Airworthiness Directive 2000-25-06
one-timeAirworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines.
What this AD requires
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.
Which aircraft AD 2000-25-06 applies to
Applies only to engines with low pressure turbine (LPT) 4th stage air seal P/N 50N478 or P/N 50N478-001 installed. Installed on but not limited to Boeing 747, 767, McDonnell Douglas MD-11, Airbus A300, A310, and A330 series airplanes.
Whether AD 2000-25-06 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.