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Airworthiness Directive 2007-26-20

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Official AD 2007-26-20 · FR doc E7-25505 · 2008-01-03 · turbine engine

Airworthiness Directives; Pratt & Whitney (PW) PW4164, PW4168, and PW4168A Turbofan Engines

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for PW PW4164, PW4168, and PW4168A turbofan engines with certain low pressure turbine (LPT) stage 4 disks, part number (P/N) 51N404, installed. This AD requires removing certain LPT stage 4 disks, listed by serial number at the next piece-part exposure or within 7,500 cycles-since-new (CSN). This AD results from a report of improperly manufactured LPT stage 4 disks. We are issuing this AD to prevent an uncontained engine failure due to low-cycle fatigue (LCF), which could result in damage to the airplane.

Which aircraft AD 2007-26-20 applies to

MakesPratt & Whitney
ModelsPW4164, PW4168, PW4168A
Serial-conditional — narrows to serials CLDLC01142–CLDLC01142, CLDLC01143–CLDLC01143, CLDLC01144–CLDLC01144, CLDLC01145–CLDLC01145, CLDLC01146–CLDLC01146, CLDLC01148–CLDLC01148, CLDLC01149–CLDLC01149, CLDLC01150–CLDLC01150, CLDLC01151–CLDLC01151, CLDLC01152–CLDLC01152, CLDLC01181–CLDLC01181, CLDLC01182–CLDLC01182, CLDLC01183–CLDLC01183, CLDLC01185–CLDLC01185, CLDLC01186–CLDLC01186, CLDLC01187–CLDLC01187.
Part-conditional — 51N404.

Applies only to engines with LPT stage 4 disk P/N 51N404 bearing one of the specific serial numbers listed in AD Table 1 (a discrete list of affected serial numbers, not a continuous range).

Whether AD 2007-26-20 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 2007-26-20 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.