Airworthiness Directive · Amendment 39-12040 · Pratt & Whitney PW4000 Series Turbofan Engines.
Pratt & Whitney PW4000 Series Turbofan Engines.
Superseded. A later AD replaced this one: AD 2001-05-07. Comply with the one in force.
This airworthiness directive is applicable to Pratt & Whitney (PW) PW4052, PW4056, PW4060, PW4060A, PW4062, PW4152, PW4156, PW4156A, PW4158, PW4164, PW4168, PW4168A, PW4460, and PW4462 turbofan engines, with low pressure turbine (LPT) 4th stage air seal, part number (P/N) 50N478 or P/N 50N478-001 installed. These engines are installed on but not limited to Boeing 747, 767, McDonnell Douglas MD-11, Airbus Industrie A300, A310, and A330 series airplanes.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney (PW) PW4000 turbofan engines with the current design low pressure turbine (LPT) 4th stage air seal installed. This action requires, based on engine model, replacement of the current design seal with a new design seal, or with a modified seal. This amendment is prompted by reports of cracks in LPT 4th stage air seals. The actions specified by this AD are intended to reduce stresses that could lead to LPT 4th stage air seal cracking, resulting in seal fracture, uncontained engine failure, and damage to the airplane.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
