EX-4.31



 Exhibit 4.31 

TRANSDIGM INC., 

TRANSDIGM GROUP INCORPORATED, 

THE GUARANTORS NAMED HEREIN, 

AND 
 THE BANK OF NEW YORK
MELLON TRUST COMPANY, N.A., 
 as Trustee 
  

 
 EIGHTH SUPPLEMENTAL INDENTURE

 Dated as of May 9, 2017 

to 
 Indenture 

Dated as of June 4, 2014 
 by
and among 
 TRANSDIGM INC., 

TRANSDIGM GROUP INCORPORATED, 

THE GUARANTORS NAMED THEREIN, 

AND 
 THE BANK OF NEW YORK
MELLON TRUST COMPANY, N.A., 
 as Trustee 
  

 
 6.500% Senior Subordinated Notes
due 2024 
 of TransDigm Inc. 







 This EIGHTH SUPPLEMENTAL INDENTURE (this “Supplemental
Indenture”), dated as of May 9, 2017, is entered into by and among North Hills Signal Processing Corp., a Delaware corporation (“North Hills”), North Hills Signal Processing Overseas Corp., a Delaware
corporation (together with North Hills, the “Guaranteeing Subsidiaries”), TransDigm Inc., a Delaware corporation (the “Company”), TransDigm Group Incorporated, a Delaware corporation (“TD
Group”), Adams Rite Aerospace, Inc., a California corporation (“Adams Rite”), MarathonNorco Aerospace, Inc., a Delaware corporation (“Marathon”), Champion Aerospace LLC, a Delaware limited
liability company (“Champion”), Avionic Instruments LLC, a Delaware limited liability company (“Avionic”), Skurka Aerospace Inc., a Delaware corporation (“Skurka”), CDA
InterCorp LLC, a Florida limited liability company (“CDA”), Aviation Technologies, Inc., a Delaware corporation (“ATI”), AvtechTyee, Inc., a Washington corporation (“Avtech”),
Transicoil LLC, a Delaware limited liability company (“Transicoil”), AeroControlex Group, Inc., a Delaware corporation (“AeroControlex”), Bruce Aerospace Inc., a Delaware corporation (“Bruce
Aerospace”), CEF Industries, LLC, a Delaware limited liability company (“CEF”), Acme Aerospace, Inc., a Delaware corporation (“Acme”), Dukes Aerospace, Inc., a Delaware corporation
(“Dukes”), Semco Instruments, Inc., a Delaware corporation, (“Semco”), Hartwell Corporation, a California corporation (“Hartwell”), McKechnie Aerospace DE, Inc., a Delaware
corporation (“McKechnie Aerospace DE”), McKechnie Aerospace Holdings, Inc., a Delaware corporation (“McKechnie Aerospace Holdings”), McKechnie Aerospace Investments, Inc., a Delaware corporation
(“McKechnie Aerospace Investments”), McKechnie Aerospace US LLC, a Delaware limited liability company (“McKechnie Aerospace US”), Texas Rotronics, Inc., a Texas corporation
(“Rotronics”), Electromech Technologies LLC (formerly Western Sky Industries, LLC), a Delaware limited liability company (“Electromech”), Schneller LLC, a Delaware limited liability company
(“Schneller”), HARCO LLC (formerly Harco Laboratories, Incorporated), a Connecticut limited liability company (“HARCO”), AmSafe Global Holdings, Inc., a Delaware corporation (“AmSafe
Global”), Bridport Holdings, Inc., a Delaware corporation (“Bridport Holdings”), AmSafe, Inc., a Delaware corporation (“AmSafe Inc.”), Shield Restraint Systems, Inc. (formerly AmSafe
Commercial Products, Inc.), a Delaware corporation (“Shield”), Bridport-Air Carrier, Inc., a Washington corporation (“Bridport-Air”), Bridport Erie Aviation, Inc., a Delaware corporation
