UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

o

Rule 13d-1(b)

x

Rule 13d-1(c)

o

Rule 13d-1(d)

1

Names of Reporting Persons.
Matrix Capital Management Company LLC

2

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

3

SEC Use Only

4

Citizenship or Place of Organization
Delaware

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5

Sole Voting Power
2,942,208 shares

6

Shared Voting Power
Not Applicable

7

Sole Dispositive Power
2,942,208 shares

8

Shared Dispositive Power
Not Applicable

9

Aggregate Amount Beneficially Owned by Each Reporting Person
2,942,208 shares

10

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* o

11

Percent of Class Represented by Amount in Row 9
6.1%

12

Type of Reporting (See Instructions)
IA, OO

1

Names of Reporting Persons.
David E. Goel

2

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

3

SEC Use Only

4

Citizenship or Place of Organization
Canada

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5

Sole Voting Power
2,942,208 shares

6

Shared Voting Power
Not Applicable

7

Sole Dispositive Power
2,942,208 shares

8

Shared Dispositive Power
Not Applicable

9

Aggregate Amount Beneficially Owned by Each Reporting Person
2,942,208 shares

10

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* o

11

Percent of Class Represented by Amount in Row 9
6.1%

12

Type of Reporting (See Instructions)
IN

Item 1(a).

Name of Issuer:
TransDigm Group Incorporated

Item 1(b).

Address of Issuer’s Principal Executive Offices:
1301 East 9th Street, Suite 3710

Cleveland, Ohio 44114

Item 2(a).

Name of Person(s) Filing:
Matrix Capital Management Company LLC

David E. Goel

Item 2(b).

Address of Principal Business Office or, if none, Residence:
Each of the Reporting Persons has its business address at:

Bay Colony Corporate Center

1000 Winter Street

Suite 4500

Waltham, MA 02451

Item 2(c).

Citizenship or Place of Organization:
Matrix Capital Management Company LLC is organized under the laws of the State of Delaware.

David E. Goel is a Canadian citizen.

Item 2(d).

Title of Class of Securities:
Common Stock, par value $0.01 per share.

Item 2(e).

CUSIP Number:
893641100

Item 3.

If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), check whether the person filing is a:

a.

o

Broker or dealer registered under section 15 of the Act.

b.

o

Bank as defined in section 3(a)(6) of the Act.

c.

o

Insurance company as defined in section 3(a)(19) of the Act.

d.

o

Investment company registered under section 8 of the Investment Company Act of 1940.

e.

o

An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

f.

o

An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

g.

o

A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);

h.

o

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

i.

o

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940;

j.

o

A non-U.S. institution in accordance with § 240.13d–1(b)(1)(ii)(J);

k.

o

Group, in accordance with § 240.13d–1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with

§ 240.13d–1(b)(1)(ii)(J), please specify the type of institution:____________________________

Item 4.

Ownership

Matrix Capital Management Company LLC, in its capacity as an investment adviser, has the sole right to vote and dispose of the Issuer’s Common Stock.  David E. Goel is the Managing Member of Matrix Capital Management Company LLC.  Matrix Capital Management Company LLC and Mr. Goel disclaim beneficial ownership of the Common Stock of the Issuer.

(a)

Amount beneficially owned:

2,942,208 shares of Common Stock

(b)

Percent of class:   

6.1%

(c)

Number of shares as to which the person has:

(1)

Sole power to vote or direct the vote:   

2,942,208 shares of Common Stock

(2)

Shared power to vote or direct the vote:    

None.

(3)

Sole power to dispose or direct the disposition of:

2,942,208 shares of Common Stock

(4)

Shared power to dispose or direct the disposition of:

None.

Item 5.

Ownership of Five Percent or Less of a Class:

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5% of the class of securities, check the following:  o

Item 6.

Ownership of More than Five Percent on Behalf of Another Person:

Not Applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company:

Not Applicable.

Item 8.

Identification and Classification of Members of the Group:

Not Applicable.

Item 9.

Notice of Dissolution of Group:

Not Applicable.

Item 10.

Certification:

Each of the Reporting Persons hereby makes the following certification:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Matrix Capital Management Company LLC

By:

/s/ David E. Goel

David E. Goel

Managing Member

/s/ David E. Goel

David E. Goel

Matrix Capital Management Company LLC

By:

/s/ David E. Goel

David E. Goel

Managing Member

/s/ David E. Goel

David E. Goel