AD 2012-18-14
Effective 10/22/2012 · Published 09/17/2012
Airworthiness Directives; Pratt & Whitney Canada, Auxiliary Power Units
Summary
We are adopting a new airworthiness directive (AD) for certain serial numbers of Pratt & Whitney Canada (P&WC) PW901A auxiliary power units (APUs) approved under Technical Standard Order TSO-C77A and installed on, but not limited to, Boeing 747-400 series airplanes. This AD requires modifications of the rear gas generator case, exhaust duct support, and turbine exhaust duct flanges. This AD was prompted by several e…