Document:

Exhibit 10.51

                         L-3 COMMUNICATIONS CORPORATION

                        THIRD OMNIBUS AMENDMENT REGARDING
                   THIRD AMENDED AND RESTATED CREDIT AGREEMENT

         This THIRD OMNIBUS AMENDMENT REGARDING THE THIRD AMENDED AND RESTATED
CREDIT AGREEMENT (this "AMENDMENT") is dated as of February 24, 2004 and entered
into by and among L-3 COMMUNICATIONS CORPORATION, a Delaware corporation (the
"BORROWER") which is wholly owned by L-3 COMMUNICATIONS HOLDINGS, INC., a
Delaware corporation ("HOLDINGS"), the Lenders party to the Credit Agreement
referred to below on the date hereof (the "LENDERS"), BANK OF AMERICA, N.A.
("BOA"), as administrative agent for the Agents (as defined below) and the
Lenders (in such capacity, the "ADMINISTRATIVE AGENT"), LEHMAN COMMERCIAL PAPER,
INC. ("LCPI") as syndication agent and documentation agent (in such capacity,
the "SYNDICATION AGENT" and the "DOCUMENTATION AGENT") and certain financial
institutions named as co-agents. All capitalized terms used herein without
definition shall have the same meanings herein as set forth in the Credit
Agreement (as defined below).

                               W I T N E S S E T H:
                               - - - - - - - - - -

         WHEREAS, the Borrower, the Lenders, the Syndication Agent, the
Documentation Agent, the Administrative Agent and certain other parties have
entered into the Third Amended and Restated Credit Agreement dated as of May 16,
2001 (as amended, supplemented, restated or otherwise modified from time to
time, the "CREDIT AGREEMENT"); and

         WHEREAS, the Borrower has requested that certain amendments be made
with respect to the Credit Agreement and certain of the other Credit Documents.

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

         SECTION 1. AMENDMENTS TO CREDIT AGREEMENT. Subject to the satisfaction
of each of the conditions to effectiveness set forth in Section 3 of this
Amendment, the Borrower and the Requisite Class Lenders party to the Credit
Agreement hereby agree to amend the Credit Agreement as follows:

     1.1 Subsection 1.1 of the Credit Agreement is hereby amended by inserting
the following defined terms in the proper alphabetical order:

         ""Consolidated Senior Debt": all Consolidated Total Debt other than
     Subordinated Debt.

         "Consolidated Senior Debt Ratio": as of the last day of any period of
     four consecutive fiscal quarters, the ratio of (a) Consolidated Senior Debt
     on such day to (b) Consolidated EBITDA for such period.

         "Designated Parent Repurchases": shall mean the sum of the Net Proceeds
     of the issuance of Permitted Convertible Securities and/or Capital Stock of
     Holdings from and after January 1, 2004 which are utilized to repurchase
     common stock of Holdings.

         "Investments": as defined in subsection 7.9.

         "Non-Wholly Owned Subsidiary": any Subsidiary of the Borrower that is
     not a Wholly Owned Subsidiary.

         "Third Omnibus Amendment Fee Letter": shall mean that certain Third
     Omnibus Amendment Fee Letter between the Administrative Agent and the
     Borrower dated on or about January 30, 2004."

     1.2 The following defined terms in subsection 1.1 of the Credit Agreement
are hereby amended and restated as follows:

         ""Consolidated EBITDA": as of the last day of any fiscal quarter,
     Consolidated Net Income of the Borrower, its Subsidiaries and, without
     duplication, the Acquired Businesses (excluding, without duplication, (v)
     impairment losses incurred on goodwill and other intangible assets or on
     debt or equity investments computed in accordance with Financial Accounting
     Standard No. 142 or other GAAP, (w) gains or losses incurred on the
     retirement of debt computed in accordance with Financial Accounting
     Standard No. 145, (x) extraordinary gains and losses in accordance with
     GAAP, (y) gains and losses in connection with asset dispositions whether or
     not constituting extraordinary gains and losses and (z) gains or losses on
     discontinued operations) for the four fiscal quarters ended on such date,
     plus (i) Consolidated Interest Expense of the Borrower and its Subsidiaries
     and all Consolidated Interest Expense of Holdings with respect to the
     Permitted Convertible Securities guaranteed by the Borrower or its
     Subsidiaries and, without duplication, the Acquired Businesses for such
     period, plus (ii) to the extent deducted in computing such Consolidated Net
     Income of the Borrower or its Subsidiaries and, without duplication, the
     Acquired Businesses, the sum of income taxes, depreciation and amortization
     for such period. For the purposes of calculating Consolidated EBITDA for
     any period of four consecutive fiscal quarters occurring after the AIS
     Acquisition (each, a "Reference Period") pursuant to any determination of
     the Debt Ratio, Consolidated EBITDA for such Reference Period shall be
     calculated after giving pro forma effect to (i) exclude from costs the
     positive difference, if any, between (A) the amount of annual corporate
     overhead costs attributed to the operations associated with the business
     comprising the AIS Acquisition by Raytheon Company prior to such
     acquisition by the Borrower and (B) the amount of annual corporate overhead
     costs that will be attributed by the Borrower to the operations associated
     with the business comprising the AIS Acquisition from and after such
     acquisition by the Borrower, (ii) exclude any losses or gains associated
     with any contract estimate at completion ("EAC"), unrecoverable inventories
     and uncollectable receivables adjustment included in the

                                       2

     historical results of operations associated with the business comprising
     the AIS Acquisition within the 12 months prior to the effective date of the
     AIS Acquisition for accounting purposes, if such contract EAC,
     unrecoverable inventories or uncollectible receivable adjustments pertained
     to contracts or assets excluded from the business comprising the AIS
     Acquisition, and (iii) exclude any losses or gains, up to a maximum amount
     of $16,000,000, associated with any contract EAC, unrecoverable inventories
     and uncollectable receivables adjustment included in the historical results
     of operations associated with the Sea Sentinel contract within the 12
     months prior to the effective date of the AIS Acquisition for accounting
     purposes; provided, however, that such adjustments to Consolidated EBITDA
     are demonstrated by appropriate footnotes to the audited financial
     statements of the business comprising the AIS Acquisition or appropriate
     schedules and other materials prepared and certified by the Borrower and
     delivered to the Administrative Agent no more than 15 days after the
     completion of the audit of the financial statements of the business
     comprising the AIS Acquisition for the fiscal year ended prior to the
     consummation of AIS Acquisition.

         "Credit Documents": this Agreement, the Notes, the Applications, the
     Guarantees, the Fee Letter, the Lender Fee Letter, the Third Omnibus
     Amendment Fee Letter and the Pledge Agreements.

         "GAAP" means generally accepted accounting principles in the United
     States set forth in the opinions and pronouncements of the American
     Institute of Certified Public Accountants and statements and pronouncements
     of the Financial Accounting Standards Board or such other principles as may
     be approved by a significant segment of the accounting profession in the
     United States, that are applicable to the circumstances as of the date of
     determination.

         "Immaterial Subsidiary": any Subsidiary of the Borrower having assets
     not exceeding five percent (5%) of the Consolidated Total Assets; provided,
     however, that if any Subsidiary is a Non-Wholly Owned Subsidiary, the
     assets of such Subsidiary to be included in the above calculation shall be
     reduced by the minority interest for such Subsidiary as reported in the
     Borrower's consolidated balance sheet.

         "Net Proceeds": the aggregate cash proceeds (including Cash
     Equivalents) received by Holdings or any of its Subsidiaries in respect of:

                  (a) any issuance by Holdings or any of its Subsidiaries of
         Indebtedness after the Closing Date and any issuance by Holdings of any
         Capital Stock after the Closing Date;

                  (b) any Asset Sale or other transaction permitted by
         subsection 7.5(c); and

                  (c) any cash payments received in respect of promissory notes
         or other evidences of indebtedness delivered to Holdings or such
         Subsidiary in respect of an Asset Sale;

                                       3

         in each case net of (without duplication) (i), (A) in the case of an
     Asset Sale or other transaction permitted by subsection 7.5(c), the amount
     required to repay any Indebtedness (other than the Loans) secured by a Lien
     on any assets of Holdings or a Subsidiary of Holdings that are sold or
     otherwise disposed of in connection with such Asset Sale or other
     transaction permitted by subsection 7.5(c) and (B) reasonable and
     appropriate amounts established by Holdings or such Subsidiary, as the case
     may be, as a reserve against liabilities associated with such Asset Sale or
     other transaction permitted by subsection 7.5(c) and retained by Holdings
     or such Subsidiary, (ii) the reasonable expenses (including legal fees and
     brokers' and underwriters' commissions, lenders fees, credit enhancement
     fees, accountants' fees, investment banking fees, survey costs, title
     insurance premiums and other customary fees, in any case, paid to third
     parties or, to the extent permitted hereby, Affiliates) incurred in
     effecting such issuance, sale or transaction and (iii) any taxes reasonably
     attributable to such sale or transaction and reasonably estimated by
     Holdings or such Subsidiary to be actually payable.

