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                                                                   Exhibit 10.25

                                 TRUST INDENTURE

                                     BETWEEN

                        PINELLAS COUNTY INDUSTRY COUNCIL

                                       AND

                        BARNETT BANKS TRUST COMPANY, N.A.

                             Dated December 17, 1987

                   $1,800,000 Pinellas County Industry Council
                Industrial Development Revenue Bond, Series 1987
                         (Aerosonic Corporation Project)

                          This Instrument Prepared By:

                            Michael D. Williams, Esq.
                         BRYANT, MILLER AND OLIVE, P.A.
                       Suite 500, 201 South Monroe Street
                           Tallahassee, Florida 32301

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                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----
Parties ...................................................................    1
Recitals ..................................................................    1
Form of Bond ..............................................................    3
Granting Clause ...........................................................   12

                                    Article I

Definitions ...............................................................   15

                                   Article II
                                    The Bonds

Section 201.    Authorized Amount of Bonds ................................   24
Section 202.    Description of Bonds ......................................   24
Section 203.    Execution and Authentication of Bonds .....................   27
Section 204.    Form of Bonds .............................................   31
Section 205.    Registration and Exchange of Bonds; Persons
                   Treated as Owners ......................................   31
Section 206.    Bonds Mutilated, Destroyed, Stolen or Lost ................   32
Section 207.    Issuance of Other Obligations .............................   32

                                   Article III
                                Creation of Funds

Section 301.    Creation of Funds .........................................   33
Section 302.    Bond Fund .................................................   33
Section 303.    Construction Fund .........................................   33
Section 304.    Security for Funds ........................................   33

                                Article IV
                  Custody and Application of Proceeds of Bonds

Section 401.    Custody of Proceeds .......................................   34
Section 402.    Application of Bond Proceeds ..............................   34

                                    Article V
                       Application of Financing Payments,
                      Application of Deposits to the Funds

Section 501.    Source of Payment of Bonds ................................   35
Section 502.    Deposits to the Bond Fund .................................   35

                                       i

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                                                                            Page
                                                                            ----
Section 503.    Application of Moneys in the Bond Fund ....................   35
Section 504.    Release to Funds Upon Payment of Bonds ....................   38
Section 505.    Charge ....................................................   38
Section 506.    Repayment to the Company from the Funds ...................   38

                                   Article VI
                                General Covenants

Section 601.    Payment of Principal and Interest .........................   39
Section 602.    Performance of Covenants; Authority .......................   39
Section 603.    Right to Finance Project; Instruments of Further
                   Assurance ..............................................   39
Section 604.    Filing, Re-Filing of Supplements ..........................   40
Section 605.    Payment of Taxes, Charges .................................   40
Section 606.    Insurance .................................................   40
Section 607.    Recordation of Agreement, Indenture and Security
                   Instruments ............................................   40
Section 608.    Inspection of Books .......................................   40
Section 609.    Maintenance of Existence ..................................   40
Section 610.    Rights Under Agreement ....................................   41
Section 611.    Protection of Bondholders .................................   41
Section 612.    Original Purchaser's, Trustee's and Paying Agents'
                   Fees, Charges, Advances and Expenses ...................   41
Section 613.    Tax Covenant ..............................................   42

                                   Article VII
                       Redemption of Bonds Before Maturity

Section 701.    Redemption Dates and Prices ...............................   43
Section 702.    Notice of Redemption ......................................   44
Section 703.    Cancellation ..............................................   44
Section 704.    Tax Indemnification Payment to Holders ....................   45
Section 705.    Non-Presentment of Bonds ..................................   45
Section 706.    Bonds Redeemed in Part ....................................   45

                                  Article VIII
                                   Investments

Section 801.    Investment of Construction Funds ..........................   46
Section 802.    Trustee's Responsibilities ................................   47
Section 803.    Arbitrage .................................................   47

                                       ii

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                                                                            Page
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                                   Article IX
                             Discharge of Indenture

Section 901.    Discharge of Lien and Security Interests ..................   48
Section 902.    Provision for Payment of Bonds ............................   48
Section 903.    Discharge of the Indenture ................................   49

                                    Article X
           Default Provisions and Remedies of Trustee and Bondholders

Section 1001.   Events of Default .........................................   50
Section 1002.   Declaration of Acceleration ...............................   50
Section 1003.   Remedies; Rights of Bondholders ...........................   51
Section 1004.   Notice to Bondholders .....................................   51
Section 1005.   Right of Bondholder to Direct Proceedings..................   51
Section 1006.   Remedies Under Agreement...................................   52
Section 1007.   No Remedy Exclusive........................................   52
Section 1008.   No Additional Waiver Implied by One Waiver.................   52
Section 1009.   Application of Moneys .....................................   52
Section 1010.   Remedies Vested in Trustee ................................   54
Section 1011.   Rights and Remedies of Bondholder .........................   54
Section 1012.   Termination of Proceedings ................................   55
Section 1013.   Waivers of Events of Default ..............................   55
Section 1014.   Notice of Defaults Under Section 1001(d);
                   Opportunity for the Company to Cure Defaults ...........   56

                                   Article XI
                             Concerning The Trustee

Section 1101.   Acceptance of Trusts; Liability ...........................   57
Section 1102.   Certain Rights of Trustee...... ...........................   58
Section 1103.   Trustee Not Responsible for Recitals and Certain
                   Matters of Bonds or Security............................   59
Section 1104.   General Limitation of Liability ...........................   59
Section 1105.   Bringing and Defending Legal Actions ......................   60
Section 1106.   Notice of Defaults ........................................   60
Section 1107.   Intervention on Behalf of Bondholders .....................   60
Section 1108.   Release of Property from Lien of this Instrument ..........   60
Section 1109.   Right of Trustee to Perform Certain Acts on Failure of
                   Issuer..................................................   61
Section 1110.   Advancement of Moneys .....................................   61
Section 1111.   Retention of Documents ....................................   62
Section 1112.   Compensation of Trustee; Lien..............................   62
Section 1113.   Trustee May Hold Bonds.....................................   62
Section 1114.   Successor Trustee .........................................   62
Section 1115.   Resignation and Removal; Appointment of Successor..........   62
Section 1116.   Concerning any Successor Trustees .........................   63
Section 1117.   Appointment of Co-Trustee..................................   64
Section 1118.   Instruments and Documents of Bondholders...................   65
Section 1119.   Determination of Bonds Outstanding.........................   65
Section 1120.   Filing of Certain Continuation Statements..................   66
Section 1121.   Several Capacities.........................................   66
Section 1122.   Obligations Under Agreement................................   66

                                      iii

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                                                                            Page
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                                   Article XII
                             Supplemental Indentures

Section 1201.   Supplemental Indentures not Requiring Consent of
                   Bondholders ............................................   67
Section 1202.   Supplemental Indentures Requiring Consent of
                   Bondholders ............................................   67
Section 1203.   Trustee Authorized to Join in Supplements;
                Reliance on Counsel .......................................   69

                                  Article XIII
                             Amendment of Agreements

Section 1301.   Amendments, Etc., to Agreement or Note
                   Requiring Consent of Bondholders .......................   70

                                   Article XIV
                                  Miscellaneous

Section 1401.   Consents, Etc., of Bondholders ............................   71
Section 1402.   Limitations of Rights .....................................   71
Section 1403.   Severability ..............................................   71
Section 1404.   Notices ...................................................   72
Section 1405.   Trustee as Bond Registrar and as Paying Agent .............   72
Section 1406.   Payments Due on Saturdays, Sundays and Holidays ...........   72
Section 1407.   Reliance by Issuer on Facts or Certificates;
                   Indemnification of Issuer ..............................   72
Section 1408.   Immunity of Officers, Members and Agents of Issuer,
                   Trustee and Original Purchaser .........................   73
Section 1409.   Headings not Part of Indenture ............................   73
Section 1410.   Counterparts ..............................................   73
Section 1411.   Applicable Law ............................................   73
Section 1412.   No Liens ..................................................   74
Section 1413.   Indenture Effective Upon Execution ........................   74
Section 1414.   Advancement of Costs ......................................   74
Section 1415.   No Usury ..................................................   74

Testimonium Clause ........................................................   75
Signatures and Seals ......................................................   76

Exhibit A - Location of Project
Exhibit B - Equipment & Machinery
Exhibit C - Promissory Note

                                       iv

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                                 TRUST INDENTURE

     THIS TRUST INDENTURE dated the 17th day of December, 1987, by and between
the PINELLAS COUNTY INDUSTRY COUNCIL, a special district and a public body
corporate and politic in Pinellas County, Florida duly organized and existing
under the laws of the State of Florida (hereinafter called the "Issuer"), and
Barnett Banks Trust Company, N.A., a national banking association duly
organized, existing and authorized to accept and execute trusts of the character
herein set out under the laws of the United States of America, with its
principal office, domicile and post office address located in the City of
Jacksonville, Florida, as trustee (hereinafter called the "Trustee");

                                   WITNESSETH:

     WHEREAS, pursuant to authority granted by the Pinellas County Industry
Council Act, Chapter 69-1490, Laws of Florida, Special Acts of 1969 and Chapter
159, Part II, Florida Statutes (the "Act"), the Issuer is authorized and
empowered to make loans to qualified companies for the cost of projects in
accordance with agreements between the Issuer and such companies; and

     WHEREAS, Aerosonic Corporation, a corporation duly organized and existing
under the laws of the State of Delaware, and authorized to do business in the
State of Florida (the "Company") is eligible to undertake the financing,
construction and equipping of a project as provided and permitted by the Act;
and

     WHEREAS, the Issuer has authorized the issuance of not exceeding $1,800,000
Pinellas County Industry Council Industrial Development Revenue Bond, Series
1987 (Aerosonic Corporation Project) (the "Bonds"), which Bonds are being issued
in the principal amount of $1,800,000 the proceeds of which will be loaned to
the Company for the purpose of constructing and equipping a manufacturing
facility and related facilities (the "Project"), which Project will be located
at 1212 Hercules Avenue, Clearwater, Florida; and

     WHEREAS, the Company; in consideration of the Issuer making the loan herein
referred to and issuing the Bonds, shall execute in favor of and deliver unto
the Issuer simultaneously with the execution of this Indenture, its
non-negotiable, but assignable, promissory note (the "Note") in the amount of
$1,800,000 to be secured as set forth in the Financing Agreement dated December
17, 1987, between the Issuer and the Company (the "Agreement"); and

     WHEREAS, the Issuer has agreed to assign and pledge to the Trustee under
the terms of this Indenture all of its rights, title and interest in the
Agreement (except certain rights reserved by

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the Issuer), the Note, the "Revenues" (hereinafter defined), the "Mortgage"
(hereinafter defined) and all amounts on deposit from time to time in the "Bond
Fund" and the "Construction Fund" (as each is hereinafter defined), as security
for the payment of the principal and purchase price of, and the redemption
premium (if any) and the interest on the Bonds; and

     WHEREAS, the Company is authorized by law to enter into the Agreement to
pay from Bond proceeds and, if necessary, from Revenues and other available
funds sufficient moneys to the Issuer to pay the Bonds with interest and other
charges upon the terms and conditions provided in the Agreement; and

     WHEREAS, the execution and delivery of this Trust Indenture (herein called
the "Indenture"), and the issuance of the Bonds under the Act have been in all
respects fully and validly authorized by resolution duly passed and approved by
the Issuer; and

     WHEREAS, it is the intention of the Issuer that this Indenture should serve
as the organic document for issuing and securing the Bonds, as herein defined;
and

     WHEREAS, the Bonds, the registration and interest payment provisions and
the Trustee's Certificate of Authentication to be endorsed thereon are all to be
in substantially the following form:

                                       2

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                         [FORM OF FULLY REGISTERED BOND]

No. R-1                                                               $1,800,000

                            UNITED STATES OF AMERICA
                                STATE OF FLORIDA
                            PINELLAS COUNTY, FLORIDA
                        PINELLAS COUNTY INDUSTRY COUNCIL
                INDUSTRIAL DEVELOPMENT REVENUE BOND, SERIES 1987
                        (AEROSONIC CORPORATION PROJECT)

     KNOW ALL MEN BY THESE PRESENTS, that the Pinellas County Industry Council,
a special district and a public body corporate and politic existing in Pinellas
County, Florida (hereinafter called the "Issuer") , for value received, hereby
promises to pay to the order of Barnett Bank of Pinellas County (the "Original
Purchaser"), or registered assigns, solely from the Revenues hereinafter
mentioned and from no other source, the principal sum of One Million Eight
Hundred Thousand Dollars ($1,800,000) and to pay solely from the Revenues,
interest from the date hereof commencing March 17, 1988 and on the 17th day of
each March, June, September and December thereafter on the unpaid balance of
said principal sum outstanding from time to time at the Base Percentage
(hereinafter defined). Principal shall be payable in equal installments of
$18,556.70 commencing December 17, 1988 and on the 17th day of each March, June,
September and December thereafter. A final payment of all unpaid principal
($18,556.80) plus accrued interest shall be due and payable on December 17,
2012.

     The "Base Percentage" shall be the percentage applied to the Prime Rate
(hereinafter defined) in determining the interest this Bond will bear. The Base
Percentage is currently 87% for the period from the date of delivery of this
Bond through December 31, 1987, and 90% thereafter subject to adjustment as
provided herein. No adjustment to the Base Percentage shall result in the
interest on this Bond accruing or becoming payable at a rate in excess of the
Taxable Rate (as hereinafter defined). The "Prime Rate" shall mean a rate of
interest equal to the announced prime rate per annum of Barnett Banks, Inc. The
Prime Rate is a reference rate for the information and use of the Original
Purchaser in establishing the actual rate to be charged to the Company. The
Prime Rate is not necessarily the rate of interest charged any particular class
of borrower. The Prime Rate shall be adjusted from time to time without notice
or demand, as of the effective date of any announced change thereof. Such rate
which is in effect as of the close for business on each business day shall be
the effective applicable rate for that day and for any succeeding non-business
day. The initial Prime Rate shall be the Prime Rate in effect at the opening of
business on the date of delivery of this Bond. The "Interest Rate" on this Bond
shall mean the Base Percentage multiplied by the Prime Rate as modified by the
adjustments provided

                                       3

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for herein, but shall not by reason of such adjustments exceed the Prime Rate
plus one percent (1%) (the "Taxable Rate"). Interest shall be computed on the
basis of a three hundred sixty (360) day year consisting of 12 30-day months.

     Determination of Taxability. In the event of a Determination of Taxability
(as defined in the Indenture as defined below) the interest rate on this Bond
shall be increased to a rate equal to the Taxable Rate and such increased rate
of interest shall be payable from the Date of Taxability (as defined in the
Indenture as defined below) and compounded quarterly until this Bond is redeemed
as required herein. Payment shall be made to the current holders of this Bond
and any former holders from the Date of Taxability until this Bond is redeemed
as required herein. Payment shall be made to such holders and former holders
from the Date of Taxability for the period of time that such person was the
registered owner of this Bond. The holder or former holder shall also be
entitled to reimbursement of any penalties, additions or interest on overdue
taxes and any taxes payable because of receipt of such reimbursement.

     The Interest Rate on this Bond shall be adjusted as follows (but shall not,
by reason of such adjustments, exceed the Taxable Rate):

     (i) Change in Maximum Corporate Tax Rate. If the maximum federal corporate
income tax rate for the holder of this Bond or its parent holding company during
any period in which interest is accruing, shall be other than 40% for 1987 or
34% for 1988 and subsequent years, then the interest on this Bond during such
period shall be modified by multiplying the Base Percentage (as adjusted) by a
fraction equal to 1 - A
                  -----
                  1 - B
where A equals the maximum marginal corporate income tax rate then in effect and
B equals the immediately preceding maximum marginal corporate income tax rate.

     (ii) Alternative Minimum Tax Where Bond Interest is a Direct Tax Preference
Item. If the holder of this Bond or its parent holding company pays an
alternative minimum tax in any tax year and the interest on this Bond is a
direct tax preference item under section 57(a)(5) or any successor provision of
the Internal Revenue Code of 1986 (the "Code") then the Interest Rate on this
Bond for the period during such tax year in which interest is accruing on this
Bond shall be increased during such accrual period by an amount equal to (A - B)
x C where:

          (a) A equals the Interest Rate on this Bond expressed as a percentage;

          (b) B equals the Adjusted Bank's Cost of Funds (as hereinafter
     defined); and

          (c) C equals the maximum marginal rate of the alternative maximum tax
     expressed as a decimal (currently .20).

                                       4

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     "Adjusted Bank's Cost of Funds" shall mean the fraction (expressed as a
percentage) and as determined by the holder of this Bond or its parent holding
company, of the total interest expense of the Original Purchaser (or any
successor institutional holder of this Bond) for each calendar year divided by
the total monthly average of all assets of the Original Purchaser (or any
successor institutional holder of this Bond) during the calendar year.

     (iii) Alternative Minimum Tax Where Bond Interest is an Indirect Tax
Preference Item. If the holder of this Bond or its parent holding company pays
an alternative minimum tax in any tax year and the interest on this Bond is not
a tax preference item under section 57(a)(5) of the Code, but is an indirect tax
preference item because of the application of Section 56(f) or Section 56(g) or
any successor provision of the Code then the Interest Rate on this Bond for the
period during such tax year in which interest is accruing on this Bond shall be
increased during such accrual period by an amount equal to (A - B) x C where:

          (a) A equals the Interest Rate on this Bond expressed as a percentage;

          (b) B equals the Adjusted Bank's Cost of Funds; and

          (c) C equals one half of the maximum marginal rate of the alternative
     minimum tax expressed as a decimal (currently 1/2 of .20 or .10) for tax
     years of the Original Purchaser beginning before January 1, 1990 and C
     equals 75% of the maximum marginal rate of the alternative minimum tax
     expressed as a decimal for tax years of the Original Purchaser beginning
     after December 31, 1989.

     (iv) Loss of Federal Income Tax Deduction for State Income Taxes. If the
federal income tax deduction for state income taxes paid on the interest
payments received under this Bond during any period is reduced because of any
change in the tax laws or regulations then the Interest Rate on this Bond shall
be increased during such period by an amount equal to A x B x C x D where:

          (a) A equals the fraction (expressed as a decimal) of the total state
     income tax disallowed as a result of such tax law change;

          (b) B equals the rate of the applicable state income tax (expressed as
     a decimal);

          (c) C equals the corporate tax rate then in effect (expressed as a
     decimal); and

          (d) D equals the Interest Rate on this Bond (expressed as a
     percentage).

                                       5

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     (v) Partial Taxability. If the interest payments received under this Bond
during any period become partially taxable because of any change in the tax laws
or regulations, then the Interest Rate on this Bond shall be increased during
such period by an amount equal to (A - B) x C where:

          (a) A equals the Taxable Rate (expressed as a percentage);

          (b) B equals the Interest Rate on this Bond (expressed as a
     percentage); and

          (c) C equals the fraction of the Interest Rate on this Bond which has
     become taxable as the result of such tax change (expressed as a decimal).

     (vi) Other Change in Tax Laws. If the tax laws or regulations are amended
to cause the interest on this Bond to be taxable, to be subject to a minimum tax
or an alternative minimum tax or to otherwise decrease the after tax yield on
this Bond to the holder of this Bond (directly or indirectly, other than a
change described in (i) through (v) above or because of a Determination of
Taxability) then the Interest Rate on this Bond shall be adjusted to cause the
interest received by the holder of this Bond, after payment of any increase in
tax, to equal the interest the holder of this Bond would have received in the
absence of such change or amendment in the tax laws or regulations. If the tax
laws or regulations are amended to increase the after tax yield on this Bond to
the holder of this Bond, then the Trustee (as defined in the Indenture as
hereinafter defined) shall adjust the Interest Rate on this Bond to cause the
interest received by the holder of this Bond to equal the interest the holder of
this Bond would have received in the absence of such change or amendment in the
tax laws or regulations.

     The above adjustments shall be cumulative, but in no event shall the
Interest Rate on this Bond exceed the maximum rate permitted by law. The above
adjustments to the Interest Rate on this Bond shall be effective on the
effective date of the applicable change in the tax laws or regulations. Interest
on this Bond and all other tax rates and interest rates are expressed as annual
rates. However, proper partial adjustment shall be made if the tax law change is
effective after the first day of the holder's tax year or if interest on this
Bond does not accrue for the entire tax year of the holder. Adjustments which
create a circular calculation because the Interest Rate on this Bond is affected
by the calculation shall be carried out sequentially, increasing the Interest
Rate accordingly in each successive calculation using as the new value the
increase in the Interest Rate on this Bond, until the change on the Interest
Rate on this Bond caused by the next successive calculation of the adjustment is
de minimis. If more than one of paragraphs (i) through (v) apply, then the
Interest Rate shall be adjusted in the order in which listed above.

                                       6

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     To the extent allowed by applicable law, in the event any payment of
interest and principal on or other amounts payable under this Bond shall not be
paid when due, the amount so due shall, to the extent legally enforceable,
continue to bear interest from the date such payment became due until payment
thereof at a rate equal to the Default Rate (as defined in the Agreement as
hereinafter defined), and, if the holder of this Bond or the Trustee (as defined
in the Indenture as hereinafter defined) should employ attorneys or incur other
expenses for the collection of amounts payable under this Bond, the Issuer shall
pay the reasonable fees of such attorneys and such other expenses so incurred by
the holder of this Bond and the Trustee.

     Principal of and interest and other payments on this Bond are payable in
lawful money of the United States of America by check or draft on the Trustee
mailed to the registered owner, at the address shown on the registration books
maintained by the Trustee as Registrar or such other address as is furnished to
the Trustee in writing by the registered owner of this Bond. Payment of the
final installment of principal of and interest on this Bond shall be made upon
the presentation and surrender of this Bond at the principal office of the
Trustee. All payments shall be applied first to accrued but unpaid interest and
then to principal, except that payments in partial redemption of this Bond shall
be applied in accordance with Section 701 of the Indenture.

