Document:

SUPPLEMENTAL INDENTURE TO BE DELIVERED
		
	 

	 
		BY GUARANTEEING SUBSIDIARIES
	 

	 
		Supplemental Indenture (this
		“Supplemental Indenture”), dated as of May 1, 2007, 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:
				

			 

 

	 
			
				
				   
				

			 	
				
				  (v)
				

			 	
				
				  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 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
				

			 

 

	 
		 
	 

	 
		 
	 

	 
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				  (vi)
				

			 	
				
				  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
				  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 
				

			 

 

	 
		 
	 

	 
		 
	 

	 
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		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:
				

			 

 

	 
			
				
				   
				

			 	
				
				  (vii)
				

			 	
				
				  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
				

			 

 

	 
			
				
				   
				

			 	
				
				  (viii)
				

			 	
				
				  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
				  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.
				

			 

 

	 
		 
	 

	 
		 
	 

	 
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				  (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 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 
				

			 

 

	 
		 
	 

	 
		 
	 

	 
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		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 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.
				

			 

 

	 
		 
	 

	 
		 
	 

	 
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		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.
	 

	 
		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.
	 

	 
		 
	 

	 
		 
	 

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

	 
		 
	 

	 
			
				
				  Dated: May 1, 2007
				

			 	
				
				   
				

			 	
				
				  L-3 COMMUNICATIONS
				  CORPORATION
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
			
				
				  Dated: May 1, 2007
				

			 

 

	 
		Apcom, Inc., a Maryland corporation
	 

	 
		Broadcast Sports Inc., a Delaware
		corporation
	 

	 
		D.P. Associates, Inc., a Virginia
		corporation
	 

	 
		Electrodynamics, Inc., an Arizona
		corporation
	 

	 
		gForce Technologies, Inc., a Massachusetts
		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
	 

	 
		LinCom Wireless, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Advanced Laser Systems
		Technology, Inc., a Florida corporation
	 

	 
		L-3 Communications Aeromet, Inc., an Oregon
		corporation
	 

	 
		L-3 Communications AIS GP Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Applied Signal and Image
		Technology, Inc., a Maryland corporation
	 

	 
		L-3 Communications Avionics Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Avisys Corporation, a
		Texas corporation
	 

	 
		L-3 Communications Aydin Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications CE Holdings, Inc., a
		Delaware corporation 
	 

	 
		L-3 Communications Cincinnati Electronics,
		Inc., an Ohio corporation
	 

	 
		L-3 Communications Crestview Aerospace
		Corporation, a Delaware corporation
	 

	 
		L-3 Communications CSI, Inc., a California
		corporation
	 

	 
		L-3 Communications CyTerra Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Dynamic Positioning and
		Control Systems, Inc., a California corporation
	 

	 
		L-3 Communications Electron Technologies,
		Inc., a Delaware corporation
	 

	 
		L-3 Communications EO/IR, Inc., a Florida
		corporation
	 

	 
		L-3 Communications EOTech, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications ESSCO, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Foreign Holdings, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Geneva Aerospace, Inc., a
		Texas corporation
	 

	 
		L-3 Communications Government Services,
		Inc., a Virginia corporation
	 

	 
		L-3 Communications ILEX Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications InfraredVision Technology
		Corporation, a California corporation
	 

	 
		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 MariPro, Inc., a
		California corporation
	 

	 
		L-3 Communications Mobile-Vision, Inc., a
		New Jersey corporation 
	 

	 
		L-3 Communications Nautronix Holdings, Inc.,
		a Delaware corporation
	 

	 
		L-3 Communications Nova Engineering, Inc.,
		an Ohio corporation
	 

	 
		L-3 Communications SafeView, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Security and Detection
		Systems, Inc., a Delaware corporation
	 

	 
		L-3 Communications Sonoma EO, Inc., a
		California corporation
	 

	 
		L-3 Communications SSG-Tinsley, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications TCS, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Tinsley Laboratories,
		Inc., a California corporation
	 

