Is AD 2001-20-02 a recurring Airworthiness Directive?

Yes — AD 2001-20-02 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2001-20-02 apply to?

AD 2001-20-02 applies to Pratt & Whitney — models PW4000-112, PW4000. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2001-20-02

recurring

Official AD 2001-20-02 · FR doc 01-24273 · 2001-10-01 · turbine engine

Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD), that is applicable to Pratt & Whitney (PW) PW4000 series turbofan engines with 2nd stage high pressure turbine (HPT) air seal assembly part number (P/N) 50L976 or P/N 50L960 installed. This amendment requires operators to recalculate 2nd stage HPT air seal assembly cycles-in- service, based on flight hour-to-cycle ratio usage. This amendment also requires upon recalculation, initial and repetitive on-wing borescope inspections of 2nd stage HPT air seal assemblies for cracks based on the newly calculated service life. This amendment also requires the removal from service of any cracked seal assemblies, and the removal of seal assemblies at or before newly calculated service life limits. This amendment is prompted by reports that thirteen 2nd stage HPT air seal assemblies have been found cracked in the rim area. Although these thirteen air seals were operating in the hottest configuration design, which is no longer in service, the current design 2nd stage HPT air seal assemblies are still operating in a temperature environment that is hotter than anticipated. The actions specified by this AD are intended to prevent 2nd stage HPT air seal assembly fracture that could result in an uncontained engine failure.

Repetitive inspection. Re-inspect. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 2001-20-02 applies to

MakesPratt & Whitney

ModelsPW4000-112, PW4000

Applies to engines with 2nd stage HPT air seal assemblies per PW Alert SB PW4G-112-A72-233 Rev 3 (bulletin-number prefix indicates the PW4000-112 variant); requires hour-to-cycle ratio calculation, borescope inspection, and new cycle limits for the air seal assemblies.

Whether AD 2001-20-02 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:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.

Date — When the work was done.

Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.

Signature & certificate — The A&P/IA who returned it to service, with certificate number.

Is AD 2001-20-02 complied with on your aircraft?

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.