     This Bond is one of an issue of Bonds of the Issuer in the aggregate
principal amount of $1,800,000 issued to finance all or a portion of the cost of
constructing and equipping a manufacturing facility and related facilities in
Pinellas County, Florida, (the "Project") for the benefit of the Company. The
Bonds will be repaid by the Issuer from installment financing payments and other
amounts under the terms of a Financing Agreement (hereinafter sometimes called
the "Agreement") and a Promissory Note (the "Note") both dated December 17,
1987. The issuance of the Bonds and the construction, equipping and financing of
the Project are under the authority of and in full compliance with the
Constitution and Statutes of the State of Florida, including particularly
Chapter 69-1490, Laws of Florida, Special Acts of 1969 and Chapter 159, Part II,
Florida Statutes (hereinafter called the "Act") and other applicable provisions
of law, and a resolution duly adopted by the Issuer on November 4, 1987, and
consented to by the Board of County Commissioners of Pinellas County on November
24, 1987 (hereinafter called the "Resolution"), and is subject to all the terms
and conditions of such Resolution.

     The Bonds are all issued under and equally and ratably secured by and
entitled to the security of a Trust Indenture dated December 17, 1987 (herein
sometimes called the "Indenture"), duly executed and delivered by the Issuer to
Barnett Banks Trust Company, N.A., as trustee under the Indenture (the
"Trustee"). Reference is made to the Indenture for the terms of the Indenture
and the provisions, among others, with respect to the nature and extent of the
security, the rights, duties and obligations of the Issuer and the Trustee and
the rights of the owners of the Bonds.

                                       7

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     As additional security for payment of the Bonds the Company has conveyed
its interest in certain real and personal property pursuant to a Mortgage and
Security Agreement dated December 17, 1987 from the Company as Mortgagor to the
Issuer as Mortgagee and assigned to the Trustee (the "Mortgage").

     The Issuer shall not be obligated to pay this Bond or the interest hereon
except from the revenues, receipts and the funds pledged to the payment of this
Bond including those payable pursuant to the Agreement and the Note and those
received by the Trustee pursuant to the Mortgage and any other moneys pledged
for such payment under the Indenture including but not limited to those moneys
on deposit from time to time in the Bond Fund and the Construction Fund, as each
is defined in the Indenture (collectively the "Revenues"), and neither the faith
and credit nor the taxing power of the State of Florida or of any other
political subdivision thereof is pledged to the payment of the principal of or
the interest on this Bond.

                     OPTIONAL REDEMPTION IN WHOLE OR IN PART

     This Bond may be redeemed by the Issuer, at the request of the Company on
any principal payment date, prior to maturity, in whole or in part (but if in
part, in $5,000 increments) , at 102% of the principal then outstanding if
redeemed on or prior to the first anniversary date of the date of delivery of
this Bond, at 101% of the principal then outstanding if redeemed after the first
anniversary date of the date of delivery of this Bond but on or before the
second anniversary date of the date of delivery of this Bond, and at 100% of the
principal then outstanding if redeemed after the second anniversary date of the
date of delivery of this Bond, plus accrued interest to the redemption date,
plus all other amounts due under the Mortgage, the Indenture or the Agreement.

                              MANDATORY REDEMPTION

     This Bond shall be redeemed in part in the manner provided in Section 2.03
of the Agreement, at par, plus accrued interest, to the extent that Bond
proceeds and investment earnings thereon exceed the amount necessary for the
construction and equipping of the Project.

                      SPECIAL MANDATORY REDEMPTION IN WHOLE

     If interest on this Bond is declared taxable as a result of a Determination
of Taxability, or should an Adjudication of Invalidity (as defined in the
Indenture, in which case the Company shall promptly notify the Trustee and
Original Purchaser of its existence) occur in connection with the Bonds then
this Bond shall be redeemed as provided in Section 8.05 of the Agreement at the
then outstanding principal amount of this Bond, plus accrued interest, plus in
the case of a Determination of Taxability all other amounts due under the
Mortgage, the Indenture or the Agreement and other amounts calculated as
provided in Section 202 of the Indenture.

                                       8

<PAGE>

                                       PUT

     This Bond may be redeemed by the holder in whole at the principal amount
plus accrued interest on the anniversary date of the date of delivery of this
Bond in the years 1992, 1997, 2002 and 2007. The holder may exercise this option
by written notice to the Trustee and the Company at least 6 months prior to the
redemption date. Upon receipt of the notice, the Company must pay all amounts
due under this Bond on or before the redemption date.

     All partial redemption of the Bonds shall be applied to principal
installments in inverse order of maturity except that partial redemption from
unexpended Bond proceeds shall be applied ratably to reduce future principal
installments.

     Notice of any such redemption shall be given in the manner required by the
Indenture.

     All Bonds so called for redemption will cease to bear interest on the
specified redemption date, provided funds for their redemption are on deposit at
the place of payment at that time, and shall no longer be protected by the
Indenture and shall not be deemed to be outstanding under the provisions of the
Indenture.

     The Issuer reserves the right to issue additional bonds payable on a parity
with the Bonds of the issue of which this Bond is one, subject to the conditions
and in the manner provided in the Agreement and the Indenture.

     Neither the Issuer, the State of Florida, nor any political subdivision
thereof, is or shall be obligated to pay this Bond or the interest hereon except
from the payments from the Company and neither the faith and credit nor the
taxing power of Pinellas County, the State of Florida or of any political
subdivision thereof is pledged to the payment of the principal of or the
interest on this Bond. The issuance of this Bond shall not directly or
indirectly or contingently obligate the State of Florida or any political
subdivision thereof to levy or to pledge any form of taxation whatever therefor
or to make any appropriation for their payment.

     NO RECOURSE SHALL BE HAD FOR THE PAYMENT OF THE PRINCIPAL OF, PREMIUM, IF
ANY, OR INTEREST ON THIS BOND OR FOR ANY CLAIM BASED THEREON OR UPON ANY
OBLIGATION, COVENANT OR AGREEMENT CONTAINED IN THIS BOND, THE INDENTURE OR THE
AGREEMENT AGAINST ANY PAST, PRESENT OR FUTURE MEMBER, OFFICER OR EMPLOYEE OF THE
ISSUER, OR ANY INCORPORATOR, MEMBER, COMMISSIONER, DIRECTOR, TRUSTEE, OFFICER OR
EMPLOYEE OF ANY SUCCESSOR OF THE ISSUER, AS SUCH, EITHER DIRECTLY OR THROUGH THE
ISSUER OR ANY SUCCESSOR OF THE ISSUER, UNDER ANY RULE OF LAW OR EQUITY, STATUTE
OR CONSTITUTION.

     The owner of this Bond shall have no right to enforce the covenants under
the Agreement or the Indenture, or to take any action with respect to any event
of default under the Agreement or

                                       9

<PAGE>

the Indenture, or to institute, appear in or defend any suit or other
proceedings with respect thereto, except as provided in the Agreement or the
Indenture.

     In certain events, on the conditions, in the manner and with the effect set
forth in the Agreement and the Indenture, the principal of the Bond issued under
the Agreement and the Indenture and then outstanding may become or may be
declared due and payable before the stated maturity thereof, together with
interest accrued thereon. Modifications or alterations of the Agreement and the
Indenture, or of any supplements thereto, may be made only to the extent and in
the circumstances permitted by the Agreement and the Indenture.

     IT IS HEREBY CERTIFIED, RECITED AND DECLARED that all acts, conditions and
things required to exist, happen and be performed precedent to and in the
execution and delivery of the Indenture and the issuance of this Bond do exist,
have happened and have been performed in due time, form and manner as required
by law; and that the issuance of this Bond and the series of which it forms a
part, together with all other obligations of the Issuer, does not exceed or
violate any constitutional or statutory limitation.

     This Bond shall have and is hereby declared to have all the qualities and
incidents, including negotiability, of investment securities under the Uniform
Commercial Code - Investment Securities law of the State of Florida.

     This Bond shall not be valid or become obligatory for any purpose or be
entitled to any security or benefit under the Indenture until the certificate of
authentication hereon shall have been duly executed by the Trustee.

     IN WITNESS WHEREOF, the Pinellas County Industry Council has issued this
Bond and has caused the same to be executed in its name by the manual signature
of its Chairman, and attested by the manual signature of its Secretary and its
official seal to be impressed hereon, the 17th day of December, 1987.

(SEAL)                                          PINELLAS COUNTY INDUSTRY COUNCIL


                                                By
                                                   -----------------------------
                                                   Chairman

ATTEST:


-----------------------------
Secretary

                                       10

<PAGE>

                     Trustee's Certificate of Authentication

     This Bond represents an issue of Bonds described in the within-mentioned
Trust Indenture.

                                                BARNETT BANKS TRUST COMPANY,
                                                N.A., as Trustee


                                                By
                                                  ------------------------------
                                                  Authorized Officer

                    PROVISIONS FOR REGISTRATION AND EXCHANGE

     As provided in the Indenture and subject to certain limitations set forth
therein, this Bond is transferable upon the books of the Trustee, by the
registered owner hereof in person or by such owner's attorney duly authorized in
writing, upon surrender hereof together with a written instrument of transfer
satisfactory to the Trustee, duly executed by the registered owner or such
owner's duly authorized attorney. Upon such transfer the Issuer will cause to be
issued in the name of the transferee a new fully registered Bond or Bonds of the
same aggregate principal amount, maturity and interest rate as the surrendered
Bond, subject to reimbursement for any tax, fee or governmental charge required
to be paid by the Issuer or the Trustee with respect to such transfer and for
any cost of printing Bonds.

                                   ASSIGNMENT

                               FOR VALUE RECEIVED

     The undersigned hereby sells, assigns and transfers unto
                                                             -------------------

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

the within Bond of the Pinellas County Industry Council, and does hereby
constitute and appoint                                    attorney to transfer
                       ----------------------------------,
the said Bond on the books of the within named Issuer, with full power of
substitution in the premises.

Date:
     ------------------------
Signature Guaranteed:
                     ------------------------                   ----------------
                                                                Registered owner

Notice: Signature(s) must be guaranteed by a member firm of the New York Stock
Exchange or a commercial bank or trust company.

                     [END OF FORM OF FULLY REGISTERED BOND]

                                       11

<PAGE>

                               FURTHER WITNESSETH:

     WHEREAS, all things necessary to make the Bonds, when authenticated by the
Trustee and issued as in this Indenture provided, the valid, binding and legal
obligations of the Issuer according to the import thereof, and to constitute
this Indenture a valid assignment and pledge of the right to make claim for,
collect, receive and receipt for the payments and revenues derived from the
Company for payment of the principal of, premium, if any, and interest on the
Bonds and a valid assignment of the rights of the Issuer under the Note, the
Mortgage and the Financing Agreement or any subsequent note, mortgage or
agreement have been done and performed, and the creation, execution and delivery
of this Indenture, and the creation, execution and issuance of the Bonds,
subject to the terms hereof, have in all respects been duly authorized;

                NOW, THEREFORE, THIS TRUST INDENTURE WITNESSETH:

     That the Issuer, in consideration of the premises, the acceptance by the
Trustee of the trusts hereby created, the purchase and acceptance of the Bonds
by the purchaser thereof, Ten Dollars ($10.00) duly paid to the Issuer by the
Trustee at or before the execution and delivery of these presents and of other
good and valuable considerations, the receipt of which is hereby acknowledged,
and in order to secure the payment of the principal of, premium, if any,
interest and any other sums payable on the Bonds Outstanding hereunder from time
to time, according to their tenor and effect, and to secure the observance and
performance by the Issuer of all covenants expressed or implied herein and in
the Bonds, retaining only its rights under the Agreement to indemnity,
reimbursement, insurance proceeds from liability insurance attributable to the
Issuer's liability, notice, and receipt of copies of all documents, certificates
and statements required by the Agreement to be provided to the Issuer and any
other rights specifically reserved to the Issuer therein does hereby grant,
bargain, sell, convey, assign, pledge and grant a security interest unto the
Trustee, and unto its successors in trust, and to its assigns forever, all of
the Issuer's estate, right, title and interest now or hereafter existing in the
following (herein called the "Trust Estate"):

                              GRANTING CLAUSE FIRST

     (a) the Project, including any and all parts thereof now owned or hereafter
acquired, and all loan payments and other revenues, proceeds and receipts to be
derived by the Issuer from the operation, sale, lease or other disposition of
the Project, which revenues, proceeds and receipts are hereby pledged
irrevocably for the payment of the principal of, premium, if any, and interest
on the Bonds and of the fees, charges, expenses and advances of the Trustee and
any Paying Agent hereunder;

                                       12

<PAGE>

     (b) the Note, the Agreement and the Mortgage including but not limited to
the Issuer's rights to receive the principal and interest payments on the Note
and other revenues, proceeds and receipts payable thereunder and under the
Agreement, which revenues, proceeds and receipts are hereby pledged irrevocably
for the payment of the principal of, premium, if any, and interest on the Bonds
and of the fees, expenses and advances of the Issuer, the Trustee and any Paying
Agent hereunder; the liens and security interests in and to the Project and
other collateral created by the Agreement or the Mortgage provided, however,
that the Issuer hereby reserves its rights under the Agreement and the Note to
be named in insurance policies and to receive certificates of insurance, and for
the Issuer and its members, officers, employees, servants, agents, contractors
and licensees to be reimbursed for expenses and to be defended, indemnified and
held harmless from costs, expenses and liabilities, all as provided in the
Agreement;

     (c) the proceeds of the Bonds (subject to provisions pertaining to the use
thereof set forth herein and in the Agreement);

     (d) any and all other property, rights and interest of writing of any kind
now or hereafter granted, bargained, sold, aliened, remised, released, conveyed,
assigned, transferred, mortgaged, pledged, hypothecated or otherwise subjected
hereto, as and for additional security hereunder, by the Company or any other
person on its behalf or with its written consent, to the Trustee, and the
Trustee is hereby authorized to receive any and all property thereof at any and
all times and to hold and apply the same subject to the terms hereof;

     (e) any funds, accounts, and investments held or to be held under this
Indenture and all income received by the Trustee from the investment of the
proceeds of the Bonds and other funds held by the Trustee hereunder; and

     (f) the proceeds of any of the foregoing.

     FURTHER PROVIDED, HOWEVER, THAT THE ISSUER HAS NOT MADE, AND DOES NOT
HEREBY MAKE, ANY REPRESENTATION, WARRANTY OR COVENANT, EXPRESS OR IMPLIED, WITH
RESPECT TO THE PROJECT OR ITS MERCHANT ABILITY, ITS FITNESS FOR A PARTICULAR
PURPOSE, ITS CONDITION, QUALITY, WORKMANSHIP, DURABILITY, OR SUITABILITY FOR THE
PURPOSES AND USES OF THE COMPANY OR AS SECURITY FOR THE BONDS, OR ANY OTHER
REPRESENTATION, WARRANTY OR COVENANT OF ANY KIND OR CHARACTER WITH RESPECT TO
THE PROJECT, OR WITH RESPECT TO THE EXTENT TO WHICH THE BOND PROCEEDS WILL BE
SUFFICIENT TO PAY THE COST TO BE INCURRED IN CONNECTION THEREWITH, AND ALL SUCH
REPRESENTATIONS, WARRANTIES AND COVENANTS BY THE ISSUER ARE HEREBY EXPRESSLY
DISCLAIMED.

     TO HAVE AND TO HOLD all and singular the Trust Estate, whether now owned or
hereafter acquired, to the Trustee and its respective successors in trust and
assigns forever;

                                       13

<PAGE>

     IN TRUST NEVERTHELESS, upon the terms and trust herein set forth for the
equal and proportionate benefit, security and protection of all present and
future Owners of the Bonds issued under and secured by this Indenture without
privilege, priority or distinction as to the lien or otherwise of any of the
Bonds over any of the other Bonds;

     PROVIDED, HOWEVER, that if the Issuer, its successors or assigns, shall
well and truly pay, or cause to be paid, the principal of Outstanding Bonds and
the interest and premium, if any, due or to become due thereon, at the times and
in the manner mentioned in the Outstanding Bonds according to the true intent
and meaning thereof, and shall cause the payments to be made as required herein
or shall provide, as permitted hereby, for the payment thereof by depositing
with the Trustee the amounts due or to become due to it in accordance with terms
and provisions hereof, then upon such final payment and upon the payment of all
fees, charges, expenses and advances of the Trustee and the Original Purchaser
and any paying agents, then upon such final payment this Indenture and the
rights hereby granted shall cease, determine and be void (except the rights of a
former Bondholder to be paid certain additional amounts in the event of a
Determination of Taxability); otherwise this Indenture shall remain in full
force and effect.

     THIS TRUST INDENTURE FURTHER WITNESSETH, and it is expressly declared, that
all Bonds issued and secured hereunder are to be issued, authenticated and
delivered and the Note, Agreement, Financing Payments (as hereinafter defined)
and Revenues hereby pledged are to be dealt with and disposed of under, upon and
subject to the terms, conditions, covenants, agreements, trusts, uses and
purposes as hereinafter expressed, and the Issuer does hereby agree and
covenant, with the Trustee and with the respective owners, from time to time, of
all Outstanding Bonds, or any part thereof, as follows:

                                       14

<PAGE>

                                    ARTICLE I

                                   DEFINITIONS

     Unless the context otherwise requires, the terms used in this Indenture
shall have the meanings specified in this Article. Words importing singular
number shall include the plural number in each case and vice versa, and words
importing persons shall include firms and corporations.

     "ACT" shall mean the Pinellas County Industry Council Act, Chapter 69-1490,
Special Acts of 1969, Laws of Florida, and Chapter 159, Part II, Florida
Statutes.

     "ADDITIONAL PARITY OBLIGATIONS" shall mean additional bonds or obligations
issued only with the consent of the Original Purchaser in compliance with the
terms, conditions and limitations contained herein and in the Agreement and
which shall have an equal lien on the Revenues to be derived by the Issuer from
the Agreement, as herein defined, and rank equally in all respects with the
Bonds initially issued pursuant to the Agreement and this Indenture.

     "ADJUDICATION OF INVALIDITY" shall mean a final, unappealable adjudication
by any court of competent jurisdiction, that the Bonds are invalid or in any
manner unenforceable for any reason whatsoever, including, without limitation,
any invalidity or irregularity in any statutory or other proceedings relating to
the formation or existence of the Issuer, to the issuance of the Bonds or to the
execution and delivery of the Agreement or this Indenture.

     "ADJUSTED BANK'S COST OF FUNDS" shall mean the fraction (expressed as a
percentage) and as determined by the holder of the Bond or its parent holding
company, of the total interest expense of the Original Purchaser (or any
successor institutional holder of the Bond) for each calendar year divided by
the total monthly average of all assets of the Original Purchaser (or any
successor institutional holder of the Bond) during the calendar year.

     "AGREEMENT" shall mean the Financing Agreement, dated December 17, 1987, by
and between the Issuer and the Company, as it may be modified from time to time.

     "ALLOCATION" shall mean the procedure under Florida law for the requesting
and receipt of a confirmation of an allocation for the Bond (as hereinafter
defined) and similar obligations from the Division of Bond Finance of the State
of Florida Department of General Services or any successor entity for the Bonds
and/or similar bonds.

     "ASSIGNMENT OF MORTGAGE" shall mean the Assignment of Mortgage and Security
Agreement, dated December 17, 1987, by and between the Issuer and the Trustee,
and any amendments, modifications or supplements thereto.

                                       15

<PAGE>

     "ASSIGNMENT OF NOTE" shall mean the document entitled Assignment to the
Trustee dated December 17, 1987, pursuant to which the Issuer assigns its rights
in the Note to the Trustee.

     "AUTHORIZED COMPANY REPRESENTATIVE" and "AUTHORIZED ISSUER REPRESENTATIVE"
shall mean any person at the time designated to act on behalf of the Issuer
pursuant to Section 2.03 of the Agreement. The Company and the Issuer will
furnish to each other and to the Trustee written certificates containing
specimen signatures of such persons and signed on behalf of the Company and the
Issuer, by their respective Authorized Officers. Such certificates may designate
an alternate or alternates. Any such representatives shall be satisfactory to
the Trustee, the Company and the Issuer and shall be replaced upon written
request of the Company or the Issuer.

     "AUTHORIZED OFFICERS" shall mean the Chairman or Vice-Chairman of the
Issuer authorized by law or resolution to sign on behalf of the Issuer and the
Secretary or any Assistant Secretary of the Issuer authorized to countersign and
attest to the signature of the Chairman or Vice-Chairman and to certify
documents of the Issuer and shall mean the President or the Secretary of the
Company.

     "BASE PERCENTAGE" shall mean the percentage applied to the Prime Rate in
determining the interest which the Bond will bear. The Base Percentage is
currently 87% for the period from the date of delivery of the Bond through
December 31, 1987, and 90% thereafter, subject to adjustment only as set forth
in Section 202 of this Indenture.

     "BOND" or "BONDS" shall mean the $1,800,000 Pinellas County Industry
Council Industrial Development Revenue Bond, Series 1987 (Aerosonic Corporation
Project), authorized by the Resolution, the Agreement and this Indenture to be
issued pursuant to the Act, together with any Additional Parity obligations
hereafter issued under the terms, conditions and limitations contained herein.

     "BOND FUND" shall mean the "Pinellas County Industry Council Industrial
Development Revenue Bond, Series 1987 (Aerosonic Corporation Project) Bond
Fund," created by this Indenture.

     "BOND YEAR" shall mean the period beginning with December 17 of each year
and extending for a period of twelve (12) months thereafter.

     "CODE" shall mean the Internal Revenue Code of 1986, as amended, and the
applicable Income Tax Regulations thereunder.

     "COMMITMENT LETTER" shall mean the Commitment Letter dated October 14,
1987, between the Company and the Original Purchaser.

                                       16

<PAGE>

     "COMPANY" shall mean Aerosonic Corporation, a corporation duly organized
and existing under the laws of the State of Delaware, and authorized to do
business in the State of Florida, and any successors or assigns and any
surviving, resulting or transferee corporation.

     "COMPANY FINANCING DOCUMENTS" shall mean the Agreement, the Note, the
Mortgage and any other Financing Document to which the Company is a party.

     "COMPLETION DATE" shall mean the date established as such pursuant to
Section 3.06 of the Agreement.

     "CONSTRUCTION CONTRACT" shall mean that certain contract between the
Company and a contractor to be designated, which provides for the construction
of the Project, the terms of which shall be reasonably acceptable to the
Original Purchaser.

     "CONSTRUCTION FUND" shall mean the "Pinellas County Industry Council
Industrial Development Revenue Bond, Series 1987 (Aerosonic Corporation Project)
Construction Fund," created by this Indenture.

     "CONSULTANT" shall mean a consulting architect or engineer approved by the
Original Purchaser or the authorized representative thereof.

