X0303 4 2009-05-28 0 0001260221 TransDigm Group INC TDG 0001355575 TD Group Holdings, LLC C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001157334 WARBURG PINCUS PRIVATE EQUITY VIII L P C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0000929408 WARBURG PINCUS & CO C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001162870 WARBURG PINCUS LLC C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001322709 Warburg Pincus Partners LLC C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 Common Stock, par value $0.01 per share 2009-05-28 4 J 0 2082582 0 D 5249436 D See Exhibit 99.1. Exhibit List Exhibit 99.1 - Explanation of Responses Exhibit 99.2 - Joint Filers' Names and Addresses Exhibit 99.3 - Joint Filers' Signatures TD GROUP HOLDINGS, LLC By: Warburg Pincus Private Equity VIII, L.P., its Sole Member By: Warburg Pincus Partners, LLC, its General Partner By: Warburg Pincus & Co., its Managing Member /s/ Scott A. Arenare (Partner) 2009-05-29