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Airworthiness Directive 2021-11081

recurring
AD 2021-11081 · 2021-05-27 · airframe

Airworthiness Directives; Carson Helicopters, Inc.; Croman Corporation; Sikorsky Aircraft Corporation; and Siller Helicopters

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for all Carson Helicopters, Inc., Model S-61L and SH-3H helicopters; Croman Corporation Model SH-3H helicopters; Sikorsky Aircraft Corporation Model S-61A, S-61D, S-61E, and S-61V helicopters; and Siller Helicopters Model CH-3E and SH-3A helicopters. This AD was prompted by an accident. This AD requires tracking hours time-in-service (TIS) and external lift cycles (lift cycles) for certain main gearbox left and right input freewheel unit (IFWU) assemblies. This AD also requires determining the type of IFWU assembly installed and depending on the results, calculating the moving average, repetitive inspections, recording certain information, replacing parts, and marking parts. The FAA is issuing this AD to address the unsafe condition on these products.

Repetitive inspection. Re-inspect every 50 hours. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 2021-11081 applies to

MakesCarson Helicopters, Inc.Croman CorporationSikorsky Aircraft CorporationSiller Helicopters
ModelsS-61L, SH-3H, S-61A, S-61D, S-61E, S-61V, CH-3E, SH-3A, S-61, SH-3, CH-3

Applies to specific manufacturer/model combinations only: Carson Helicopters, Inc. Model S-61L and SH-3H; Croman Corporation Model SH-3H; Sikorsky Aircraft Corporation Model S-61A, S-61D, S-61E, and S-61V; Siller Helicopters Model CH-3E and SH-3A; certificated in any category including restricted.

Whether AD 2021-11081 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 2021-11081 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.