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 98-20439 · 1998-07-31 · airframe

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

What this AD requires

This amendment clarifies information contained in Airworthiness Directive (AD) 98-11-01 R1, which currently requires replacing the fuel tank vent valves and drilling a 4.8 millimeter (0.1875 inch) hole in each fuel filler cap on certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. AD 98-11-01 R1 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. The intent of AD 98-11-01 R1 was to provide the option of incorporating new modified fuel tank vent valves instead of the replacement, drilling, and POH insertion requirements. The new modified vent valves cannot be incorporated without removing the fuel tank vent valves installed as originally required by AD 97-23-04 and carried over in the current AD. This provision of removing those vent valves is currently not provided for. This document clarifies and corrects this procedure. The actions specified in this AD are intended to continue to prevent moisture from entering the fuel tank inward vent valve and then freezing after a cold soak at altitude, which 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, 28-004, and 28-005 (or POH temporary revision) to prevent moisture ingress/freezing in the fuel tank inward vent valve. 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.

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.