Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Leary John F
 2. Date of Event Requiring Statement (Month/Day/Year)
05/31/2012		 3. Issuer Name and Ticker or Trading Symbol
TransDigm Group INC [TDG]
(Last)
(First)
(Middle)
C/O HARTWELL CORPORATION, 900 RICHFIELD RD		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Executive Vice President
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

PLACENTIA, CA 92870		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option 09/30/2004 08/05/2013 Common Stock 8,664 $ 6.68 D  
Stock Option 08/05/2003 08/05/2013 Common Stock 38,896 $ 6.68 D  
Stock Option 09/28/2005 08/05/2013 Common Stock 748 $ 13.37 D  
Stock Option 09/30/2009(1) 11/17/2018 Common Stock 60,000 $ 27.08 D  
Stock Option 09/30/2011(2) 04/27/2021 Common Stock 12,000 $ 80.8 D  
Stock Option 09/30/2012(3) 11/14/2021 Common Stock 45,500 $ 97.42 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Leary John F
C/O HARTWELL CORPORATION
900 RICHFIELD RD
PLACENTIA, CA 92870		       Executive Vice President  

Signatures

Halle Fine Terrion as attorney in fact for John Leary 06/05/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Vest based on the achievement of annual and cumulative per share operating performance targets between fiscal 2009 and fiscal 2013.
(2) Vest based on the achievement of annual per share operating performance targets between fiscal 2014 and fiscal 2015.
(3) Vest based on the achievement of annual and cumulative per share operating performance targets between fiscal 2012 and fiscal 2016.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

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