         "Permitted Stock Payments": (A) dividends by the Borrower to Holdings
     in amounts equal to the amounts required for Holdings to (i) pay franchise
     taxes and other fees required to maintain its legal existence and (ii)
     provide for other operating costs of up to $1,000,000 per fiscal year, (B)
     dividends by the Borrower to Holdings in amounts equal to amounts required
     for Holdings to pay federal, state and local income taxes to the extent
     such income taxes are actually due and owing, provided that the aggregate
     amount paid under this clause (B) does not exceed the amount that the
     Borrower would be required to pay in respect of the income of the Borrower
     and its Subsidiaries if the Borrower were a stand alone entity that was not
     owned by Holdings, (C) from and after January 1, 2004, dividends by the
     Borrower to Holdings in an aggregate amount not to exceed $25,000,000 in
     any fiscal quarter of the Borrower so long as at the time of declaring and
     paying any such dividend no Default or Event of Default shall have occurred
     and be continuing, (D) dividends by the Borrower to Holdings to fund
     interest expense or dividends in respect of the Permitted Convertible
     Securities issued by Holdings, provided that such dividends under this
     clause (D) shall not, in any fiscal year, exceed an amount equal to the
     interest or dividends actually accruing on the outstanding principal amount
     of such Permitted Convertible Securities in such fiscal year less the sum
     of all intercompany advances funded pursuant to subsection 7.9(l) hereof by
     the Borrower to Holdings in respect of such Permitted Convertible
     Securities in such fiscal year, (E) from and after January 1, 2004,
     dividends by the Borrower to Holdings in an amount not to exceed
     $200,000,000 less the Designated Parent Repurchases to permit Holdings to
     repurchase common stock of Holdings, so long as such dividends are paid
     from the Net Proceeds of the issuance of Additional Subordinated
     Indebtedness issued after January 1, 2004 and (F) from and after January 1,
     2004, dividends by the Borrower to Holdings in an aggregate amount up to
     $10,000,000 in any fiscal year of the Borrower to fund cash payments to
     repurchase common stock of Holdings held by any employee, director,
     officer, consultant or agent (a "Benefit Plan Beneficiary") of the
     Borrower, Holdings or their Subsidiaries pursuant to any restricted stock
     plan or to which any such Benefit Plan Beneficiary has a right under any
     option plan of the Borrower or Holdings (or to repurchase other common
     stock of Holdings held by any such Benefit Plan Beneficiary having a value
     not exceeding the amount of the exercise price of an option being exercised
     by such Benefit Plan Beneficiary and the amount of the obligations of

                                       4

     such Benefit Plan Beneficiary under the Code with respect to the common
     stock underlying such option) in order to enable (i) the Borrower, Holdings
     or such Benefit Plan Beneficiary to comply with obligations under the Code,
     (ii) the Borrower or Holdings to issue cash to such Benefit Plan
     Beneficiary in lieu of fractional shares of common stock or (iii) the
     payment of the exercise price of an option held by such Benefit Plan
     Beneficiary."

     1.3 Section 1 of the Credit Agreement is hereby amended by (a) deleting the
text appearing in subsection 1.2(b) and inserting "[INTENTIONALLY OMITTED]" in
place thereof and (b) adding a new subsection 1.6 at the end thereof as follows:

         "1.6 Accounting Terms.

         (a) All accounting terms not specifically or completely defined herein
     shall be construed in conformity with, and all financial covenants,
     financial ratios and other financial calculations contained in this
     Agreement shall be prepared in conformity with GAAP as in effect from time
     to time, applied consistently throughout the periods reflected therein,
     except as otherwise specifically prescribed herein.

         (b) If at any time any change in GAAP after January 1, 2004 would
     affect the computation of any financial ratio or requirement set forth in
     any Credit Document, and either the Borrower or the Required Lenders shall
     so request, the Administrative Agent, the Lenders and the Borrower shall
     negotiate in good faith to amend such ratio or requirement to preserve the
     original intent thereof in light of such change in GAAP (subject to the
     approval of the Required Lenders); provided that, until so amended, (i)
     such ratio or requirement shall continue to be computed in accordance with
     GAAP prior to such change therein and (ii) if a request for such an
     amendment has been made, the Borrower shall provide to the Administrative
     Agent and the Lenders financial statements and other documents required
     under this Agreement or as reasonably requested hereunder setting forth a
     reconciliation between calculations of such ratio or requirement made
     before and after giving effect to such change in GAAP."

     1.4 Subsection 2.1(a) of the Credit Agreement is hereby amended and
restated in its entirety to read as follows:

         (a) Revolving Credit Loans. Subject to the terms and conditions hereof,
     each Revolving Credit Lender severally agrees to make revolving credit
     loans to the Borrower, from time to time during the Revolving Credit
     Commitment Period, in an aggregate principal amount at any one time
     outstanding which, when added to the aggregate principal amount of
     outstanding Swing Line Loans in which such Lender has purchased a
     participation (or, in the case of the Swing Line Lender, the Swing Line
     Loans made by such Swing Line Lender less the participations purchased in
     such Swing Line Loans by any other Lender) and such Lender's Commitment
     Percentage of the then outstanding L/C Obligations, does not exceed the
     amount of such Lender's Revolving Credit Commitment. During the Revolving
     Credit Commitment Period, the Borrower may use the Revolving Credit
     Commitments by borrowing, prepaying the Revolving Credit

                                       5

     Loans, in whole or in part, and reborrowing, all in accordance with the
     terms and conditions hereof.

         At any time not less than thirty (30) days prior to the Termination
     Date, the Borrower may increase the aggregate Commitments by (I) entering
     into a binding written agreement, substantially in the form of Exhibit G
     hereto, with any Lender to increase the Commitment of such Lender (an
     "Increased Commitment Agreement") which Increased Commitment Agreement
     shall be presented to the Agents for acknowledgment and acceptance (which
     shall not be withheld unless the effect thereof would be to exceed the
     maximum permitted amount herein for all Commitments, Facility B Commitments
     and Facility C Commitments (if Facility C exists) in the aggregate) and/or
     (II) subject to the First Offer Requirement (as defined below) enter into a
     binding written agreement substantially in the form of Exhibit H hereto (a
     "Lender Addition Agreement") with any bank, financial institution, or
     Investment Fund to become a Lender under this Agreement by making a
     Commitment and causing such Person to take all other actions required to
     become a new Lender hereunder (a "New Lender"); provided that the sum of
     (i) the aggregate Commitments of all Lenders (including New Lenders), (ii)
     the aggregate Facility B Commitments of all Facility B Lenders and (iii)
     the aggregate Facility C Commitments (if Facility C exists) of all Facility
     C Lenders (if Facility C exists) may not exceed, as of the date all or any
     portion of the Indebtedness comprising the Incremental Facility (as defined
     below) is incurred, an aggregate amount that would cause the Consolidated
     Senior Debt Ratio for the Borrower's most recently ended four full fiscal
     quarters for which internal financial statements are available to be
     greater than 2.0 to 1.0 (determined on a pro forma basis, assuming for
     purposes of this subsection 2.1(a) only, all of the proposed additional
     commitments had been incurred at the beginning of such four-quarter period
     and all Commitments of all Lenders, all Facility B Commitments of all
     Facility B Lenders and all Facility C Commitments (if Facility C exists) of
     all Facility C Lenders (if Facility C exists) that are outstanding
     immediately prior to giving effect to the incurrence of such proposed
     additional commitments have been drawn in full, but taking into account any
     payment or prepayment of any Term Loans or term loans under Facility C (if
     Facility C exists)) (such new or increased commitments, the "Incremental
     Facility"); and provided, further that, no consent of any Lender shall be
     required for such Incremental Facility except for the consents described
     under clauses (I) and (II) above. In order to become a New Lender, a party
     must execute a Lender Addition Agreement and deliver the same to the
     Administrative Agent, the Syndication Agent and the Borrower for
     counter-execution. On the Eurodollar Loans Maturity Date (or, subject to
     compliance with subsection 2.16, on any Business Day) occurring on or
     immediately following the date that (i) the Agents have acknowledged their
     acceptance of any Increased Commitment Agreement delivered pursuant to
     clause (I) above or (ii) any Lender Addition Agreement has been executed by
     all necessary parties and delivered to the Agents, the increase in any such
     Lender's Commitment contemplated thereby shall become effective and/or the
     New Lender shall become a party to this Agreement, as applicable. Promptly
     thereafter, the Administrative Agent shall amend Schedule I hereto to
     accurately reflect the Commitments of the Lenders then in existence,
     whereupon such amended Schedule I shall be substituted for the pre-existing
     Schedule I, be deemed a part of this Agreement without any further action
     or consent of any party and be promptly distributed to each Lender and the
     Borrower by the Administrative Agent. The

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     Incremental Facility shall have such economic terms (i.e., pricing, amount,
     tenor, amortization) as shall be agreed at the time with the lenders
     participating therein, and shall, otherwise, be on the same terms as this
     Agreement; provided that without the written consent of Required Class
     Lenders for each Class, (i) the applicable interest rate margin under the
     Incremental Facility shall not exceed the Applicable Margin under this
     Agreement or the "Applicable Margin" under and as defined in the Facility B
     Credit Agreement by more than fifty basis points and (ii) the maturity date
     of the Incremental Facility shall be equal to or occurring after the
     scheduled Termination Date under this Agreement or the "Termination Date"
     under and as defined in the Facility B Credit Agreement; provided, further,
     that if the Borrower chooses to implement the Incremental Facility pursuant
     to clause (I) or (II) above, the Incremental Facility shall have the same
     economic terms (i.e. pricing, tenor, amortization) as this Agreement. In
     the alternative, without the consent of any Lender, Borrower may cause the
     Incremental Facility to be implemented and separately documented as
     Facility C, which shall have BOA as the administrative agent and provide
     for a ratable sharing of all Collateral and Guarantee Obligations under the
     Guarantees among and between the Lenders, the Facility B Lenders and the
     Facility C Lenders. In any case, the Administrative Agent shall have the
     right to execute, on behalf of the Lenders, any amendments and/or other
     documents necessary to implement the Incremental Facility; provided that
     such amendments and/or other documents do not affect any of the rights or
     obligations of any Lender for which the written consent of such Lender is
     necessary under subsection 10.1 unless the written consent of such Lender
     is received by the Administrative Agent. When the Incremental Facility is
     not implemented and separately documented as Facility C, the Borrower shall
     send the Administrative Agent (for distribution to each Lender) a written
     offer to participate in the Incremental Facility pursuant to clause (I)
     above, and each such Lender shall have the right, but no obligation, to
     commit to a ratable portion of the Incremental Facility, provided that no
     later than fourteen (14) days after receipt of such written request, each
     such Lender shall advise the Administrative Agent and the Borrower whether
     it intends to participate in the Incremental Facility and the amount of its
     proposed commitment (the "First Offer Requirement"). Only after satisfying
     the First Offer Requirement and allocating requested commitments to Lenders
     requesting participation in such Incremental Facility shall Borrower be
     permitted to offer participation in any remaining commitments for the
     Incremental Facility to any proposed New Lender pursuant to clause (II)
     above."

