Is AD 97-23-04 a recurring Airworthiness Directive?

No — AD 97-23-04 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 97-23-04 apply to?

AD 97-23-04 applies to Pilatus. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 97-23-04

one-time

Official AD 97-23-04 · FR doc 97-29236 · 1997-11-06 · airframe

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

What this AD requires

This amendment adopts a new airworthiness directive (AD) that applies to Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. This AD requires replacing the fuel tank vent valves with modified fuel tank vent valves. This AD is the result of mandatory continued airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to prevent the fuel tank inward vent valve from freezing, which, if followed by a cold soak at altitude, could result in wing airfoil distortion and structural damage with consequent degradation of the airplane's handling qualities.

Which aircraft AD 97-23-04 applies to

MakesPilatus

Specific model/serial applicability list is in the preceding applicability provision, not present in this excerpt. Requires replacing fuel tank inward vent valves per Pilatus Service Bulletin No. 28-003, Revision 1, to prevent valve freezing and resulting wing airfoil distortion (also addressed by Swiss AD HB 97-432A).

Whether AD 97-23-04 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 97-23-04 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.