	 
		L-3 Communications Titan Corporation, a
		Delaware corporation
	 

	 
		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
	 

	 
		SPD Electrical Systems, Inc., a Delaware
		corporation
	 

	 
		SPD Switchgear Inc., a Delaware
		corporation
	 

	 
		SYColeman Corporation, a Florida
		corporation
	 

	 
		Titan Facilities, Inc., a Virginia
		corporation
	 

	 
		Troll Technology Corporation, a California
		corporation
	 

	 
		Wescam Air Ops Inc., a Delaware
		corporation
	 

	 
		Wescam Holdings (US) Inc., a Delaware
		corporation
	 

	 
		Wolf Coach, Inc., a Massachusetts
		corporation
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  As Guaranteeing Subsidiaries
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Integrated Systems L.P.,
		a Delaware limited partnership
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

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

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Flight Capital LLC, a
		Delaware limited liability company
	 

	 
		L-3 Communications Flight International
		Aviation LLC, a Delaware limited liability company
	 

	 
		L-3 Communications Vector International
		Aviation LLC, a Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS VERTEX
				  AEROSPACE LLC, as Sole Member
 
 By:
				  L-3 COMMUNICATIONS INTEGRATED SYSTEMS L.P., as Sole Member
 

				  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, a
		Delaware limited liability company
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS INTEGRATED
				  SYSTEMS L.P., as Sole Member
 
 By:
				  L-3 COMMUNICATIONS AIS GP CORPORATION, as General Partner
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam Air Ops LLC, a Delaware limited
		liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS EO/IR, INC.,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam LLC, a Delaware limited liability
		company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C. Cambria
				  
 Title: Senior Vice President
				

			 

 

	 
		 
	 

	 
		L-3 Communications Germany Holdings, LLC, a
		Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		 
	 

	 
			
				
				  Dated: May 1, 2007
				

			 	
				
				   
				

			 	
				
				  THE BANK OF NEW YORK,

				  as Trustee
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name:

				  Title: Assistant Vice President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		NOTATION ON SENIOR SUBORDINATED NOTE
		RELATING TO SUBSIDIARY GUARANTEE
	 

	 
		Pursuant to the Supplemental Indenture (the
		“Supplemental
		Indenture”) dated as of May 1,
		2007 among L-3 Communications Corporation, the Guarantors
		party thereto (each a “Guarantor”
		and collectively the “Guarantors”) and The Bank of New York, as trustee (the
		“Trustee”), each Guarantor (i) has jointly
		and severally unconditionally guaranteed (a) the due and punctual payment of
		the principal of, and premium, interest and Additional Amounts on the Notes,
		whether at maturity or an interest payment date, by acceleration, call for
		redemption or otherwise, (b) the due and punctual payment of interest on the
		overdue principal and premium of, and interest and Additional Amounts on the
		Notes, and (c) in case of any extension of time of payment or renewal of any
		Notes or any of such other Obligations, 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 and (ii) has agreed to pay any
		and all costs and expenses (including reasonable attorneys’ fees) incurred
		by the Trustee or any Holder in enforcing any rights under the Subsidiary
		Guarantee (as defined in the Supplemental Indenture).
	 

	 
		Notwithstanding the foregoing, the
		Subsidiary Guarantee of each Guarantor shall be subordinated to the prior
		payment in full of all Senior Debt (as defined in the Indenture) of that
		Guarantor (in the same manner and to the same extent that the Notes are
		subordinated to the Senior Debt), which shall include all guarantees of Senior
		Debt.
	 

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

	 
		No past, present or future director,
		officer, employee, agent, incorporator, stockholder or agent of any Guarantor,
		as such, shall have any liability for any Obligations of the Company or any
		Guarantor under the Notes, any Subsidiary Guarantee, the Indenture, any
		supplemental indenture delivered pursuant to the Indenture by such Guarantor,
		or for any claim based on, in respect of or by reason of such Obligations or
		their creation. Each Holder by accepting a Note waives and releases all such
		liability.
	 