     1.5 Subsection 2.12(a) of the Credit Agreement is hereby amended and
restated in its entirety to read as follows:

         "(a) Each borrowing by the Borrower from the Revolving Credit Lenders
     hereunder, each payment by the Borrower on account of any commitment fee
     hereunder and any reduction of the Revolving Credit Commitments of
     Revolving Credit Lenders shall be made pro rata according to the respective
     Commitment Percentages of the Revolving Credit Lenders. Except during any
     period in which an Event of Default has occurred and is continuing, each
     payment (including each prepayment) by the Borrower on account of principal
     of and interest on the Revolving Credit Loans, and any application by the
     Administrative Agent of the proceeds of any Collateral, shall be made pro
     rata according to the respective outstanding principal amounts of such
     Loans then

                                       7

     held by the Lenders. All payments (including prepayments) to be made by the
     Borrower hereunder in respect of any Loan, whether on account of principal,
     interest, Reimbursement Obligations (whether in respect of Domestic L/Cs or
     Foreign L/Cs), fees, expenses or otherwise, shall be made without set off
     or counterclaim and shall be made prior to 11:00 A.M., New York City time,
     on the due date thereof to the Administrative Agent, for the account of the
     Lenders with respect to such Loans, at the Administrative Agent's office
     specified in subsection 10.2, in Dollars and in immediately available
     funds; provided, that with respect to any Reimbursement Obligations of the
     Borrower arising from the presentment to the Issuing Lender of a draft
     under a Foreign L/C, the Borrower may make payment in the applicable
     Alternative Currency if such payment is received by the Issuing Lender on
     the date such draft is paid by the Issuing Lender.

         At any time that an Event of Default has occurred and is continuing,
     all payments (including prepayments) made by the Borrower hereunder and any
     application by the Administrative Agent of the proceeds of any Collateral
     and/or payment under any Guarantee shall be applied in the following order:
     (1) to the ratable payment of all amounts due and owing by the Borrower
     pursuant to subsection 10.5 of this Agreement, subsection 10.5 of the
     Facility B Credit Agreement or subsection 10.5 of the Facility C Credit
     Agreement (if Facility C exists) to the Agents, the Facility B Agents
     and/or the Facility C Agents (if Facility C exists) and, after payment in
     full thereof, to any other Lender, Facility B Lender or Facility C Lender
     (if Facility C exists); (2) to the ratable payment of all interest, fees
     and commissions due and owing under this Agreement, the Facility B Credit
     Agreement or the Facility C Credit Agreement (if Facility C exists) or to
     the Agents, the Facility B Agents, the Facility C Agents (if Facility C
     exists), the Swing Line Lender, any Lender, any Facility B Lender or any
     Facility C Lender (if Facility C exists); and (3) to the ratable payment
     (or cash collateralization) of all other obligations of the Borrower to the
     Agents, the Facility B Agents, the Facility C Agents (if Facility C
     exists), the Swing Line Lender, any Lender, any Facility B Lender or any
     Facility C Lender (if Facility C exists) under any Credit Document,
     Facility B Credit Document, Facility C Credit Document (if Facility C
     exists) or Interest Rate Agreement with any Lender, any Facility B Lender
     or any Facility C Lender (if Facility C exists), including, without
     limitation the aggregate outstanding principal amount of Loans, Facility B
     Loans and Facility C Loans (if Facility C exists), the aggregate L/C
     Obligations, Facility B L/C Obligations and Facility C L/C Obligations (if
     Facility C exists) and the aggregate outstanding amount of Interest Rate
     Agreement Obligations to any Lender, any Facility B Lender and any Facility
     C Lender (if Facility C exists). For purposes of applying payments and
     proceeds distributed under clause 3 above, each Lender will first apply
     such amounts to all outstanding Loans and Interest Rate Agreement
     Obligations then due and owing to such Lender before such amounts will be
     held as cash collateral for L/C Obligations in which such Lender is a L/C
     Participant.

         The Administrative Agent, the Facility B Administrative Agent and the
     Facility C Administrative Agent (if Facility C exists) shall ratably
     distribute such payments to the applicable Lenders, the Facility B Lenders
     and the Facility C Lenders (if Facility C exists) promptly upon receipt in
     like funds as received. If any payment hereunder becomes due and payable on
     a day other than a Business Day, such payment shall be extended to the next
     succeeding Business Day, and, with respect to payments of

                                       8

     principal, interest thereon shall be payable at the then applicable rate
     during such extension."

     1.6 Subsection 6.10(b) of the Credit Agreement is hereby amended and
restated in its entirety to read as follows:

         "(b) With respect to any Person that, subsequent to the Original
     Closing Date, becomes a direct or indirect Subsidiary of the Borrower,
     promptly (and in any event within 30 days after such Person becomes a
     Subsidiary): (i) cause such new Subsidiary to become a party to the
     Subsidiary Guarantee and, to the extent such Subsidiary holds any Capital
     Stock of any Subsidiary that is not an Immaterial Subsidiary, to the
     Subsidiary Pledge Agreement and (ii) if requested by the Administrative
     Agent or the Required Lenders, deliver to the Administrative Agent legal
     opinions relating to the matters described in clause (i) immediately
     preceding, which opinions shall be in form and substance, and from counsel,
     reasonably satisfactory to the Administrative Agent. Notwithstanding the
     foregoing, no Immaterial Subsidiary, Foreign Subsidiary, Non-Wholly Owned
     Subsidiary or TCAS Subsidiary (except as provided below) of the Borrower or
     its Subsidiaries shall be required to execute a Subsidiary Guarantee or
     Subsidiary Pledge Agreement, and no more than 65% of the total combined
     voting power of the Capital Stock of or equity interests in (A) any direct
     or indirect Foreign Subsidiary of the Borrower or (B) any direct or
     indirect Subsidiary of the Borrower if more than 65% of the assets of such
     Subsidiary are securities of foreign companies (such determination to be
     made on the basis of fair market value), and no Subsidiary of any Person
     described in clause (A) or (B), shall be required to be pledged hereunder;
     provided, that if, after the consummation of any sale of a portion of
     Capital Stock of the TCAS Subsidiary, the TCAS Subsidiary thereafter
     becomes a Wholly Owned Subsidiary, then the TCAS Subsidiary shall become a
     party to the Subsidiary Guarantee and Subsidiary Pledge Agreement and the
     Borrower shall promptly (and in any event within 30 days after such event
     occurs) comply with the requirements of this subsection 6.10(b) with
     respect to the TCAS Subsidiary; provided, further, that if any Non-Wholly
     Owned Subsidiary thereafter becomes a Wholly Owned Subsidiary, then such
     Subsidiary shall become a party to the Subsidiary Guarantee and Subsidiary
     Pledge Agreement and Borrower shall promptly (and in any event within 30
     days after such event occurs) comply with the requirements of this
     subsection 6.10(b) with respect to such Subsidiary; provided, further, that
     if the Borrower shall be required to cause any Immaterial Subsidiary
     (including, without limitation, any Immaterial Subsidiary which is also a
     Non-Wholly Owned Subsidiary) to become bound by any guarantee of
     Indebtedness for borrowed money in respect of any Subordinated Indebtedness
     or Indebtedness incurred pursuant to subsection 7.2(d), the Borrower shall
     cause such Subsidiary to execute a Subsidiary Guarantee and cause the same
     to be delivered to the Administrative Agent promptly (and in any event
     within 30 days after such event occurs); provided, further, that no
     Guarantee Obligation of any Immaterial Subsidiary in effect at the time
     such Subsidiary becomes a Subsidiary of the Borrower shall trigger a
     requirement that the Borrower cause such Subsidiary to execute and deliver
     a Subsidiary Guarantee pursuant to the immediately preceding proviso unless
     the Borrower is required, by virtue of such Guarantee Obligation, to cause
     such Subsidiary to become bound by a guarantee of Indebtedness for borrowed
     money in respect of any Subordinated Indebtedness.

                                       9

     Notwithstanding anything to the contrary contained in this Agreement, the
     Borrower shall cause at all times Subsidiaries that, together with the
     Borrower, comprise not less than seventy-five percent (75%) of Consolidated
     Total Assets to be party to the Subsidiary Guarantee; provided that for
     purposes of determining compliance with this requirement, the value of
     Capital Stock of any Subsidiary shall be deemed excluded; provided,
     further, that if any Subsidiary is a Non-Wholly Owned Subsidiary, the
     assets of such Subsidiary to be included in the above calculation shall be
     reduced by the minority interest for such Subsidiary as reported in the
     Borrower's consolidated balance sheet."

     1.7 Subsection 7.1(a) of the Credit Agreement is hereby amended and
restated in its entirety to read as follows:

         "(a) Debt Ratio. Permit the Debt Ratio at the last day of any fiscal
     quarter to be greater than the ratio set forth below opposite the date on
     which such fiscal quarter ends:

        Fiscal Quarter Ending                                Ratio
        ---------------------                                -----

        September 30, 2003                                   4.25
        December 31, 2003                                    4.25
        March 31, 2004                                       4.25
        June 30, 2004                                        4.25
        September 30, 2004                                   4.00
        December 31, 2004                                    4.00
        March 31, 2005                                       4.00
        June 30, 2005                                        4.00
        September 30, 2005 and thereafter                    3.50"

     1.8 Subsection 7.1 of the Credit Agreement is hereby amended and restated
in its entirety by inserting a new subclause (c) therein as follows:

         "(c) Consolidated Senior Debt Ratio. Permit the Consolidated Senior
     Debt Ratio at the last day of the fiscal quarter ending December 31, 2003
     and each fiscal quarter ending thereafter to be greater than 2.50 to 1.00."

