Is AD 99-11780 a recurring Airworthiness Directive?

No — AD 99-11780 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 99-11780 apply to?

AD 99-11780 applies to Pilatus — models 45, PC-12. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-11780

one-time

AD 99-11780 · 1999-05-11 · airframe

Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-12 and PC-12/45 Airplanes

What this AD requires

This action confirms the effective date of Airworthiness Directive (AD) 99-06-17, which applies to certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. AD 99-06-17 requires installing a support bracket and a cut-out relay for the second generator control unit. AD 99-06-17 also requires making all the wiring additions and adjustments necessary for the above-referenced installations. This AD was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified in this AD are intended to prevent damage to electrical components because incorrectly connected cables or broken or damaged wires cause excessive voltages to the second generator, which could result in loss of electrical power during any phase of flight.

Which aircraft AD 99-11780 applies to

MakesPilatus

Models45, PC-12

certain

Whether AD 99-11780 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 99-11780 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.