Is AD 2011-20-08 a recurring Airworthiness Directive?

No — AD 2011-20-08 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2011-20-08 apply to?

AD 2011-20-08 applies to Leonardo — models AB139, AW139. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2011-20-08

one-time

Official AD 2011-20-08 · FR doc 2011-27772 · 2011-11-04 · airframe

Airworthiness Directives; Agusta S.p.A. (Agusta) Model AB139 and AW139 Helicopters

What this AD requires

This amendment adopts a new airworthiness directive (AD) for the specified Agusta model helicopters. This action requires inspecting certain modules and related connectors for corrosion. If there is corrosion on the connectors, this AD requires cleaning the connectors before further flight. If there is corrosion on a module, before further flight, this AD requires replacing the module with an airworthy module. This AD also requires modifying the Number 2 Modular Avionic Unit (MAU) ventilation duct. This amendment is prompted by some in- flight emergencies due to internal corrosion of the MAU circuit card assemblies. The actions specified in this AD are intended to detect corrosion of certain modules to prevent the display of misleading data to the flight crew, disengagement of the flight director modes of the autopilot or other alert system, increased workload of the flight crew, and subsequent loss of control of the helicopter.

Which aircraft AD 2011-20-08 applies to

MakesLeonardo

ModelsAB139, AW139

Serial-conditional — narrows to serials 31005–31157, 41001–41023.

Applies to S/N 31005 through S/N 31157 (except S/Ns 31007, 31094 and 31149) and S/N 41001 through S/N 41023.

Whether AD 2011-20-08 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 2011-20-08 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.