     1.9 Subsection 7.2(b) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(b) Indebtedness of the Borrower incurred to finance the acquisition
     of fixed or capital assets (whether pursuant to a loan, a Financing Lease
     or otherwise) in an aggregate principal amount not exceeding $50,000,000 at
     any time outstanding, and refundings or refinancings thereof, provided that
     no such refunding or refinancing shall shorten the maturity or increase the
     principal amount of the original Indebtedness;"

     1.10 Subsection 7.2(c) of the Credit Agreement is hereby amended and
restated to read as follows:

                                       10

         "(c) Indebtedness assumed in connection with any Investment permitted
     pursuant to subsection 7.9(k) hereof, and refundings or refinancings
     thereof, provided that no such refunding or refinancing shall shorten the
     maturity or increase the principal amount of the original Indebtedness;"

     1.11 Subsection 7.2(d) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(d) additional Indebtedness of the Borrower and/or its Subsidiaries
     not constituting Subordinated Debt (of which up to $100,000,000 may be
     secured by Liens permitted pursuant to subsection 7.3(i) hereof) so long as
     (i) on the date such additional Indebtedness is incurred no Default or
     Event of Default shall have occurred and be continuing or would occur as a
     consequence thereof, (ii) the Consolidated Senior Debt Ratio for the
     Borrower's most recently ended four full fiscal quarters for which internal
     financial statements are available immediately preceding the date on which
     such additional Indebtedness is incurred (assuming for purposes of this
     subsection 7.2(d) only, all Commitments of all Lenders, all Facility B
     Commitments of all Facility B Lenders and all Facility C Commitments (if
     Facility C exists) of Facility C Lenders (if Facility C exists) have been
     drawn in full, but taking into account any payment or prepayment of any
     Term Loans or term loans under Facility C (if Facility C exists)) would
     have been no greater than 2.0 to 1.0, determined on a pro forma basis
     (including a pro forma application of the Net Proceeds therefrom) as if the
     additional Indebtedness had been incurred at the beginning of such
     four-quarter period and (iii) not later than two (2) Business Days after
     the incurrence of such Indebtedness the Administrative Agent shall have a
     received certificate of a Responsible Officer setting forth, in reasonable
     detail, the pro forma computation of the Consolidated Senior Debt Ratio
     required to determine compliance with this subsection 7.2(d) and certifying
     the satisfaction of the conditions in this subsection 7.2(d) to the
     incurrence of such Indebtedness;"

     1.12 Subsection 7.2(i) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(i) Indebtedness secured by Permitted Liens, and refundings or
     refinancings thereof, provided that no such refunding or refinancing shall
     shorten the maturity or increase the principal amount of the original
     Indebtedness;"

     1.13 Subsection 7.3(i) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(i) Liens (not otherwise permitted hereunder) which secure obligations
     not exceeding (as to the Borrower and all Subsidiaries) $100,000,000 in
     aggregate amount at any time outstanding;"

     1.14 Subsection 7.4(b) of the Credit Agreement is hereby amended and
restated to read as follows:

                                       11

         "(b) Guarantee Obligations of Holdings, Borrower or its Subsidiaries
     incurred after the date hereof in respect of an aggregate amount of
     obligations (together with obligations permitted to be guaranteed under
     subsection 7.4(i)) not to exceed $100,000,000 at any one time outstanding;"

     1.15 Subsection 7.4(c) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(c) Guarantee Obligations of Holdings, Borrower or any Subsidiary in
     respect of any Subordinated Debt and refundings and refinancings thereof,
     provided such Guarantee Obligations are subordinated to the Obligations on
     terms no less favorable to the Lenders, Facility B Lenders and Facility C
     Lenders (if Facility C exists) than those governing the Subordinated Debt
     and no such refunding or refinancing shortens the maturity of the original
     Indebtedness;"

     1.16 Subsection 7.4 of the Credit Agreement is hereby amended by (i)
deleting the word "and" appearing at the end of subsection (g) thereof, (ii)
deleting the period "." at the end of subsection (h) thereof and inserting ";
and" in place thereof and (iii) adding the following as subsection (i) thereto:

         "(i) Guarantee Obligations of any Subsidiary in effect at the time such
     Subsidiary was acquired through an Investment permitted pursuant to
     subsection 7.9(i) hereof in respect of an aggregate amount of obligations
     (together with obligations permitted to be guaranteed under subsection
     7.4(b)) not to exceed $100,000,000 at any one time outstanding, and
     extensions, renewals and replacements thereof; provided, however, that no
     such extension, renewal or replacement shall shorten the fixed maturity or
     increase the principal amount of the Indebtedness guaranteed by the
     original guarantee."

     1.17 Subsection 7.5 of the Credit Agreement is hereby amended by (i)
deleting the word "and" appearing at the end of subsection (a) thereof, (ii)
deleting the period "." at the end of subsection (b) thereof and inserting ";
and" in place thereof and (iii) adding the following as subsection (c) thereto:

         "(c) Borrower or any Subsidiary of Borrower may convey, sell, lease,
     assign, transfer or otherwise dispose of the Capital Stock of any
     Subsidiary or any Subsidiary may enter into any merger, consolidation or
     amalgamation or convey, sell, lease, assign, transfer or otherwise dispose
     of, all or substantially all of its property, business or assets; provided
     that the Net Proceeds thereof shall be applied pursuant to subsection
     2.6(b)(ii)."

     1.18 Subsection 7.6(j) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(j) the conveyance, sale, assignment or contribution to any new
     Subsidiary of the Borrower or any existing Subsidiary of the Borrower of
     assets of the Borrower or any Subsidiary of the Borrower provided, that if
     such Subsidiary to which the assets are conveyed, sold, assigned or
     contributed is not a party to a Subsidiary Guarantee, such assets shall not
     exceed five percent (5%) of the Consolidated Total Assets;"

                                       12

     1.19 Subsection 7.9(k) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(k) (i) Investments in the form of advances, loans or other extensions
     of credit to any Person (other than Borrower or any of its Subsidiaries)
     that is engaged in a Similar Business, so long as the aggregate outstanding
     amount of loans, advances or other extensions of credit made pursuant to
     this subsection 7.9(k) do not exceed an amount equal to five percent (5%)
     of the Consolidated Total Assets; and (ii) Investments made to acquire (A)
     all or any portion of the Capital Stock, or all or any portion of the
     assets, of any Person (other than the Borrower or any of its Subsidiaries)
     that is engaged in a Similar Business, or (B) all or substantially all of
     the assets of any division of any Person (other than the Borrower or any of
     its Subsidiaries) that is engaged in a Similar Business; provided, that (I)
     if such Investment is an acquisition of a majority of the Voting Stock of
     any Person, such Person's board of directors or similar governing body
     shall have approved such acquisition and (II) at the time of each such
     Investment described above in clauses (i) and (ii) (both before and after
     giving effect to such Investment), there shall exist no Default or Event of
     Default; provided, further, that in connection with each individual, or
     series of related, Investments made pursuant to this subsection 7.9(k)
     exceeding $50,000,000, the Borrower shall deliver to the Administrative
     Agent, no later than two (2) Business Days after the consummation of such
     Investment or Investments, a certificate of a Responsible Officer that
     certifies that no Default or Event of Default has occurred and is
     continuing or will be caused as a result of consummating such proposed
     Investment;"

     1.20 Subsection 7.11(a) of the Credit Agreement is hereby amended and
restated to read as follows:

         "(a) Enter into any transaction, including, without limitation, any
     purchase, sale, lease or exchange of property or the rendering of any
     service, with any Affiliate (other than the Borrower or any Wholly Owned
     Subsidiary which is a party to the Subsidiary Guarantee) unless such
     transaction is (i) otherwise permitted under this Agreement and (ii) upon
     fair and reasonable terms no less favorable to the Borrower or such
     Subsidiary, as the case may be, than it would obtain in a comparable arm's
     length transaction with a Person which is not an Affiliate."

         SECTION 2. Omnibus Amendment to CERTAIN CReDIT documents. Subject to
the satisfaction of each of the conditions to effectiveness set forth in Section
3 of this Amendment, the Borrower and the Requisite Class Lenders party to the
Credit Agreement hereby agree to amend the Credit Documents referenced below as
follows:

     2.1 The definition of "Permitted Parent Distributions" in Section 1.1(b) of
the Parent Guarantee is hereby amended and restated to read as follows:

         ""Permitted Parent Distributions": (a) the issuance by Holdings of
     options or other equity securities of Holdings to outside directors,
     members of management or employees of Holdings in the ordinary course of
     business, (b) cash payments made in lieu of issuing fractional shares of
     Holdings' common stock or preferred stock, (c) from and

                                       13

     after January 1, 2004, Parent Distributions funded solely with the proceeds
     of dividends received from the Borrower pursuant to clause (C) of the
     definition of Permitted Stock Payments in the Credit Agreements so long as
     at the time of declaring and paying any such Parent Distribution no Default
     or Event of Default shall have occurred and be continuing (the "Clause (C)
     Dividends"), (d) the application of up to $2,000,000 of the proceeds of the
     sale of common stock of Holdings to the repurchase of common stock of
     Holdings from management of Holdings or the Borrower, (e) from and after
     January 1, 2004, cash payments to repurchase common stock of Holdings
     solely with proceeds of (i) Clause (C) Dividends, (ii) dividends received
     from the Borrower pursuant to clause (E) of the definition of Permitted
     Stock Payments in the Credit Agreement (the "Clause (E) Dividends") and
     (iii) Net Proceeds of the issuance of Capital Stock of Holdings and/or
     Permitted Convertible Securities issued after January 1, 2004; provided,
     however, that the cash payments to repurchase common stock of Holdings
     deriving from Clause (E) Dividends, issuances of Capital Stock of Holdings
     and/or issuances of Permitted Convertible Securities shall not exceed
     $200,000,000 in the aggregate from and after January 1, 2004 and (f) from
     and after January 1, 2004, cash payments in an aggregate amount up to
     $10,000,000 in any fiscal year of the Borrower to repurchase common stock
     of Holdings held by any employee, director, officer, consultant or agent (a
     "Benefit Plan Beneficiary") of the Borrower, Holdings or their Subsidiaries
     pursuant to any restricted stock plan or to which any such Benefit Plan
     Beneficiary has a right under any option plan of the Borrower or Holdings
     (or to repurchase other common stock of Holdings held by any such Benefit
     Plan Beneficiary having a value not exceeding the amount of the exercise
     price of an option being exercised by such Benefit Plan Beneficiary and the
     amount of the obligations of such Benefit Plan Beneficiary under the Code
     with respect to the common stock underlying such option) in order to enable
     (i) the Borrower, Holdings or such Benefit Plan Beneficiary to comply with
     obligations under the Code, (ii) the Borrower or Holdings to issue cash to
     such Benefit Plan Beneficiary in lieu of fractional shares of common stock
     or (iii) the payment of the exercise price of an option held by such
     Benefit Plan Beneficiary."

     2.2 Section 4.2 of the Parent Guarantee is hereby amended by inserting
"(c)," after the reference to "Subsection 7.4(b),".

