Exhibit 10.1

JOINDER AGREEMENT

THIS JOINDER AGREEMENT dated as of June 26, 2013 (this “Agreement”), is entered
into between WHIPPANY ACTUATION SYSTEMS, LLC, a Delaware limited liability
company (the “New Subsidiary”), and CREDIT SUISSE AG, as administrative agent
and collateral agent (in such capacities, the “Agent”), under that certain
Amended and Restated Credit Agreement dated as of February 28, 2013 (as the same
may be further amended, supplemented or otherwise modified from time to time,
the “Credit Agreement”), among TransDigm Inc., a Delaware corporation (the
“Borrower”), TransDigm Group Incorporated, a Delaware corporation, the
Subsidiaries of the Borrower from time to time party thereto, the Lenders from
time to time party thereto and the Agent. All capitalized terms used herein and
not otherwise defined shall have the meanings set forth in the Credit Agreement.

The New Subsidiary and the Agent, for the benefit of the Lenders, hereby agree
as follows:

1.    The New Subsidiary hereby acknowledges, agrees and confirms that, by its
execution of this Agreement, the New Subsidiary will be deemed to be a Loan
Party under the Credit Agreement and a Subsidiary Guarantor for all purposes of
the Credit Agreement and shall have all of the obligations of a Loan Party and a
Subsidiary Guarantor thereunder as if it had executed the Credit Agreement. The
New Subsidiary hereby ratifies, as of the date hereof, and agrees to be bound
by, all of the terms, provisions and conditions contained in the Credit
Agreement, including without limitation (a) all of the representations and
warranties of the Loan Parties set forth in Article III of the Credit Agreement
(to the extent made or deemed made on or after the effective date hereof),
(b) all of the covenants set forth in Articles V and VI of the Credit Agreement
and (c) all of the guaranty obligations set forth in the Guarantee and
Collateral Agreement. Without limiting the generality of the foregoing terms of
this paragraph 1, the New Subsidiary, subject to the limitations set forth in
the Guarantee and Collateral Agreement, hereby absolutely and unconditionally
guarantees, jointly and severally with the other Guarantors, to the Agent and
the Lenders, the prompt payment of the Additional Obligations in full when due
(whether at stated maturity, upon acceleration or otherwise) to the extent of
and in accordance with Guarantee and Collateral Agreement.

2.    If required, the New Subsidiary is, simultaneously with the execution of
this Agreement, executing and delivering such Collateral Documents (and such
other documents and instruments) as reasonably requested by the Agent in
accordance with the Credit Agreement.

3.    The New Subsidiary hereby waives acceptance by the Agent and the Lenders
of the guaranty by the New Subsidiary upon the execution of this Agreement by
the New Subsidiary.

4.    This Agreement may be executed in any number of counterparts, each of
which when so executed and delivered shall be an original, but all of which
shall constitute one and the same instrument.

5.    THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER
SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF
NEW YORK.

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IN WITNESS WHEREOF, the New Subsidiary has caused this Agreement to be duly
executed by its authorized officer, and the Agent, for the benefit of the
Lenders, has caused the same to be accepted by its authorized officer, as of the
day and year first above written.

 

WHIPPANY ACTUATION SYSTEMS, LLC by   /s/ Gregory Rufus             Name: Gregory
Rufus   Title:   Secretary and Treasurer

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Acknowledged and accepted:

 

CREDIT SUISSE AG, as Agent by   /s/ Kevin Buddhdew   Name: Kevin Buddhdew  
Title:   Authorized Signatory

 

by   /s/ Patrick Freytag   Name: Patrick Freytag   Title:   Authorized Signatory