Is AD 98-20-28 a recurring Airworthiness Directive?

No — AD 98-20-28 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 98-20-28 apply to?

AD 98-20-28 applies to Pilatus — models PC-12, PC-12/45. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 98-20-28

one-time

Official AD 98-20-28 · FR doc 98-25478 · 1998-09-24 · 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. Models PC-12 and PC-12/45 airplanes. This AD requires revising the FAA-approved Airplane Flight Manual (AFM) to specify procedures that would prohibit flight in severe icing conditions (as determined by certain visual cues), limit or prohibit the use of various flight control devices while in severe icing conditions, and provide the flight crew with recognition cues for, and procedures for exiting from, severe icing conditions. This AD is prompted by the results of a review of the requirements for certification of these airplanes in icing conditions, new information on the icing environment, and icing data provided currently to the flight crew. The actions specified by this AD are intended to minimize the potential hazards associated with operating these airplanes in severe icing conditions by providing more clearly defined procedures and limitations associated with such conditions.

Which aircraft AD 98-20-28 applies to

MakesPilatus

ModelsPC-12, PC-12/45

Whether AD 98-20-28 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 98-20-28 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.