Is AD 2010-05-51 a recurring Airworthiness Directive?

No — AD 2010-05-51 is a one-time directive. Verify it was complied with in the aircraft's records.

Airworthiness Directive 2010-05-51

Q: Which aircraft does AD 2010-05-51 apply to?

Applicability depends on the aircraft's type certificate; check it against the specific tail.

one-time

Official AD 2010-05-51 · FR doc 2010-9007 · 2010-04-29 · airframe

Airworthiness Directives; Eurocopter France (ECF) Model EC120B Helicopters

What this AD requires

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2010-05-51, which was sent previously to all known U.S. owners and operators of ECF Model EC120B helicopters by individual letters. This AD requires, at specified intervals, inspecting the main rotor head rotor hub (rotor hub) for a crack. If you find scoring, paint flaking or left-over identification plate adhesive, the AD requires sanding the area until the primer coat becomes visible and inspecting the rotor hub for a crack. If you find a crack, the AD requires, before further flight, replacing the rotor hub with an airworthy rotor hub. This amendment is prompted by a mandatory continuing airworthiness information (MCAI) AD issued by the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community. The MCAI AD states that ECF has been informed of an emergency landing due to excessive vibrations originating from the main rotor. After an investigation, it was determined that the main rotor head rotor hub (rotor hub) had failed in the attachment area of one of the three drag damper fittings. The actions specified by the AD are intended to prevent failure of a hub, excessive vibrations, loss of a main rotor blade, and subsequent loss of control of the helicopter.

Which aircraft AD 2010-05-51 applies to

Applicability depends on the aircraft’s type certificate — check it against the specific tail.

Whether AD 2010-05-51 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 2010-05-51 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.