FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN 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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1. Name and Address of Reporting Person * Howley W Nicholas   2. Issuer Name and Ticker or Trading Symbol TransDigm Group INC [TDG] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) 1301 EAST NINTH STREET, SUITE 3710 3. Date of Earliest Transaction (Month/Day/Year) 01/30/2012 (Street) CLEVELAND, OH 44114 4. If Amendment, Date Original Filed(Month/Day/Year) 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 Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 01/30/2012   M   33,000 A $ 6.68 33,000 D   Common Stock 01/30/2012   S   13,014 D $ 100.6976 (1) 19,986 D   Common Stock 01/30/2012   S   19,986 D $ 101.8572 (2) 0 D   Common Stock 01/30/2012   M   2,500 A $ 6.68 2,500 I Bratenahl Investments, Ltd. Common Stock 01/30/2012   S   1,132 D $ 100.8419 (3) 1,368 I Bratenahl Investments, Ltd. Common Stock 01/30/2012   S   1,368 D $ 101.9024 (4) 0 I Bratenahl Investments, Ltd.

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Stock Option

$ 6.68

01/30/2012

M

33,000

09/30/2004

08/05/2013

Common Stock

33,000

$ 0

109,623

D

Stock Option

$ 6.68

01/30/2012

M

2,500

09/30/2004

08/05/2013

Common Stock

2,500

$ 0

8,180

I

Bratenahl Investments, Ltd.

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Howley W Nicholas 1301 EAST NINTH STREET SUITE 3710 CLEVELAND, OH 44114	X		Chief Executive Officer

Signatures

Halle Fine Terrion as attorney in fact for W. Nicholas Howley		01/31/2012
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(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)	Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $100.25 - $101.22. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
(2)	Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $101.28 - $102.25. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
(3)	Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $100.43 - $101.28. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
(4)	Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $101.51 - $102.15. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
Remarks: All transactions reported hereunder made pursuant to an established 10b5-1 plan.

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