     "CONTRACTOR" shall mean the contractor to be designated by the Company
acceptable to the Original Purchaser.

     "CORPORATE TAX RATE" shall mean the rate of federal income tax applicable
to the highest bracket of taxable income for the holder of the Bond, as it may
hereafter be amended, and which on the date hereof is forty percent (40%).

     "DATE OF TAXABILITY" shall mean the first date on which interest on the
Bond is subject to federal income taxation as a result of a Determination of
Taxability.

     "DEFAULT RATE" shall mean an interest rate equal to the maximum rate
allowed by applicable law.

     "DETERMINATION OF TAXABILITY" shall mean (a) the receipt by the Company of
an original or copy of an Internal Revenue Service technical advice memorandum
or statutory notice of deficiency which holds that any interest payable on any
of the Bonds is includable in the gross income of the Bondholder (other than a
holder who is a "substantial user" of the Project or a "related person") because
the limit described in Section 144(a) of the Code has been exceeded or because
the Bonds have become arbitrage bonds within the meaning of Section 148 of the
Code;

                                       17

<PAGE>

     (b) The issuance of a public or private ruling of the Internal Revenue
Service that any interest payable on any of the Bonds is includable in the gross
income of any Bondholder (other than a holder who is a "substantial user" or a
"related person") for either of the reasons set forth in (a) above;

     (c) An expenditure by the Company which causes the Company to to exceed the
maximum amount of capital expenditures permitted under Section 144(a) of the
Code; or

     (d) receipt by the Trustee of an opinion of counsel that any interest on
any Bond has become includable in the gross income of the Bondholder for federal
income tax purposes. For all purposes of this Indenture a Determination of
Taxability shall be deemed to occur on the date as of which the Bonds are deemed
includable in the gross income of the Bondholder.

     "EQUIPMENT" shall mean those items of machinery and equipment and other
personal property required or permitted by the Agreement to be acquired in whole
or in part with proceeds of the Bonds or located on the Project Site, including
but not limited to the property described in Exhibit B hereto.

     "EVENT OF DEFAULT" shall mean those events described in Section 1001
hereof.

     "EVENT OF TAXABILITY" shall mean the occurrence of a Determination of
Taxability or the incurring of capital expenditures in excess of those permitted
in Section 144(a) of the Code or the taking of any other action by the Company,
or Related Person which has the effect of causing the interest payable on the
Bonds to become includable in the gross income of the holders of the Bonds
(other than a holder who is a "substantial user" or a "related person" as such
terms are used in Section 147(a) of the Code.)

     "FINANCING DOCUMENTS" shall mean this Indenture, the Agreement, the Note,
the Assignment of Note, the Mortgage and the Assignment of Mortgage.

     "FINANCING PAYMENTS" or "PAYMENTS" means the payments made or to be made on
the Note for the payment of the principal, interest and redemption premiums, if
any, on the Bonds pursuant to the terms of the Note and the Agreement.

     "GOVERNMENT OBLIGATIONS" shall mean (a) direct obligations of, or
obligations the principal of and interest on which are unconditionally
guaranteed by, the United States of America; (b) bonds, debentures or notes
issued or unconditionally guaranteed by any of the following Federal agencies:
Banks for Cooperatives, Federal Intermediate Credit Banks, Federal Home Loan
Banks, Export-Import Bank of the United States, Government National Mortgage
Association, or Federal Land Banks; and (c) an agreement by a

                                       18

<PAGE>

bank or trust company (including the Trustee), which shall be authorized to
engage in the banking business and a member in good standing of the Federal
Reserve System, to pay sums of money on definitive dates with interest;
provided, however, that each such time deposit shall require that the moneys be
available for use at the time provided therein and that each such time deposit
shall be continuously secured by lodging with a bank or trust company, approved
by the Issuer and the Trustee, as custodian, as collateral security, obligations
of the character described in clause (a) or (b) of this definition having a
market value at all times (exclusive of accrued interest) not less than the
amount of such time deposit.

     "GOVERNMENTAL AUTHORITY" shall mean the United States, any state of the
United States and any county, city or political subdivision thereof and any
board, bureau, council, commission, department, agency, court, legislative body
or other instrumentality of the United States, any state of the United States or
any county, city or political subdivision thereof.

     "GOVERNMENTAL REQUIREMENT" shall mean any constitution, law, statute, code,
ordinance, resolution, rule, regulation, requirement, directive, judgment, writ,
injunction, order, decree or demand of any Governmental Authority.

     "INDENTURE" or "TRUST INDENTURE" shall mean this Trust Indenture, dated
December 17, 1987, by and between the Issuer and the Trustee, as it may be
modified from time to time.

     "INVESTMENT SECURITIES" shall mean: (a) Government Obligations, (b)
certificates of deposit or other interest-bearing obligations of any bank or
trust company (including the Trustee) authorized to engage in the banking
business which shall be a member in good standing of the Federal Reserve System
and have a combined capital and surplus aggregating not less than five million
dollars ($5,000,000), (c) bonds and other obligations issued by or by authority
of any state of the United States, or any political subdivision thereof, with a
Moody's rating of A (or the equivalent) or higher, (d) other corporate debt
securities with a Moody's rating of A (or the equivalent) or higher, (e)
repurchase agreements with a bank or trust company (including the Trustee),
which shall be authorized to engage in the banking business and a member of the
Federal Reserve System, with respect to Government Obligations, (f) negotiable
certificates of deposit issued by any bank, trust company or national banking
association (including the Trustee) which is a member of the Federal Reserve
System, or (g) commercial or finance paper rated at least P-1 or A-1 by Moody's
Investors Services, Inc. or Standard & Poor's Corporation, or (h) money market
instruments customarily invested in by the Trustee, or (i) tax exempt municipal
securities customarily invested in by the Trustee.

                                       19

<PAGE>

     "ISSUANCE COSTS" shall mean all costs and expenses of issuance of the
Bonds, including, but not limited to: (i) Original Purchaser's discount and
fees; (ii) counsel fees, including bond counsel, original Purchaser's counsel,
Company's counsel, as well as any specialized counsel fees; (iii) financial
advisor fees; (iv) trustee fees and trustee counsel fees; (v) paying agent and
certifying and authenticating agent fees related to issuance of the Bonds; (vi)
accountant fees; (vii) publication costs associated with the financing
proceedings; and (viii) costs of engineering and feasibility studies necessary
to the issuance of the Bonds.

     "ISSUER" shall mean the Pinellas County Industry Council.

     "LOCAL FACILITIES" shall mean facilities (A) located within the same
corporate municipal area of the Project or located outside of such corporate
municipal area but contiguous and integrated with the Project and (B) the
principal user (within the meaning of Section 144(a)(2) of the Code) of which is
or will be a Principal Project User.

     "MORTGAGE" shall mean that Mortgage and Security Agreement dated December
17, 1987 from the Company as mortgagor to the Issuer as mortgagee creating a
first and prior lien on the real property described in Exhibit A hereto and
certain improvements thereto, and creating a security interest in other property
therein described, as it may be modified from time to time.

     "NET PROCEEDS" when used with respect to any insurance (including title
insurance) or condemnation award, shall mean the gross proceeds from the
insurance or condemnation award remaining after payment of all expenses
(including attorneys' fees and expenses of attorneys) incurred in the collection
of such gross proceeds.

     "ORIGINAL PURCHASER" shall mean Barnett Bank of Pinellas County,
Clearwater, Florida or its successor in interest.

     "OUTSTANDING" in connection with Bonds (or a series of Bonds) means, as of
the time in question, all Bonds (or all Bonds of such series) authenticated and
delivered under the Resolution, the Agreement and this Indenture, except:

         (A) Bonds theretofore canceled or required to be canceled pursuant to
this Indenture;

         (B) Bonds for the payment or redemption of which the necessary amount
shall have been or shall concurrently be deposited with the Trustee or for which
provision for the payment of which has been made in accordance with this
Indenture; provided that, if

                                       20

<PAGE>

such Bonds are being redeemed prior to maturity, the required notice of
redemption shall have been given or provision satisfactory to the Trustee shall
have been made therefor; and

     (C) Bonds in substitution for which other Bonds have been authenticated and
delivered pursuant to this Indenture.

     "OWNER OF THE BONDS", "BONDHOLDERS", "OWNERS", "HOLDER" or any similar term
shall mean any person who shall be the registered-owner of any Outstanding Bond
or Bonds.

     "PAYING AGENT" shall mean the Trustee.

     "PERMITTED ENCUMBRANCES" shall mean those exceptions to title acceptable to
the Original Purchaser.

     "PLANS AND SPECIFICATIONS" when used with reference to the construction of
the Project, shall mean the plans and specifications prepared for the
construction of the Project by the Consultant, Contractor and/or subcontractors,
certified by an Authorized Company Representative (and approved by the Original
Purchaser and/or its designated inspecting architect prior to purchase of the
Bonds) and filed with the Trustee as provided in the Agreement, as the same may
be revised from time to time during the construction period in accordance with
the provisions of the Agreement, and when used with reference to any
modification, repair, restoration or replacement of the Project means any plans
and specifications prepared by the Consultant, certified by an Authorized
Company Representative, and filed with the Trustee (and approved by the Original
Purchaser and/or its designated inspecting architect) prior to the making of any
modification, repair, restoration or replacement of the Project, as the same may
be revised from time to time in accordance with the provisions of the Agreement.

     "PRIME RATE" shall mean a rate of interest equal to the announced prime
rate per annum of Barnett Banks, Inc. The Prime Rate is a reference rate for the
information and use of the Original Purchaser in establishing the actual rate to
be charged to the Company. The Prime Rate shall be adjusted from time to time
without notice or demand, as of the effective date of any announced change
thereof. The Prime Rate is not necessarily the rate of interest charged to any
particular class of borrower.

     "PRINCIPAL PROJECT USER" shall mean the Company, any other principal user
(within the meaning of Section 144(a)(2) of the Code) of the Project and any
Related Person (within the meaning of 144(a)(3) of the Code) of the Company or
any such principal user of the Project.

     "PROJECT" shall mean the constructing and equipping of a manufacturing
facility and related facilities located at 1212 Hercules Avenue, Clearwater,
Florida.

                                       21

<PAGE>

     "PROJECT SITE" shall mean the real estate described in the Mortgage.

     "PROMISSORY NOTE" or "NOTE" shall mean the promissory note from the Company
to the Issuer dated December 17, 1987, evidencing the loan described herein,
which shall be in substantially the form attached hereto as Exhibit C and any
amendments, modifications and supplements thereto, as approved by the Original
Purchaser.

     "REGISTRAR" shall mean the Trustee.

     "RELATED PERSON" shall mean any person who or which is a related person
within the meaning of "related person" under Section 144(a)(3) of the Code,
except that when the term Related Person is used in the context of a "Related
Person" to a Substantial User, the term Related Person shall include in addition
to the person identified above any person who or which is a related person
within the meaning of Section 147(a)(2) of the Code.

     "RESOLUTION" shall mean the resolution of the Issuer dated November 4,
1987, and consented to by the Board of County Commissioners of Pinellas County,
Florida on November 24, 1987, authorizing the Bonds and approving the
Agreement, this Indenture, the Mortgage and the Assignment of Mortgage.

     "REVENUES" shall mean all moneys at any time payable to the Trustee under
the Agreement, or from the Note, the Mortgage or otherwise, and such sums as are
authorized by this Indenture to be retained by the Trustee for its services and
expenses in performing under the Agreement and this Indenture, all in the manner
provided herein.

     "SECTION 103 OBLIGATIONS" shall mean obligations the interest on which is
excluded from gross income pursuant to Section 103 of the Code heretofore issued
or to be issued by or on behalf of any state, territory or possession of the
United States, or any political subdivision of any of the foregoing, or the
District of Columbia.

     "SECTION 144(a)(4) CAPITAL EXPENDITURES" shall mean capital expenditures
described in Section 144(a)(4) of the Code, but shall not include capital
expenditures described in Section 144(a)(4)(C) of the Code.

     "STATE" shall mean the State of Florida.

     "SUBSTANTIAL USER" shall mean, with respect to any "facilities" (as the
term "facilities" is used in Section 144(a)(4)(B) of the Code), a "substantial
user" of such "facilities" within the meaning of Section 147(a)(1) of the Code.

     "TAXABLE RATE" shall mean the Prime Rate plus one percent (1%) compounded
quarterly.

                                       22

<PAGE>

     "TRUST ESTATE" shall mean the rights granted to the Trustee under the
paragraph in this Indenture appearing immediately beneath the phrase "Granting
Clause" of this Indenture.

     "TRUSTEE" shall mean initially, Barnett Banks Trust Company, N.A., and any
bank with trust powers or a trust company organized and existing under the laws
of the United States or one of the states having its principal office within or
without the State of Florida, at the time serving as its successor Trustee under
this Indenture, such term may also include any co-Trustee appointed to same
under the terms of this Indenture.

     "U.C.C." shall mean the Uniform Commercial Code of the State, as now or
hereafter amended.

     Except as specifically stated otherwise, all accounting terms used herein
shall have the meanings ascribed to them under generally accepted accounting
principles and usage and shall be applied on a consolidated basis with respect
to the Company, and any of its consolidated subsidiaries.

                                       23

<PAGE>

                                   ARTICLE II

                                    THE BONDS

     SECTION 201. AUTHORIZED AMOUNT OF BONDS. No Bonds may be issued under the
provisions of the Resolution and this Indenture except in accordance with this
Article. The total principal amount of Bonds that may be issued is hereby
expressly limited to not to exceed $1,800,000. Additional Bonds may be issued
only as provided in Article X of the Agreement.

     SECTION 202. DESCRIPTION OF BONDS. The original issue of Bonds shall be
known as "Pinellas County Industry Council Industrial Development Revenue Bond,
Series 1987 (Aerosonic Corporation Project)," dated December 17, 1987, the date
of issuance, shall be numbered R-1 and shall be in the denomination of
$1,800,000.

     Interest on the outstanding principal balance of the Bond from the date
hereof until the Bond is fully paid or redeemed shall be payable at the Base
Percentage. Such interest shall never accrue or be payable at a rate in excess
of the Taxable Rate (except for periods during which an Event of Default exists
when the interest rate shall be the Default Rate). Such interest shall be
payable on the 17th day of each March, June, September and December commencing
March 17, 1988. The initial Prime Rate shall be the Prime Rate in effect upon
the delivery of the Bond. Interest shall be computed on the basis of a three
hundred sixty (360) day year consisting of 12 30-day months.

     In the event of a Determination of Taxability the interest rate on the Bond
shall be increased to the Taxable Rate and such increased rate of interest shall
be payable from the Date of Taxability until the Bond is redeemed as required
herein. Payment shall be made to such holders and former holders from the Date
of Taxability and compounded quarterly until the Bond is redeemed as required
herein. Payment shall be made to such holders and former holders from the Date
of Taxability for the period of time that such person was the registered owner
of the Bond. The holder or former holder shall also be entitled to reimbursement
of any penalties, additions or interest on overdue taxes and any taxes payable
because of receipt of such reimbursement.

     The Interest Rate on the Bond shall be adjusted as follows (but shall not,
by reason of such adjustments, exceed the Taxable Rate):

     (i) Change in Maximum Corporate Tax Rate. If the maximum federal corporate
income tax rate for the holder of the Bond or its parent holding company during
any period in which interest is accruing, shall be other than 40% for 1987 or
34% for 1988 and subsequent years, then the interest on the Bond

                                       24

<PAGE>

during such period shall be modified by multiplying the Base Percentage (as
adjusted) by a fraction equal to 1 - A
                                 -----
                                 1 - B
where A equals the maximum marginal corporate income tax rate then in effect and
B equals the immediately preceding maximum marginal corporate income tax rate.

     (ii) Alternative Minimum Tax Where Bond Interest is a Direct Tax Preference
Item. If the holder of the Bond or its parent holding company pays an
alternative minimum tax in any tax year and the interest on the Bond is a direct
tax preference item under section 57(a)(5) or any successor provision of the
Code then the Interest Rate on the Bond for the period during such tax year in
which interest is accruing on the Bond shall be increased during such accrual
period by an amount equal to (A - B) x C where:

          (a) A equals the Interest Rate on the Bond expressed as a percentage;

          (b) B equals the Adjusted Bank's Cost of Funds; and

          (c) C equals the maximum marginal rate of the alternative maximum tax
     expressed as a decimal (currently .20).

     (iii) Alternative Minimum Tax Where Bond Interest is an Indirect Tax
Preference Item. If the holder of the Bond or its parent holding company pays an
alternative minimum tax in any tax year and the interest on the Bond is not a
tax preference item under section 57(a)(5) of the Code, but is an indirect tax
preference item because of the application of Section 56(f) or Section 56(g) or
any successor provision of the Code then the Interest Rate on the Bond for the
period during such tax year in which interest is accruing on the Bond shall be
increased during such accrual period by an amount equal to (A - B) x C where:

          (a) A equals the Interest Rate on the Bond expressed as a percentage;

          (b) B equals the Adjusted Bank's Cost of Funds; and

          (c) C equals one half of the maximum marginal rate of the alternative
     minimum tax expressed as a decimal (currently 1/2 of .20 or .10) for tax
     years of the Original Purchaser beginning before January 1, 1990 and C
     equals 75% of the maximum marginal rate of the alternative minimum tax
     expressed as a decimal for tax years of the Original Purchaser beginning
     after December 31, 1989.

     (iv) Loss of Federal Income Tax Deduction for State Income Taxes. If the
federal income tax deduction for state income taxes paid on the interest
payments received under the Bond during any period is reduced because of any
change in the tax laws or

                                       25

<PAGE>

regulations then the Interest Rate on the Bond shall be increased during such
period by an amount equal to A x B x C x D where:

          (a) A equals the fraction (expressed as a decimal) of the total state
     income tax disallowed as a result of such tax law change;

          (b) B equals the rate of the applicable state income tax (expressed as
     a decimal);

          (c) C equals the corporate tax rate then in effect (expressed as a
     decimal); and

          (d) D equals the Interest Rate on the Bond (expressed as a
     percentage).

     (v) Partial Taxability. If the interest payments received under the Bond
during any period become partially taxable because of any change in the tax laws
or regulations, then the Interest Rate on the Bond shall be increased during
such period by an amount equal to (A - B) x C where:

          (a) A equals the Taxable Rate (expressed as a percentage);

          (b) B equals the Interest Rate on the Bond (expressed as a
     percentage); and

          (c) C equals the fraction of the Interest Rate on the Bond which has
     become taxable as the result of such tax change (expressed as a decimal).

     (vi) Other Change in Tax Laws. If the tax laws or regulations are amended
to cause the interest on the Bond to be taxable, to be subject to a minimum tax
or an alternative minimum tax or to otherwise decrease the after tax yield on
the Bond to the holder of the Bond (directly or indirectly, other than a change
described in (i) through (v) above or because of a Determination of Taxability)
then the Interest Rate on the Bond shall be adjusted to cause the interest
received by the holder of the Bond, after payment of any increase in tax, to
equal the interest the holder of the Bond would have received in the absence of
such change or amendment in the tax laws or regulations. If the tax laws or
regulations are amended to increase the after tax yield on the Bond to the
holder of the Bond, then the Trustee shall adjust the Interest Rate on the Bond
to cause the interest received by the holder of the Bond to equal the interest
the holder of the Bond would have received in the absence of such change or
amendment in the tax laws or regulations.

     The above adjustments shall be cumulative, but in no event shall the
Interest Rate on the Bond exceed the maximum rate permitted by law. The above
adjustments to the Interest Rate on

                                       26

<PAGE>

the Bond shall be effective on the effective date of the applicable change in
the tax laws or regulations. Interest on the Bond and all other tax rates and
interest rates are expressed as annual rates. However, proper partial adjustment
shall be made if the tax law change is effective after the first day of the
holder's tax year or if interest on the Bond does not accrue for the entire tax
year of the holder. Adjustments which create a circular calculation because the
Interest Rate on the Bond is affected by the calculation shall be carried out
sequentially, increasing the Interest Rate accordingly in each successive
calculation using as the new value the increase in the Interest Rate on the
Bond, until the change on the Interest Rate on the Bond caused by the next
successive calculation of the adjustment is de minimis. If more than one of
paragraphs (i) through (v) apply, then the Interest Rate shall be adjusted in
the order in which listed above.

     To the extent allowed by applicable law, in the event any payment of
interest and principal on or other amounts payable under the Bond shall not be
paid when due, the amount so due shall, to the extent legally enforceable,
continue to bear interest from the date such payment became due until payment
thereof at a rate equal to the Default Rate, and, if the holder of the Bond or
the Trustee should employ attorneys or incur other expenses for the collection
of amounts payable under the Bond, the Issuer shall pay the reasonable fees of
such attorneys and such other expenses so incurred by the holder of the Bond and
the Trustee.

     The Bond shall mature on December 17, 2012 with principal payable on the
17th day of each March, June, September and December commencing December 17,
1988 in equal installments in the amounts of $18,556.70 each. Any remaining
unpaid principal ($18,556.80) and interest shall be due on the maturity date of
the Bond.

     Such Bond shall be issued in the form of one typewritten, fully registered
Bond without coupons. Installment payments of the principal of and interest on
fully registered Bonds shall be made by the Trustee on each interest payment
date to the person appearing as the registered owner thereof on the registration
books of the Issuer, hereinafter provided for, by check or draft or any other
agreeable method mailed to each such registered owner at his address as appears
on such registration books. Payment of the final installment of principal of and
interest on all Bonds shall be made upon the presentation and surrender of such
Bonds as the same shall become due and payable. All the principal of and
interest on the Bonds shall be payable in such coin or currency of the United
States of America which, on the respective dates of payment thereof, shall be
legal tender for the payment of public and private debts.

     SECTION 203. EXECUTION AND AUTHENTICATION OF BONDS. The Bond shall be
executed in the name of the Issuer and countersigned and attested by its
Authorized Officers, as provided by law, by

                                       27

<PAGE>

the manual signature of said officers and its official seal shall be affixed
thereto or reproduced thereon. In case any officer whose signature shall appear
on any Bond shall cease to be such officer before the delivery of such Bond,
such signature or facsimile shall nevertheless be valid and sufficient for all
purposes the same as if he had remained in office until after such delivery. Any
Bonds may be signed and sealed on behalf of the Issuer by such person who at the
actual time of the execution of such Bonds shall hold the proper office with the
Issuer, and any Bond so signed and sealed shall be valid and enforceable,
notwithstanding that at the date of delivery of such Bonds such person does not
hold such office or is not so authorized.