     2.3 Name Changes. The table below sets forth the new name of each
Subsidiary whose name has changed. Each of the Borrower Pledge Agreement
(including, without limitation, Schedules 1 and 2 thereto), the Subsidiary
Guarantee Agreement and the Subsidiary Pledge Agreement (including, without
limitation, Schedules 1 and 2 thereto) is hereby amended by deleting each
reference to the names listed in the "Old Name" column below in such document
and substituting therefor the corresponding name in the "New Name" column.

Old Name                             New Name

Goodrich Avionics Systems, Inc.      L-3 Communications Avionics Systems, Inc.

                                       14

Goodrich Aerospace Component         L-3 Communications Avionics

Overhaul & Repair, Inc.              Component Overhaul and Repair, Inc.

Goodrich FlightSystems, Inc.         L-3 Communications FlightSystems
                                     Corporation

Atlantic Science and Technology      L-3 Communications Atlantic Science and

Corporation                          Technology Corporation

Coleman Research Corporation         SYColeman Corporation

EER Systems, Inc.                    L-3 Communications Government
                                     Services, Inc.

Celerity Systems Incorporated        L-3 Communications CSI, Inc.

L-3 Communications AeroTech LLC      L-3 Communications Vertex Aerospace  LLC

     2.4 Dissolutions. The Borrower hereby represents and warrants to the
Administrative Agent and Lenders that:

         (a) Telos Corporation ("Telos"), formerly a party to the Subsidiary
     Guarantee Agreement and the Subsidiary Pledge Agreement, was merged into
     L-3 Communications ILEX Systems, Inc. ("L-3 ILEX") on August 8, 2003 in a
     transaction permitted under the Credit Agreements, that L-3 ILEX was the
     surviving corporation in the merger and that Telos ceased to exist as a
     result of the merger;

         (b) L-3 Communications Analytics Corporation ("L-3 Analytics"),
     formerly a party to the Subsidiary Guarantee Agreement and the Subsidiary
     Pledge Agreement, was merged into L-3 Communications Government Services,
     Inc. ("L-3 GSI") on September 26, 2003 in a transaction permitted under the
     Credit Agreements, that L-3 GSI was the surviving corporation in the merger
     and that L-3 Analytics ceased to exist as a result of the merger;

         (c) AMI Instruments, Inc., formerly a party to the Subsidiary Guarantee
     Agreement and the Subsidiary Pledge Agreement, was merged into the Borrower
     on November 21, 2003 in a transaction permitted under the Credit Agreements
     and ceased to exist as a result of the merger;

         (d) SPD Holdings, Inc., formerly a party to the Subsidiary Guarantee
     Agreement and the Subsidiary Pledge Agreement, was merged into L-3
     Communications SPD Technologies, Inc. on November 21, 2003 in a transaction
     permitted under the Credit Agreements, L-3 Communications SPD Technologies,
     Inc. was the surviving

                                       15

     corporation in the merger and SPD Holdings, Inc. ceased to exist as a
     result of the merger;

         (e) L-3 Communications SPD Technologies, Inc., formerly a party to the
     Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into the Borrower on November 21, 2003 in a transaction permitted
     under the Credit Agreements and ceased to exist as a result of the merger;

         (f) Southern California Microwave, Inc., formerly a party to the
     Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into the Borrower on November 21, 2003 in a transaction permitted
     under the Credit Agreements and ceased to exist as a result of the merger;

         (g) L-3 Communications Avionics Component Overhaul and Repair, Inc.,
     formerly a party to the Subsidiary Guarantee Agreement and the Subsidiary
     Pledge Agreement, was merged into L-3 Communications Avionics Systems, Inc.
     on November 21, 2003 in a transaction permitted under the Credit
     Agreements, L-3 Communications Avionics Systems, Inc. was the surviving
     corporation in the merger and L-3 Communications Avionics Component
     Overhaul and Repair, Inc. ceased to exist as a result of the merger;

         (h) L-3 Communications FlightSystems Corporation, formerly a party to
     the Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into L-3 Communications Avionics Systems, Inc. on November 21, 2003
     in a transaction permitted under the Credit Agreements, L-3 Communications
     Avionics Systems, Inc. was the surviving corporation in the merger and L-3
     Communications FlightSystems Corporation ceased to exist as a result of the
     merger;

         (i) L-3 Communications IMC Corporation, formerly a party to the
     Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into L-3 Communications Government Services, Inc. on December 31,
     2003 in a transaction permitted under the Credit Agreements, L-3
     Communications Government Services, Inc. was the surviving corporation in
     the merger and L-3 Communications IMC Corporation ceased to exist as a
     result of the merger;

         (j) L-3 Communications TMA Corporation, formerly a party to the
     Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into L-3 Communications Government Services, Inc. on December 31,
     2003 in a transaction permitted under the Credit Agreements, L-3
     Communications Government Services, Inc. was the surviving corporation in
     the merger and L-3 Communications TMA Corporation ceased to exist as a
     result of the merger;

         (k) L-3 Communications Atlantic Science and Technology Corporation,
     formerly a party to the Subsidiary Guarantee Agreement and the Subsidiary
     Pledge Agreement, was merged into L-3 Communications ILEX Systems, Inc. on
     December 31, 2003 in a transaction permitted under the Credit Agreements,
     L-3 Communications ILEX Systems, Inc. was the surviving corporation in the
     merger and L-3 Communications

                                       16

     Atlantic Science and Technology Corporation ceased to exist as a result of
     the merger; and

         (l) L-3 Communications DBS Microwave, Inc., formerly a party to the
     Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement, was
     merged into the Borrower on April 27, 2002 in a transaction permitted under
     the Credit Agreements and ceased to exist as a result of the merger.

     The parties to this Amendment accordingly agree that each reference in the
Borrower Pledge Agreement (including, without limitation, Schedules 1 and 2
thereto), the Subsidiary Guarantee Agreement and the Subsidiary Pledge Agreement
(including, without limitation, Schedules 1 and 2 thereto) to Telos Corporation,
L-3 Communications Analytics Corporation, AMI Instruments, Inc., SPD Holdings,
Inc., L-3 Communications SPD Technologies, Inc., Southern California Microwave,
Inc., L-3 Communications Avionics Component Overhaul and Repair, Inc., L-3
Communications FlightSystems Corporation, L-3 Communications IMC Corporation,
L-3 Communications TMA Corporation, L-3 Communications Atlantic Science and
Technology Corporation and L-3 Communications DBS Microwave, Inc. is hereby
deleted.

     2.5 Schedules. To more fully reflect the foregoing amendments described in
Sections 2.3 and 2.4 of this Amendment, Schedule 1 to the Borrower Pledge
Agreement is hereby amended and restated to read as provided on Schedule B-1
attached hereto and Schedules 1 and 2 to the Subsidiary Pledge Agreement are
hereby amended and restated to read as provided on Schedules S-1 and S-2
attached hereto.

         SECTION 3. CONDITIONS TO EFFECTIVENESS OF SECTIONS 1 AND 2. The
provisions of Sections 1 and 2 of this Amendment shall be deemed effective as of
the date when each of the following conditions have been satisfied (such
effective date occurring upon satisfaction of such conditions being referred to
herein as the "AMENDMENT EFFECTIVE DATE"):

     3.1 The Borrower shall have delivered to Administrative Agent executed
copies of this Amendment and each of the other Credit Parties shall have
delivered to the Administrative Agent executed copies of the Guarantors' Consent
and Acknowledgment to this Amendment in the form attached hereto;

     3.2 The Requisite Class Lenders party to the Credit Agreement shall have
delivered to the Administrative Agent an executed original or facsimile
counterpart of its signature page to this Amendment;

     3.3 The Administrative Agent shall have received a secretary's or assistant
secretary's certificate of the Borrower certifying board resolutions authorizing
the execution, delivery and performance of this Amendment by the Borrower;

     3.4 The representations and warranties contained in Section 4 hereof shall
be true and correct in all respects; and

                                       17

     3.5 All conditions to effectiveness set forth in Sections 5.1, 5.2, 5.3,
and 5.4 in the Consent, Waiver and Third Omnibus Amendment Regarding Second
Amended and Restated 364 Day Credit Agreement of even date herewith shall have
been satisfied.

         SECTION 4. REPRESENTATIONS AND WARRANTIES. In order to induce Lenders
to enter into this Amendment, the Borrower represents and warrants to each
Lender that the following statements are true, correct and complete:

     4.1 Authorization and Enforceability. (a) The Borrower has all requisite
corporate power and authority to enter into this Amendment and to carry out the
transactions contemplated by, and perform its obligations under, the Credit
Agreement as modified by this Amendment (the "AGREEMENT"), (b) the execution and
delivery of this Amendment has been duly authorized by all necessary corporate
action on the part of the Borrower and (c) this Amendment and the Agreement have
been duly executed and delivered by the Borrower and, when executed and
delivered, will be the legally valid and binding obligations of the Borrower,
enforceable against the Borrower in accordance with their respective terms,
subject to (i) the effects of bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium or similar laws relating to or limiting creditors'
rights generally, (ii) general equitable principles (whether considered in a
proceeding, in equity or at law) and (iii) an implied covenant of good faith and
fair dealing.

     4.2 Incorporation of Representations and Warranties From Credit Agreement.
The representations and warranties contained in Section 4 of the Credit
Agreement, after giving effect to the amendments contained in Sections 1 and 2
of this Amendment, are and will be true, correct and complete in all material
respects on and as of each of the Amendment Effective Date, to the same extent
as though made on and as of such date, except to the extent such representations
and warranties specifically relate to an earlier date, in which case they were
true, correct and complete in all material respects on and as of such earlier
date.

     4.3 Absence of Default and Setoff. No event has occurred and is continuing
or will result from the consummation of the transactions contemplated by this
Amendment that constitutes a Default or an Event of Default and no defense,
setoff or counterclaim of any kind, nature or description exists to the payment
and performance of the obligations owing by the Borrower to the Agents and the
Lenders.

         SECTION 5. MISCELLANEOUS.

