Is AD 2006-21-09 a recurring Airworthiness Directive?

No — AD 2006-21-09 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2006-21-09 apply to?

AD 2006-21-09 applies to Boeing — models 777-200, 777. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2006-21-09

one-time

Official AD 2006-21-09 · FR doc E6-17428 · 2006-10-19 · airframe

Airworthiness Directives; Boeing Model 777-200 Series Airplanes Equipped with General Electric GE90-94B Engines

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 777-200 series airplanes equipped with General Electric GE90-94B engines. This AD requires inspecting to determine the part number of the identification plate of the torque box on the thrust reversers (TRs), and investigative and corrective actions if necessary. This AD results from engine certification testing which revealed that TRs on GE90-94B engines have inner walls that could develop disbonding in the upper bifurcation radii. Disbonding was found in an equivalent inner wall used during the testing. We are issuing this AD to prevent failure of a TR and adjacent components and their consequent separation from the airplane during flight or during a refused takeoff (RTO). These separated components could cause structural damage to the airplane or damage to other airplanes and possible injury to people on the ground. TR failure during a RTO could also cause the engine to produce forward thrust, resulting in asymmetric thrust and possible runway excursion.

Which aircraft AD 2006-21-09 applies to

MakesBoeing

Models777-200, 777

Applies to 777-200 series airplanes equipped with General Electric GE90-94B engines, as identified in Boeing Alert Service Bulletin 777-78A0056, dated April 20, 2006.

Whether AD 2006-21-09 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 2006-21-09 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.