	 
		The Subsidiary Guarantee shall be binding
		upon each Guarantor and its successors and assigns and shall inure to the
		benefit of the successors and assigns of the Trustee and the Holders and, in
		the event of any transfer or assignment of rights by any Holder or the Trustee,
		the rights and privileges herein conferred upon that party shall automatically
		extend to and be vested in such transferee or assignee, all subject to the
		terms and conditions hereof.
	 

	 
		The Subsidiary Guarantee shall not be valid
		or obligatory for any purpose until the certificate of authentication on the
		Note upon which the Subsidiary Guarantee is noted has been executed by the
		Trustee under the Indenture by the manual signature of one of its authorized
		officers. Capitalized terms used herein have the meaning assigned to them in
		the Indenture, dated as of May 21, 2003, among L-3 Communications Corporation,
		the Guarantors party thereto and the Trustee.
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		Dated: May 1, 2007
	 

	 
		Apcom, Inc., a Maryland corporation
	 

	 
		Broadcast Sports Inc., a Delaware
		corporation
	 

	 
		D.P. Associates, Inc., a Virginia
		corporation
	 

	 
		Electrodynamics, Inc., an Arizona
		corporation
	 

	 
		gForce Technologies, Inc., a Massachusetts
		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
	 

	 
		LinCom Wireless, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Advanced Laser Systems
		Technology, Inc., a Florida corporation
	 

	 
		L-3 Communications Aeromet, Inc., an Oregon
		corporation
	 

	 
		L-3 Communications AIS GP Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Applied Signal and Image
		Technology, Inc., a Maryland corporation
	 

	 
		L-3 Communications Avionics Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Avisys Corporation, a
		Texas corporation
	 

	 
		L-3 Communications Aydin Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications CE Holdings, Inc., a
		Delaware corporation 
	 

	 
		L-3 Communications Cincinnati Electronics,
		Inc., an Ohio corporation
	 

	 
		L-3 Communications Crestview Aerospace
		Corporation, a Delaware corporation
	 

	 
		L-3 Communications CSI, Inc., a California
		corporation
	 

	 
		L-3 Communications CyTerra Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Dynamic Positioning and
		Control Systems, Inc., a California corporation
	 

	 
		L-3 Communications Electron Technologies,
		Inc., a Delaware corporation
	 

	 
		L-3 Communications EO/IR, Inc., a Florida
		corporation
	 

	 
		L-3 Communications EOTech, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications ESSCO, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Foreign Holdings, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Geneva Aerospace, Inc., a
		Texas corporation
	 

	 
		L-3 Communications Government Services,
		Inc., a Virginia corporation
	 

	 
		L-3 Communications ILEX Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications InfraredVision Technology
		Corporation, a California corporation
	 

	 
		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 MariPro, Inc., a
		California corporation
	 

	 
		L-3 Communications Mobile-Vision, Inc., a
		New Jersey corporation 
	 

	 
		L-3 Communications Nautronix Holdings, Inc.,
		a Delaware corporation
	 

	 
		L-3 Communications Nova Engineering, Inc.,
		an Ohio corporation
	 

	 
		L-3 Communications SafeView, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Security and Detection
		Systems, Inc., a Delaware corporation
	 

	 
		L-3 Communications Sonoma EO, Inc., a
		California corporation
	 

	 
		L-3 Communications SSG-Tinsley, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications TCS, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Tinsley Laboratories,
		Inc., a California corporation
	 