(“Bridport Erie”), Arkwin Industries, Inc., a New York corporation (“Arkwin”), Whippany Actuation Systems, LLC, a Delaware limited liability company (“Whippany”), Aerosonic LLC,
a Delaware limited liability company (“Aerosonic”), Avionics Specialties, Inc., a Virginia corporation (“Avionics Specialties”), Airborne Global, Inc., a Delaware corporation (“Airborne
Global”), Airborne Holdings, Inc., a Delaware Corporation (“Airborne Holdings”), Airborne Acquisition, Inc., a Delaware corporation (“Airborne Acquisitions”), Airborne Systems NA Inc., a
Delaware corporation (“Airborne Systems NA”), Airborne Systems North America Inc., a Delaware corporation (“Airborne Systems North America”), Airborne Systems North America of CA Inc., a Delaware
corporation (“Airborne Systems North America CA”), Airborne Systems North America of NJ Inc., a New Jersey corporation (“Airborne Systems North America NJ”), Telair US LLC, a Delaware limited liability
company (“Telair US”), Telair International LLC, a Delaware limited liability company (“Telair International”), Pexco Aerospace, Inc., a Delaware corporation (“Pexco
Aerospace”), PneuDraulics, Inc., a California corporation (“PneuDraulics”), Breeze-Eastern LLC, a Delaware limited liability company (“Breeze-Eastern”), ILC Holdings, Inc., a Delaware
corporation (“ILC Holdings”), ILC Industries, LLC, a Delaware limited liability company (“ILC Industries”), Data Device Corporation, a Delaware corporation (“DDC”), Beta
Transformer Technology Corporation, a New York corporation (“Beta Corporation”), Beta Transformer Technology LLC, a Delaware limited liability company (“Beta LLC”), Young & Franklin Inc., a
New York corporation (“Young & Franklin”), Tactair Fluid Controls, Inc., a New York corporation (“Tactair”), Johnson Liverpool LLC, a Delaware limited liability company (“Johnson
Liverpool”), SCHROTH Safety Products LLC, a Delaware limited liability company (“SCHROTH”) and Interiors In Flight LLC, a Delaware limited liability company (collectively with TD Group, Adams Rite, Marathon,
Champion, Avionic, Skurka, CDA, ATI, Avtech, Transicoil, AeroControlex, Bruce Aerospace, CEF, Acme, Dukes, Semco, Hartwell, McKechnie Aerospace DE, McKechnie Aerospace Holdings, McKechnie Aerospace Investments, McKechnie Aerospace US, Rotronics,
Electromech, Schneller, HARCO, AmSafe Global, Bridport Holdings, AmSafe Inc., Shield, Bridport-Air, Bridport Erie, Arkwin, Whippany, Aerosonic, Avionics Specialties, Airborne Global, Airborne Holdings, Airborne Acquisitions, Airborne Systems NA,
Airborne Systems North America, Airborne Systems North America CA, Airborne Systems North America NJ, Telair US, Telair International, Pexco Aerospace, PneuDraulics, Breeze-Eastern, ILC Holdings, ILC Industries, DDC, Beta Corporation, Beta LLC,
Young & Franklin, Tactair, Johnson Liverpool and SCHROTH the “Existing Guarantors”), and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”) under the Indenture
referred to below. Capitalized terms used herein and not otherwise defined shall have the meaning assigned to them in the Indenture. 

