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

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.