     Only such of the Bonds as shall have endorsed thereon a certificate of
authentication substantially in the form set forth in the "Form of Bond", duly
executed by the Trustee, shall be entitled to any benefit or security under
this Indenture. No Bond shall be valid or obligatory for any purpose unless and
until such certificate of authentication shall have been duly executed by the
Trustee, and such certificate of the Trustee upon any Bond shall be conclusive
evidence that such Bond has been duly authenticated and delivered pursuant to
this Indenture. The signature of the Trustee or at least one of the Authorized
Officers shall be manually subscribed. The Trustee's certificate of
authentication on any Bond shall be deemed to have been duly executed if signed
by an authorized officer of the Trustee, but it shall not be necessary that the
same officer sign the certificate of authentication on all of the Bonds. The
Bonds shall be executed substantially in the form and manner herein provided and
shall be deposited with the Trustee for authentication, but prior to or
simultaneously with the authentication and delivery of the Bonds by the Trustee
there shall have been filed with the Trustee the following:

     (A) A copy, certified by an Authorized Officer of the Issuer, of the
Resolution, evidencing that the same has been duly adopted by the Issuer which
Resolution shall be in full force and effect on the date on which the Bonds are
issued hereunder;

     (B) Executed counterparts of the Agreement, this Indenture, the Mortgage
and the Assignment of Mortgage;

     (C) Executed original Note together with the original executed Assignment
of Note;

     (D) An opinion of counsel for the Company stating that the signer is of the
opinion that the execution and delivery of the Agreement, the Note and the
Mortgage have been duly authorized by the Company, that the Agreement, the Note
and the Mortgage are in the form so authorized and have been duly executed by
the Company and that, assuming proper authorization and execution of the
Agreement by the Issuer, the Agreement, the Note and the Mortgage

                                       28

<PAGE>

are valid and binding in accordance with their respective terms (subject as to
enforcement of remedies to applicable bankruptcy, reorganization, insolvency and
discretionary equitable remedies and similar laws and to moratorium laws from
time to time in effect) and such other matters as shall be reasonably requested
by the Trustee and the Issuer;

     (E) An executed copy of the approving opinion of Bryant, Miller and Olive,
P.A., Tallahassee, Florida, as bond counsel;

     (F) A written request of the Issuer to the Trustee requesting the Trustee
to authenticate and deliver the Bonds in the aggregate principal amount of
$1,800,000 to the Original Purchaser;

     (G) An A.L.T.A. title insurance policy for the face amount of the Bond
issued by a title insurer acceptable to the Original Purchaser, which title
policy shall insure the Original Purchaser of a valid first mortgage lien on the
real property encumbered by the Mortgage and shall insure title in the Original
Purchaser free of exceptions, other than exceptions acceptable to the Original
Purchaser. The real property shall be free of any mechanics or materialman's
liens or special assessments for work completed or under construction;

     (H) The exact legal description of the real property encumbered by the
Mortgage shall be provided by the Company to the Issuer and the Original
Purchaser pursuant to a current survey prepared by a licensed Florida surveyor
and showing all easements, set back lines, encroachments and existing
improvements, such survey shall be acceptable to the Original Purchaser as to
form and content and shall conform with the requirements contained in Exhibit B
to the Commitment Letter;

     (I) The insurance policies required by Section 6.02 of the Agreement;

     (J) An M.A.I. appraisal of the Project which is satisfactory to the
Original Purchaser;

     (K) The Original Purchaser's approval of the general contractor, which
general contractor must be bonded;

     (L) The Original Purchaser or its designated inspecting architect's
approval of plans, specifications and general contractor's contract (guaranteed
maximum with 10% retainage);

     (M) A certified cost breakdown, acceptable to the Original Purchaser and
certified by the Company, itemizing all costs including overhead, interest carry
and all other hard and soft costs which will be incorporated by reference into
the Financing Documents as the basis on which advances of Bond proceeds will be
made;

                                       29

<PAGE>

     (N) A soil report from the design architect and engineer stating that the
soil conditions have been reviewed and the foundation and building have been
adequately designed for the soil conditions;

     (O) The Original Purchaser's approval of the construction contract pursuant
to which the general contractor will construct the Project, together with a
breakdown certified to be true and correct by the Company and the general
contractor setting forth, in such detail as the Original Purchaser may request,
the cost for each class of work included in the contract price, which costs
shall be subject to review and approval by the Original Purchaser;

     (P) Letters from the general contractor, the architect and the engineer
agreeing to continue performance of their contracts for the Trustee should the
Company default;

     (Q) Evidence satisfactory to the Original Purchaser of the availability of
all necessary permits and licenses to construct, occupy and operate the Project
including, without limitation, permits, licenses and approvals required under
state, federal and/or local laws or regulations with respect to zoning, highway
access, safety, subdivision, drainage, building, fire protection, environmental
and similar matters;

     (R) Evidence satisfactory to the Original Purchaser of adequate sewage
treatment capacity, adequate water for the Project and electricity and other
utilities necessary to service the Project in accordance with the Plans and
Specifications;

     (S) Evidence satisfactory to the Original Purchaser that ingress and egress
to the real property is available from a paved and public street dedicated to
and accepted by the appropriate governmental authority; and

     (T) Opinions of counsel for the Company addressing such legal issues
concerning the Bond and the Project as the Original Purchaser or its counsel may
require including, without limitation, the organization of the Company, the
authorization for the execution and delivery of the Financing Documents, the
proper execution and delivery of the Financing Documents, the enforceability of
the Financing Documents, absence of violations of usury or consumer credit laws,
as a result of the payment of any interest, fees or charges due under the
Financing Documents and compliance of construction and intended use of the
Project regarding zoning, land use and environmental laws; and

     (U) Such other documents or opinions as shall be required by bond counsel,
the Trustee or the Original Purchaser.

     When the documents mentioned in clauses (A) to (U), inclusive, next above,
shall have been filed with the Trustee, the

                                       30

<PAGE>

Trustee shall authenticate the Bonds and deliver the same to the purchaser or
purchasers named in the resolution mentioned in clause (A) above, but only upon
payment to the Trustee of the purchase price of the Bonds. The Trustee shall be
entitled to rely upon said resolution as to the amount of such purchase price.

     SECTION 204. FORM OF BONDS. The Bonds and the certificate of authentication
by the Trustee to be endorsed on all Bonds issued under this Indenture shall be
substantially in the form hereinabove set forth with such appropriate
variations, omissions and insertions as are permitted or required by this
Indenture or the Resolution.

     SECTION 205. REGISTRATION AND EXCHANGE OF BONDS; PERSONS TREATED AS OWNERS.
The Issuer shall cause books for the registration and for the transfer of the
Bonds as provided in this Indenture to be kept by the Trustee, which is hereby
constituted and appointed the Registrar. At reasonable times and under
reasonable regulations established by the Trustee, such list may be inspected
and copied by the Issuer or by owners (or a designated representative thereof)
of 15% or more in aggregate principal amount of Bonds then Outstanding.

     Upon surrender for transfer of any Bond at its principal office, the
Registrar shall authenticate and deliver in the name of the transferee or
transferees a new Bond or Bonds of authorized denominations of the same interest
rate and maturity for the aggregate principal amount which the registered owner
is entitled to receive. Bonds may, at the option of the registered owner
thereof, be exchanged for an equal aggregate principal amount of Bonds of the
same maturity and interest rate of any other authorized denomination.

     All Bonds presented for transfer, exchange, redemption or payment (if so
required by the Issuer or Trustee), shall be accompanied by a written instrument
or instruments of transfer or authorization for exchange, in form and with
guaranty of signature satisfactory to Issuer and Trustee, duly executed by the
registered Owner or by his duly authorized attorney. A service charge not in
excess of actual costs may be made for any exchange or transfer, and the Trustee
may require payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in relation thereto. The Issuer and Trustee shall not
be required (a) to issue, transfer or exchange any Bonds during a period
beginning at the opening of business on the 15th day next preceding either any
interest payment date or any date of selection of Bonds to be redeemed and
ending at the close of business on the interest payment date or day on which the
applicable notice of redemption is given or (b) to transfer or exchange any
Bonds selected, called or being called for redemption in whole or in part.

                                       31

<PAGE>

     New Bonds delivered upon any transfer or exchange shall be valid limited
obligations of the Issuer, evidencing the same debt as the Bonds surrendered,
shall be secured by this Indenture and shall be entitled to all of the security
and benefits hereof to the same extent as the Bonds surrendered.

     The person in whose name any registered Bond is registered may be deemed
the owner thereof by the Issuer and the Registrar, and any notice to the
contrary shall not be binding upon the Issuer or the Registrar.

     SECTION 206. BONDS MUTILATED, DESTROYED, STOLEN OR LOST. In case any Bond
shall become mutilated, or be destroyed, stolen or lost, the Issuer may, in its
discretion, issue and cause the Trustee to deliver a new Bond of like tenor as
the Bond so mutilated, destroyed, stolen or lost, in exchange and substitution
for such mutilated Bond, upon surrender and cancellation of such mutilated Bond
or in lieu of and in substitution for the Bond destroyed, stolen or lost and
upon the Owner's furnishing the Trustee proof of his ownership thereof and
satisfactory indemnity and complying with such other reasonable regulations and
conditions as the Issuer or the Trustee may prescribe and paying such expenses
as the Issuer or the Trustee may incur. All Bonds so surrendered shall be
canceled by the Trustee. If any such Bonds shall have matured or be about to
mature, instead of causing the Issuer to issue a substitute Bond, the Trustee
may pay the same, upon being indemnified as aforesaid, and if such Bond be lost,
stolen or destroyed, without surrender thereof.

     Any such duplicate Bond, if any, issued pursuant to this Section shall
constitute an original, additional contractual obligation on the part of the
Issuer whether or not the lost, stolen or destroyed Bonds be at any time found
by anyone, and such duplicate Bonds shall be entitled to equal and proportionate
benefits and rights as to lien on and source and security for payment from the
Revenues, as hereinafter pledged, to the same extent as all other Bonds issued
hereunder.

     SECTION 207. ISSUANCE OF OTHER OBLIGATIONS. The Issuer will not issue any
other obligations payable from the Financing Payments or the Revenues, except
for the purposes, under the conditions and in the manner provided in Article X
of the Agreement, nor voluntarily create or cause or permit to be created any
debt, lien, pledge, assignment, encumbrance or other charge having priority over
or being on a parity with the lien of the Bonds and the interest thereon, upon
said Financing Payments or the Revenues.

                                       32

<PAGE>

                                   ARTICLE III

                                CREATION OF FUNDS

     SECTION 301. CREATION OF FUNDS. There are hereby created and established
with the Trustee the special trust funds described in Sections 302 and 303.

     SECTION 302. BOND FUND. The "Pinellas County Industry Council Industrial
Development Revenue Bond, Series 1987 (Aerosonic Corporation Project) Bond Fund"
(hereinafter sometimes called the "Bond Fund"), to the credit of which deposits
shall be made as required by Sections 402 and 502 herein.

     SECTION 303. CONSTRUCTION FUND. The "Pinellas County Industry Council
Industrial Development Revenue Bond, Series 1987 (Aerosonic Corporation Project)
Construction Fund" (herein sometimes called the "Construction Fund"), to the
credit of which such deposits may be made as are required by the Agreement and
Section 402(2) herein.

     (1) As soon as practicable after the delivery of the Bonds, the Trustee
shall pay from the Construction Fund established for such Bonds, but not in
excess of $36,000, to the firms, corporations or persons entitled thereto the
legal, administrative, financing and incidental expenses of the Issuer and of
the Trustee and of the Original Purchaser relating to the issuance of such
Bonds. Amounts in excess of $36,000 due for fees and expenses of issuing and
delivering the Bonds shall be paid from the Company's own funds.

     (2) Except as otherwise provided in this Indenture or a supplemental
indenture hereto, any moneys deposited in such Construction Fund (after payment
of items in paragraph (1) of this Section) shall be used only to pay the costs
of or relating to the Project, including any fees or charges, and necessary
incidental expenses of the Issuer and reimbursement to the Company for such
Project for costs and expenses paid by the Company in connection with such
Project as are approved by the Company and the Consultant.

     (3) Payments pursuant to paragraph (2) of this Section shall be made only
in accordance with the procedures and upon the certifications required by
Section 2.03 of the Agreement.

     SECTION 304. SECURITY FOR FUNDS. All moneys received by the Trustee
pursuant to this Indenture shall be and constitute trust funds, to be applied
solely as provided herein. The moneys at any time on deposit in the Construction
Fund and the Bond Fund shall be and at all times remain funds impressed with a
trust for the purpose for which each of said funds was created.

                                       33

<PAGE>

                                   ARTICLE IV

                  CUSTODY AND APPLICATION OF PROCEEDS OF BONDS

     SECTION 401. CUSTODY OF PROCEEDS. When the documents mentioned in Section
203 herein shall have been filed with the Trustee and when the Bonds shall have
been executed and authenticated as required herein, the Trustee shall deliver
said Bonds at one time to, or upon the order of, the purchaser named in the
resolution of the Issuer, but only upon receipt of the Bond proceeds and accrued
interest thereon by the Trustee. The Trustee shall then become custodian of the
Bond proceeds and shall deposit such proceeds in the various trust funds herein
established with the Trustee.

     SECTION 402. APPLICATION OF BOND PROCEEDS. The proceeds, including accrued
interest and premium, if any, received from the sale of any or all of the Bonds
shall be applied simultaneously with the delivery of such Bonds to the purchaser
thereof, as follows:

     (1) The accrued interest, if any, shall be deposited by the Trustee in the
Bond Fund herein created and shall be used only for the purpose of paying
interest becoming due on the Bonds.

     (2) The balance of moneys received from the sale of the Bonds shall be paid
into the Construction Fund created in Section 303 of this Indenture and be held
and administered by the Trustee solely for the payment of issuance expenses and
construction and equipping of the Project by the Company as provided in the
Agreement.

                                       34

<PAGE>

                                    ARTICLE V

                       APPLICATION OF FINANCING PAYMENTS,
                      APPLICATION OF DEPOSITS TO THE FUNDS

     SECTION 501. SOURCE OF PAYMENT OF BONDS. The Bonds herein authorized and
all payments by the Issuer hereunder are not general obligations of the Issuer
but are limited obligations payable solely from Revenues and as authorized by
the Act and provided herein. The Bonds are secured as provided herein.

     SECTION 502. DEPOSITS TO THE BOND FUND. All Financing Payments and Revenues
derived by the Issuer pursuant to Section 4.03 of the Agreement on and after the
date on which any Bonds are delivered to the purchasers thereof shall be
collected by the Trustee for the benefit of the Issuer and deposited promptly to
the credit of the Bond Fund. The Trustee shall deposit to the Bond Fund all
other moneys received pursuant to the Agreement, the Note or the Mortgage, which
are required to be deposited into the Bond Fund as well as any other moneys
which in the direction of the payor are to be deposited into the Bond Fund.

     SECTION 503. APPLICATION OF MONEYS IN THE BOND FUND. The Bond Fund shall be
in the custody of and under the control of the Trustee but in the name of the
Issuer and the Issuer hereby authorizes and directs the Trustee to withdraw
sufficient funds from the Bond Fund to pay the principal of, premium, if any,
and interest on all Bonds as the same become due and payable, whether by
maturity or call for redemption, which authorization and direction the Trustee
hereby accepts. The moneys deposited to the credit of the Bond Fund shall be
applied as follows:

     (A) Commencing on March 17, 1988 and on the 17th day of each March, June,
September and December thereafter, to the payment of the interest accrued on the
outstanding principal amount of the Bond coming due and payable on such date,
including any deficiency and crediting any amounts remaining in the Bond Fund
from previous payments due to fluctuations in the Base Percentage.

     (B) Commencing December 17, 1988 and on the 17th day of each March, June,
September and December thereafter, to the payment of principal for the Bond
payable on such date in the amounts of $18,556.70, with the remaining principal
($18,556.80) due and payable on December 17, 2012.

     (C) As invoiced, the annual fee of the Trustee and the payment of all
reasonable fees and expenses including reasonable attorney fees of the Trustee
or the Original Purchaser which may be charged in connection with the
performance of its duties and services with respect to such current payments of
principal and/or

                                       35

<PAGE>

interest and as otherwise required or indicated herein and in the Agreement.

     (D) On any interest payment date, the reimbursement to the Trustee and the
Issuer of all reasonable expenses and expenditures made or incurred by the
Trustee and the Issuer by reason of any advance made pursuant to the Agreement
and interest thereon as provided in the Agreement.

     (E) On any interest payment date, the payment of all deficiencies in prior
payments due by reason of the provisions of this subsection, plus interest
thereon at the Default Rate.

     (F) On the date specified in the Bonds, any other amounts payable under the
Bonds.

     (G) A Rebate Account is hereby established in the Bond Fund. There shall be
deposited into the Rebate Account the Rebate Amount (as set forth in the
certificate of the certified public accountant described in Section 8.10 of the
Agreement) from the Bond Fund or from other funds of the Company, within five
days following receipt of the certificate mentioned herein. The Trustee shall
pay the Rebate Amount (or specified portion thereof) to the United States upon
receipt of direction from the Company pursuant to Section 8.10 of the Agreement,
or otherwise when due. Such payments to the United States shall be made to the
address and at the times specified in Treasury Regulations, Section 1.103-15AT.
Funds on deposit in the Rebate Account shall be used only to pay the Rebate
Amount and for no other purpose until the final payment of the Rebate Amount is
paid to the United States following payment of the entire principal amount of
the Bonds, at the time and in the manner specified in Treasury Regulations,
Section 1.103-15AT.

     (1) The Trustee shall deposit the following sums to the Rebate Account:

          (A) The excess of the aggregate amount earned from the date of
     issuance of the Bonds on all investments in the Construction Fund over the
     amount that would have been earned if the yield on such investments had
     been equal to the yield on the Bonds; plus

          (B) Any deficiency in the Rebate Account as determined by the Trustee
     upon consultation with a certified public accountant, nationally recognized
     bond counsel or such other consultant as deemed appropriate by the Trustee
     to assure compliance with applicable Treasury Regulations. Such
     deficiencies shall be payable from the following sources in the order
     listed or at the option of the Company, from the source designated by the
     Company (i) from moneys on deposit in the Construction Fund; (ii) from
     moneys on deposit in the Bond Fund; or (iii) from funds of the Company paid
     pursuant to Section 8.10 of the Agreement. Such amounts shall be

                                       36

<PAGE>

     deposited to the Rebate Account within five days of notice from the Trustee
     to the Company stating the amount of such deficiency and requesting the
     Company to designate the source of payment.

     (2) All earnings from sums on deposit in the Rebate Account shall be
retained therein and shall be applied as described below.

     (3) Funds on deposit in the Rebate Account shall be applied as follows:

          (A) If the gross proceeds as defined in temporary treasury regulation
     1.103-15AT(b)(6) of the Bonds (excluding any amounts on deposit in a bona
     fide debt service fund) are fully spent for the governmental purpose for
     which the Bonds were issued within six months from the date of issuance of
     the Bonds, then the amounts on deposit in the Rebate Account may be applied
     to pay qualified Costs of the Project (as defined in Section 2.03 of the
     Agreement), provided such amounts are applied for such purpose within the
     six month period mentioned herein.

          (B) If the condition set forth in the above paragraph is not met, then
     the full amount required to be rebated to the United States, as set forth
     in Section 148(f) of the Code, shall be withdrawn from the Rebate Account
     and paid to the United States Treasury on the earlier of (i) the year
     during which all sums in the Construction Fund are spent or in which the
     Completion Date occurs; (ii) the date on which the last Bond is redeemed,
     or (iii) a date not in excess of five years from the date of issuance. Such
     payments to the United States shall be made to the address and at the times
     specified in Treasury Regulations, Section 1.103-15AT. Funds on deposit in
     the Rebate Account which are not expended for Costs of the Project pursuant
     to paragraph (b)(3)(A) above shall be used only to pay the Rebate Amount
     and for no other purpose until the final payment of the Rebate Amount is
     paid to the United States following payment of the entire principal amount
     of the Bonds, at the time and in the manner specified in Treasury
     Regulations, Section 1.103-15AT.

     (4) The Company will determine any rebate to the U.S. Treasury which is
required by Section 148 of the Code.

     Whenever the amount in the Bond Fund from any source whatsoever is
sufficient to effect the redemption of all outstanding Bonds on the earliest
date at which they may be redeemed in accordance with the provisions of this
Indenture, to pay all interest which may accrue thereon on or prior to such
date, to pay all administration expenses due or which will become due upon
redemption of the Bonds, and to pay any Rebate Amount due or to

                                       37

<PAGE>

become due following redemption of the Bonds, the Trustee shall take appropriate
action to redeem all such Bonds on such date and the moneys held in the Bond
Fund shall be applied to the redemption of such Bonds and to the payment of such
interest, administration expenses and Rebate Amount and, when such redemption
shall have been effected no further payment into the Bond Fund need be made.

     SECTION 504. RELEASE OF FUNDS UPON PAYMENT OF BONDS. Any amounts remaining
in the Bond Fund after payment in full of the Bonds, the administration
expenses, the Rebate Amount and all other amounts required to be paid hereunder
shall be paid or applied to the Company as provided in the Agreement if there is
no default thereunder.

     SECTION 505. CHARGE. Subject to the terms and conditions set forth in this
Indenture, moneys deposited to the credit of the various funds herein are hereby
pledged to and charged with the payments mentioned in this Article, and such
moneys held in trust constitute part of the Trust Estate and are subject to a
lien and charge in favor of the Owners of the Bonds issued and Outstanding under
this Indenture and for the further security of such Owners until paid out or
transferred as herein provided.

     SECTION 506. REPAYMENT TO THE COMPANY FROM THE FUNDS. Should this Indenture
be discharged under the provisions of Article IX herein, any amounts in excess
of amounts needed for redemption of Bonds or to make any payments due to the
United States pursuant to Section 503(G) hereof or all for charges, fees and
expenses and advances of the Original Purchaser, the Trustee and any paying
agent, remaining in the various funds established under the provisions of this
Indenture shall be paid to the Company.

