Is AD 2021-04-01 a recurring Airworthiness Directive?

No — AD 2021-04-01 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2021-04-01 apply to?

AD 2021-04-01 applies to Leonardo S.P.A. — models AB139, AW139. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2021-04-01

one-time

Official AD 2021-04-01 · FR doc 2021-05199 · 2021-03-11 · airframe

Airworthiness Directives; Leonardo S.p.a. Helicopters

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. (Leonardo) Model AB139 and AW139 helicopters. This AD requires removing certain forward facing center seats (seats). This AD was prompted by a design deficiency that affects seats on certain main cabin floor installations. The actions of this AD are intended to address an unsafe condition on these products.

Which aircraft AD 2021-04-01 applies to

MakesLeonardo S.P.A.

ModelsAB139, AW139

Serial-conditional — narrows to serials 31400–31882, 41300–41570.

Applies to helicopters within the specified S/N ranges having one or two forward-facing first-row center seats and a cabin floor composed of 3 panels, identified by configuration in Figures 1 through 13 of Leonardo Alert Service Bulletin No. 139-633, Rev. A, dated September 2, 2020.

Whether AD 2021-04-01 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 2021-04-01 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.