Is AD 2001-12-20 a recurring Airworthiness Directive?

Yes — AD 2001-12-20 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2001-12-20 apply to?

AD 2001-12-20 applies to General Electric — models CF6-50, CF6. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2001-12-20

recurring

Official AD 2001-12-20 · FR doc 01-15446 · 2001-06-21 · turbine engine

Airworthiness Directives; General Electric Company (GE) CF6-50 Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-50 turbofan engines. This amendment requires removal of old high pressure compressor (HPC) air ducts and mating hardware and replacement with newly designed air ducts and reworked mating hardware. This amendment also requires the repetitive inspection of certain reworked mating hardware. This amendment is prompted by reports of an uncontained low pressure turbine (LPT) disk failure that resulted from an air duct failure that caused a fan mid shaft (FMS) separation. The actions specified by this AD are intended to prevent HPC air duct failures that could result in FMS failures, that in turn could result in rejected takeoffs or uncontained LPT events, and to prevent HPC rear shaft failures that could result in uncontained engine failures.

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 2001-12-20 applies to

MakesGeneral Electric

ModelsCF6-50, CF6

Part-conditional — 9128M36G03, 9128M36G04, 9128M36G05, 9128M36G06, 9128M36G08, 9128M36G20, 9128M36G21, 1644M16G03.

At next HPC rotor exposure, replace HPC air duct assembly (P/N 9128M36 series or 1644M16G03) and mating hardware per GE SB CF6-50 72-1200; inspect rear shaft (P/N 1999M25P01-P07) per GE ASB CF6-50 72-A0958 Rev 3, to prevent HPC air duct/rear shaft failures leading to uncontained LPT/engine failure.

Whether AD 2001-12-20 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 2001-12-20 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.