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                         L-3 COMMUNICATIONS CORPORATION

                                 FIRST AMENDMENT
                 TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT


         This FIRST AMENDMENT TO THE THIRD AMENDED AND RESTATED CREDIT AGREEMENT
(this "AMENDMENT") is dated as of October 17, 2001 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") and certain financial institutions named as co-agents,
LEHMAN COMMERCIAL PAPER, INC. ("LCPI") as syndication agent and documentation
agent (in such capacity, the "SYNDICATION AGENT" and the "DOCUMENTATION AGENT").
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 desires that the Lenders consent to an amendment
of certain provisions of the Credit Agreement and related Credit Documents to,
inter alia, (i) allow Holdings to issue certain convertible debt securities and
(ii) make certain related amendments;

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

SECTION 1. AMENDMENTS. Subject to the satisfaction of each of the conditions to
effectiveness set forth in Section 2 of this Amendment, the Borrower and the
Required Lenders hereby agree to amend the Credit Agreement as follows:

     1.1 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 Borrower and its Subsidiaries and, without
     duplication, the Acquired Businesses (excluding, without duplication, (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)



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     Consolidated Interest Expense of 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 Borrower
     and its Subsidiaries and, without duplication, the Acquired Businesses, the
     sum of income taxes, depreciation and amortization for such period.

         "Consolidated Cash Interest Expense": as of the last day of any fiscal
     quarter, the amount of interest expense, payable in cash, of Borrower and
     its Subsidiaries and the amount of interest expense, payable in cash, of
     Holdings with respect to the Permitted Convertible Securities guaranteed by
     the Borrower or its Subsidiaries, for the four fiscal quarters ended on
     such date, determined on a consolidated basis in accordance with GAAP for
     such period.

         "Consolidated Total Debt": at any date, the sum of (i) all Indebtedness
     of the Borrower and its Subsidiaries outstanding on such date for borrowed
     money or the deferred purchase price of property, including, without
     limitation, in respect of Financing Leases but excluding Indebtedness
     permitted pursuant to subsection 7.2(g) and (ii) the outstanding amount of
     Permitted Convertible Securities guaranteed by the Borrower or its
     Subsidiaries.

     1.2 Subsection 2.6(b)(i) of the Credit Agreement is hereby amended by
inserting the phrase "and the issuance of Permitted Convertible Securities by
Holdings" after the phrase "(other than Indebtedness permitted pursuant to
subsection 7.2" in the first sentence of subsection 2.6(b)(i).

     1.3 Subsection 7.4(g) of the Credit Agreement is hereby amended and
restated in their entirety to read as follows:

              "(g) Guarantee Obligations in respect of Convertible Securities
     issued by Holdings (the "Permitted Convertible Securities"); and"

         SECTION 2. CONDITIONS TO EFFECTIVENESS FOR SECTION 1. The provisions of
Section 1 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"):

         2.1 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;

         2.2 The Required Lenders shall have delivered to the Administrative
Agent an executed original or facsimile of a counterpart of this Amendment;

         2.3 The representations and warranties contained in Section 3 hereof
shall be true and correct in all respects;




                                       2
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         2.4 All conditions to effectiveness set forth in Section 2 in the First
Amendment to the Second Amended and Restated 364 Day Credit Agreement of even
date herewith shall have been satisfied.

        SECTION 3. REPRESENTATIONS AND WARRANTIES. In order to induce Lenders to
enter into this Amendment and to amend the Credit Agreement in the manner
provided herein, the Borrower represents and warrants to each Lender that the
following statements are true, correct and complete:

         3.1 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 amended by this Amendment (the "AMENDED 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 Amended 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.

         3.2 Incorporation of Representations and Warranties From Credit
Agreement. The representations and warranties contained in Section 4 of the
Credit Agreement are and will be true, correct and complete in all material
respects on and as of the Amendment Effective Date, to the same extent as though
made on and as of that 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.

         3.3 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 would constitute an Event of Default or a potential 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
Borrower to the Agents and the Lenders.

         SECTION 4. MISCELLANEOUS.

         4.1 Effect on the Credit Agreement and the other Credit Documents.
Except as specifically amended by 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.

         4.2 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


                                       3
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and its counsel with respect to this Amendment and the documents and
transactions contemplated hereby shall be for the account of the Borrower.

         4.3 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.

         4.4 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.

         4.5 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 Section 1 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.



                            [SIGNATURE PAGES FOLLOW]



                                       4
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         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


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


                                         BANK OF AMERICA, N.A.,
                                          as a Lender


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


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


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





            [SIGNATURE PAGES TO FIRST AMENDMENT TO THIRD AMENDED AND
                           RESTATED CREDIT AGREEMENT]


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                     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 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.

Date: October 17, 2001



                                        L-3 COMMUNICATIONS HOLDINGS, INC.


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


                                        HYGIENETICS ENVIRONMENTAL SERVICES, INC.


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


                                        L-3 COMMUNICATIONS ILEX SYSTEMS, INC.


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


                                        L-3 COMMUNICATIONS SPD TECHNOLOGIES INC.


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





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                TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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                                         L-3 COMMUNICATIONS AYDIN
                                         CORPORATION


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


                                         MICRODYNE CORPORATION


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










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                TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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                                          THE BANK OF NEW YORK


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






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                           RESTATED CREDIT AGREEMENT]

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


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






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                           RESTATED CREDIT AGREEMENT]


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                                       FLEET NATIONAL BANK


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






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                           RESTATED CREDIT AGREEMENT]


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                                       CREDIT LYONNAIS NEW YORK BRANCH


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






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                           RESTATED CREDIT AGREEMENT]


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                                       FIRST UNION COMMERCIAL CORPORATION


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






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                           RESTATED CREDIT AGREEMENT]


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                                       THE FUJI BANK, LIMITED


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







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                           RESTATED CREDIT AGREEMENT]


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                                       HSBC BANK USA


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








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                           RESTATED CREDIT AGREEMENT]


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                                       THE GOVERNOR AND COMPANY OF THE
                                       BANK OF IRELAND


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


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










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                           RESTATED CREDIT AGREEMENT]


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                                       BANK OF TOKYO-MITSUBISHI TRUST COMPANY


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










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                           RESTATED CREDIT AGREEMENT]


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                                       COMERICA BANK


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










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                                       CREDIT INDUSTRIEL ET COMMERCIAL


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










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                           RESTATED CREDIT AGREEMENT]


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                                       THE DAI-ICHI KANGYO BANK, LTD.


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










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                           RESTATED CREDIT AGREEMENT]


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                                       BARCLAYS BANK PLC


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










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                           RESTATED CREDIT AGREEMENT]


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                                       RZB FINANCE LLC


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










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                           RESTATED CREDIT AGREEMENT]


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                                       ERSTE BANK, NEW YORK


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










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                                       GENERAL ELECTRIC  CAPITAL CORPORATION


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










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                           RESTATED CREDIT AGREEMENT]


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                                       THE INDUSTRIAL BANK OF JAPAN, LIMITED


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










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                           RESTATED CREDIT AGREEMENT]


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                                       THE MITSUBISHI TRUST AND BANKING
                                       CORPORATION


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










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                           RESTATED CREDIT AGREEMENT]


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                                       SOCIETE GENERALE


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










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                           RESTATED CREDIT AGREEMENT]


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                                       SUNTRUST BANK


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










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                           RESTATED CREDIT AGREEMENT]


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                                       WEBSTER BANK


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










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                           RESTATED CREDIT AGREEMENT]