Is AD 2011-25-12 a recurring Airworthiness Directive?

No — AD 2011-25-12 is a one-time directive. Verify it was complied with in the aircraft's records.

Airworthiness Directive 2011-25-12

Q: Which aircraft does AD 2011-25-12 apply to?

AD 2011-25-12 applies to Pratt & Whitney Canada — models PT6A-15AG, PT6A-27, PT6A-28, PT6A-34, PT6A-34AG, PT6A-34B, PT6A-36, PT6A. Serial/part conditions may narrow it to specific aircraft.

one-time

Official AD 2011-25-12 · FR doc 2011-31868 · 2011-12-13 · turboprop engine

Airworthiness Directives; Pratt & Whitney Canada Turboprop Engines

What this AD requires

We are adopting a new airworthiness directive (AD) for Pratt & Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, and -36 series turboprop engines. This AD requires the removal of certain affected part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage reduction sun gears and/or the interacting planetary gear sets from the propeller reduction gearbox assembly. This AD was prompted by a failure report of a certain TAATI PMA sun gear, installed since December 22, 2008. We are issuing this AD to prevent failure of the sun gear, which will result in an engine in- flight shut down, possible uncontained engine failure, aircraft damage, and serious injuries.

Which aircraft AD 2011-25-12 applies to

MakesPratt & Whitney Canada

ModelsPT6A-15AG, PT6A-27, PT6A-28, PT6A-34, PT6A-34AG, PT6A-34B, PT6A-36, PT6A

Serial-conditional — narrows to serials PC5-051–PC5-089, SG36-051–SG36-120, EE-051–EE-197, EE-4051–EE-4094, EE-4113–EE-4113.

Part-conditional — E3024765, E3101455-02.

Applies only to engines that have had maintenance done to the power section module involving first stage reduction sun gear or planetary gear set replacement since December 22, 2008, and having a TAATI PMA replacement first stage reduction sun gear, P/N E3024765 (S/N PC5-051 through PC5-089, or SG36-051 through SG36-120), installed; or a TAATI PMA replacement planetary gear set, P/N E3101455-02 (S/N EE-051 through EE-197, or EE-4051 through EE-4094, or EE-4113), installed.

Whether AD 2011-25-12 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 2011-25-12 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.