	 
		L-3 Communications Titan Corporation, a
		Delaware corporation
	 

	 
		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
	 

	 
		SPD Electrical Systems, Inc., a Delaware
		corporation
	 

	 
		SPD Switchgear Inc., a Delaware
		corporation
	 

	 
		SYColeman Corporation, a Florida
		corporation
	 

	 
		Titan Facilities, Inc., a Virginia
		corporation
	 

	 
		Troll Technology Corporation, a California
		corporation
	 

	 
		Wescam Air Ops Inc., a Delaware
		corporation
	 

	 
		Wescam Holdings (US) Inc., a Delaware
		corporation
	 

	 
		Wolf Coach, Inc., a Massachusetts
		corporation
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  As Guaranteeing Subsidiaries
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Integrated Systems L.P.,
		a Delaware limited partnership
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

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

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Flight Capital LLC, a
		Delaware limited liability company
	 

	 
		L-3 Communications Flight International
		Aviation LLC, a Delaware limited liability company
	 

	 
		L-3 Communications Vector International
		Aviation LLC, a Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS VERTEX
				  AEROSPACE LLC, as Sole Member
 
 By:
				  L-3 COMMUNICATIONS INTEGRATED SYSTEMS L.P., as Sole Member
 

				  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, a
		Delaware limited liability company
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS INTEGRATED
				  SYSTEMS L.P., as Sole Member
 
 By:
				  L-3 COMMUNICATIONS AIS GP CORPORATION, as General Partner
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam Air Ops LLC, a Delaware limited
		liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS EO/IR, INC.,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam LLC, a Delaware limited liability
		company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C. Cambria
				  
 Title: Senior Vice President
				

			 

 

	 
		 
	 

	 
		L-3 Communications Germany Holdings, LLC, a
		Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  PresidentSUPPLEMENTAL INDENTURE TO BE DELIVERED
		
	 

	 
		BY GUARANTEEING SUBSIDIARIES
	 

	 
		Supplemental Indenture (this
		“Supplemental Indenture”), dated as of May 1, 2007, 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 December 22, 2003 providing for the issuance of an unlimited amount of 6
		1/8% Senior Subordinated Notes due 2014 (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:
				

			 

 

	 
			
				
				   
				

			 	
				
				  (ix)
				

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

			 

 

	 
		 
	 

	 
		 
	 

	 
		1
	 

	 
		 
	 

	 
	 

	 

	 
			
				
				   
				

			 	
				
				  (x)
				

			 	
				
				  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
				  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 
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		2
	 

	 
		 
	 

	 
	 

	 

	 
		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:
				

			 

 

	 
			
				
				   
				

			 	
				
				  (xi)
				

			 	
				
				  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
				

			 

 

	 
			
				
				   
				

			 	
				
				  (xii)
				

			 	
				
				  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
				  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 
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		3
	 

	 
		 
	 

	 
	 

	 

	 
		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 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 
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		4
	 

	 
		 
	 

	 
	 

	 

	 
		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 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 
	 

	 
		 
	 

	 
		 
	 

	 
		5
	 

	 
		 
	 

	 
	 

	 

	 
		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.
	 

	 
		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.
	 

	 
		 
	 

	 
		 
	 

	 
		6
	 

	 
		 
	 

	 
	 

	 

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

	 
		 
	 

	 
			
				
				  Dated: May 1, 2007
				

			 	
				
				   
				

			 	
				
				  L-3 COMMUNICATIONS
				  CORPORATION
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		Dated: May 1, 2007
	 

	 
		Apcom, Inc., a Maryland corporation
	 

	 
		Broadcast Sports Inc., a Delaware
		corporation
	 

	 
		D.P. Associates, Inc., a Virginia
		corporation
	 

	 
		Electrodynamics, Inc., an Arizona
		corporation
	 

	 
		gForce Technologies, Inc., a Massachusetts
		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
	 

	 
		LinCom Wireless, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Advanced Laser Systems
		Technology, Inc., a Florida corporation
	 

	 
		L-3 Communications Aeromet, Inc., an Oregon
		corporation
	 

	 
		L-3 Communications AIS GP Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Applied Signal and Image
		Technology, Inc., a Maryland corporation
	 

	 
		L-3 Communications Avionics Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Avisys Corporation, a
		Texas corporation
	 