                                       38

<PAGE>

                                   ARTICLE VI

                                GENERAL COVENANTS

     SECTION 601. PAYMENT OF PRINCIPAL AND INTEREST. The Issuer covenants that
it will promptly pay the principal of, premium, if any, and interest on every
Bond issued under this Indenture in the manner provided herein and in said
Bonds. The principal, interest and premium, if any, are payable solely from the
Revenues derived by the Issuer from the payments, as provided herein and in the
Agreement, which Financing Payments and Revenues are hereby specifically pledged
to the payment thereof as herein specified, and nothing in the Bonds or in this
Indenture should be considered as pledging any other funds or assets of the
Issuer. Neither the County of Pinellas, the Issuer, nor the State of Florida or
any of its political subdivisions shall be liable for the payment of the
principal of, premium, if any, or interest on any of the Bonds or for the
performance of any pledge, obligation or agreement undertaken by the Issuer,
except as provided in this Indenture and the Agreement.

     SECTION 602. PERFORMANCE OF COVENANTS; AUTHORITY. The Issuer covenants that
it will faithfully perform at all times any and all covenants, undertakings,
stipulations and provisions contained in this Indenture, and in any Bond
executed, authenticated and delivered hereunder. The Issuer covenants that it is
duly authorized under the Constitution and laws of the State of Florida,
including particularly and without limitation the Act, to issue the Bonds
authorized hereby and to execute this Indenture; and the Agreement and pledge
the Revenues hereby pledged in the manner and to the extent herein set forth;
that all action on its part for the issuance of the Bonds and the execution and
delivery of this Indenture has been duly and effectively taken, and that the
Bonds in the hands of the owners thereof are and will be valid and enforceable
obligations of the Issuer according to the import thereof.

     SECTION 603. RIGHT TO FINANCE PROJECT; INSTRUMENTS OF FURTHER ASSURANCE.
The Issuer represents that it has the right to finance the Project. The Issuer
covenants that it will defend its interest in the Trust Estate, the proceeds
from the Agreement and any Financing Payment or other payment required by the
Agreement and the Revenues for the benefit of the Owners of the Bonds against
the claims and demands of all persons whomsoever, subject to indemnification by
the Company as provided in Section 1112 herein and Section 6.07 of the
Agreement. The Issuer covenants that it will take such further actions as the
Trustee may reasonably require for the better assuring, pledging, assigning and
confirming unto the Trustee all and singular the rights assigned hereby to the
payment of the principal of, premium, if any, and

                                       39

<PAGE>

interest on the Bonds, subject to indemnification by the Company as provided in
Section 1112 herein and Section 6.07 of the Agreement. The Issuer covenants and
agrees that, except as herein and in the Agreement provided, it has not and will
not sell, convey, mortgage, encumber or otherwise dispose of any part of its
interest and rights in the Trust Estate, Financing Payments, Revenues or of its
rights under the Financing Documents.

     SECTION 604. FILING, RE-FILING OF SUPPLEMENTS. Promptly after any filing,
registration, recording, re-filing, re-registering, or re-recording of this
Indenture, the Agreement, any supplement to any of said instruments, any
financing statement or any instrument of further assurance which is required
pursuant to Section 603 hereof the Issuer will cause the Company to deliver to
the Trustee a certificate to the effect that such filing, registration,
recording, refiling, re-registration or re-recording has been duly accomplished
and setting forth the particulars thereof.

     SECTION 605. PAYMENT OF TAXES, CHARGES. The Issuer will cause the Company
to pay all lawful taxes, assessments and charges at any time levied or assessed
against or with respect to the Company which are required to be maintained or
paid under the provisions of the Agreement.

     SECTION 606. INSURANCE. The Issuer will cause the Company to insure the
Project as provided in Section 6.02 of the Agreement.

     SECTION 607. RECORDATION OF AGREEMENT, INDENTURE AND SECURITY INSTRUMENTS.
The Issuer shall cause the Mortgage, the Assignment of Mortgage, all supplements
hereto and thereto, and other agreements, if any, and other security instruments
as may be required from time to time to be recorded and filed by the Company in
such manner as may be required by law in order to fully preserve and protect the
security of the owners of the Bonds and the rights of the Trustee hereunder and
under any other Financing Document.

     SECTION 608. INSPECTION OF BOOKS. The Issuer covenants and agrees that all
books and documents in its possession relating to the Project and the Financing
Payments and the Revenues shall at all times be open to inspection by such
agents as the Trustee may from time to time designate.

     SECTION 609. MAINTENANCE OF EXISTENCE. For as long as any of the principal
and interest on any of the Bonds shall be outstanding and unpaid, the Issuer
covenants with the owners of any and all Outstanding Bonds that unless
terminated pursuant to legislation it will maintain its corporate existence,
will not dissolve or otherwise dispose of all or substantially all of its
assets, and will not consolidate with or merge into another body

                                       40

<PAGE>

politic or permit another body politic or corporation, as the case may be, to
consolidate with or merge into it, unless there exists at the time a surviving,
resulting or successor body politic which assumes in writing or by operation of
law all of the obligations of the Issuer or the Trustee, as the case may be,
herein and hereunder.

     SECTION 610. RIGHTS UNDER AGREEMENT. The Agreement sets forth the covenants
and obligations of the Issuer and the Company, and reference is hereby made to
the Agreement for a detailed statement of said covenants and obligations. The
Issuer agrees that the Trustee in its name or in the name of the Issuer may
enforce all rights of the Issuer and all obligations of the Company under and
pursuant to the Agreement for and on behalf of the Bondholders, whether or not
the Issuer is in default hereunder.

     SECTION 611. PROTECTION OF BONDHOLDERS. The Issuer hereby covenants and
agrees that as long as any of the Bonds issued hereunder are Outstanding it will
deposit in the Bond Fund sufficient sums from the Financing Payments and the
Revenues and other amounts derived from the Company promptly to meet and pay the
principal of, premium, if any, and interest on the Outstanding Bonds as the same
become due and payable.

     SECTION 612. ORIGINAL PURCHASER'S, TRUSTEE'S AND PAYING AGENTS' FEES,
CHARGES, ADVANCES AND EXPENSES. Pursuant to the provisions of the Agreement the
Company has covenanted to pay to the Original Purchaser and the Trustee,
commencing with the execution and delivery of this Indenture and continuing
until the principal of, premium, if any, and interest on the Bonds shall have
been fully paid or provided for in accordance with the provisions of this
Indenture: (1) an amount equal to the annual fee of the Trustee, as Trustee, and
its ordinary expenses incurred under this Indenture, as and when the same become
due, (2) the reasonable fees, charges and expenses of the Trustee, as Registrar
and Paying Agent, and any paying agents acting as paying agent as herein
provided, as and when the same become due, (3) the reasonable fees, charges and
expenses of the Trustee for any necessary extraordinary services and expenses of
the Trustee under this Indenture in excess of those services usually rendered
and those expenses usually incurred by a Trustee under instruments similar to
this Indenture, as and when the same become due, (4) any advances made by the
Trustee or the Original Purchaser, together with interest, pursuant to Section
6.05 of the Agreement, and (5) the reasonable fees, charges and expenses of the
Original Purchaser incurred by the Original Purchaser in connection with its
ownership of the Bond or its enforcement of its right to receive payments under
the Bond. References in this Indenture to fees and expenses of the Trustee or
the Original Purchaser shall be deemed to include reasonable attorney's fees and
any sales or service tax thereon, whether or not litigation results, incurred by
the Trustee in carrying out his duties hereunder.

                                       41

<PAGE>

     SECTION 613. TAX COVENANT. The Issuer covenants with the Trustee and with
the bondholders that it will not authorize the moneys held under this Indenture
to be invested in any manner which would result in the Bonds being treated as an
obligation not described in Section 103(a) of the Code because of a failure to
comply with the provisions contained in Section 148 of the Code. The Issuer
additionally covenants to take all action necessary to maintain the exclusion
from gross income for federal income tax purposes of the interest on the Bond.

                                       42

<PAGE>

                                   ARTICLE VII

                       REDEMPTION OF BONDS BEFORE MATURITY

     SECTION 701. (A) REDEMPTION DATES AND PRICES. The Bonds and any other
Additional Parity Obligations to the extent set forth in such Additional Parity
Obligations shall be redeemable as follows:

                     OPTIONAL REDEMPTION IN WHOLE OR IN PART

     The Bond may be redeemed by the Issuer, at the request of the Company on
any principal payment date, prior to maturity, in whole or in part (but if in
part, in $5,000 increments) , at 102% of the principal then outstanding if
redeemed on or prior to the first anniversary date of the date of delivery of
the Bond, at 101% of the principal then outstanding if redeemed after the first
anniversary date of the date of delivery of the Bond but on or before the second
anniversary date of the date of delivery of the Bond, and at 100% of the
principal then outstanding if redeemed after the second anniversary date of the
date of delivery of the Bond, plus accrued interest to the redemption date, plus
all other amounts due under the Mortgage, this Indenture or the Agreement.

                              MANDATORY REDEMPTION

     The Bond shall be redeemed in part in the manner provided in Section 2.03
of the Agreement, at par, plus accrued interest, to the extent that Bond
proceeds and investment earnings thereon exceed the amount necessary for the
construction and equipping of the Project.

                      SPECIAL MANDATORY REDEMPTION IN WHOLE

     If interest on the Bond is declared taxable as a result of a Determination
of Taxability or should an Adjudication of Invalidity occur (in which case the
Company shall promptly notify the Trustee and Original Purchaser of its
existence) in regard to the Bonds then the Bond shall be redeemed as provided in
Section 8.05 of the Agreement at the then outstanding principal amount of the
Bond, plus accrued interest, plus in the case of a Determination of Taxability
all other amounts due under the Mortgage, this Indenture or the Agreement and
other amounts calculated as provided in Section 202 of this Indenture.

                                       PUT

     The Bond may be redeemed by the holder in whole at the principal amount
plus accrued interest on the anniversary date of the date of delivery of the
Bond in the years 1992, 1997, 2002 and 2007. The holder may exercise this option
by written notice to the Trustee and the Company at least 6 months prior to the
redemption date. Upon receipt of the notice, the Company must pay all amounts
due under the Bond on or before the redemption date.

                                       43

<PAGE>

     All partial redemptions of the Bond shall be applied to principal
installments in inverse order of maturity except that partial redemption from
unexpended Bond proceeds shall be applied ratably to reduce future principal
installments.

     Notice of any such redemption shall be given in the manner required by
Section 702 hereof.

     All Bonds so called for redemption will cease to bear interest on the
specified redemption date, provided funds for their redemption are on deposit at
the place of payment at that time, and shall no longer be protected by the
Indenture and shall not be deemed to be outstanding under the provisions of the
Indenture.

     (B) SELECTION OF BONDS TO BE CALLED FOR REDEMPTION. Except as provided in
Section 2.03 of the Agreement concerning mandatory redemption from unexpended
Bond proceeds, if less than all of the Bond is to be redeemed, such portion of
the Bond to be called for redemption shall be applied to pay installments of
principal of the Bond in inverse order of maturity. The Issuer shall direct the
Trustee to call Bonds for optional redemption only after it shall have been
notified by the Company or the Holders of 100% of the Bonds then Outstanding, of
the proposed redemption and the Company has notified the Trustee of a
corresponding prepayment under this Indenture and which Bond is to be redeemed.

     SECTION 702. NOTICE OF REDEMPTION. Notice of the call for redemption
identifying the Bonds to be redeemed shall be given by mailing a copy of the
redemption notice by registered or certified mail at least thirty (30) days but
not more than sixty (60) days prior to the date fixed for redemption to the
registered owner of each Bond to be redeemed at the address shown on the
registration books; provided, however, that failure to give such notice by
mailing, or any defect therein, shall not affect the validity of any proceedings
for the redemption of the Bonds.

     Prior to the date that the redemption notice is mailed as aforesaid the
Issuer shall place in trust with the Trustee sufficient funds to pay such Bonds
and accrued interest thereon and the premium, if any, to the redemption date.
Notice of redemption having been given as aforesaid, the Bonds or portions
thereof so to be redeemed shall, on the date fixed for redemption, become due
and payable at the redemption price herein specified and on and after such
redemption date (unless the Issuer shall default in the payment of the
redemption price), the Bonds or portion thereof thus called shall not bear
interest, shall no longer be protected by this Indenture and shall not be deemed
to be Outstanding.

     SECTION 703. CANCELLATION. All Bonds which have been redeemed shall be
canceled and destroyed by the Trustee and a certificate of destruction shall be
furnished by the Trustee to the Issuer and the Company.

                                       44

<PAGE>

     SECTION 704. TAX INDEMNIFICATION PAYMENTS TO HOLDERS. If the Bonds are
required to be redeemed as a result of the occurrence of a Determination of
Taxability, all moneys paid to the Trustee with respect to the Bonds not
outstanding on the date of such redemption shall be held by the Trustee in a
separate trust account and shall be paid to the Holders as provided in Section
202 hereof. Before making any payments to the Holders of the Bonds, the Trustee
will mail notice of the availability of the amounts payable to such Holders in
the manner set forth for notice of redemption in Section 702 hereof. All moneys
so deposited with the Trustee shall be held for the benefit of such Holders for
two (2) years. After that date, any moneys so deposited shall be repaid to the
Company, and thereupon and thereafter no such claimant shall have any rights to
or in respect of such moneys.

     SECTION 705. NON-PRESENTMENT OF BONDS. In the event any Bonds shall not be
presented for payment either at maturity or at the date fixed for redemption
thereof, if funds sufficient to pay such Bonds shall have been made available to
the Trustee, for the benefit of the Owner or Owners thereof, all liability of
the Issuer to the Owner thereof for the payment of such Bond shall forthwith
cease, determine and be completely discharged. Thereupon it shall be the duty of
the Trustee, as paying agent, to hold such funds for an additional period of six
(6) years, without liability for interest thereon, for the benefit of the Owner
of such Bond, who shall thereafter be restricted exclusively to such funds for
any claim of whatever nature on his part under this Indenture or on, or with
respect to, said Bond, and at the termination of such six (6) year period the
Trustee, as paying agent, shall pay such unclaimed funds to the Company, as
successor paying agent, who shall hold such unclaimed funds, without liability
for interest, for the account of the person, persons, or entities entitled
thereto, subject to such obligations as the Company may have under the Florida
Abandoned Property Act or any law of similar import.

     SECTION 706. BONDS REDEEMED IN PART. Any Bond which is to be redeemed only
in part shall, at the option of the Owner thereof, either (1) be presented for
notation thereon by the Trustee of the payment as of the redemption date of the
redeemed portion of the principal thereof, or (2) be surrendered (with, if the
Issuer or the Trustee so requires, due endorsement by, or a written instrument
of transfer in form satisfactory to the Issuer and the Trustee duly executed by,
the Owner thereof or his attorney duly authorized in writing) and the Issuer
shall execute and the Trustee shall authenticate and deliver to the Owner of
such Bond, with reasonable service charge, a new Bond or Bonds, of any
authorized denomination or denominations as requested by such Owner, and in an
aggregate principal amount equal to the unredeemed portion of the principal of
the Bonds surrendered.

                                       45

<PAGE>

                                  ARTICLE VIII

                                   INVESTMENTS

     SECTION 801. INVESTMENTS OF CONSTRUCTION FUNDS. (A) As promptly as
practicable following the issuance and sale of any Bonds and from time to time
thereafter the Trustee will request and thereafter the Company will furnish to
the Trustee a written certificate stating in what to invest. Promptly after
receipt of each such certificate, the Trustee will, at the written direction of
the Company, or if there shall be no written direction, invest in the Trustee's
Automatic Cash Management T-fund, to the extent practicable, cause the
Construction Fund moneys certified in the said certificate to be invested in
Investment Securities which mature, or which are subject to redemption by the
holder, no later than the dates on which moneys will be required as shown in the
said certificate. All income on such investments shall be deposited in the
Construction Fund and any loss suffered on such investments shall be a charge
against the Construction Fund. The Trustee may from time to time cause any such
Investment Securities to be sold or otherwise converted into cash, and shall
cause such Investment Securities to be sold or otherwise converted into cash
whenever cash is needed for the purpose for which the Construction Fund was
established.

     Following completion of the Project any moneys in the Construction Fund
shall be applied to partial redemption of the Bond in the manner provided in
Section 2.03 of the Agreement.

     (B) Any moneys held as part of the Bond Fund, except as otherwise provided
in Sections 704 and 705 hereof, shall be kept fully invested or reinvested by
the Trustee at the written direction of the Company, or, if there shall be no
written direction, invested in the Trustee's Automatic Cash Management T-fund,
to the extent that such investment is feasible and consistent with the purposes
of said fund. Moneys held in the Bond Fund shall be invested only in Investment
Securities redeemable at the option of the obligee or maturing not later than
the times when the moneys so invested are reasonably expected to be used for the
purposes of such fund. All income and all profits realized on the investment of
moneys in the Bond Fund during the period prior to completion of the Project
shall be paid into the Construction Fund, and all such income and profits
realized after completion of the construction of the Project shall remain in the
Bond Fund and shall be credited against the next maturing Financing Payment due
under Section 4.03 of the Agreement and applied to the next installment of
principal or interest coming due on the Bonds. The Trustee may make any
investments through its own bond department, money center or affiliated bank.

                                       46

<PAGE>

     Notwithstanding anything herein to the contrary, investment earnings on any
moneys on deposit in the Rebate Account shall be maintained on deposit therein
and shall be used only for payment of the Rebate Amount in the manner set forth
in Section 503(G) of this Indenture.

     SECTION 802. TRUSTEE'S RESPONSIBILITY. The Trustee shall invest funds
hereunder only upon receipt of written directions from the Company or, if there
shall be no written directions, in the Trustee's automatic cash management fund.
The Trustee shall sell or dispose of Nonpurpose Obligations (as defined in
Treasury Regulations, Section 1.103-15AT) immediately upon receipt of directions
from the Company pursuant to Section 8.10 of the Agreement. The Trustee shall
have no liability or responsibility for any loss resulting from investments made
under this Indenture (except liability for its own grossly negligent failure to
follow the Company's instructions) or from the redemption and sale of any such
investment or failure to invest or to meet or achieve maximum earnings. The
Trustee shall provide to the Company monthly statements of the aggregate amount
earned on all Nonpurpose Obligations in which proceeds of the Bonds are
invested, pursuant to the provisions of Section 8.10 of the Agreement.

     SECTION 803. ARBITRAGE. The Company has covenanted in the Agreement not to
use or apply Bond proceeds and not to direct the Trustee to act in such a manner
as to violate Section 148 of the Code. The Trustee shall have no liability for
compliance with Section 148 of the Code, except for its duty to follow the
advice of accountants, counsel or experts concerning rebate of arbitrage
earnings and its duty to follow the written directions of the company concerning
the investment of funds.

                                       47

<PAGE>

                            ASSIGNMENT TO THE TRUSTEE

     For value received, the Pinellas County Industry Council hereby grants,
bargains, sells, conveys and assigns unto Barnett Banks Trust Company, N.A., as
Trustee under the Trust Indenture mentioned in the foregoing Promissory Note,
and unto its successors in trust, and to its assigns all of the Issuer's right,
title and interest in and the present and continuing rights to make claim for,
collect, receive and receipt for the payments and revenues arising from the
Issuer's rights in the foregoing Promissory Note dated December 17, 1987 and the
right to bring actions and proceedings under the said Promissory, Note.

     Dated this 17th day of December, 1987.

                                                PINELLAS COUNTY INDUSTRY COUNCIL

(SEAL)


                                                By:/s/ Charles E. Rainey
                                                   -----------------------------
                                                   Chairman

ATTEST:


/s/ William M. Castoro
------------------------------------
Secretary

<PAGE>

                                   ARTICLE IX

                             DISCHARGE OF INDENTURE

     SECTION 901. DISCHARGE OF LIEN AND SECURITY INTERESTS. If the Issuer shall
pay or cause to be paid the principal of, and the redemption premium (if any),
and the interest on the Bonds at the times and in the manner stipulated therein
and herein, and shall pay or cause to be paid all fees and expenses of the
Original Purchaser, the Trustee, the Registrar and the Paying Agent due or to
become due in connection with the payment of the Bonds and all other amounts due
or to become due hereunder, and if the Issuer shall keep, perform and observe
all and singular the covenants and agreements in the Bonds and in this Indenture
expressed as to be kept, performed and observed by it or on its part, then the
lien of this Indenture, these presents and the Trust Estate shall cease,
terminate and be discharged, and thereupon the Trustee shall execute and deliver
to the Issuer such instruments in writing as shall be required to cancel and
discharge this Indenture, the Agreement, the Mortgage and the Note and assign
and deliver to the Issuer so much of the Trust Estate as may be in its
possession or subject to its control, except moneys or direct obligations of the
United States deposited with the Trustee for the payment of the principal of,
and the redemption premium (if any) and the interest on the Bonds which have
become due but have not yet been presented for payment and moneys in the Bond
Fund required to be paid to the Company pursuant to Section 506; provided,
however, such cancellation and discharge of this Indenture shall not terminate
the powers and rights granted to the Trustee with respect to the payment,
registration and transfer and exchange of the Bonds, nor any indemnification
provisions or any provisions relating to payment upon a Determination of
Taxability.

     SECTION 902. PROVISION FOR PAYMENT OF BONDS. Subject to the provisions of
this Indenture relating to payment upon a Determination of Taxability, Bonds
shall be deemed to have been paid within the meaning of Section 901 if the
Issuer shall pay or shall make provision for payment satisfactory to the Trustee
and the Original Purchaser of all fees, expenses, charges and advancements of
the Trustee and the Original Purchaser:

     (A) the principal of, redemption premium (if any) and all interest on all
Bonds have been paid in accordance with the terms thereof; or

     (B) there shall have been irrevocably deposited with the Trustee either:

          (1) sufficient moneys, or

          (2) non-callable direct obligations of the United States of such
     maturities and interest payment dates and bearing

                                       48

<PAGE>

     such interest as will, without further investment or reinvestment of either
     the principal amount thereof or the interest earnings thereon (said
     earnings to be held in trust also), be sufficient together with any moneys
     referred to in subsection (B)(1) above,

for the payment at their respective maturities or redemption dates prior to
maturity, of the principal thereof and the interest to accrue thereon to such
maturity or redemption dates, as the case may be; provided, however, that such
deposit will not affect the tax exempt status of the interest on any of the
Bonds or cause the Bonds to violate the provisions of Section 613 hereof.
Neither the moneys nor obligations deposited with the Trustee in trust pursuant
to this paragraph shall be withdrawn or used for any purpose other than for the
payment of the principal and redemption premium, if any, and interest on the
Bonds and any rebate payments, any subsequent litigation, any taxability
premiums and any other expenses of the Trustee.

