Is AD 98-11-01 a recurring Airworthiness Directive?

No — AD 98-11-01 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 98-11-01 apply to?

AD 98-11-01 applies to Pilatus — models PC-12. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 98-11-01

one-time

Official AD 98-11-01 · FR doc 98-13060 · 1998-05-18 · airframe

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

What this AD requires

This amendment supersedes Airworthiness Directive (AD) 97-23- 04, which currently requires replacing the fuel tank vent valves with modified fuel tank vent valves on certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. This AD retains the fuel tank vent valves replacement required by AD 97-23-04, and requires drilling a 4.8 millimeter (0.1875 inch) hole in each fuel filler cap. This AD also requires inserting a temporary revision in the Pilot's Operating Handbook (POH) that specifies checking to assure that the fuel filler cap hole is clear of ice and foreign objects. 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 98-11-01 applies to

MakesPilatus

ModelsPC-12

Requires replacement/modification of fuel tank vent valves and fuel filler caps per Pilatus SB Nos. 28-003 Rev 1 and 28-004 (or POH temporary revision) to prevent freezing of the fuel tank inward vent valve after cold soak at altitude. Model identified as PC-12 via reference to 'PC-12 Pilot's Operating Handbook' in the text; specific serial-number applicability not present in this excerpt. Alternative methods of compliance previously approved under superseded AD 97-23-04 remain valid.

Whether AD 98-11-01 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 98-11-01 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.