus or final prospectus
contained therein, or any amendment or supplement thereof, or arise out of or
are based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and will reimburse each such seller, each such underwriter and each
such controlling person for any legal or other expenses reasonably incurred by
them in connection with investigating or defending any such loss, claim, damage,
liability or action; provided, however, that the Company will not be liable in
any such case if and to the extent that any such loss, claim, damage or
liability arises out of or is based upon an untrue statement or alleged untrue
statement or omission or alleged omission so made in conformity with information
furnished by such seller, such underwriter or such controlling person in writing
specifically for use in such registration statement or prospectus.

                                      13
<PAGE>
 
     In the event of a registration of any of the Restricted Securities under
the Securities Act pursuant to Section 4, 5 or 6 hereof, each seller of such
Restricted Securities thereunder, severally and not jointly, will indemnify and
hold harmless the Company and each person, if any, who controls the Company
within the meaning of the Securities Act, each officer of the Company who signs
the registration statement, each director of the Company, each underwriter and
each person who controls any underwriter within the meaning of the Securities
Act, against all losses, claims, damages or liabilities, joint or several, to
which the Company or such officer or director or underwriter or controlling
person may become subject under the Securities Act or otherwise, insofar as such
losses, claims, damages or liabilities (or actions in respect thereof) arise out
of or are based upon any untrue statement or alleged untrue statement of any
material fact contained in the registration statement under which such
Restricted Securities was registered under the Securities Act pursuant to
Section 4, 5 or 6, any preliminary prospectus or final prospectus contained
therein, or any amendment or supplement thereof, or arise out of or are based
upon the omission or alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading,
and will reimburse the Company and each such officer, director, underwriter and
controlling person for any legal or other expenses reasonably incurred by them
in connection with investigating or defending any such loss, claim, damage,
liability or action; provided, however, that such seller will be liable
hereunder in any such case if and only to the extent that any such loss, claim,
damage or liability arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission made in reliance upon
and in conformity with information pertaining to such seller, as such, furnished
in writing to the Company by such seller specifically for use in such
registration statement or prospectus; provided, further, however, that the
liability of each seller hereunder shall be limited to the proceeds (net of
underwriting discounts and commissions) received by such seller from the sale of
Restricted Securities covered by such registration statement.

     Promptly after receipt by an indemnified party hereunder of notice of the
commencement of any action, such indemnified party shall, if a claim in respect
thereof is to be made against the indemnifying party hereunder, notify the
indemnifying party in writing thereof, but the omission so to notify the
indemnifying party shall not relieve it from any liability which it may have to
any indemnified party other than under this Section 9.  In case any such action
shall be brought against any indemnified party and it shall notify the
indemnifying party of the commencement thereof, the indemnifying party shall be
entitled to participate in and, to the extent it shall wish, to

                                      14
<PAGE>
 
assume and undertake the defense thereof with counsel satisfactory to such
indemnified party, and, after notice from the indemnifying party to such
indemnified party of its election so to assume and undertake the defense
thereof, the indemnifying party shall not be liable to such indemnified party
under this Section 9 for any legal expenses subsequently incurred by such
indemnified party in connection with the defense thereof; provided, however,
that, if the defendants in any such action include both the indemnified party
and the indemnifying party and the indemnified party shall have reasonably
concluded that there may be reasonable defenses available to it which are
different from or additional to those available to the indemnifying party, or if
the interests of the indemnified party reasonably may be deemed to conflict with
the interests of the indemnifying party, the indemnified party shall have the
right to select a separate counsel and to assume such legal defenses and
otherwise to participate in the defense of such action, with the reasonable
expenses and fees of such separate counsel and other expenses related to such
participation to be reimbursed by the indemnifying party as incurred.

