Is AD 2021-18-06 a recurring Airworthiness Directive?

No — AD 2021-18-06 is a one-time directive. Verify it was complied with in the aircraft's records.

Airworthiness Directive 2021-18-06

Q: Which aircraft does AD 2021-18-06 apply to?

AD 2021-18-06 applies to Airbus Helicopters — models EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, AS 365 N3, EC155, SA-365. Serial/part conditions may narrow it to specific aircraft.

one-time

Official AD 2021-18-06 · FR doc 2021-18441 · 2021-08-26 · airframe

Airworthiness Directives; Airbus Helicopters

What this AD requires

The FAA is superseding Airworthiness Directive (AD) 2021-11- 03, which applied to certain Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters. AD 2021-11-03 required inspecting the main gearbox (MGB) fixed cowling front fitting (MGB front fitting), and depending on findings, corrective action. This AD retains the requirements of AD 2021-11-03, and includes service information that was omitted for Airbus Helicopter Model EC 155B and EC155B1 helicopters, as specified in a European Aviation Safety Agency (now European Union Aviation Safety Agency) (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

Which aircraft AD 2021-18-06 applies to

MakesAirbus Helicopters

ModelsEC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, AS 365 N3, EC155, SA-365, AS-365

Applicability limited to the specific helicopters identified in EASA AD 2019-0008, dated January 22, 2019.

Whether AD 2021-18-06 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 2021-18-06 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.