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Airworthiness Directive 2011-21-18

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Official AD 2011-21-18 · FR doc 2011-30939 · 2011-12-05 · airframe

Airworthiness Directives; Eurocopter France Model EC 120B Helicopters

What this AD requires

This amendment adopts a new airworthiness directive (AD) for the Eurocopter France Model EC 120B helicopters. This AD requires modifying the pilot cyclic control friction device by replacing a certain thrust washer with two thrust washers. This AD is prompted by an incident in which the pilot encountered a sudden restriction of the cyclic control movement during flight. The actions specified by this AD are intended to prevent jamming of a pilot cyclic control stick and subsequent loss of control of the helicopter.

Which aircraft AD 2011-21-18 applies to

MakesEurocopter
ModelsEC120B, EC120
Serial-conditional — narrows to serials ?–1385.
Part-conditional — C671A1006201, C671A1007101, C671A1007102, C671A1003102.

Applies to helicopters with serial numbers up to and including 1385, with thrust washer P/N C671A1006201 installed on the pilot cyclic control stick friction device, and a pilot cyclic stick P/N C671A1007101, C671A1007102, or C671A1003102 installed.

Whether AD 2011-21-18 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 2011-21-18 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.