Is AD 2021-12-06 a recurring Airworthiness Directive?

No — AD 2021-12-06 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2021-12-06 apply to?

AD 2021-12-06 applies to Airbus Helicopters — models AS-365N2, AS-365N3, SA-365N, SA-365N1, AS-365, SA-365. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2021-12-06

one-time

Official AD 2021-12-06 · FR doc 2021-12461 · 2021-06-15 · airframe

Airworthiness Directives; Airbus Helicopters

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for Airbus Helicopters Model AS-365N2, AS 365 N3, SA-365N, and SA-365N1 helicopters. This AD requires replacing the main gearbox (MGB), or as an alternative, replacing the epicyclic reduction gear module for certain serial numbered planet gear assemblies installed on the MGB. This AD also requires inspecting the MGB magnetic plugs and oil filter for particles. Depending on the outcome of the inspections, this AD requires further inspections and replacing certain parts. This AD was prompted by failure of an MGB second stage planet gear. The FAA is issuing this AD to correct an unsafe condition on these products.

Which aircraft AD 2021-12-06 applies to

MakesAirbus Helicopters

ModelsAS-365N2, AS-365N3, SA-365N, SA-365N1, AS-365, SA-365

Whether AD 2021-12-06 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 2021-12-06 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.