     Notwithstanding the foregoing, any indemnified party shall have the right
to retain its own counsel in any such action, but the fees and disbursements of
such counsel shall be at the expense of such indemnified party unless (i) the
indemnifying party shall have failed to retain counsel for the indemnified
person as aforesaid or (ii) the indemnifying party and such indemnified party
shall have mutually agreed to the retention of such counsel.  It is understood
that the indemnifying party shall not, in connection with any action or related
actions in the same jurisdiction, be liable for the fees and disbursements of
more than one separate firm qualified in such jurisdiction to act as counsel for
the indemnified party.  The indemnifying party shall not be liable for any
settlement of any proceeding effected without its written consent, but if
settled with such consent or if there be a final judgment for the plaintiff, the
indemnifying party agrees to indemnify the indemnified party from and against
any loss or liability by reason of such settlement or judgment.

     If the indemnification provided for in the first two paragraphs of this
Section 9 is unavailable or insufficient to hold harmless an indemnified party
under such paragraphs in respect of any losses, claims, damages or liabilities
or actions in respect thereof referred to therein, then each indemnifying party
shall in lieu of indemnifying such indemnified party contribute to the amount
paid or payable by such indemnified party as a result of such losses, claims,
damages, liabilities or actions in such proportion as appropriate to reflect the
relative fault of the Company, on the one hand, and the underwriters and the
sellers of such Restricted Securities, on the other, in 

                                      15
<PAGE>
 
connection with the statements or omissions which resulted in such losses,
claims, damages, liabilities or actions as well as any other relevant equitable
considerations, including the failure to give any notice under the third
paragraph of this Section 9. The relative fault shall be determined by reference
to, among other things, whether the untrue or alleged untrue statement of a
material fact relates to information supplied by the Company, on the one hand,
or the underwriters and the sellers of such Restricted Securities, on the other,
and to the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission. The Company and
you agree that it would not be just and equitable if contributions pursuant to
this paragraph were determined by pro rata allocation (even if all of the
sellers of such Restricted Securities or by any other method of allocation which
did not take account of the equitable considerations referred to above in this
paragraph. The amount paid or payable by an indemnified party as a result of the
losses, claims, damages, liabilities or action in respect thereof, referred to
above in this paragraph, shall be deemed to include any legal or other expenses
reasonably incurred by such indemnified party in connection with investigating
or defending any such action or claim. Notwithstanding the provisions of this
paragraph, the sellers of such Restricted Securities shall not be required to
contribute any amount in excess of the amount, if any, by which the total price
at which the Common Stock sold by each of them was offered to the public exceeds
the amount of any damages which they would have otherwise been required to pay
by reason of such untrue or alleged untrue statement or omission. No person
guilty of fraudulent misrepresentations (within the meaning of Section 11(f) of
the Securities Act), shall be entitled to contribution from any person who is
not guilty of such fraudulent misrepresentation.

     The indemnification of underwriters provided for in this Section 9 shall be
on such other terms and conditions as are at the time customary and reasonably
required by such underwriters.  In that event the indemnification of the sellers
of Restricted Securities in such underwriting shall at the sellers' request be
modified to conform to such terms and conditions.

     10. Changes in Common Stock and/or Notes.  If, and as often as, there are
any changes in the Common Stock and/or Notes by way of stock split, stock
dividend, combination or reclassification, or through merger, consolidation,
reorganization or recapitalization, or by any other means, appropriate
adjustment shall be made in the provisions hereof, as may be required, so that
the rights and privileges granted hereby shall continue with respect to the
Common Stock or Notes, as the case may be, as so changed.

                                      16
<PAGE>
 
     11. Representations and Warranties of the Company. The Company represents
and warrants to you as follows:

     (a) The execution, delivery and performance of this Agreement by the
Company have been duly authorized by all requisite corporate action and will not
violate any provision of law, any order of any court or other agency of
government, the Certificate of Incorporation or By-laws of the Company, or any
provision of any indenture, agreement or other instrument to which it or any of
its properties or assets is bound, or conflict with, result in a breach of or
constitute (with due notice or lapse of time or both) a default under any such
indenture, agreement or other instrument, or result in the creation or
imposition of any lien, charge or encumbrance of any nature whatsoever upon any
of the properties or assets of the Company.

