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Airworthiness Directive 2001-17-30

recurring
Official AD 2001-17-30 · FR doc 01-21893 · 2001-08-30 · turbine engine

Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD), that is applicable to Pratt & Whitney JT9D-7R4 series turbofan engines. This amendment requires initial and repetitive fluorescent penetrant inspection (FPI) of the high pressure turbine (HPT) 1st stage disk aft lugs, and if the aft lug(s) are cracked, replacement of the HPT 1st stage disk and HPT 1st stage airseals. Also, for certain configuration HPT disk assemblies, this amendment requires replacement of the HPT 1st stage airseals with newly designed airseals at the next accessibility. This amendment is prompted by reports of cracks in HPT 1st stage disk firtrees and failure of firtree lugs. The actions specified by this AD are intended to prevent 1st stage HPT disk firtree fracture, which could result in an uncontained engine failure, and damage to the airplane.

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 2001-17-30 applies to

MakesPratt & Whitney
ModelsJT9D-7R4, JT9D
Part-conditional — 787521, 797621, 820121, 825701, 827201, 829401, 797355, 796760.

Applies to JT9D-7R4 series turbofan engines with HPT 1st stage disk assembly P/N 787521 or P/N 797621; requires HPT 1st stage airseal replacement (to P/N 820121) at next piece-part opportunity per PW SB JT9D-7R4-72-566, and FPI inspection of the disk aft lug fillet radius with initial/repetitive intervals that vary by the specific disk/airseal part-number combination per Table 1 (table truncated in source).

Whether AD 2001-17-30 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 2001-17-30 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.