Is AD 2001-25-11 a recurring Airworthiness Directive?

Yes — AD 2001-25-11 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2001-25-11 apply to?

AD 2001-25-11 applies to Pratt & Whitney — models PW4000. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2001-25-11

recurring

Official AD 2001-25-11 · FR doc 01-31296 · 2002-01-02 · turbine engine

Airworthiness Directives; Pratt and Whitney PW4000 Series Turbofan Engines

What this AD requires

This amendment supersedes two airworthiness directives (AD's), AD 99-17-16 and AD 2001-15-12. Those AD's both apply to Pratt and Whitney (PW) model PW4000 series turbofan engines. AD 99-17-16 generally requires that operators limit the number of PW4000 engines with potentially reduced stability margin to no more than one engine on each airplane, and requires initial and repetitive on-wing and test cell engine stability tests. It also establishes reporting requirements for stability testing data. AD 2001-15-12 also limits the number of PW4000 engines with potentially reduced stability on each airplane by applying rules based on airplane and engine configuration. In addition, AD 2001-15-12 also requires that engines that exceed high pressure compressor (HPC) cyclic limits based on cycles-since-overhaul (CSO) are removed from service, limits the number of engines with the HPC cutback stator (CBS) configuration to one on each airplane, and establishes a minimum rebuild standard for engines that are returned to service. These AD's were prompted by reports of surges during takeoff on airplanes equipped with PW4000 series turbofan engines. This amendment continues the limitation on the number of PW4000 engines with potentially reduced stability on each airplane to no more than one, and introduces a new cool engine fuel spike test to allow engines to be returned to service after having exceeded cyclic limits or undergone work in the shop. This AD also continues the limitation on the number of engines with HPC CBS configuration to one on each airplane, places a cyclic limit on how long a CBS engine may remain in service, and establishes a minimum rebuild standard for engines that are returned to service. This amendment is prompted by further analyses of compressor surges in PW4000 engines, and continuing reports of surges in the PW4000 fleet. The actions specified by this AD are intended to prevent engine power losses due to HPC surge.

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 2001-25-11 applies to

MakesPratt & Whitney

ModelsPW4000

Applies to Pratt & Whitney PW4000-series engines; required action depends on engine configuration/category (Phase 1, Phase 1 with HPT 1st-turbine-vane-cut-back per any revision of SB PW4ENG 72-514, Phase 3, etc.) determined per the AD's configuration table, to prevent HPC surge.

Whether AD 2001-25-11 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 2001-25-11 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.