Is AD 2004-15-21 a recurring Airworthiness Directive?

No — AD 2004-15-21 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2004-15-21 apply to?

AD 2004-15-21 applies to Agusta — models A109K2, A109. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2004-15-21

one-time

Official AD 2004-15-21 · FR doc 04-17369 · 2004-08-02 · airframe

Airworthiness Directives; Agusta S.p.A. Model A109K2 Helicopters

What this AD requires

This amendment adopts a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model A109K2 helicopters. This action requires dye-penetrant inspecting the tail rotor trunnion (trunnion) assembly for a crack at specified intervals, replacing any cracked trunnion with an airworthy trunnion, and reporting any failed trunnion. This amendment is prompted by the report of an accident involving a tail rotor hub and blade assembly separating from the helicopter due to fatigue failure of the trunnion. The cause for the crack in the trunnion has not been determined and is still under investigation. This condition, if not detected, could result in failure of the trunnion, loss of the tail rotor hub and blade assembly, and subsequent loss of control of the helicopter.

Which aircraft AD 2004-15-21 applies to

MakesAgusta

ModelsA109K2, A109

Part-conditional — 109-0131-05.

Applies only to A109K2 helicopters with tail rotor trunnion assembly P/N 109-0131-05 (all dash numbers) installed.

Whether AD 2004-15-21 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 2004-15-21 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.