     (b) This Agreement has been duly executed and delivered by the Company and
constitutes the legal, valid and binding obligation of the Company, enforceable
in accordance with its terms, subject to considerations of public policy in the
case of the indemnification provisions hereof.

     11A. Representations and Warranties of the Purchaser. The Purchaser
represents and warrants to the Company as follows:

     (c) The execution, delivery and performance of this Agreement by the
Purchaser have been duly authorized by all requisite corporate action and will
not violate any provision of law, any order of any court or other agency of
government, the charter and other organizational documents of the Purchaser, or
any provision of any indenture, agreement or other instrument to which it or any
of its properties or assets is bound, or conflict with, result in a breach of or
constitute (with due notice or lapse of time or both) a default under any such
indenture, agreement or other instrument, or result in the creation or
imposition of any lien, charge or encumbrance of any nature whatsoever upon any
of the properties or assets of the Purchaser.

     (d) This Agreement has been duly executed and delivered by the Purchaser
and constitutes the legal, valid and binding obligation of the Purchaser,
enforceable in accordance with its terms, subject to considerations of public
policy in the case of the indemnification provisions hereof.


     12. Reporting.  The Company agrees with you as follows:

                                      17
<PAGE>
 
     (a) The Company shall at all times make and keep public information
available, as those terms are understood and defined in Rule 144 under the
Securities Act.

     (b) The Company shall file with the Commission in a timely manner all
reports and other documents as the Commission may prescribe under Section 13(a)
or 15(d) of the Exchange Act at any time that the Company is subject to such
reporting requirements of the Exchange Act.

     (c) The Company shall furnish to each holder of Restricted Securities
forthwith upon request (i) a written statement by the Company as to its
compliance with the reporting requirements of Rule 144 (at any time that it is
subject to such reporting requirements), (ii) a written statement by the Company
as to its compliance with the reporting requirements of the Securities Act and
the Exchange Act (at any time that it is subject to such reporting requirements,
(iii) a copy of the most recent annual or quarterly report of the Company, and
(iv) such other reports and documents so filed as a holder may reasonably
request to avail itself of any rule or regulation of the Commission allowing a
holder of Restricted Securities to sell any such securities without
registration.

     13. Miscellaneous.

     (a) All covenants and agreements contained in this Agreement by or on
behalf of any of the parties hereto shall bind and inure to the benefit of the
respective successors and assigns of the parties hereto whether so expressed or
not. Without limiting the generality of the foregoing, the registration rights
conferred herein on the holders of Restricted Securities shall inure to the
benefit of any and all subsequent holders from time to time of the Restricted
Securities for so long as the certificates representing the Restricted
Securities or Founders Stock, as the case may be, shall bear the legend
specified in Section 2 hereof.

     (b) All notices, requests, consents and other communications hereunder
shall be in writing and shall be mailed by first class registered mail, postage
prepaid, addressed as follows:

                                      18
<PAGE>
 
     if to the Company, to it at

     Offshore Logistics, Inc.
     224 Rue de Jean
     Lafayette, Louisiana 70505
 
     Attention: Secretary

     if to the Purchaser, to it at

     Caledonia Industrial & Services Limited
     Cayzer House
     1 Thomas More Street
     London E1 9AR
     England
 
     Attention: Secretary


     if to any subsequent holder of Restricted Securities to such holder at such
     address as may have been furnished to the Company in writing by such
     holder;

     or, in any case, at such other address or addresses as shall have been
     furnished in writing to the Company (in the case of a holder of Restricted
     Securities) or to the holders of Restricted Securities (in the case of the
     Company).

     (c) This Agreement shall be governed by and construed in accordance with
the laws of the State of Delaware.

     (d) This Agreement constitutes the entire agreement of the parties with
respect to the subject matter hereof.  This Agreement may not be modified or
amended except in writing signed by the Company and the holders of not less than
80% of the Restricted Securities then outstanding (based upon the both number of
shares of Common Stock and the principal amount of Notes), provided that no
modification or amendment shall deprive any holder of Restricted Securities of
any material right under this Agreement without such holder's consent.

