Is AD 98-8579 a recurring Airworthiness Directive?

No — AD 98-8579 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 98-8579 apply to?

AD 98-8579 applies to Twin Commander — models 500, 520, 560, 680, 681, 685, 690, 695. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 98-8579

one-time

AD 98-8579 · 1998-04-06 · airframe

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 520, 560, 680, 681, 685, 690, 695, and 720 Series Airplanes

What this AD requires

This amendment supersedes Airworthiness Directive (AD) 94-04- 17, which currently requires the following on Twin Commander Aircraft Corporation (Twin Commander) 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes: inspecting (one-time) the flap system for cables with broken wires or pulleys with worn cable clips, replacing any damaged parts, and replacing the master pulley and cable with new parts of improved design. This AD requires inspecting all flap system cable grooves for the correct width, inspecting all flap system pulleys for rubbing on the support brackets, inspecting all flap pulley cable assemblies for frayed wires, and reworking or replacing any parts with discrepancies. This AD results from several reports of worn and frayed flap system cables attributed to flap pulley grooves that are too narrow. The actions specified by this AD are intended to prevent failure of a flap system cable caused by fatigue, which could result in loss of control of the airplane.

Which aircraft AD 98-8579 applies to

MakesTwin Commander

Models500, 520, 560, 680, 681, 685, 690, 695, 720

applicability derived from the AD summary — confirm the model/serial from the records

Whether AD 98-8579 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 98-8579 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.