     5.1 Effect on the Credit Agreement and the other Credit Documents. Except
as specifically provided in this Amendment, the Credit Agreement and the other
Credit Documents shall remain in full force and effect and are hereby ratified
and confirmed. The execution, delivery and performance of this Amendment shall
not, except as expressly provided herein, constitute a waiver of any provision
of, or operate as a waiver of any right, power or remedy of the Administrative
Agent or any Lender under, the Credit Agreement or any of the other Credit
Documents.

     5.2 Fees and Expenses. The Borrower acknowledges that all costs, fees and
expenses as described in Section 10.5 of the Credit Agreement incurred by
Administrative Agent and its

                                       18

counsel with respect to this Amendment and the documents and transactions
contemplated hereby shall be for the account of the Borrower.

     5.3 GOVERNING LAW. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN
ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

     5.4 SUBMISSION TO JURISDICTION; WAIVERS; WAIVER OF JURY TRIAL;
ACKNOWLEDGMENTS; CONFIDENTIALITY. Each of the terms and conditions set forth in
Sections 10.12, 10.13, 10.14 and 10.15 of the Credit Agreement are hereby
incorporated into this Amendment as if set forth fully herein except that each
reference to "Agreement" therein shall be deemed to be a reference to
"Amendment" herein.

     5.5 Counterparts; Effectiveness. This Amendment may be executed in any
number of counterparts and by different parties hereto in separate counterparts,
each of which when so executed and delivered shall be deemed an original, but
all such counterparts together shall constitute but one and the same instrument.
Except for the terms of Sections 1 and 2 hereof (which shall only become
effective on the Amendment Effective Date), this Amendment shall become
effective upon the execution of a counterpart hereof by the Borrower and the
Required Lenders and receipt by the Borrower and the Administrative Agent of
written or telephonic notification of such execution and authorization of
delivery thereof.

     5.6 Amendment Fee. Subject to the occurrence of the Amendment Effective
Date, the Borrower hereby agrees to pay to each Lender submitting to the
Administrative Agent an executed counterpart to this Amendment on or before
February 19, 2004 (each such Lender, a "CONSENTING LENDER") a non-refundable fee
(the "AMENDMENT FEE") in the amount set forth in the Third Omnibus Amendment Fee
Letter regarding this Amendment, which Amendment Fee will be based and payable
on that portion of such Consenting Lender's Commitment. The Amendment Fee owing
to each Consenting Lender shall be paid in immediately available funds by the
Borrower to the Administrative Agent for the benefit of such Consenting Lenders
not later than noon (New York time) on the first Business Day following the
occurrence of the Amendment Effective Date.

                            [SIGNATURE PAGES FOLLOW]

                                       19

         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered by their proper and duly authorized officers as of
the day and year first above written.

                                        L-3 COMMUNICATIONS CORPORATION

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

                                        BANK OF AMERICA, N.A., as Administrative
                                          Agent and as a Lender

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

                                        LEHMAN COMMERCIAL PAPER INC., as
                                          Documentation Agent and Syndication
                                          Agent

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

           [SIGNATURE PAGES TO SECOND OMNIBUS AMENDMENT REGARDING THE
                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                     Guarantors' Acknowledgment and Consent

         Each of the undersigned hereby acknowledges receipt of the attached
Amendment and consents to the execution and performance thereof by L-3
Communications Corporation. Each of the undersigned hereby also reaffirms that
the guarantee and any applicable Pledge Agreement of such undersigned in favor
of the Administrative Agent for the ratable benefit of the Lenders and the
Agents remains in full force and effect and acknowledges and agrees that there
is no defense, setoff or counterclaim of any kind, nature or description to
obligations arising under such guarantee or any applicable Pledge Agreement

Dated as of February 24, 2004

                                        L-3 COMMUNICATIONS HOLDINGS, INC.

                                        By:
                                           -----------------------------------
                                        Name: Christopher C. Cambria
                                        Title: Vice President, General Counsel
                                               and Secretary

                                        L-3 COMMUNICATIONS INTEGRATED SYSTEMS
                                        L.P.

                                           By: L-3 COMMUNICATIONS AIS GP
                                           CORPORATION, as General Partner

                                           By:
                                              --------------------------------
                                           Name:  Christopher C. Cambria
                                           Title:  Vice President and Secretary

                                        L-3 COMMUNICATIONS VERTEX AEROSPACE LLC
                                        L-3 COMMUNICATIONS FLIGHT INTERNATIONAL
                                             AVIATION LLC
                                        L-3 COMMUNICATIONS FLIGHT CAPITAL LLC
                                        L-3 COMMUNICATIONS VECTOR INTERNATIONAL
                                             AVIATION LLC
                                        WESCAM LLC
                                        WESCAM AIR OPS LLC

                                        By:
                                           -----------------------------------
                                           Name: Christopher C. Cambria
                                           Title: Authorized Person

           [SIGNATURE PAGES TO GUARANTORS' ACKNOWLEDGMENT AND CONSENT
                 TO THIRD OMNIBUS AMENDMENT REGARDING THE THIRD
                     AMENDED AND RESTATED CREDIT AGREEMENT]

                              APCOM, INC.
                              BROADCAST SPORTS INC.
                              ELECTRODYNAMICS, INC.
                              HENSCHEL, INC.
                              HYGIENETICS ENVIRONMENTAL SERVICES, INC.
                              INTERSTATE ELECTRONICS CORPORATION
                              KDI PRECISION PRODUCTS, INC.
                              L-3 COMMUNICATIONS AEROMET, INC.
                              L-3 COMMUNICATIONS AIS GP CORPORATION
                              L-3 COMMUNICATIONS AVIONICS SYSTEMS, INC.
                              L-3 COMMUNICATIONS AYDIN CORPORATION
                              L-3 COMMUNICATIONS CSI, INC.
                              L-3 COMMUNICATIONS ESSCO, INC.
                              L-3 COMMUNICATIONS GOVERNMENT SERVICES, INC.
                              L-3 COMMUNICATIONS ILEX SYSTEMS, INC.
                              L-3 COMMUNICATIONS INVESTMENTS INC.
                              L-3 COMMUNICATIONS KLEIN ASSOCIATES, INC.
                              L-3 COMMUNICATIONS MAS (US) CORPORATION
                              L-3 COMMUNICATIONS SECURITY AND DETECTION SYSTEMS
                                   CORPORATION CALIFORNIA
                              L-3 COMMUNICATIONS SECURITY AND DETECTION SYSTEMS
                                   CORPORATION DELAWARE
                              L-3 COMMUNICATIONS SECURITY SYSTEMS CORPORATION
                              L-3 COMMUNICATIONS STORM CONTROL SYSTEMS, INC.
                              L-3 COMMUNICATIONS WESTWOOD CORPORATION
                                   MCTI ACQUISITION CORPORATION
                              MICRODYNE COMMUNICATIONS TECHNOLOGIES INCORPORATED
                              MICRODYNE CORPORATION
                              MICRODYNE OUTSOURCING INCORPORATED
                              MPRI, INC.
                              PAC ORD, INC.
                              POWER PARAGON, INC.
                              SHIP ANALYTICS, INC.
                              SHIP ANALYTICS INTERNATIONAL, INC.
                              SHIP ANALYTICS USA, INC.
                              SPD ELECTRICAL SYSTEMS, INC.
                              SPD SWITCHGEAR, INC.
                              SYCOLEMAN CORPORATION
                              TROLL TECHNOLOGY CORPORATION
                              WESCAM SONOMA INC.
                              WESCAM AIR OPS INC.
                              WESCAM INCORPORATED
                              WESCAM HOLDINGS (US) INC.
                              WOLF COACH, INC.

                              By:
                                  -------------------------------------------
                                   Name:  Christopher C. Cambria
                                   Title:  Vice President and Secretary

           [SIGNATURE PAGES TO GUARANTORS' ACKNOWLEDGMENT AND CONSENT
                 TO THIRD OMNIBUS AMENDMENT REGARDING THE THIRD
                     AMENDED AND RESTATED CREDIT AGREEMENT]

                                        THE BANK OF NEW YORK

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

            [SIGNATURE PAGES TO THIRD OMNIBUS AMENDMENT REGARDING THE
                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                        BANK ONE, N.A. (Main Office Chicago)

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

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                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                        FLEET NATIONAL BANK

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

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                                        CREDIT LYONNAIS NEW YORK BRANCH

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

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                                        WACHOVIA BANK NATIONAL ASSOCIATION
                                        (f/k/a First Union Commercial
                                        Corporation)

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

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                                        HSBC BANK USA

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

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                                        THE GOVERNOR AND COMPANY OF THE BANK OF
                                        IRELAND

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

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

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                                        COMERICA BANK

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                                           Title:

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                                        CREDIT INDUSTRIEL ET COMMERCIAL

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                                           Title:

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                                        BARCLAYS BANK PLC

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                                           Title:

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                                        RZB FINANCE LLC

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                                           ------------------------------------
                                           Title:

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                                        ERSTE BANK, NEW YORK

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

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                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                        THE MITSUBISHI TRUST AND BANKING
                                        CORPORATION

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

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                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                        SOCIETE GENERALE

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                                           Title:

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                                        SUNTRUST BANK

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                                           Title:

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                                        WEBSTER BANK

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                                           ------------------------------------
                                           Title:

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                                        THE BANK OF NOVA SCOTIA

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                                           Title:

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                                        CREDIT SUISSE FIRST BOSTON

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                                        GENERAL ELECTRIC CAPITAL CORPORATION

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                                           Title:

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                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                        MIZUHO CORPORATE BANK, LTD. (successor
                                        to The Fuji Bank, Limited, The Dai-Ichi
                                        Kanho Bank, Ltd. and The Industrial Bank
                                        of Japan, Limited)

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

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                                        FORTIS CAPITAL CORP.

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                                        FORTIS CAPITAL CORP.