     (e) This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

                                      19
<PAGE>
 
     Please indicate your acceptance of the foregoing by signing and returning
the enclosed counterpart of this letter, whereupon this letter (herein sometimes
called "this Agreement") shall be a binding agreement between the Company and
you.

                                       Very truly yours,

                                       OFFSHORE LOGISTICS, INC.



                                       By_____________________
                                       Title:
AGREED TO AND ACCEPTED
as of the date first
above written.

CALEDONIA INDUSTRIAL & SERVICES
     LIMITED



By_____________________
Title:

                                      20

<PAGE>
 
                                   EXHIBIT 11
                       COMPUTATION OF EARNINGS PER SHARE


<TABLE>
<CAPTION>
                                           THREE MONTHS ENDED      SIX MONTHS ENDED 
                                              DECEMBER 31,           DECEMBER 31,
                                         ----------------------  ----------------------
                                            1996        1995        1996        1995
                                         ----------  ----------  ----------  ----------
<S>                                      <C>         <C>         <C>         <C>
PRIMARY:
 
Weighted average shares outstanding....  19,744,314  19,487,534  19,621,567  19,469,989
 
Net effect of dilutive stock warrants
 based on the Treasury Stock method
 using average market price............      31,974      15,767      25,681      22,396
 
Net effect of dilutive stock options
 based on the Treasury Stock method
 using average market price............     397,816     225,121     322,095     255,699
                                         ----------  ----------  ----------  ----------
                                         20,174,104  19,728,422  19,969,343  19,748,084
                                         ==========  ==========  ==========  ==========
 
FULLY DILUTED:
 
Weighted average shares outstanding....  19,744,314  19,487,534  19,621,567  19,469,989
 
Net effect of dilutive stock warrants
 based on the Treasury Stock method
 using end of period market price......      37,715      17,908      33,103      24,466
 
Net effect of dilutive stock options
 based on the Treasury Stock method
 using end of period market price......     456,490     231,346     386,447     264,911
                                         ----------  ----------  ----------  ----------
                                         20,238,519  19,736,788  20,041,117  19,759,366
                                         ==========  ==========  ==========  ==========
 
                                        (thousands of dollars, except per share data)
 
Net income.............................     $5,608      $3,456      $11,463      $7,115
                                            ======      ======      =======       =====
Per share amount - Primary.............     $ 0.28      $ 0.18      $  0.57      $ 0.36
                                            ======      ======      =======      ======
Per share amount - Fully diluted.......     $ 0.28      $ 0.18      $  0.57      $ 0.36
                                            ======      ======      =======      ======
 
</TABLE>

<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          JUN-30-1997
<PERIOD-START>                             JUL-01-1996
<PERIOD-END>                               DEC-31-1996
<CASH>                                          27,971
<SECURITIES>                                         0
<RECEIVABLES>                                   82,601
<ALLOWANCES>                                         0
<INVENTORY>                                     72,832
<CURRENT-ASSETS>                               184,173
<PP&E>                                         521,619
<DEPRECIATION>                                  68,661
<TOTAL-ASSETS>                                 685,370
<CURRENT-LIABILITIES>                          119,996
<BONDS>                                        206,151
                                0
                                          0
<COMMON>                                           210
<OTHER-SE>                                     236,702
<TOTAL-LIABILITY-AND-EQUITY>                   685,370
<SALES>                                         91,600
<TOTAL-REVENUES>                                92,323
<CGS>                                           67,006
<TOTAL-COSTS>                                   79,092
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 970
<INCOME-PRETAX>                                 16,883
<INCOME-TAX>                                     5,403
<INCOME-CONTINUING>                             11,463
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    11,463
<EPS-PRIMARY>                                      .57
<EPS-DILUTED>                                      .57
        

</TABLE>


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