Is AD 2021-05-05 a recurring Airworthiness Directive?

Yes — AD 2021-05-05 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Airworthiness Directive 2021-05-05

Q: Which aircraft does AD 2021-05-05 apply to?

AD 2021-05-05 applies to Airbus Helicopters — models SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC155B, EC155B1, AS365, SA366. Serial/part conditions may narrow it to specific aircraft.

recurring

Official AD 2021-05-05 · FR doc 2021-05142 · 2021-03-12 · airframe

Airworthiness Directives; Airbus Helicopters

What this AD requires

The FAA is superseding Airworthiness Directive (AD) 2016-23- 05, which applied to certain Airbus Helicopters Model SA-365N1, AS- 365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. AD 2016- 23-05 required repetitive checks of the oil level of the tail rotor gearbox and, if necessary, filling the oil to the maximum level; and replacement of a certain control rod double bearing (bearing) with a new bearing. This AD retains the requirements of AD 2016-23-05 and also requires modifying the helicopter by replacing the tail gearbox (TGB) control shaft guide bushes; repetitive inspections of the TGB magnetic plug and corrective actions if necessary; repetitive replacements of the bearing; and modifying the helicopter by replacing the TGB; as specified in a European Aviation Safety Agency (now European Union Aviation Safety Agency) (EASA) AD, which is incorporated by reference. This AD also adds helicopters to the applicability. This AD was prompted by reports of occurrences of loss of yaw control due to failure of the TGB bearing. The FAA is issuing this AD to address the unsafe condition on these products.

Repetitive inspection. Re-inspect. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 2021-05-05 applies to

MakesAirbus Helicopters

ModelsSA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC155B, EC155B1, AS365, SA366, EC155

Applies to all serial numbers, certificated in any category.

Whether AD 2021-05-05 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 2021-05-05 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.