	 
		L-3 Communications Aydin Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications CE Holdings, Inc., a
		Delaware corporation 
	 

	 
		L-3 Communications Cincinnati Electronics,
		Inc., an Ohio corporation
	 

	 
		L-3 Communications Crestview Aerospace
		Corporation, a Delaware corporation
	 

	 
		L-3 Communications CSI, Inc., a California
		corporation
	 

	 
		L-3 Communications CyTerra Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Dynamic Positioning and
		Control Systems, Inc., a California corporation
	 

	 
		L-3 Communications Electron Technologies,
		Inc., a Delaware corporation
	 

	 
		L-3 Communications EO/IR, Inc., a Florida
		corporation
	 

	 
		L-3 Communications EOTech, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications ESSCO, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Foreign Holdings, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Geneva Aerospace, Inc., a
		Texas corporation
	 

	 
		L-3 Communications Government Services,
		Inc., a Virginia corporation
	 

	 
		L-3 Communications ILEX Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications InfraredVision Technology
		Corporation, a California corporation
	 

	 
		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 MariPro, Inc., a
		California corporation
	 

	 
		L-3 Communications Mobile-Vision, Inc., a
		New Jersey corporation 
	 

	 
		L-3 Communications Nautronix Holdings, Inc.,
		a Delaware corporation
	 

	 
		L-3 Communications Nova Engineering, Inc.,
		an Ohio corporation
	 

	 
		L-3 Communications SafeView, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Security and Detection
		Systems, Inc., a Delaware corporation
	 

	 
		L-3 Communications Sonoma EO, Inc., a
		California corporation
	 

	 
		L-3 Communications SSG-Tinsley, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications TCS, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Tinsley Laboratories,
		Inc., a California corporation
	 

	 
		L-3 Communications Titan Corporation, a
		Delaware corporation
	 

	 
		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
	 

	 
		SPD Electrical Systems, Inc., a Delaware
		corporation
	 

	 
		SPD Switchgear Inc., a Delaware
		corporation
	 

	 
		SYColeman Corporation, a Florida
		corporation
	 

	 
		Titan Facilities, Inc., a Virginia
		corporation
	 

	 
		Troll Technology Corporation, a California
		corporation
	 

	 
		Wescam Air Ops Inc., a Delaware
		corporation
	 

	 
		Wescam Holdings (US) Inc., a Delaware
		corporation
	 

	 
		Wolf Coach, Inc., a Massachusetts
		corporation
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  As Guaranteeing Subsidiaries
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Integrated Systems L.P.,
		a Delaware limited partnership
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

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

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Flight Capital LLC, a
		Delaware limited liability company
	 

	 
		L-3 Communications Flight International
		Aviation LLC, a Delaware limited liability company
	 

	 
		L-3 Communications Vector International
		Aviation LLC, a Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS VERTEX
				  AEROSPACE LLC, as Sole Member
 
 By:
				  L-3 COMMUNICATIONS INTEGRATED SYSTEMS L.P., as Sole Member
 

				  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, a
		Delaware limited liability company
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS INTEGRATED
				  SYSTEMS L.P., as Sole Member
 
 By:
				  L-3 COMMUNICATIONS AIS GP CORPORATION, as General Partner
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam Air Ops LLC, a Delaware limited
		liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS EO/IR, INC.,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam LLC, a Delaware limited liability
		company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C. Cambria
				  
 Title: Senior Vice President
				

			 

 

	 
		 
	 

	 
		L-3 Communications Germany Holdings, LLC, a
		Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		 
	 

	 
			
				
				  Dated: May 1, 2007
				

			 	
				
				   
				

			 	
				
				  THE BANK OF NEW YORK,

				  as Trustee
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: 

				  Title: Assistant Vice President
				

			 

 

	 
		 
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		NOTATION ON SENIOR SUBORDINATED NOTE
		RELATING TO SUBSIDIARY GUARANTEE
	 

