Is AD 90-12-05 a recurring Airworthiness Directive?

No — AD 90-12-05 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 90-12-05 apply to?

AD 90-12-05 applies to Pratt & Whitney Canada — models PT6A series, PT6A. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 90-12-05

one-time

AD 90-12-05 · 1990-01-01 · turboprop engine

Airworthiness Directives; HEADING: PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. AC

Which aircraft AD 90-12-05 applies to

MakesPratt & Whitney Canada

ModelsPT6A series, PT6A

Applies only to PT6A series engines repaired by Gregory Flying Service/Airforce Turbine Service — confirm repair history and exact model/serial from the records

Whether AD 90-12-05 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 90-12-05 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 →

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.