     SECTION 903. DISCHARGE OF THE INDENTURE. Notwithstanding the fact that the
lien of this Indenture upon the Trust Estate may have been discharged and
cancelled in accordance with Section 901, this Indenture and the rights granted
especially under Section 1112 hereof and duties imposed hereby, to the extent
not inconsistent with the fact that the lien upon the Trust Estate may have been
discharged and cancelled, shall nevertheless continue and subsist until the
principal of, the redemption premium (if any), and the interest on all of the
Bonds and any rebate payments, any subsequent litigation, any taxability
premiums and any other expenses of the Trustee shall have been paid in full or
the Trustee shall have returned to the Company pursuant to Section 705 hereof
all funds theretofore held by the Trustee for payment of any Bonds not
theretofore presented for payment.

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                                    ARTICLE X

           DEFAULT PROVISIONS AND REMEDIES OF TRUSTEE AND BONDHOLDERS

     SECTION 1001. EVENTS OF DEFAULT. If any of the following events shall occur
and be continuing it shall constitute an "Event of Default" under this
Indenture:

     (a) Failure by the Issuer to pay the principal of or interest on the Bond
on or before the date the same becomes due as therein and herein provided,
whether such shall become due by maturity or otherwise.

     (b) Failure by the Issuer to perform any of the agreements on its part
herein contained (other than its agreement to pay the principal of and the
interest on the Bond) after thirty (30) days written notice of such failure made
by the Trustee to the Issuer or made to the Issuer and the Trustee by the
holders of ten percent (10%) in principal amount of the Bonds then outstanding
and secured hereby, unless during such period or any extension thereof the
Issuer has taken steps reasonably calculated to remedy such default.

     (c) Appointment with the consent or acquiescence of the Issuer, by a court
having jurisdiction of a receiver for the Issuer, or the approval by a court of
competent jurisdiction of any petition for rearrangement or readjustment of the
obligations of the Issuer under any provisions of the bankruptcy laws of the
United States, and if such approval was without the consent or acquiescence of
the Issuer, the continuation of such appointment or approval unstayed and in
effect for a period of sixty (60) consecutive days.

     (d) An Event of Default under the Agreement.

     SECTION 1002. DECLARATION OF ACCELERATION. If an Event of Default shall
have occurred the Trustee may, and upon the written request of the Owners of a
two-thirds (2/3) in aggregate principal amount of Bonds then outstanding shall,
by notice in writing delivered to the Issuer and the Company, to the extent
permitted by law, declare the principal of all Bonds then outstanding, plus any
premium, if any, and accrued interest thereon which shall have become payable
prior to such declaration, immediately due and payable. Upon any such
declaration, all amounts payable under the Note and Section 4.03 of the
Agreement shall become immediately due and payable in accordance with Section
9.02 of the Agreement. All amounts not paid when due shall bear interest from
the date due until paid at the Default Rate. Such declaration may be rescinded
as provided in Section 1013 hereof.

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<PAGE>

     SECTION 1003. REMEDIES; RIGHTS OF BONDHOLDERS.

     (a) If an Event of Default shall have occurred, the Trustee may pursue any
available remedy at law or equity by suit, action, mandamus or other proceeding
to enforce the payment of the principal of, premium, if any, and interest on
the Bonds then Outstanding, and to specifically enforce and compel the
performance of the duties and obligations of the Issuer as herein set forth and
the duties and obligations of the Company under the Agreement and other
instruments assigned to the Trustee, and including any and all other remedies
provided for herein. While any Bonds are outstanding, the Issuer shall not
exercise any of the remedies specified in Section 9.02 of the Agreement or
otherwise available to the Issuer without the prior written consent of the
Trustee.

     If an Event of Default shall have occurred and if requested so to do by the
holders of two-thirds of the principal amount of the Bonds then outstanding and
upon being indemnified as provided in Section 1105 hereof, the Trustee shall be
obligated to exercise such one or more of the rights and powers conferred by
this Section as the Trustee shall deem most expedient in the interests of the
Bondholders.

     No remedy by the terms of this Indenture conferred upon or reserved to the
Trustee (or to the Bondholders) is intended to be exclusive of any other remedy,
but each and every such remedy shall be cumulative and shall be in addition to
any other remedy given to the Trustee or to the Bondholders hereunder or now or
hereafter existing at law or in equity or by statute.

     No delay or omission to exercise any right, power or remedy accruing upon
any Event of Default shall impair any such right, power or remedy or shall be
construed to be a waiver of any such Event of Default or acquiescence therein;
and every such right, power or remedy may be exercised from time to time and as
often as may be deemed expedient.

     No waiver of any Event of Default hereunder, whether by the Trustee or by
the Bondholders, shall extend to or shall affect any other or any subsequent
Event of Default or shall impair any rights or remedies consequent thereon.

     SECTION 1004. NOTICE TO BONDHOLDERS. The Trustee shall give written notice
by registered mail of the occurrence of every Event of Default to every
Bondholder who shall have filed with the Trustee his address for such purpose.

     SECTION 1005. RIGHT OF BONDHOLDERS TO DIRECT PROCEEDINGS. Anything in this
Indenture to the contrary notwithstanding, the holders of two-thirds of the
principal amount of the Bonds then outstanding shall have the right, at any
time, by an instrument or

                                       51

<PAGE>

instruments in writing executed and delivered to the Trustee, to direct the
time, the method and place of conducting all proceedings to be taken in
connection with the enforcement of the terms and conditions of this Indenture
and the exercise of all remedies available to the Trustee hereunder and under
the Financing Documents; provided, that such direction shall not be otherwise
than in accordance with the provisions of law and of this Indenture. The Trustee
shall be fully protected in acting on any direction of the Bondholders hereunder
and shall not be liable or responsible in any manner to any person for so
acting.

     SECTION 1006. REMEDIES UNDER AGREEMENT. The Trustee shall be entitled, as a
matter of right, to exercise any or all remedies available to the Issuer or the
Trustee under the Agreement. The Issuer may exercise any of the remedies
available to the Issuer under the Agreement, subject, however, to the paramount
and superior right of the Trustee to exercise such remedies.

     SECTION 1007. NO REMEDY EXCLUSIVE. No remedy herein conferred upon or
reserved to the Trustee or to the Issuer, or existing at law or in equity, shall
be exclusive of any other available remedy or remedies, but each and every such
remedy shall be cumulative and shall be in addition to every other remedy given
under this Indenture or now or hereafter existing at law or in equity or by
statute. No delay or omission to exercise any right or power accruing upon any
default shall impair any such right or power or shall be construed to be a
waiver thereof, but any such right and power may be exercised from time to time
as often as may be deemed expedient. In order to entitle the Trustee or the
Issuer to exercise any remedy reserved to it in this Indenture or the Agreement,
or existing in law or in equity, it shall not be necessary to give notice, other
than such notice as may be herein expressly required.

     SECTION 1008. NO ADDITIONAL WAIVER IMPLIED BY ONE WAIVER. In the event any
agreement contained in the Agreement or this Indenture should be breached by any
party thereto or hereto and thereafter waived by the other party, such waiver
shall be limited to the particular breach so waived and shall not be deemed to
waive any other breach hereunder.

     SECTION 1009. APPLICATION OF MONEYS. All moneys received by the Trustee
pursuant to any right given or action taken under the provisions of this Article
or by virtue of action taken or remedies exercised under provisions of any of
the Financing Documents shall, after payment of the costs and expenses of the
proceedings resulting in the collection of such moneys and of the expenses,
liabilities and advances incurred or made by the Trustee or the Original
Purchaser, be deposited in the Bond Fund, and all moneys in the Bond Fund (other
than moneys held by the Trustee in the Bond Fund pursuant to Section 704 or
Section 705 of this Indenture) shall be applied as follows:

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<PAGE>

     (a) Unless the principal of the Bonds shall become or shall be declared due
and payable, all such moneys shall be applied as follows:

          FIRST -- To the payment to the persons entitled thereto of all
     installments of interest then due on the Bonds, in the order of the
     maturity of the installments of such interest and, if the amount available
     shall not be sufficient to pay in full any particular installment, then to
     the payment ratably, according to the amounts due on such installment, to
     the persons entitled thereto, without any discrimination or privilege;

          SECOND -- To the payment to the persons entitled thereto of the unpaid
     principal of and premium, if any, on the Bonds which shall have become due
     (other than the Bonds matured or called for redemption for the payment of
     which moneys are held pursuant to the provisions of this Indenture), in
     the order of its due dates, with interest on the Bonds and, if the amount
     available shall not be sufficient to pay in full the Bonds due on any
     particular date, together with such interest, then to the payment ratably,
     according to the amount of principal and such interest due on such date, to
     the persons entitled thereto without any discrimination or privilege; and

          THIRD -- To be deposited in the Bond Fund and held for the payment to
     the persons entitled thereto as the same shall become due of the principal
     of, premium, if any, and interest on the remaining Bonds upon maturity or
     call for redemption prior to maturity and, if the amount available shall
     not be sufficient to pay in full the Bonds due on any particular date,
     together with interest then due and owing thereon, payment shall be made
     ratably according to the amount of principal due on such date to the
     persons entitled thereto without any discrimination or privilege.

     (b) If the principal of the Bonds has become due or shall have been
declared due and payable, all such moneys shall be applied to the payment of the
principal and interest then due and unpaid on the Bonds (other than the Bonds
matured or called for redemption for the payment of which moneys are held
pursuant to the provisions of this Indenture), without preference or priority of
principal over interest or of interest over principal, or of any installment of
interest over any other installment of interest, or of the Bonds over any other
Bonds, ratably, according to the amounts due respectively for principal and
interest, to the persons entitled thereto without any discrimination or
privilege.

     (c) If the principal of the Bonds shall have been declared due and payable,
and if such declaration shall thereafter have been rescinded under the
provisions of Section 1013 of this

                                       53

<PAGE>

Indenture then, subject to the provisions of subsection (b) of this Section in
the event that the principal of the Bonds shall later become due or be declared
due and payable, the moneys shall be applied in accordance with the provisions
of subsection (a) of this Section.

     Whenever moneys are to be applied pursuant to the provisions of this
Section, such moneys shall be applied at such times, and from time to time, as
the Trustee shall determine, having due regard to the amount of such moneys
available for application and the likelihood of additional moneys becoming
available for such application in the future. Whenever the Trustee shall apply
such funds, it shall fix the date (which shall be an interest payment date
unless it shall deem another date more suitable) upon which such application is
to be made and upon such date interest on the amounts of principal to be paid on
such dates shall cease to accrue. The Trustee shall give such notice as it may
deem appropriate of the deposit with it of any such moneys and of the fixing of
any such date.

     Whenever all principal of, premium, if any, interest on and any other
amounts payable under the Bonds has been paid under the provisions of this
Section and all expenses, fees and charges of the Trustee and any paying agent
have been paid, any balance remaining in the Bond Fund shall be paid to the
Company as provided in Section 506 hereof.

     SECTION 1010. REMEDIES VESTED IN TRUSTEE. All rights of action (including
the right to file proofs of claim) under this Indenture or under the Bonds may
be enforced by the Trustee without the possession of the Bonds or the production
thereof in any trial or other proceedings relating thereto. Any such action or
proceeding instituted by the Trustee shall be brought in its name as Trustee
without the necessity of joining as plaintiffs or defendants any holders of the
Bonds, and any recovery or judgment shall be for the equal and ratable benefit
of the holders of the Bonds.

     SECTION 1011. RIGHTS AND REMEDIES OF BONDHOLDER. No holder of the Bonds
shall have any right to institute any suit, action or proceeding in equity or at
law for the enforcement of this Indenture or for the execution of any trust
hereof or for the appointment of a receiver or any other remedy hereunder,
unless (i) an Event of Default has occurred of which the Trustee has been
notified as provided in Section 1106 hereof, or of which by such subsection it
is deemed to have notice, (ii) any time permitted for cure after notice of such
Event of Default has expired, (iii) the holders of not less than two-thirds of
the principal amount of the Bonds then outstanding shall have made written
request that the Trustee exercise a particular right or remedy or institute any
such suit, action or proceeding and shall have offered reasonable

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<PAGE>

opportunity either to proceed to exercise the remedies and powers herein granted
or to institute such suit, action, or proceeding in its own name, as Trustee,
and shall have offered to the Trustee indemnity as provided in Section 1105
hereof and (iv) the Trustee shall thereafter fail or refuse for a period of at
least sixty (60) days to exercise the remedies and powers herein granted, or to
institute such action, suit or proceeding in its own name, as Trustee. No one
holder of the Bonds shall have any right in any manner whatsoever to enforce any
right hereunder except in the manner herein provided, and all suits, actions and
proceedings at law or in equity shall be instituted, had and maintained in the
manner herein provided and for the equal and ratable benefit of the holders of
the Bonds then outstanding. Nothing in this Indenture contained shall, however,
affect or impair the right of the Bondholder to enforce the payment of the
principal of, premium, if any, interest on and other amounts payable under the
Bonds at and after the maturity thereof.

     SECTION 1012. TERMINATION OF PROCEEDINGS. In case the Trustee shall have
proceeded to exercise any remedy under this Indenture and such proceedings shall
have been discontinued or abandoned for any reason (other than a discontinuance
by the Trustee at the request of the Company in which the Trustee reserves, in
writing delivered to the Company, the right to reinstate such proceedings if the
event upon which the proceeding is based is not corrected to the satisfaction of
the Trustee), or shall have been determined adversely, then and in every such
case the Issuer, the Company, the Bondholder and the Trustee shall be restored
to their former positions, rights and obligations hereunder, and all rights,
remedies and powers of the Trustee shall continue as if no such proceedings had
been taken.

     SECTION 1013. WAIVERS OF EVENTS OF DEFAULT. The Trustee may in its
discretion waive any Event of Default hereunder and its consequences and rescind
any declaration of maturity of principal of and interest on the Bonds, and shall
do so upon the written request of the holders of (1) the Bonds then outstanding
in respect of which default in the payment of principal, premium, if any,
interest or other amounts payable thereunder exists, or (2) the holders of not
less than two-thirds of the principal amount of the Bonds then outstanding in
the case of any other Event of Default; provided, however, that there shall not
be waived (a) any default in the payment of the principal (due other than by
reason of acceleration) of any outstanding Bonds when due (whether at maturity
or by optional redemption) or (b) any default in the payment when due of the
interest on the Bonds unless, prior to such waiver or rescission, all arrears of
principal (due other than by reason of acceleration) and interest, and all fees,
charges and expenses of the Trustee in connection with such Event of Default
shall have been paid or provided for. In the case of any such waiver or
rescission, or in case any proceeding taken by

                                       55

<PAGE>

the Trustee on account of any such Event of Default shall have been discontinued
or abandoned or determined adversely, then and in every such case the Issuer,
the Company, the Trustee and the Bondholder shall be restored to their former
positions, rights and obligations hereunder, respectively, but no such waiver or
rescission shall affect any subsequent or other Event of Default or impair any
rights or remedies consequent thereon.

     SECTION 1014. NOTICE OF DEFAULTS UNDER SECTION 1001(b); OPPORTUNITY FOR THE
COMPANY TO CURE DEFAULTS. Anything herein to the contrary notwithstanding, no
event occurring under Section 1001(b) shall constitute an Event of Default until
actual notice of such event by registered or certified mail shall be given to
the Issuer and the Company by the Trustee or to the Issuer, the Company and the
Trustee by the holders of the Bonds then outstanding and the Company and the
Issuer shall have had thirty (30) days after receipt of such notice to correct
such event or cause it to be corrected, and shall not have corrected such event
or caused it to be corrected.

     With regard to any event concerning which notice is given to the Company
under the provisions of this Section 1014, the Issuer hereby grants the Company
full authority for account of the Issuer to perform or observe any covenant,
condition or agreement alleged in such notice not to have been performed or
observed, in the name and stead of the Issuer, with full power to do any and all
things and acts to the same extent that the Issuer could do in order to correct
or remedy such event.

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<PAGE>

                                   ARTICLE XI

                             CONCERNING THE TRUSTEE

     SECTION 1101. ACCEPTANCE OF TRUSTS; LIABILITY. The Trustee accepts the
trusts and assumes the duties imposed and created by this Indenture. The Trustee
shall, prior to an event of default as defined in Section 1001, and after the
curing of all such events of default which may have occurred, perform such
duties and only such duties as are specifically set forth in this Indenture.

     (a) Except during the continuance of an Event of Default,

          (1) the Trustee undertakes to perform such duties and only such duties
as are specifically set forth in this Indenture and no implied covenants or
obligations shall be read into this Indenture against the Trustee, and

          (2) in the absence of bad faith on its part, the Trustee may
conclusively rely, as to the truth of the statements and the correctness of the
opinions expressed therein, upon certificates or opinions furnished to the
Trustee and conforming to the requirements of this Indenture;

     (b) In case the Trustee has actual notice that an Event of Default has
occurred and is continuing, the Trustee shall exercise such of the rights and
powers vested in it by this Indenture as a prudent man would exercise under the
circumstances in the conduct of his own affairs. Until the Trustee receives such
notice, the Trustee, in the absence of gross negligence or bad faith, shall have
no liability hereunder;

     (c) The Trustee shall not be liable for any error or judgment made in good
faith by a responsible officer or officers of the Trustee unless it shall be
proved that the Trustee or such officer was grossly negligent in ascertaining
the pertinent facts;

     (d) The Trustee shall not be liable with respect to any action taken or
omitted to be taken by it in good faith in accordance with the direction of the
holders of a majority in principal amount of the Outstanding Bonds relating to
the time, method and place of conducting any proceeding for any remedy available
to the Trustee, or exercising any trust or power conferred upon the Trustee,
under this Indenture;

     (e) 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, unless repayment of such funds or adequate indemnity against such risk
of liability is assured to it; and

                                       57

<PAGE>

     (f) Whether or not therein expressly so provided, every 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 1102. CERTAIN RIGHTS OF TRUSTEE. Except as otherwise provided in
Section 1101:

     (a) the Trustee may conclusively 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,
coupon or other paper or document signed or presented by any party or parties
authorized under this Indenture or the Agreement;

     (b) any request, direction, election, order or demand of the Issuer shall
be sufficiently evidenced by an instrument signed in the name of the Issuer by
an Authorized officer (unless otherwise in this Indenture specifically
prescribed), and any resolution of the Issuer may be evidenced to the Trustee
by a copy thereof certified by the Secretary or any Assistant Secretary of the
Issuer;

     (c) any request, direction, election, order or demand of the Company shall
be sufficiently evidenced by an instrument signed in the name of the Company by
the Authorized Company Representative (unless otherwise in this Indenture
specifically prescribed) and any resolution of the Company may be evidenced to
the Trustee by a copy thereof certified by the Authorized Company
Representative;

     (d) the Trustee may consult with counsel including counsel who rendered the
approving opinion on the Bonds to the Original Purchaser thereof and the written
advice on opinion of such 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) whenever, in the administration of the trusts of this Indenture, the
Trustee shall deem it necessary or desirable that a matter be proved or
established prior to taking, suffering or omitting any action hereunder, such
matters (unless other evidence in respect thereof be herein specifically
prescribed) may be deemed conclusively proved and established by a certificate
of the Issuer, and such certificate of the Issuer shall be full warranty to the
Trustee for any action taken, suffered or omitted by it under the provisions of
this Indenture upon the faith thereof;

     (f) the Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Bondholders pursuant to this Indenture, unless such Bondholders shall have
offered to the

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<PAGE>

Trustee security or indemnity against the costs, expenses (including attorney's
fees) and liabilities which might be incurred by it in compliance with such
request or direction;

     (g) 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,
coupon or 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;

     (h) the Trustee shall have no duty to determine the genuineness of any
signature, or except as provided in paragraphs (b) and (c) of this Section, the
authority of any person to execute any certificate or other document; and

     (i) whenever the Trustee is vested with a discretionary right hereunder, or
in the Agreement, it is expressly granted the right to seek direction or consent
of 100% of the holders of the Outstanding Bonds and any action taken by the
Trustee at the direction or consent of said holders shall be conclusively deemed
prudent for all purposes.

     SECTION 1103. TRUSTEE NOT RESPONSIBLE FOR RECITALS AND CERTAIN MATTERS OF
BONDS OR SECURITY. The recitals contained herein and in the Bond, except the
Trustee's certificate of authentication, shall be taken as the representations
of the Issuer, 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 the Bond. The Trustee is not responsible for the recording of
this Indenture, the Agreement or the Mortgage or for the payment of taxes,
charges, assessments and liens upon the Trust Estate, or for insuring the Trust
Estate or the maintenance thereof, or for the sufficiency of the security for
the Bonds issued hereunder or intended to be secured hereby, or for the value or
title of any of the Trust Estate, or otherwise as to the maintenance of the
security hereof.

     SECTION 1104. GENERAL LIMITATION OF LIABILITY. The permissive right of the
Trustee to do things enumerated in this Indenture shall not be construed as a
duty of the Trustee and the Trustee shall be answerable only as provided in
Section 1101 hereof. The Trustee shall not be required to give any bonds or
surety in respect of the execution of the said trusts and powers or otherwise in
respect of the premises. The Trustee shall not be liable for any debts
contracted or for damages to persons or to personal property injured or damaged,
or for salaries or nonfulfillment of contracts during any period in which it may
be in the possession of or managing the Trust Estate except only as provided in
Section 1101 hereof, if such debts, damages, salaries or contracts have

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<PAGE>

been incurred, suffered, earned or made in connection with such possession or
management.

