Is AD 2021-22-16 a recurring Airworthiness Directive?

No — AD 2021-22-16 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2021-22-16 apply to?

AD 2021-22-16 applies to Airbus Helicopters — models EC155B, EC155B1, EC155. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2021-22-16

one-time

Official AD 2021-22-16 · FR doc 2021-25703 · 2021-11-26 · airframe

Airworthiness Directives; Airbus Helicopters

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for Airbus Helicopters Model EC 155B and EC155B1 helicopters. This AD was prompted by the failure of a main gearbox (MGB) second stage planet gear. This AD requires replacing the 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 MGB filter for particles, and for certain serial-numbered planet gear assemblies, inspecting the oil sump for particles. Depending on the outcome of these inspections, this AD requires further inspections and replacing certain parts. This AD also prohibits installing certain parts. The FAA is issuing this AD to address the unsafe condition on these products.

Which aircraft AD 2021-22-16 applies to

MakesAirbus Helicopters

ModelsEC155B, EC155B1, EC155

Whether AD 2021-22-16 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 2021-22-16 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.