	 
		Pursuant to the Supplemental Indenture (the
		“Supplemental
		Indenture”) dated as of May 1,
		2007 among L-3 Communications Corporation, the Guarantors
		party thereto (each a “Guarantor”
		and collectively the “Guarantors”) and The Bank of New York, as trustee (the
		“Trustee”), each Guarantor (i) has jointly
		and severally unconditionally guaranteed (a) the due and punctual payment of
		the principal of, and premium, interest and Additional Interest on the Notes,
		whether at maturity or an interest payment date, by acceleration, call for
		redemption or otherwise, (b) the due and punctual payment of interest on the
		overdue principal and premium of, and interest and Additional Interest on the
		Notes, and (c) in case of any extension of time of payment or renewal of any
		Notes or any of such other Obligations, 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 and (ii) has agreed to pay any
		and all costs and expenses (including reasonable attorneys’ fees) incurred
		by the Trustee or any Holder in enforcing any rights under the Subsidiary
		Guarantee (as defined in the Supplemental Indenture).
	 

	 
		Notwithstanding the foregoing, the
		Subsidiary Guarantee of each Guarantor shall be subordinated to the prior
		payment in full of all Senior Debt (as defined in the Indenture) of that
		Guarantor (in the same manner and to the same extent that the Notes are
		subordinated to the Senior Debt), which shall include all guarantees of Senior
		Debt.
	 

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

	 
		No past, present or future director,
		officer, employee, agent, incorporator, stockholder or agent of any Guarantor,
		as such, shall have any liability for any Obligations of the Company or any
		Guarantor under the Notes, any Subsidiary Guarantee, the Indenture, any
		supplemental indenture delivered pursuant to the Indenture by such Guarantor,
		or for any claim based on, in respect of or by reason of such Obligations or
		their creation. Each Holder by accepting a Note waives and releases all such
		liability.
	 

	 
		The Subsidiary Guarantee shall be binding
		upon each Guarantor and its successors and assigns and shall inure to the
		benefit of the successors and assigns of the Trustee and the Holders and, in
		the event of any transfer or assignment of rights by any Holder or the Trustee,
		the rights and privileges herein conferred upon that party shall automatically
		extend to and be vested in such transferee or assignee, all subject to the
		terms and conditions hereof.
	 

	 
		The Subsidiary Guarantee shall not be valid
		or obligatory for any purpose until the certificate of authentication on the
		Note upon which the Subsidiary Guarantee is noted has been executed by the
		Trustee under the Indenture by the manual signature of one of its authorized
		officers. Capitalized terms used herein have the meaning assigned to them in
		the Indenture, dated as of December 22, 2003, among L-3 Communications
		Corporation, the Guarantors party thereto and the Trustee.
	 

	 
		 
	 

	 
		 
	 

	 
	 

	 

	 
		Dated: May 1, 2007
	 

	 
		Apcom, Inc., a Maryland corporation
	 

	 
		Broadcast Sports Inc., a Delaware
		corporation
	 

	 
		D.P. Associates, Inc., a Virginia
		corporation
	 

	 
		Electrodynamics, Inc., an Arizona
		corporation
	 

	 
		gForce Technologies, Inc., a Massachusetts
		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
	 

	 
		LinCom Wireless, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Advanced Laser Systems
		Technology, Inc., a Florida corporation
	 

	 
		L-3 Communications Aeromet, Inc., an Oregon
		corporation
	 

	 
		L-3 Communications AIS GP Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Applied Signal and Image
		Technology, Inc., a Maryland corporation
	 

	 
		L-3 Communications Avionics Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Avisys Corporation, a
		Texas corporation
	 

	 
		L-3 Communications Aydin Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications CE Holdings, Inc., a
		Delaware corporation 
	 

	 
		L-3 Communications Cincinnati Electronics,
		Inc., an Ohio corporation
	 

	 
		L-3 Communications Crestview Aerospace
		Corporation, a Delaware corporation
	 

	 
		L-3 Communications CSI, Inc., a California
		corporation
	 

	 
		L-3 Communications CyTerra Corporation, a
		Delaware corporation
	 

	 
		L-3 Communications Dynamic Positioning and
		Control Systems, Inc., a California corporation
	 