     SECTION 1105. BRINGING AND DEFENDING LEGAL ACTIONS. The Trustee shall be
under no obligation to institute any suit, or to take any action or conduct any
proceeding under this Indenture, or to enter any appearance or in any way defend
in any suit in which it may be made defendant, or to take any steps in the
execution of the trusts hereby created or in the enforcement of any rights and
powers hereunder, until it shall be indemnified to its satisfaction against any
and all costs and expenses, outlays and counsel fees and other reasonable
disbursements, and against all liability; the Trustee may nevertheless after
written notice to the Company, begin suit, or appear in and defend suit, make
advances as provided herein or in the Agreement or Mortgage, or do anything else
in its judgment proper to be done by it as such Trustee, without indemnity, and
in such case the Company shall reimburse the Trustee for all costs and expenses,
outlays and counsel fees and other reasonable disbursements properly incurred in
connection therewith, plus interest on disbursements therefor at the Default
Rate not to exceed any legal maximum. If the Company shall fail to make such
reimbursement, the Trustee may reimburse itself from any moneys in its
possession under the provisions of this Indenture and notwithstanding any
provision in this Indenture to the contrary the Trustee shall be entitled to a
preference therefor over any of the Bonds then Outstanding.

     SECTION 1106. NOTICE OF DEFAULTS. Within ninety (90) days after the
occurrence of any Event of Default hereunder, the Trustee shall transmit by mail
to the holders of registered Bonds at the address shown therefor in the bond
register, notice of such Event of Default known to the Trustee; provided,
however, that except in the case of a default in the payment of the principal or
(or premium, if any) or interest on the Bond, the Trustee shall be protected in
withholding such notice if and so long as an officer of the Trustee in good
faith determines that the withholding of such notice is in the interests of the
Bondholders.

     SECTION 1107. INTERVENTION ON BEHALF OF BONDHOLDERS. In any judicial
proceeding to which the Company is a party and which, in the opinion of the
Trustee and its counsel, has a substantial adverse bearing on the interests of
Owners of Bonds, the Trustee may intervene on behalf of Bondholders and shall do
so if requested in writing by the Owners of at least two-thirds of the aggregate
principal amount of Bonds Outstanding hereunder and idemnified as provided in
Section 1105 hereof. The rights and obligations of the Trustee under this
Section are subject to the approval of the court having jurisdiction in the
premises, if such approval is required by law as a condition to such
intervention.

     SECTION 1108. RELEASE OF PROPERTY FROM LIEN OF THIS INSTRUMENT. The
resolutions, opinions, certificates and other

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<PAGE>

instruments provided for in this Indenture may be accepted by the Trustee as
conclusive evidence of the facts and conclusions stated therein and shall be
full protection and authority to the Trustee for the release of property and the
withdrawal of such hereunder; but the Trustee may, in its unrestricted
discretion, and shall, if requested in writing so to do by the Owners of not
less than two-thirds in aggregate principal amount of Bonds then Outstanding,
cause to be made such independent investigation as it may see fit, and in that
event may decline to release such property or pay over such cash unless
satisfied by such investigation of the truth and accuracy of the matters so
investigated. The expenses of such investigation shall be paid by the Company
or, if paid by the Trustee, shall be reimbursed to the Trustee, plus interest on
disbursements therefor at the Default Rate, by the Company, and if the Company
shall fail to make such reimbursement, the Trustee may reimburse itself from any
moneys in its possession under the provisions of this Indenture and shall be
entitled to a preference therefor over any of the Bonds then Outstanding.

     SECTION 1109. RIGHT OF TRUSTEE TO PERFORM CERTAIN ACTS ON FAILURE OF
ISSUER. In case the Issuer or the Company shall fail seasonably to pay or to
cause to be paid any tax, assessments, governmental or other charge upon any
part of the property comprising the Trust Estate or the premiums on insurance on
such property, the Trustee may pay such tax, assessment, governmental charge,
premiums or expenses without prejudice, however, to any rights of the Trustee or
the Bondholders hereunder arising in consequence of such failure; and any amount
at any time so paid under this Section, with interest thereon from the date of
payment at a rate equal to the Default Rate, shall be repaid by the Company upon
demand, and shall become so much additional indebtedness secured by this
Indenture, and the same shall be given a preference in payment over any of the
Bonds and shall be paid out of the proceeds of any sale of the Trust Estate if
not otherwise paid by the Company, but the Trustee shall be under no obligation
to make any such payment unless it shall have been requested to do so by the
holders of at least twenty-five per centum (25%) of the aggregate principal
amount of Bonds Outstanding hereunder and shall have been provided with adequate
funds for the purpose of such payment.

     SECTION 1110. ADVANCEMENT OF MONEYS. Except as provided in Sections 1105
and 1108 hereof, all sums at any time advanced by the Trustee from its own funds
shall bear interest at the Default Rate from the date of such advance, and the
Trustee shall be entitled to be paid the amount of such interest by the Company
upon demand and, if not paid by the Company, the Trustee shall have a preference
for the payment to it of such interest over any of the Bonds and shall be paid
the amount thereof out of the Trust Estate.

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     SECTION 1111. RETENTION OF DOCUMENTS. The Trustee shall retain all
documents furnished by the Issuer and the Company in accordance with this
Indenture and the Agreement so long as any of the Bonds shall be Outstanding;
provided, however, that the Trustee shall not be required to retain after the
Completion Date any written orders submitted by the Company pursuant to Section
2.03 of the Agreement for more than 3 years after receipt of any other documents
furnished to it.

     SECTION 1112. COMPENSATION OF TRUSTEE; LIEN. Subject only to the obligation
to pay the Rebate Amount, the Trustee shall have a first lien on the Project and
the other property securing payment of the Bonds, and the revenues and receipts
pledged hereunder and all funds held or collected by the Trustee as such (except
funds held in trust for the benefit of the holders of particular Bonds) with
right of payment prior to payment on account of interest or principal or
premium, if any, of the Bonds issued hereunder, for reasonable compensation for
all services rendered by it hereunder and for all administrative expenses
including reasonable expenses, advances, disbursements and counsel fees (whether
or not incurred in collection, trial, appeal or bankruptcy action or in seeking
or obtaining the appointment of a successor trustee or co-trustee) incurred or
made in and about the execution of the trusts hereby created and exercised and
performance of the powers and duties of the Trustee hereunder and the cost and
expense incurred in defending against any liability in the premises of any
character whatsoever.

     SECTION 1113. TRUSTEE MAY HOLD BONDS. The Trustee in its individual or any
other capacity, may become the owner or pledgee of Bonds and may otherwise deal
with the Issuer or the Company with the same rights it would have if it were not
Trustee.

     SECTION 1114. SUCCESSOR TRUSTEE. Any corporation or association into which
the Trustee may be converted or merged, or with which it may be consolidated, or
to which it may sell or transfer its trust business and assets as a whole or
substantially as a whole, or any corporation or association resulting from any
such conversion, sale, merger, consolidation or transfer to which it is a party,
ipso facto, shall be and become successor trustee hereunder and vested with all
of the title to the trust estate and all the trusts, powers, discretions,
immunities, privileges, responsibilities, liabilities and all other matters as
was its predecessor, without the execution or filing of any instrument or any
further act, deed or conveyance on the part of any of the parties hereto,
anything hereto to the contrary notwithstanding.

     SECTION 1115. 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

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<PAGE>

effective until the acceptance of appointment by the successor Trustee under
Section 1116 hereof;

     (b) The Trustee may resign at any time by giving written notice hereof to
the Issuer and to the Company. If an instrument of acceptance by a successor
Trustee shall not have been delivered to the Trustee within thirty (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 and such court is hereby authorized to appoint a successor Trustee under
this Indenture;

     (c) The Trustee may be removed at any time by the holders of a majority in
principal amount of the Outstanding Bonds by an instrument or instruments in
writing delivered to the Trustee, the Issuer and the Company;

     (d) If at any time 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 (i) the Issuer may remove the Trustee, or (ii)
any Bondholder who has been a bona fide holder of a Bond for at least six (6)
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; and

     (e) If the Trustee shall resign, be removed or become incapable of acting,
or if a vacancy shall occur in the office of the Trustee for any cause, the
Issuer shall promptly appoint a successor Trustee. If, within one (1) year
after such resignation, removal or incapability, or the occurrence of such
vacancy, a successor Trustee shall be appointed by a majority in principal
amount of Outstanding Bonds by an instrument or instruments in writing delivered
to the Issuer, the retiring Trustee and the Company, the successor Trustee so
appointed shall, forthwith upon its acceptance of such appointment, become the
successor Trustee shall have been so appointed by the Issuer or the Bondholders
and accepted appointment in the manner hereinafter provided, any Bondholder who
has been a bona fide holder of a Bond at least six (6) months may, on behalf of
himself and all others similarly situated, petition any court of competent
jurisdiction for the appointment of a successor Trustee.

     SECTION 1116. CONCERNING ANY SUCCESSOR TRUSTEES. Every successor trustee
appointed hereunder shall execute, acknowledge and deliver to its immediate
predecessor and to the Issuer and the Company an instrument in writing accepting
such appointment hereunder, and thereupon such successor, without any further
act, deed

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or conveyance, shall become fully vested with all of the estates, properties,
rights, powers, trusts, duties and obligations hereby vested or intended to be
vested in the predecessor trustee, but such predecessor shall, nevertheless, on
the written request of either its successor, the Issuer or the Company, execute
and deliver an instrument transferring to such successor all the estate,
properties, rights, powers and trusts of such predecessor hereunder; and every
predecessor trustee shall deliver all securities and moneys held by it as
Trustee hereunder to its successor. Should any deed, conveyance or instrument
in writing from the Issuer or the Company be required by any successor trustee
for more fully and certainly vesting in such successor the estates, rights,
powers and duties hereby vested or intended to be vested in the predecessor
trustee, any and all such deeds, conveyances and instruments in writing shall,
on request, be executed, acknowledged and delivered by the Issuer and the
Company. The resignation of any Trustee and the instrument or instruments
removing any Trustee and appointing a successor hereunder, together with all
deeds, conveyances and other instruments provided for in this Indenture and the
Agreement shall, at the expense of the Company, be forthwith filed or recorded
by the successor trustee in each recording office where this Indenture and the
Agreement shall have been filed or recorded.

     SECTION 1117. APPOINTMENT OF CO-TRUSTEE. In any situation in which the
Trustee deems that by reason of any present or future law of any jurisdiction it
may not exercise any of the powers, rights or remedies granted by this Indenture
to Trustee or hold title to the properties, in trust, as therein granted, or
take any other action which may be desirable or necessary in connection
therewith, Trustee may appoint an additional individual or institution as a
separate or co-Trustee, in which event each and every remedy, power, right,
claim, demand, cause of action, immunity, estate, title, interest and lien
expressed or intended by such Indenture to be exercised by or vested in or
conveyed to Trustee with respect thereto shall be exercisable by and vest in
such separate or co-Trustee, but only to the extent necessary to enable such
separate or co-Trustee to exercise such powers, rights and remedies, and every
covenant and obligation necessary to the exercise thereof by such separate or
co-Trustee shall run to and be enforceable by either of them.

     Should any deed, conveyance or instrument in writing from Issuer be
required by the separate or co-Trustee so appointed by Trustee for more fully
and certainly vesting in and confirming to him or it such properties, rights,
powers, trusts, duties and obligations, any and all such deeds, conveyances and
instruments in writing shall, on request be executed, acknowledged and delivered
by Issuer. In case any separate or co-Trustee, or a successor to either, shall
die, become incapable of acting, resign or be removed, all the estates,
properties, rights, powers, trusts,

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<PAGE>

duties and obligations of such separate or co-Trustee, so far as permitted by
law, shall vest in and be exercised by Trustee until the appointment of a new
Trustee or successor to such separate or co-Trustee.

     SECTION 1118. INSTRUMENTS AND DOCUMENTS OF BONDHOLDERS. Any request,
direction, consent or other instrument in writing signed or executed by the
Bondholders may be in any number of concurrent instruments of similar tenor and
may be signed or executed by such Bondholders in person or by agent duly
appointed by an instrument in writing. Proof of the execution of any such
instrument and of the ownership of the Bonds shall be sufficient for any purpose
of this Indenture and shall be conclusive in favor of the Trustee with regard to
any action taken by it under such instrument if made in the following manner:

     (A) The fact and date of the execution by any person of any such instrument
may be proved by the certificate of any officer in any jurisdiction who, by the
laws thereof, has power to take acknowledgments of deeds to be recorded within
such jurisdiction, to the effect that the person signing such instrument
acknowledged to him the execution thereof, or by an affidavit of a witness to
such execution.

     (B) The ownership of fully registered Bonds shall be proved by the
registration books kept under the provisions of this Indenture.

     Nothing contained in this Section shall be construed as limiting the
Trustee to the proof above specified, it being intended that the Trustee may
accept any other evidence of the matters herein stated which it may deem
sufficient. Any request or consent of the Owner of any Bond shall bind every
future Owner of the same Bond in respect of anything done by the Trustee in
pursuance of such request or consent.

     SECTION 1119. DETERMINATION OF BONDS OUTSTANDING. In determining whether
the Owners of the requisite aggregate principal of Bonds have concurred in any
demand, request, direction, consent or waiver under this Indenture, Bonds which
are owned by the Company or by any other obligor on the Bonds or guarantor
thereof or of the performance of the Agreement, or by any person directly or
indirectly controlling or controlled by or under common control with the Company
or any other obligor on the Bonds or guarantor thereof or of the performance of
the Agreement, shall be disregarded and deemed not to be Outstanding for the
purpose of any such determination. Bonds so owned which have been pledged in
good faith may be regarded as Outstanding for the purposes of this Section if
the pledgee shall establish to the satisfaction of the Trustee the pledgee's
right to vote such Bonds and that the pledgee is not a person directly or
indirectly controlling or

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<PAGE>

controlled by or under common control with the Company or any other obligor on
the Bonds or guarantor thereof or of the performance of the Agreement. In case
of a dispute as to such right, any decision by the Trustee taken upon advice of
independent counsel shall be full protection to the Trustee.

     SECTION 1120. FILING OF CERTAIN CONTINUATION STATEMENTS. The Company has
covenanted in the Agreement to file or cause to be filed continuation statements
for the purpose of continuing without lapse the effectiveness of (i) those
financing statements which shall have been filed at or prior to the issuance of
the Bonds in connection with the security for the Bonds pursuant to the
authority of the U.C.C., and (ii) any previously filed continuation statements
which shall have been filed as herein required. In addition, the Issuer and the
Company shall sign and deliver to the Trustee or its designee such continuation
statements as may be requested of it from time to time by the Trustee. Upon the
filing of any such continuation statement the Company shall immediately notify
the Issuer and the Trustee that the same has been accomplished.

     SECTION 1121. SEVERAL CAPACITIES. Anything in this Indenture to the
contrary notwithstanding, the same entity may serve hereunder as the Trustee,
the Paying Agent or a Co-Paying Agent, the Registrar or a Co-Registrar and any
other combination of such capacities, to the extent permitted by law.

     SECTION 1122. OBLIGATIONS UNDER AGREEMENT. The Agreement imposes certain
duties and obligations upon the Trustee, as more particularly provided therein.
The Trustee acknowledges and agrees to perform such duties and obligations in
accordance with the provisions of the Agreement as if each such duty and
obligation is set forth in full in this Indenture.

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<PAGE>

                                   ARTICLE XII

                             SUPPLEMENTAL INDENTURES

     SECTION 1201. SUPPLEMENTAL INDENTURES NOT REQUIRING CONSENT OF BONDHOLDERS.
The Issuer and the Trustee may, without the consent of or notice to any of the
Bondholders, enter into an indenture or indentures supplemental to this
Indenture as shall not be inconsistent with the terms and provisions hereof for
any one or more of the following purposes:

     (a) To cure any ambiguity or formal defect or omission in this Indenture;
or

     (b) To grant to or confer upon the Trustee for the benefit of the
Bondholders any additional rights, remedies, powers or authority that may
lawfully be granted to or conferred upon the Bondholders or the Trustee or
either of them; or

     (c) To subject to the lien and pledge of this Indenture additional
revenues; or

     (d) Upon the request of the Company to amend the Project and Project
description to add to or change the Project; or

     (e) To assure compliance with Federal "arbitrage" and tax provisions
applicable to the Bonds in effect from time to time.

     (f) To modify, amend or supplement this Indenture or any indenture
supplemental hereto in such manner as to permit the qualification hereof and
thereof under the Trust Indenture Act of 1939, as amended, or any similar
Federal statute hereafter in effect or to permit the qualification of the Bonds
for sale under the securities laws of any of the states of the United States of
America, and, if they so determine, to add hereto or to any indenture
supplemental hereto such other terms, conditions and provisions as may be
permitted by said Trust Indenture Act of 1939 or similar Federal statute;

     (g) To evidence the appointment of a separate Trustee or Co-Trustee or the
succession of a new Trustee or Paying Agent hereunder.

     SECTION 1202. SUPPLEMENTAL INDENTURES REQUIRING CONSENT OF BONDHOLDERS.
Exclusive of supplemental indentures covered by Section 1201 hereof and subject
to the terms and provisions contained in this Section, and not otherwise, the
Owners of not less than two-thirds in aggregate principal amount of the Bonds
then Outstanding shall have the right, from time to time, anything contained in
this Indenture to the contrary notwithstanding, to consent to and approve the
execution by the Issuer and the Trustee of such other indentures supplemental
hereto as shall be deemed

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<PAGE>

necessary and desirable by the Issuer for the purpose of modifying, altering,
amending, adding to or rescinding, in any particular, any of the terms or
provisions contained in this Indenture or in any supplemental indenture;
provided, however, that nothing in this Section shall permit or be construed as
permitting (a) an extension of the stated maturity or reduction in the principal
amount of, or reduction in the rate, or extension of the time of payment, of
interest on, or reduction of any premium payable on the redemption of, any
Bonds, without the consent of the Owner of such Bonds, or (b) a reduction in the
aforesaid aggregate principal amount of Bonds the Owners of which are required
to consent to any such supplemental indenture, without the consent of the Owners
of all the Bonds at the time Outstanding which would be affected by the action
to be taken, or (c) modify the rights, duties or immunities of the Trustee,
without the written consent of the Trustee.

     If at any time the Issuer shall request the Trustee to enter into any such
supplemental indenture for any of the purposes of this Section, the Trustee
shall, upon being satisfactorily indemnified with respect to expenses, cause
notice of the proposed execution of such supplemental indenture to be mailed to
the Owners of the Bonds at least sixty (60) days prior to execution of such
supplemental indenture. Such notice shall briefly set forth the nature of the
proposed supplemental indenture, shall state that copies thereof are on file at
the principal office of the Trustee for inspection by all Bondholders and, in
the case of any such notice mailed to the Original Purchaser, shall be
accompanied by a copy of such proposed supplemental indenture. If, within sixty
days or such longer period as shall be prescribed by the Issuer following the
mailing of such notice, the Owners of not less than two-thirds in aggregate
principal amount of the Bonds Outstanding at the time of the execution of any
such supplemental indenture (subject, however, to the consent requirements set
forth in the proviso to the first sentence of this Section 1202) shall have
consented to and approved the execution thereof as herein provided, no Owner of
any Bond shall have any right to object to any of the terms and provisions
contained therein, or the operation thereof, or in any manner to question the
propriety of the execution thereof, or to enjoin or restrain the Trustee or the
Issuer from executing the same or from taking any action pursuant to the
provisions thereof. Upon the execution of any such supplemental indenture as in
this Section permitted and provided, this Indenture shall be and be deemed to be
modified and amended in accordance therewith. The Trustee may receive an opinion
of counsel (who may be counsel for the Issuer or the Company or both) that any
such supplemental indenture entered into by the Issuer and the Trustee complied
with the provisions of this Article and the Trustee may rely upon such opinion.

     Anything herein to the contrary notwithstanding, a supplemental indenture
under this Article which affects any rights of the

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<PAGE>

Company shall not become effective unless and until the Company shall have
consented to the execution and delivery of such supplemental indenture.

     SECTION 1203. TRUSTEE AUTHORIZED TO JOIN IN SUPPLEMENTS; RELIANCE ON
COUNSEL. The Trustee is authorized to join with the Issuer in the execution and
delivery of any supplemental indenture permitted by this Article XII and, in so
doing, shall be fully protected by an opinion of independent counsel that such
supplemental indenture is so permitted and has been duly authorized by the
Issuer and that all things necessary to make it a valid and binding supplemental
indenture have been done.

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<PAGE>

                                  ARTICLE XIII

                             AMENDMENT OF AGREEMENTS

     SECTION 1301. AMENDMENTS, ETC., TO AGREEMENT OR NOTE REQUIRING CONSENT OF
BONDHOLDERS. Neither the Issuer nor the Trustee shall consent to any other
amendment, change or modification of the Agreement or Note (other than
amendments, changes or modifications to the Agreement or Note necessary to bring
such documents in compliance with changes made to the Indenture pursuant to
Section 1201 hereof) without notice to and the written approval or consent of
the Owners of not less than two-thirds in aggregate principal amount of the
Bonds at the time Outstanding given and procured as provided in Section 1202
hereof. If at any time the Issuer and the Company shall request the consent of
the Trustee to any such proposed amendment, change or modification of an
Agreement or Note the Trustee shall, upon being satisfactorily indemnified with
respect to expenses, cause notice of such proposed amendment, change or
modification to be mailed in the same manner as provided by Section 1202 hereof
with respect to supplemental indentures. Such notice shall briefly set forth the
nature of such proposed amendment, change or modification, shall state that
copies of the instrument embodying the same are on file at the principal office
of the Trustee for inspection by all Bondholders, and, in the case of any notice
to an Original Purchaser, shall be accompanied by a copy of such instrument.

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                                   ARTICLE XIV

                                  MISCELLANEOUS

     SECTION 1401. CONSENTS, ETC., OF BONDHOLDERS. Any consent, request,
direction, approval, objection or other instrument required by this Indenture to
be signed and executed by the Bondholders may be in any number of concurrent
writings of similar tenor and may be signed or executed by such Bondholders in
person or by agent appointed in writing. Proof of the execution of any such
consent, request, direction, approval, objection or other instrument or of the
writing appointing any such agent and proof of the ownership of any Bond not
registered as to principal, or registered as to bearer, may be by affidavit and
shall be sufficient for any of the aforesaid purposes of this Indenture and
shall be conclusive in favor of the Trustee with regard to any action taken
under such request or other instrument, if the fact and date of the execution by
any person of any such writing is proved by certificate of any officer in any
jurisdiction who by law has power to take acknowledgments within such
jurisdiction that the person signing such writing acknowledged before him the
execution thereof, or is proved by affidavit of any witness to such execution.
It shall not be necessary to surrender or present any Bond to the Trustee for
any of the aforesaid purposes.