  
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 WITNESSETH: 

WHEREAS, the Company and the Existing Guarantors have heretofore executed and delivered to the Trustee an indenture, dated as of
June 4, 2014 (as supplemented by the First Supplemental Indenture thereto, dated as of April 9, 2015, the Second Supplemental Indenture thereto, dated as of June 12, 2015, the Third Supplemental Indenture thereto, dated as of
August 28, 2015, the Fourth Supplemental Indenture thereto, dated as of April 1, 2016, the Fifth Supplemental Indenture thereto, dated as of July 8, 2016, the Sixth Supplemental Indenture thereto, dated as of October 28, 2016,
and the Seventh Supplemental Indenture thereto, dated as of March 31, 2017, the “Indenture”), providing for the issuance by the Company of 6.500% Senior Subordinated Notes due 2024 (the “Notes”)
and the guarantees thereof by each of the Existing Guarantors; 
 WHEREAS, the Indenture provides that under certain circumstances
described therein, newly created or acquired Domestic Restricted Subsidiaries shall execute and deliver to the Trustee a supplemental indenture to the Indenture providing for a senior subordinated guarantee of payment of the Notes by such Domestic
Restricted Subsidiary (the “Guarantee”); 
 WHEREAS, all things necessary to make this Supplemental Indenture
the legal, valid and binding obligation of the Company, the Existing Guarantors and the Guaranteeing Subsidiaries have been done; and 

WHEREAS, pursuant to Section 9.01(g) of the Indenture, the Trustee is authorized to execute and deliver this Supplemental
Indenture without the consent of the Holders of the Notes. 
 NOW, THEREFORE, in consideration of the foregoing and for other good
and valuable consideration, the receipt of which is hereby acknowledged, each of the Guaranteeing Subsidiaries covenants and agrees 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.	GUARANTEE, ETC. Each of the Guaranteeing Subsidiaries hereby agrees that from and after the date hereof it shall be a Guarantor under the Indenture and be bound by the terms thereof applicable to Guarantors and
shall be entitled to all of the rights and subject to all the obligations of a Guarantor thereunder. 

  

	 	3.	RATIFICATION OF INDENTURE; SUPPLEMENTAL INDENTURE PART OF INDENTURE. The Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force
and effect. This Supplemental Indenture shall form a part of the Indenture for all purposes, and every holder of Notes heretofore or hereafter authenticated and delivered shall be bound hereby. 


 

	 	4.	EXECUTION AND DELIVERY. Each of the Guaranteeing Subsidiaries agrees that the Guarantee granted by it pursuant to the terms hereof shall remain in full force and effect notwithstanding any failure to endorse on
each Note a notation of such Guarantee. 

  

	 	5.	NO RECOURSE AGAINST OTHERS. No past, present or future director, officer, employee, incorporator, stockholder or agent of any of the Guaranteeing Subsidiaries (or any successor entity) (other than the Company or
the Existing Guarantors), as such, shall have any liability for any obligations of the Company, TD Group, the Guaranteeing Subsidiaries or any other Guarantor under the Notes, any Guarantee, 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.


  

	 	6.	NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE AND THE GUARANTEE GRANTED HEREUNDER WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY. 


  
 - 3 - 









	 	7.	COUNTERPART ORIGINALS. 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. 


 

	 	8.	EFFECT OF HEADINGS. The Section headings have been inserted for convenience of reference only, are not to be considered part of this Supplemental Indenture and shall in no way modify or restrict any of the terms
or provisions hereof. 

  

	 	9.	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, the Existing Guarantors and the Company. 


[Signature page follows.] 

  
 - 4 - 








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

			
	NORTH HILLS SIGNAL PROCESSING CORP.
	NORTH HILLS SIGNAL PROCESSING OVERSEAS CORP.
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: Chief Executive Officer
	
	TRANSDIGM INC.
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: Executive Vice President and
		 	          Chief Financial Officer
	
	TRANSDIGM GROUP INCORPORATED
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title Executive Vice President,
		 	          Chief Financial Officer and Treasurer
	
