Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for The Boeing Company Model 777 airplanes equipped with Rolls-Royce Trent 800 series engines. This AD was prompted by reports of in-flight separation of the engine's aft plug from the forward plug, which are the two parts of the turbine exhaust plug assembly. This AD requires installation of a serviceable turbine exhaust plug assembly (for certain airplanes), and a general visual inspection (for certain airplanes) to determine the diameter of the bolt used at the forward and aft plug interface, and applicable corrective actions. We are issuing this AD to prevent separation of the aft plug from the forward plug of the turbine exhaust plug assembly, which could result in parts departing the airplane and hitting the empennage, and destabilizing the airplane during a critical flight phase. In addition, parts remaining on a runway could pose a hazard to another airplane.