     SECTION 1402. LIMITATIONS OF RIGHTS. With the exception of rights herein
expressly conferred, nothing expressed or mentioned in or to be implied from
this Indenture, or the Bonds, is intended or shall be construed to give to any
person or company other than the Company and the parties hereto, and the Owners
of the Bonds, any legal or equitable right, remedy or claim under or in respect
to this Indenture or any covenants, conditions and provisions herein contained;
this Indenture and all of the covenants, conditions and provisions hereof being
intended to be and being for the sole and exclusive benefit of the parties
hereto and the Owners of the Bonds as herein provided.

     SECTION 1403. SEVERABILITY. If any provision of this Indenture shall be
held or deemed to be or shall, in fact, be inoperative or unenforceable as
applied in any particular case in any jurisdiction or jurisdictions or in all
jurisdictions, or in all cases because it conflicts with any other provision or
provisions hereof or any other reason, such circumstances shall not have the
effect of rendering the provision in question inoperative or unenforceable in
any other case or circumstance, or of rendering any other provision or
provisions herein contained invalid, inoperative, or unenforceable to any extent
whatever.

     The invalidity of any one or more phrases, sentences, clauses or sections
in this Indenture contained, shall not affect the remaining portions of this
Indenture, or any part thereof.

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<PAGE>

     SECTION 1404. NOTICES. It shall be sufficient service of any notice,
request, complaint, demand or other paper in the parties hereto if the same
shall be duly mailed, postage prepaid, return receipt requested, addressed as
follows:

     (a) If to the Issuer, to Pinellas County Industry Council, 2300 Tall Pines
Drive, Suite 113, Largo, Florida 34641.

     (b) If to the Company, to Aerosonic Corporation, 1212 N. Hercules Avenue,
Clearwater, Florida 34625, Attention: President.

     (c) If to the Trustee, to Barnett Banks Trust Company, N.A., 801 Riverside
Avenue, Jacksonville, Florida 32204, Attention: Corporate Trust Department.

     (d) If to the Original Purchaser, to Barnett Bank of Pinellas County, Post
Office Drawer 5128, Clearwater, Florida 33518, Attention: Mr. M. P. Freeman.

     A duplicate copy of any notice, certificate or other communication required
to be given hereunder by any of the parties shall also be simultaneously given
to all other parties. The Issuer, the Company, the Trustee and the Original
Purchaser may, by notice given hereunder, designate any further or different
addresses to which subsequent notices, certificates or other communications
shall be sent, but such notice of change of address shall be effective only when
received by the Trustee on behalf of the Bondholders, and by each other party
hereto.

     SECTION 1405. TRUSTEE AS BOND REGISTRAR AND AS PAYING AGENT. The Trustee is
hereby designated and agrees to act as Registrar and as Paying Agent for and in
respect to the Bonds.

     SECTION 1406. PAYMENTS DUE ON SATURDAYS, SUNDAYS AND HOLIDAYS. In any case
where the date of maturity of interest on or principal of the Bonds or the date
fixed for redemption of any Bonds shall be on a Saturday, Sunday or a legal
holiday or a day on which banking institutions are authorized by law to close in
the City of Jacksonville, Florida, then payment of interest or principal (and
premium, if any) need not be made on such date but may be made on the next
succeeding business day not a Saturday, Sunday or a legal holiday or a day upon
which banking institutions are authorized by law to close.

     SECTION 1407. RELIANCE BY ISSUER ON FACTS OR CERTIFICATES; INDEMNIFICATION
OF ISSUER. Anything in this Indenture to the contrary notwithstanding, it is
expressly understood and agreed by the parties hereto that (a) the Issuer may
rely conclusively on the truth and accuracy of any certificate, opinion, notice
or other instrument furnished to the Issuer by the Trustee or the Company as to
the existence of any fact or state of affairs required hereunder to be noticed
by the Issuer; (b) the Issuer shall not be under any obligation hereunder to
perform any record

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<PAGE>

keeping or to provide any legal services, it being understood that such services
shall be performed by the Company; and (c) none of the provisions of this
Indenture shall require the Issuer or the Trustee to expend or risk its own
funds or to otherwise incur financial liability in the performance of any of its
duties or in the exercise of any of its rights or powers hereunder, unless it
shall first have been adequately indemnified to its satisfaction against the
cost, expenses and liability which may be incurred thereby.

     SECTION 1408. IMMUNITY OF OFFICERS, MEMBERS AND AGENTS OF ISSUER, TRUSTEE
AND ORIGINAL PURCHASER. No recourse shall be had for the enforcement of any
obligation, covenant, promise or agreement of the Issuer, Trustee or the
Original Purchaser contained in this Indenture or in any Bond issued hereunder
or for any claim based hereon or otherwise in respect hereof or upon any
obligation, covenant, promise or agreement of the Issuer contained in the
Agreement, against any officer, member or agent, as such in his individual
capacity, past, present or future, of the Issuer, Trustee or the Original
Purchaser or of any successor corporation, whether by virtue of any
constitutional provision, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise; it being expressly agreed and understood
that no personal liability whatsoever shall attach to, or be incurred by, any
officer, member or agent, past, present or future, of the Issuer, Trustee or the
Original Purchaser or of any successor corporation, either directly or by reason
of the obligations, covenants, promises or agreements entered into between the
Issuer and the Trustee, or by the Issuer, the Trustee or the Original Purchaser
under any agreements entered into or executed by the Issuer, the Trustee or the
Original Purchaser in connection with the issuance of the Bond, to be implied
therefrom as being supplemental hereto or thereto and that all personal
liability of that character against every such officer and member is, by the
execution of this Indenture and the Bonds, and as a condition of, and as part of
the consideration for, the execution of this Indenture and the Bonds, expressly
waived and released.

     SECTION 1409. HEADINGS NOT PART OF INDENTURE. Any headings preceding the
text of the several Articles or Sections hereof, and any table of contents or
marginal notes appended to copies hereof, shall be solely for convenience of
reference and shall not constitute a part of this Indenture, nor shall they
affect its meaning, construction or effect.

     SECTION 1410. COUNTERPARTS. This Indenture may be simultaneously executed
in several counterparts, each of which shall be an original and all of which
shall constitute but one and the same instrument.

     SECTION 1411. APPLICABLE LAW. This Indenture shall be governed exclusively
by the applicable laws of the State of Florida.

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<PAGE>

     SECTION 1412. NO LIENS. Except as expressly permitted hereunder or in the
Agreement, no lien, encumbrance or other right shall be permitted with respect
to the Trust Estate which is prior to or on a parity with the lien of this
Indenture.

     SECTION 1413. INDENTURE EFFECTIVE UPON EXECUTION. This Indenture shall not
become effective and shall be of no force and effect, unless and until it shall
be executed. Any supplement to this Indenture authorized by this Indenture and
any such supplemental indenture shall become effective upon its execution and
delivery.

     SECTION 1414. ADVANCEMENT OF COSTS. Prior to the filing or recording of any
documents contemplated in connection herewith, the Trustee may advance funds to
pay any necessary closing costs including without limitation Florida documentary
stamp taxes and intangible taxes, if any, and recording costs. If for any reason
the sale of the Bonds is not completed, the Company agrees to reimburse the
Trustee for all such disbursements.

     SECTION 1415. NO USURY. Nothing herein or in the Bonds shall permit or
require the payment of interest or charges in the nature of interest in excess
of that permitted by law.

                  [Remainder of page intentionally left blank]

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<PAGE>

     IN WITNESS WHEREOF, the Pinellas County Industry Council has caused these
presents to be signed in its name and behalf by its Chairman, and its official
seal to be hereunto affixed and attested by its Secretary, and to evidence its
acceptance of the trusts hereby created, Barnett Banks Trust Company, N.A. has
caused these presents to be signed in its name and behalf by one of its
authorized officers, its official seal to be hereunto affixed, executed and
delivered by the Trustee this 17th day of December, 1987.

(SEAL)                                        PINELLAS COUNTY INDUSTRY COUNCIL


                                              By /s/ Charles E. Rainey
                                                 -------------------------------
                                                 Chairman

ATTEST:


/s/ William M. Castoro
-------------------------------
Secretary

STATE OF FLORIDA    :

COUNTY OF PINELLAS  :

     On the 17th day of December, 1987, before me personally appeared Charles E.
Rainey and William M. Castoro with whom I am personally acquainted and who upon
their several oaths acknowledged themselves to be the Chairman and Secretary,
respectively, of the Pinellas County Industry Council; that they as such
officers being authorized so to do, executed the foregoing instrument for the
purpose therein contained by signing the name of said Issuer, that they know the
seal of said Issuer, that the seal affixed to said instrument is such official
seal, that it was so affixed by order of the Pinellas County Industry Council,
and that each of them signed his name thereto by like order.

     IN WITNESS WHEREOF, I have hereunto set my hand and official seal.


                                               /s/ Notary
                                               ---------------------------------
                                               Notary Public
                                               State of Florida at Large

My Commission Expires:

     Notary Public, State of Florida at Large.
     My Commission Expires November 5, 1988,

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<PAGE>

(SEAL)                                         BARNETT BANKS TRUST COMPANY,
                                                  N.A., as Trustee


                                               By /s/ Ramsay D. Breazeale
                                                  ------------------------------
                                                  Its: Assistant Vice President

STATE OF FLORIDA

COUNTY OF DUVAL

     On the 17th day of December, 1987 before me personally appeared Ramsay
Breazeale with whom I am personally acquainted and who upon oath acknowledged
himself/herself to be Asst. Vice President of Barnett Banks Trust Company, N.A.,
the within named Trustee; that he/she as such officer being authorized so to do,
executed the foregoing instrument for the purpose therein contained by signing
the name of said corporation, that the seal affixed to said instrument is such
corporate seal, that it was so affixed by order of said corporation, and that
he/she signed his or her name thereto by like order.

     IN WITNESS WHEREOF, I have hereunto set my hand and official seal.


                                               /s/ Notary
                                               ---------------------------------
                                               Notary Public
                                               State of Florida at Large

My Commission Expires:

     Notary Public, State of Florida at Large.
     My Commission Expires November 5, 1988,

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<PAGE>

                      ACKNOWLEDGMENT AND CONSENT OF COMPANY

     The undersigned, on behalf of Aerosonic Corporation, a Delaware corporation
authorized to transact business in the State of Florida, HEREBY ACKNOWLEDGES
NOTICE OF, AND HEREBY CONSENTS TO (a) the assignment provisions contained within
the Granting Clauses of the foregoing Trust Indenture, and (b) all terms and
conditions set forth in said Trust Indenture, and intending to be legally bound,
HEREBY AGREES with the PINELLAS COUNTY INDUSTRY COUNCIL and BARNETT BANKS TRUST
COMPANY, N.A., as Trustee, to perform, accept or be bound by any applicable
terms and conditions set forth in said Trust Indenture.

     IN WITNESS WHEREOF, the undersigned has caused this instrument to be
executed as of December 17, 1987.


                                               By: /s/ David S. Goldman
                                                   -----------------------------
                                                   Executive Vice President

(SEAL)

Attest:


/s/ Rita Redman
----------------------------
Authorized Officer

     NOTARY PUBLIC STATE OF FLORIDA
     MY  COMMISSION EXP. MAY 14, 1988
     BONDED THRU GENERAL INS. UND.

                                       77

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                                   Exhibit "A"

DESCRIPTION:

     Begin at the Northeast corner of the Southeast 1/4, of the Northwest 1/4,
     of Section 12, Twp. 29, Rng. 15e; Thence run S.00DEG. 16' 59" W., along the
     North/South center of section a distance of 350.0 feet; thence run N.89DEG.
     20' 05" W. a distance of 50.0 feet for a point of begining. Thence continue
     N.89DEG. 20' 05" W. a distance of 450.00 feet, thence S.00DEG. 16' 59" W. a
     distance of 415.00 feet, thence S.89DEG. 20' 05" E. a distance of 450.00
     feet, thence N.00DEG. 16' 59" E. a distance of 415.00 feet to the point of
     begining; all being in tract "A" of the re-plat of blocks 1 through 19,
     inclusive, of MARYMONT SUBDIVISION, as recorded in Plat Book 39, Page 31,
     of the Public Records of Pinellas County, Florida.

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                                    EXHIBIT B

     The following, whether now owned or hereafter acquired:

     All minerals, soil, flowers, shrubs, crops, trees, timber and other
emblements now or hereafter on the Real Estate described in Exhibit A (the "Real
Estate") or under or above the same or any part or parcel thereof.

     All machinery, apparatus, equipment, fittings, fixtures, including, but
without limiting the generality of the foregoing, all after acquired property
and property not financed with the proceeds of the Bond, all heating, air
conditioning, freezing, lighting, laundry, incinerating and power equipment;
engines; pipes; pumps; tanks; motors; conduits; switchboards; plumbing, lifting,
cleaning, fire prevention, fire extinguishing, refrigerating, ventilating and
communication apparatus; boilers, ranges, furnaces, oil burners or units
thereof; appliances; air-cooling and air conditioning apparatus; vacuum cleaning
systems; elevators; escalators; shades; awnings; screens; storm doors and
windows; stoves; wall beds; built-in refrigerators; attached cabinets;
partitions; ducts and compressors; rugs and carpets; draperies; together with
all building materials and equipment now or hereafter delivered to the Real
Estate and intended to be installed therein, including but not limited to
lumber, plaster, cement, shingles, roofing, plumbing fixtures, pipe, lath,
wallboard, cabinets, nails, sinks, toilets, furnaces, heaters, brick, tile,
water heaters, screens, window frames, glass, doors, flooring paint and lighting
fixtures; together with all additions and accessions thereto and replacements
thereof.

     All of the water, sanitary and storm sewer systems which are now or
hereafter located by, over, and upon the Real Estate or any part and parcel
thereof, and which water system includes all water mains, service laterals,
hydrants, valves and appurtenances, and which sewer system includes all sanitary
sewer lines, including mains, laterals, manholes and appurtenances.

     All paving for streets, roads, walkways or entrance ways which are now or
hereafter located on the Real Estate or any part or parcel thereof.

     All interest as lessor in and to all leases or rental arrangements of the
Real Estate, or any part thereof, heretofore made and entered into, and in and
to all leases or rental arrangements hereafter made and entered into, together
with any and all guarantees of such leases or rental arrangements and including
all present and future security deposits and advance rentals.

<PAGE>

     All machinery, furniture, equipment and other tangible personal property of
every kind and description acquired directly or indirectly with proceeds of the
Pinellas County Industry Council Industrial Development Revenue Bond, Series
1987 (Aerosonic Corporation Project).

     All rights under agreements to sell or otherwise convey the Real Estate or
any collateral listed herein and all cash and noncash proceeds thereof,
including purchase money, promissory notes and installment sales agreements, and
any rights in collateral or guaranties securing any such notes or other
proceeds.

     Any and all awards or payments, including interest thereon, and the right
to receive the same, as a result of (a) the exercise of the right of eminent
domain, (b) the alteration of the grade of any street, or (c) any other injury
to, taking of, or decrease in the value of the Real Estate, all improvements
thereof and other collateral in this Exhibit.

     All unearned premiums accrued, accruing or to accrue under any and all
insurance policies now or hereafter provided pursuant to the terms of security
agreements, and all proceeds or sums payable for the loss of or damage to (a)
the Real Estate, any improvements thereto, or the collateral described herein,
or (b) rents, revenues, income, profits or proceeds from leases, franchises,
concessions or licenses of or on any part of the Real Estate.

     All contracts and contract rights arising from contracts entered into in
connection with development, construction upon, operation or sale of part or all
of the Real Estate, including contract or sales deposits, and all proceeds
thereof.

     All architectural and engineering plans and specifications, surveys, site
plans, appraisals, feasibility studies and development proposals and other
general intangibles now or hereafter existing pertaining to the construction of
the Real Estate.

     All rights under payment, performance, and other types of bonds relating to
the ownership, development, construction or operation of the Real Estate or any
improvements thereto and all rights under governmental and nongovernmental
permits, licenses and agreements relating to the ownership, development,
construction or operation of the Real Estate or improvements thereto.

     All rights under any covenants or restrictions now or hereafter affecting
the Real Estate, including the right to grant waivers and releases and all other
rights of the owner or declarant thereunder.

     All substitutions for, amendments to or modifications, extensions or
renewals of any collateral described herein and all proceeds thereof, in
whatever form.

<PAGE>

                                    EXHIBIT C

                                 PROMISSORY NOTE

                                December 17, 1987

$1,800,000                                              PINELLAS COUNTY, FLORIDA

     On or before December 17, 2012, for value received, the undersigned
promises to pay to the order of the PINELLAS COUNTY INDUSTRY COUNCIL, a special
district and a public body corporate and politic in Pinellas County, Florida
(the "Issuer"), the principal sum of one Million Eight Hundred Thousand Dollars
($1,800,000), together with interest and other amounts from the date hereof at
the rate and as specified in the Financing Agreement of even date herewith (the
"Agreement") to which a copy of this Note is annexed as Exhibit "C" thereto and
incorporated by reference therein and as specified in the Trust Indenture (the
"Indenture") of even date herewith between the Issuer and Barnett Banks Trust
Company, N.A., as trustee (the "Trustee") under the Indenture.

     The principal payments on this Note shall be payable on the 17th day of
each March, June, September and December commencing on December 17, 1988 as
provided in the Agreement with all principal and interest due and payable not
later than December 17, 2012.

     Aerosonic Corporation, a Delaware corporation authorized to transact
business in the State of Florida (the "Company"), specifically agrees to make
payment hereunder at such times and in such amounts as are necessary for payment
or prepayment of the principal of, premium, if any, interest on and other
amounts payable under the Issuer's $1,800,000 Industrial Development Revenue
Bond, Series 1987 (Aerosonic Corporation Project) (the "Bond"), the Indenture,
the Agreement and the Mortgage (as hereinafter defined) and it is specifically
agreed and understood, notwithstanding anything herein to the contrary, that
each payment under this Note shall at all times be sufficient to pay the total
amount of each payment or prepayment on the Bond when due. The obligations of
the Company to make payments under this Note are absolute and unconditional and
are not subject to diminution by set-off, counterclaim, abatement or otherwise.

     This Note is secured by collateral, including but not limited to, the
Agreement and by a Mortgage and Security Agreement (the "Mortgage") by and
between the Company, as mortgagor, and the Issuer, as mortgagee, of even date
herewith pledging and creating a lien on certain property of the maker, and is
further secured by the Indenture, all of which is provided for and set forth in
the Agreement, the Mortgage and the Indenture. It is expressly agreed that all
terms, covenants, conditions and agreements contained in the Agreement, the
Mortgage and the Indenture executed in

<PAGE>

connection herewith are hereby incorporated by reference in this instrument as
though fully set forth at length herein and the rate of interest hereon,
prepayment provisions and all other substantive terms hereof shall be as set
forth in said documents. In the event of conflict between this Note and the
Agreement, the Mortgage or the Indenture, the terms and conditions of the
Agreement shall control. This Note shall be deemed to be in default upon the
occurrence of any event of default which under the terms of the Agreement, the
Mortgage or the Indenture securing this Note constitutes an event of default.
Upon the occurrence of an event of default the holder of this Note may, at its
option, declare all unpaid indebtedness evidenced by this Note and any
modifications thereof immediately due and payable without notice regardless of
the date of maturity. Failure at any time to exercise this option does not
constitute a waiver of the right to exercise the same at any other time.

     Additional payments, including additional interest, are payable on this
Note upon the occurrence of a Determination of Taxability, as set forth in the
Agreement and the Bond. Except as provided for such additional payments, this
Note is subject to prepayment by the Company in full or in part at any time and
from time to time at 102% of the principal amount of this Note on and before the
first anniversary date of this Note, at 101% of the principal amount of the Note
after the first anniversary date of this Note but on or before the second
anniversary date of this Note, and without payment of penalty and premium after
the second anniversary date of this Note.

     The Bondholder has the option to require redemption of the Bond, pursuant
to and on the terms specified in the Bond, and in such event this Note shall be
prepaid in the same amount and at the same time as redemption required on the
Bond.

     Each maker and endorser for itself, its legal representatives, successors
and assigns, severally and expressly waives presentment demand, protest, notice
of dishonor, notice of nonpayment, notice of maturity, diligence in collection,
and the benefit of any exemption under any exemption or insolvency laws, and
consents that the holder hereof at the request of any other person or entity
liable hereon, without notice, may release or surrender, exchange or substitute,
any personal property now held or which may hereinafter be held as security for
the payment of this Note, and may extend the time for payment or otherwise
modify the terms of payment of any part or the whole of the debt evidenced
hereby and such consent shall not alter nor diminish the liability of any other
person or entity liable hereon.

     This Note is assignable to the Trustee as provided in the Indenture.

     This Note shall be governed by the laws of the State of Florida, which laws
shall be applicable in the interpretation,

<PAGE>

construction and enforcement hereof. Nothing herein or in the Agreement shall
permit or require the payment of interest or charges in the nature of interest
in excess of that permitted by law.

(SEAL)                                         AEROSONIC CORPORATION

ATTEST:


/s/ Rita Redman                                /s/ David S. Goldman
---------------------------------              ---------------------------------
Authorized Officer                             Executive Vice President

<PAGE>

                           ASSIGNMENT TO THE TRUSTEE

     For value received, the Pinellas County Industry Council hereby grants,
bargains, sells, conveys and assigns unto Barnett Banks Trust Company, N.A., as
Trustee under the Trust Indenture mentioned in the foregoing Promissory Note,
and unto its successors in trust, and to its assigns all of the Issuer's right,
title and interest in and the present and continuing rights to make claim for,
collect, receive and receipt for the payments and revenues arising from the
Issuer's rights in the foregoing Promissory Note dated December 17, 1987 and the
right to bring actions and proceedings under the said Promissory Note.

     Dated this 17th day of December, 1987.

(SEAL)                                         PINELLAS COUNTY INDUSTRY COUNCIL

ATTEST:


/s/ William M. Castoro                         By: /s/ Charles E. Rainey
-----------------------------                     -----------------------------
Secretary                                         Chairman

<PAGE>

construction and enforcement hereof. Nothing herein or in the Agreement shall
permit or require the payment of interest or charges in the nature of interest
in excess of that permitted by law.

(SEAL)                                         AEROSONIC CORPORATION

ATTEST:


/s/ Rita Redman                                /s/ David S. Goldman
---------------------------------              ---------------------------------
Authorized Officer                             Executive Vice President