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                                        BANK OF TOKYO-MITSUBISHI TRUST COMPANY

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                                        CHIAO TUNG BANK CO., LTD. NEW YORK
                                        AGENCY

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

            [SIGNATURE PAGES TO THIRD OMNIBUS AMENDMENT REGARDING THE
                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

                                 SCHEDULE B-1*

         [SEE ATTACHED AMENDED SCHEDULE 1 TO BORROWER PLEDGE AGREEMENT]

-----------------------
* BORROWER TO PROVIDE NEW SCHEDULE

                                 SCHED. B-1 - 1

                                  SCHEDULE S-1

       [SEE ATTACHED AMENDED SCHEDULE 1 TO SUBSIDIARY PLEDGE AGREEMENT]*

-----------------------
* BORROWER TO PROVIDE NEW SCHEDULE

                                 SCHED. S-1 - 1

                                  SCHEDULE S-2

       [SEE ATTACHED AMENDED SCHEDULE 2 TO SUBSIDIARY PLEDGE AGREEMENT]*

-----------------------
* BORROWER TO PROVIDE NEW SCHEDULE

                                 SCHED. S-2 - 1EXHIBIT 10.55

                     SUPPLEMENTAL INDENTURE TO BE DELIVERED
                          BY GUARANTEEING SUBSIDIARIES

     Supplemental Indenture (this "Supplemental Indenture"), dated as of
February 25, 2004, among L-3 Communications Corporation (or its permitted
successor), a Delaware corporation (the "Company"), each a direct or indirect
subsidiary of the Company signatory hereto (each, a "Guaranteeing Subsidiary",
and collectively, the "Guaranteeing Subsidiaries"), and The Bank of New York, as
trustee under the indenture referred to below (the "Trustee").

                               W I T N E S S E T H
                               - - - - - - - - - -

     WHEREAS, the Company has heretofore executed and delivered to the Trustee
an indenture (the "Indenture"), dated as of May 21, 2003 providing for the
issuance of an unlimited amount of 6 1/8% Senior Subordinated Notes due 2013
(the "Notes");

     WHEREAS, the Indenture provides that under certain circumstances the
Guaranteeing Subsidiaries shall execute and deliver to the Trustee a
supplemental indenture pursuant to which the Guaranteeing Subsidiaries shall
unconditionally guarantee all of the Company's Obligations (as defined in the
Indenture) under the Notes and the Indenture on the terms and conditions set
forth herein (the "Subsidiary Guarantee"); and

     WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

     NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guaranteeing Subsidiaries and the Trustee mutually covenant and agree for the
equal and ratable benefit of the Holders of the Notes as follows:

     1. CAPITALIZED TERMS. Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

     2. AGREEMENT TO GUARANTEE. Each Guaranteeing Subsidiary hereby agrees as
follows:

         (a)   Such Guaranteeing Subsidiary, jointly and severally with all
               other current and future guarantors of the Notes (collectively,
               the "Guarantors" and each, a "Guarantor"), unconditionally
               guarantees to each Holder of a Note authenticated and delivered
               by the Trustee and to the Trustee and its successors and assigns,
               regardless of the validity and enforceability of the Indenture,
               the Notes or the Obligations of the Company under the Indenture
               or the Notes, that:

               (i)  the principal of, premium, interest and Additional Amounts,
                    if any, on the Notes will be promptly paid in full when due,
                    whether at maturity, by acceleration, redemption

                                        1

                    or otherwise, and interest on the overdue principal of,
                    premium, interest and Additional Amounts, if any, on the
                    Notes, to the extent lawful, and all other Obligations of
                    the Company to the Holders or the Trustee thereunder or
                    under the Indenture will be promptly paid in full, all in
                    accordance with the terms thereof; and

               (ii) in case of any extension of time for payment or renewal of
                    any Notes or any of such other Obligations, that the same
                    will be promptly paid in full when due in accordance with
                    the terms of the extension or renewal, whether at stated
                    maturity, by acceleration or otherwise.

         (b)   Notwithstanding the foregoing, in the event that this Subsidiary
               Guarantee would constitute or result in a violation of any
               applicable fraudulent conveyance or similar law of any relevant
               jurisdiction, the liability of such Guaranteeing Subsidiary under
               this Supplemental Indenture and its Subsidiary Guarantee shall be
               reduced to the maximum amount permissible under such fraudulent
               conveyance or similar law.

     3. EXECUTION AND DELIVERY OF SUBSIDIARY GUARANTEES.

         (a)   To evidence its Subsidiary Guarantee set forth in this
               Supplemental Indenture, such Guaranteeing Subsidiary hereby
               agrees that a notation of such Subsidiary Guarantee substantially
               in the form of Exhibit F to the Indenture shall be endorsed by an
               officer of such Guaranteeing Subsidiary on each Note
               authenticated and delivered by the Trustee after the date hereof.

         (b)   Notwithstanding the foregoing, such Guaranteeing Subsidiary
               hereby agrees that its Subsidiary Guarantee set forth herein
               shall remain in full force and effect notwithstanding any failure
               to endorse on each Note a notation of such Subsidiary Guarantee.

         (c)   If an Officer whose signature is on this Supplemental Indenture
               or on the Subsidiary Guarantee no longer holds that office at the
               time the Trustee authenticates the Note on which a Subsidiary
               Guarantee is endorsed, the Subsidiary Guarantee shall be valid
               nevertheless.

         (d)   The delivery of any Note by the Trustee, after the authentication
               thereof under the Indenture, shall constitute due delivery of the
               Subsidiary Guarantee set forth in this Supplemental Indenture on
               behalf of each Guaranteeing Subsidiary.

         (e)   Each Guaranteeing Subsidiary hereby agrees that its Obligations
               hereunder shall be unconditional, regardless of the validity,
               regularity or enforceability of the Notes or the Indenture, the

                                       2

               absence of any action to enforce the same, any waiver or consent
               by any Holder of the Notes with respect to any provisions hereof
               or thereof, the recovery of any judgment against the Company, any
               action to enforce the same or any other circumstance which might
               otherwise constitute a legal or equitable discharge or defense of
               a guarantor.

         (f)   Each Guaranteeing Subsidiary hereby waives diligence,
               presentment, demand of payment, filing of claims with a court in
               the event of insolvency or bankruptcy of the Company, any right
               to require a proceeding first against the Company, protest,
               notice and all demands whatsoever and covenants that its
               Subsidiary Guarantee made pursuant to this Supplemental Indenture
               will not be discharged except by complete performance of the
               Obligations contained in the Notes and the Indenture.

         (g)   If any Holder or the Trustee is required by any court or
               otherwise to return to the Company or any Guaranteeing
               Subsidiary, or any custodian, Trustee, liquidator or other
               similar official acting in relation to either the Company or such
               Guaranteeing Subsidiary, any amount paid by either to the Trustee
               or such Holder, the Subsidiary Guarantee made pursuant to this
               Supplemental Indenture, to the extent theretofore discharged,
               shall be reinstated in full force and effect.

         (h)   Each Guaranteeing Subsidiary agrees that it shall not be entitled
               to any right of subrogation in relation to the Holders in respect
               of any Obligations guaranteed hereby until payment in full of all
               Obligations guaranteed hereby. Each Guaranteeing Subsidiary
               further agrees that, as between such Guaranteeing Subsidiary, on
               the one hand, and the Holders and the Trustee, on the other hand:

               (i)  the maturity of the Obligations guaranteed hereby may be
                    accelerated as provided in Article 6 of the Indenture for
                    the purposes of the Subsidiary Guarantee made pursuant to
                    this Supplemental Indenture, notwithstanding any stay,
                    injunction or other prohibition preventing such acceleration
                    in respect of the Obligations guaranteed hereby; and

               (ii) in the event of any declaration of acceleration of such
                    Obligations as provided in Article 6 of the Indenture, such
                    Obligations (whether or not due and payable) shall forthwith
                    become due and payable by such Guaranteeing Subsidiary for
                    the purpose of the Subsidiary Guarantee made pursuant to
                    this Supplemental Indenture.

         (i)   Each Guaranteeing Subsidiary shall have the right to seek
               contribution from any other non-paying Guaranteeing Subsidiary so
               long as the exercise of such right does not impair the rights of

                                       3

               the Holders or the Trustee under the Subsidiary Guarantee made
               pursuant to this Supplemental Indenture.

     4. GUARANTEEING SUBSIDIARY MAY CONSOLIDATE, ETC. ON CERTAIN TERMS.

         (a)   Except as set forth in Articles 4 and 5 of the Indenture, nothing
               contained in the Indenture, this Supplemental Indenture or in the
               Notes shall prevent any consolidation or merger of any
               Guaranteeing Subsidiary with or into the Company or any other
               Guarantor or shall prevent any transfer, sale or conveyance of
               the property of any Guaranteeing Subsidiary as an entirety or
               substantially as an entirety, to the Company or any other
               Guarantor.

         (b)   Except as set forth in Article 4 and 5 of the Indenture, nothing
               contained in the Indenture, this Supplemental Indenture or in the
               Notes shall prevent any consolidation or merger of any
               Guaranteeing Subsidiary with or into a corporation or
               corporations other than the Company or any other Guarantor (in
               each case, whether or not affiliated with the Guaranteeing
               Subsidiary), or successive consolidations or mergers in which a
               Guaranteeing Subsidiary or its successor or successors shall be a
               party or parties, or shall prevent any sale or conveyance of the
               property of any Guaranteeing Subsidiary as an entirety or
               substantially as an entirety, to a corporation other than the
               Company or any other Guarantor (in each case, whether or not
               affiliated with the Guaranteeing Subsidiary) authorized to
               acquire and operate the same; provided, however, that each
               Guaranteeing Subsidiary hereby covenants and agrees that (i)
               subject to the Indenture, upon any such consolidation, merger,
               sale or conveyance, the due and punctual performance and
               observance of all of the covenants and conditions of the
               Indenture and this Supplemental Indenture to be performed by such
               Guaranteeing Subsidiaries, shall be expressly assumed (in the
               event that such Guaranteeing Subsidiary is not the surviving
               corporation in the merger), by supplemental indenture
               satisfactory in form to the Trustee, executed and delivered to
               the Trustee, by the corporation formed by such consolidation, or
               into which such Guaranteeing Subsidiary shall have been merged,
               or by the corporation which shall have acquired such property and
               (ii) immediately after giving effect to such consolidation,
               merger, sale or conveyance no Default or Event of Default exists.