	 
		L-3 Communications Electron Technologies,
		Inc., a Delaware corporation
	 

	 
		L-3 Communications EO/IR, Inc., a Florida
		corporation
	 

	 
		L-3 Communications EOTech, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications ESSCO, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Foreign Holdings, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Geneva Aerospace, Inc., a
		Texas corporation
	 

	 
		L-3 Communications Government Services,
		Inc., a Virginia corporation
	 

	 
		L-3 Communications ILEX Systems, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications InfraredVision Technology
		Corporation, a California corporation
	 

	 
		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 MariPro, Inc., a
		California corporation
	 

	 
		L-3 Communications Mobile-Vision, Inc., a
		New Jersey corporation 
	 

	 
		L-3 Communications Nautronix Holdings, Inc.,
		a Delaware corporation
	 

	 
		L-3 Communications Nova Engineering, Inc.,
		an Ohio corporation
	 

	 
		L-3 Communications SafeView, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications Security and Detection
		Systems, Inc., a Delaware corporation
	 

	 
		L-3 Communications Sonoma EO, Inc., a
		California corporation
	 

	 
		L-3 Communications SSG-Tinsley, Inc., a
		Delaware corporation
	 

	 
		L-3 Communications TCS, Inc., a Delaware
		corporation
	 

	 
		L-3 Communications Tinsley Laboratories,
		Inc., a California corporation
	 

	 
		L-3 Communications Titan Corporation, a
		Delaware corporation
	 

	 
		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
	 

	 
		SPD Electrical Systems, Inc., a Delaware
		corporation
	 

	 
		SPD Switchgear Inc., a Delaware
		corporation
	 

	 
		SYColeman Corporation, a Florida
		corporation
	 

	 
		Titan Facilities, Inc., a Virginia
		corporation
	 

	 
		Troll Technology Corporation, a California
		corporation
	 

	 
		Wescam Air Ops Inc., a Delaware
		corporation
	 

	 
		Wescam Holdings (US) Inc., a Delaware
		corporation
	 

	 
		Wolf Coach, Inc., a Massachusetts
		corporation
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  As Guaranteeing Subsidiaries
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Integrated Systems L.P.,
		a Delaware limited partnership
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

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

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		L-3 Communications Flight Capital LLC, a
		Delaware limited liability company
	 

	 
		L-3 Communications Flight International
		Aviation LLC, a Delaware limited liability company
	 

	 
		L-3 Communications Vector International
		Aviation LLC, a Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS VERTEX
				  AEROSPACE LLC, as Sole Member
 
 By:
				  L-3 COMMUNICATIONS INTEGRATED SYSTEMS L.P., as Sole Member
 

				  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, a
		Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS INTEGRATED
				  SYSTEMS L.P., as Sole Member
 
 By:
				  L-3 COMMUNICATIONS AIS GP CORPORATION, as General Partner
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam Air Ops LLC, a Delaware limited
		liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS EO/IR, INC.,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

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

			 

 

	 
		 
	 

	 
		Wescam LLC, a Delaware limited liability
		company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C. Cambria
				  
 Title: Senior Vice President
				

			 

 

	 
		 
	 

	 
		L-3 Communications Germany Holdings, LLC, a
		Delaware limited liability company
	 

	 
		 
	 

	 
			
				
				   
				

			 	
				
				   
				

			 	
				
				  By: L-3 COMMUNICATIONS CORPORATION,
				  as Sole Member
				

			 
	
				
				

			 	
				
				   
				

			 	
				
				  
 By: 
				

			 	
				
				   
				

			 
	
				
				   
				

			 	
				
				   
				

			 	
				
				  Name: Christopher C.
				  Cambria
 Title: Senior Vice
				  President

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