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Airworthiness Directive 01-4890

recurring
AD 01-4890 · 2001-03-06 · turbine engine

Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines. This amendment requires initial and repetitive detailed eddy current inspections for cracks in 1st stage high pressure turbine (HPT) disks, and, if necessary, replacement with serviceable parts. This amendment is prompted by the discovery of a crack in the web of one cooling air hole on a 1st stage HPT disk. The actions specified by this AD are intended to prevent 1st stage HPT disk cracking, which could result in an uncontained engine failure and damage to the aircraft.

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 01-4890 applies to

MakesPratt & Whitney
ModelsJT9D-7R4D, JT9D-7R4D1, JT9D-7R4E, JT9D-7R4E1, JT9D-7, JT9D-7A, JT9D-7AH, JT9D-7H, JT9D-7F, JT9D-20, JT9D

JT9D-7R4E1 engines are also referred to as AI-500.

Whether AD 01-4890 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 01-4890 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.