         (c)   In case of any such consolidation, merger, sale or conveyance and
               upon the assumption by the successor corporation, by supplemental
               indenture, executed and delivered to the Trustee and satisfactory
               in form to the Trustee, of the Subsidiary Guarantee made pursuant
               to this Supplemental Indenture and the due and

                                       4

               punctual performance of all of the covenants and conditions of
               the Indenture and this Supplemental Indenture to be performed by
               such Guaranteeing Subsidiary, such successor corporation shall
               succeed to and be substituted for such Guaranteeing Subsidiary
               with the same effect as if it had been named herein as the
               Guaranteeing Subsidiary. Such successor corporation thereupon may
               cause to be signed any or all of the Subsidiary Guarantees to be
               endorsed upon the Notes issuable under the Indenture which
               theretofore shall not have been signed by the Company and
               delivered to the Trustee. All the Subsidiary Guarantees so issued
               shall in all respects have the same legal rank and benefit under
               the Indenture and this Supplemental Indenture as the Subsidiary
               Guarantees theretofore and thereafter issued in accordance with
               the terms of the Indenture and this Supplemental Indenture as
               though all of such Subsidiary Guarantees had been issued at the
               date of the execution hereof.

     5. RELEASES.

         (a)   Concurrently with any sale of assets (including, if applicable,
               all of the Capital Stock of a Guaranteeing Subsidiary), all
               Liens, if any, in favor of the Trustee in the assets sold thereby
               shall be released; provided that in the event of an Asset Sale,
               the Net Proceeds from such sale or other disposition are treated
               in accordance with the provisions of Section 4.10 of the
               Indenture. If the assets sold in such sale or other disposition
               include all or substantially all of the assets of a Guaranteeing
               Subsidiary or all of the Capital Stock of a Guaranteeing
               Subsidiary, then the Guaranteeing Subsidiary (in the event of a
               sale or other disposition of all of the Capital Stock of such
               Guaranteeing Subsidiary) or the Person acquiring the property (in
               the event of a sale or other disposition of all or substantially
               all of the assets of such Guaranteeing Subsidiary) shall be
               released from and relieved of its Obligations under this
               Supplemental Indenture and its Subsidiary Guarantee made pursuant
               hereto; provided that in the event of an Asset Sale, the Net
               Proceeds from such sale or other disposition are treated in
               accordance with the provisions of Section 4.10 of the Indenture.
               Upon delivery by the Company to the Trustee of an Officers'
               Certificate to the effect that such sale or other disposition was
               made by the Company or the Guaranteeing Subsidiary, as the case
               may be, in accordance with the provisions of the Indenture and
               this Supplemental Indenture, including without limitation,
               Section 4.10 of the Indenture, the Trustee shall execute any
               documents reasonably required in order to evidence the release of
               the Guaranteeing Subsidiary from its Obligations under this
               Supplemental Indenture and its Subsidiary Guarantee made pursuant
               hereto. If the Guaranteeing Subsidiary is not released from its
               obligations under its Subsidiary Guarantee, it shall remain
               liable for the full amount

                                       5

               of principal of and interest on the Notes and for the other
               obligations of such Guaranteeing Subsidiary under the Indenture
               as provided in this Supplemental Indenture.

         (b)   Upon the designation of a Guaranteeing Subsidiary as an
               Unrestricted Subsidiary in accordance with the terms of the
               Indenture, such Guaranteeing Subsidiary shall be released and
               relieved of its Obligations under its Subsidiary Guarantee and
               this Supplemental Indenture. Upon delivery by the Company to the
               Trustee of an Officers' Certificate and an Opinion of Counsel to
               the effect that such designation of such Guaranteeing Subsidiary
               as an Unrestricted Subsidiary was made by the Company in
               accordance with the provisions of the Indenture, including
               without limitation Section 4.07 of the Indenture, the Trustee
               shall execute any documents reasonably required in order to
               evidence the release of such Guaranteeing Subsidiary from its
               Obligations under its Subsidiary Guarantee. Any Guaranteeing
               Subsidiary not released from its Obligations under its Subsidiary
               Guarantee shall remain liable for the full amount of principal of
               and interest on the Notes and for the other Obligations of any
               Guaranteeing Subsidiary under the Indenture as provided herein.

         (c)   Each Guaranteeing Subsidiary shall be released and relieved of
               its obligations under this Supplemental Indenture in accordance
               with, and subject to, Section 4.18 of the Indenture.

     6. NO RECOURSE AGAINST OTHERS. No past, present or future director,
officer, employee, incorporator, stockholder or agent of any Guaranteeing
Subsidiary, as such, shall have any liability for any Obligations of the Company
or any Guaranteeing Subsidiary under the Notes, any Subsidiary Guarantees, the
Indenture or this Supplemental Indenture or for any claim based on, in respect
of, or by reason of, such Obligations or their creation. Each Holder of the
Notes by accepting a Note waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Notes. Such waiver may
not be effective to waive liabilities under the federal securities laws and it
is the view of the SEC that such a waiver is against public policy.

     7. SUBORDINATION OF SUBSIDIARY GUARANTEES; ANTI-LAYERING. No Guaranteeing
Subsidiary shall incur, create, issue, assume, guarantee or otherwise become
liable for any Indebtedness that is subordinate or junior in right of payment to
any Senior Debt of a Guaranteeing Subsidiary and senior in any respect in right
of payment to any of the Subsidiary Guarantees. Notwithstanding the foregoing
sentence, the Subsidiary Guarantee of each Guaranteeing Subsidiary shall be
subordinated to the prior payment in full of all Senior Debt of that
Guaranteeing Subsidiary (in the same manner and to the same extent that the
Notes are subordinated to Senior Debt), which shall include all guarantees of
Senior Debt.

     8. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                                       6

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

     10. EFFECT OF HEADINGS. The Section headings herein are for convenience
only and shall not affect the construction hereof.

     11. THE TRUSTEE. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the Guaranteeing Subsidiaries and the Company.

                                       7

     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed, all as of the date first above written.

Dated: February 25, 2004               L-3 COMMUNICATIONS CORPORATION

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

Dated: February 25, 2004    APCOM, INC., a Maryland corporation
                            BROADCAST SPORTS INC., a Delaware corporation
                            ELECTRODYNAMICS, INC., an Arizona corporation
                            HENSCHEL INC., a Delaware corporation
                            HYGIENETICS ENVIRONMENTAL SERVICES, INC., a
                              Delaware corporation
                            INTERSTATE ELECTRONICS CORPORATION, a
                              California corporation
                            KDI PRECISION PRODUCTS, INC., a Delaware corporation
                            L-3 COMMUNICATIONS AEROMET, INC., an Oregon
                              corporation
                            L-3 COMMUNICATIONS VERTEX AEROSPACE LLC, a Delaware
                              limited liability company
                            L-3 COMMUNICATIONS AIS GP CORPORATION, a Delaware
                              corporation
                            L-3 COMMUNICATIONS AVIONICS SYSTEMS, INC., a
                              Delaware corporation
                            L-3 COMMUNICATIONS AYDIN CORPORATION, a Delaware
                              corporation
                            L-3 COMMUNICATIONS CSI, INC., a California
                              corporation
                            L-3 COMMUNICATIONS ESSCO, INC., a Delaware
                              corporation
                            L-3 COMMUNICATIONS FLIGHT INTERNATIONAL AVIATION
                              LLC, a Delaware limited liability company
                            L-3 COMMUNICATIONS FLIGHT CAPITAL LLC, a Delaware
                              limited liability company
                            L-3 COMMUNICATIONS GOVERNMENT SERVICES, INC., a
                              Virginia corporation
                            L-3 COMMUNICATIONS ILEX SYSTEMS, INC., a Delaware
                              corporation
                            L-3 COMMUNICATIONS INTEGRATED SYSTEMS L.P., a
                              Delaware limited partnership
                            L-3 COMMUNICATIONS INVESTMENTS INC., a Delaware
                              corporation
                            L-3 COMMUNICATIONS KLEIN ASSOCIATES, INC., a
                              Delaware corporation
                            L-3 COMMUNICATIONS MAS (US) CORPORATION, a Delaware
                              corporation
                            L-3 COMMUNICATIONS SECURITY AND DETECTION SYSTEMS
                              CORPORATION CALIFORNIA, a California corporation
                            L-3 COMMUNICATIONS SECURITY AND DETECTION SYSTEMS
                              CORPORATION DELAWARE, a Delaware corporation
                            L-3 COMMUNICATIONS SECURITY SYSTEMS CORPORATION, a
                              Delaware corporation
                            L-3 COMMUNICATIONS STORM CONTROL SYSTEMS, INC., a
                              California corporation

                            L-3 COMMUNICATIONS VECTOR INTERNATIONAL AVIATION
                              LLC, a Delaware limited liability company
                            L-3 COMMUNICATIONS WESTWOOD CORPORATION, a Nevada
                              corporation
                            MCTI ACQUISITION CORPORATION, a Maryland
                              corporation
                            MICRODYNE COMMUNICATIONS TECHNOLOGIES INCORPORATED,
                              a Maryland corporation
                            MICRODYNE CORPORATION, a Maryland corporation
                            MICRODYNE OUTSOURCING INCORPORATED, a Maryland
                              corporation
                            MPRI, INC., a Delaware corporation
                            PAC ORD INC., a Delaware corporation
                            POWER PARAGON, INC., a Delaware corporation
                            SHIP ANALYTICS, INC., a Connecticut corporation
                            SHIP ANALYTICS INTERNATIONAL, INC., a Delaware
                              corporation
                            SHIP ANALYTICS USA, INC., a Connecticut corporation
                            SPD ELECTRICAL SYSTEMS, INC., a Delaware corporation
                            SPD SWITCHGEAR INC., a Delaware corporation
                            SYCOLEMAN CORPORATION, a Florida corporation
                            TROLL TECHNOLOGY CORPORATION, a California
                              corporation
                            WESCAM AIR OPS INC., a Delaware corporation
                            WESCAM AIR OPS LLC, a Delaware limited liability
                              company
                            WESCAM HOLDINGS (US) INC., a Delaware corporation
                            WESCAM INCORPORATED, a Florida corporation
                            WESCAM LLC, a Delaware limited liability company
                            WESCAM SONOMA INC., a California corporation
                            WOLF COACH, INC., a Massachusetts corporation
                                                 As Guaranteeing Subsidiaries

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

Dated:  February 25, 2004              THE BANK OF NEW YORK,
                                       as Trustee

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

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00061-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00061-of-00352.parquet"}]]