	ACME AEROSPACE, INC.
	ADAMS RITE AEROSPACE, INC.
	AIRBORNE SYSTEMS NORTH AMERICA OF NJ INC.
	AMSAFE GLOBAL HOLDINGS, INC.
	AMSAFE, INC.
	ARKWIN INDUSTRIES, INC.
	AVTECHTYEE, INC.
	BETA TRANSFORMER TECHNOLOGY CORPORATION
	BETA TRANSFORMER TECHNOLOGY LLC
	 By:
	 	Beta Transformer Technology Corporation, as its sole member
	BRUCE AEROSPACE, INC.
	DATA DEVICE CORPORATION
	DUKES AEROSPACE, INC.
	ELECTROMECH TECHNOLOGIES LLC
	 By:
	 	McKechnie Aerospace Investments, Inc., as its sole member
	HARTWELL CORPORATION
	JOHNSON LIVERPOOL LLC
	 By:
	 	Young & Franklin Inc., as its sole member
	MARATHONNORCO AEROSPACE INC.
	MCKECHNIE AEROSPACE INVESTMENTS, INC.
	PEXCO AEROSPACE, INC.
	PNEUDRAULICS, INC.
	SEMCO INSTRUMENTS, INC.
	SHIELD RESTRAINT SYSTEMS, INC.
	SKURKA AEROSPACE INC.
	TACTAIR FLUID CONTROLS, INC.
	TEXAS ROTRONICS, INC.
	YOUNG & FRANKLIN INC.
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: Chief Executive Officer


 [Signature page to the Eighth Supplemental Indenture – 2024 Notes] 







 
			
	AEROCONTROLEX GROUP, INC.
	AIRBORNE ACQUISITION, INC.
	AIRBORNE GLOBAL, INC.
	AIRBORNE HOLDINGS, INC.
	AVIATION TECHNOLOGIES, INC.
	BRIDPORT-AIR CARRIER, INC.
	BRIDPORT HOLDINGS, INC.
	MCKECHNIE AEROSPACE DE, INC.
	MCKECHNIE AEROSPACE US LLC
	    By:	 	McKechnie Aerospace DE, Inc., as its sole member
	TRANSICOIL LLC
	    By:	 	Aviation Technologies, Inc., as its sole member
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: President and Chief Executive Officer
	AEROSONIC LLC
	AVIONIC INSTRUMENTS LLC
	BREEZE-EASTERN LLC
	CDA INTERCORP LLC
	CEF INDUSTRIES, LLC
	CHAMPION AEROSPACE LLC
	HARCO LLC
	INTERIORS IN FLIGHT LLC
	SCHNELLER LLC
	SCHROTH SAFETY PRODUCTS LLC
	TELAIR US LLC
	TELAIR INTERNATIONAL LLC
	 By:
	 	Telair US LLC, as its sole member
	WHIPPANY ACTUATION SYSTEMS, LLC
	 Each By:
	 	TransDigm Inc., as its sole member
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title:   Executive Vice President and
		 	           Chief Financial Officer
	
	AIRBORNE SYSTEMS NA INC.
	AIRBORNE SYSTEMS NORTH AMERICA INC.
	AVIONICS SPECIALTIES, INC.
	ILC HOLDINGS, INC.
	ILC INDUSTRIES, LLC
	    By:	 	ILC Holdings, Inc., as its sole member
	MCKECHNIE AEROSPACE HOLDINGS, INC.
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: President
	
	BRIDPORT ERIE AVIATION, INC.
		
	By:	 	 /s/ Terrance M. Paradie

		 	Name: Terrance M. Paradie
		 	Title: Vice President and Treasurer


 [Signature page to the Eighth Supplemental Indenture – 2024 Notes] 







 
			
	AIRBORNE SYSTEMS NORTH AMERICA OF CA INC.
		
	By:	 	 /s/ Halle F. Terrion

		 	Name: Halle F. Terrion
		 	Title:   Secretary


 [Signature page to the Eighth Supplemental Indenture – 2024 Notes] 







 
			
	THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., AS TRUSTEE
		
	By:	 	 /s/ Lawrence M. Kusch

		 	Name: Lawrence M. Kusch
		 	Title:   Vice President


 [Signature page to the Eighth Supplemental Indenture – 2024 Notes]