Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 777-200 and -300 series airplanes equipped with Rolls-Royce Trent 800 series engines. This proposed AD was prompted by a report of multiple cases of heat damage to the strut aft fairing heat shield primary seal, as well as heat and wear damage to the heat shield insulation blankets. This proposed AD would require repetitive inspections for heat damage to the strut aft fairing lower spar web structure (a flammable fluid zone barrier and fire wall) and heat shield primary seal, and heat and wear damage to heat shield insulation blankets; and related investigative and corrective actions if necessary. This proposed AD would also provide optional terminating action for the repetitive inspections. We are proposing this AD to detect and correct heat damage to the strut aft fairing lower spar web structure and heat shield primary seal, as well as heat and wear damage to the heat shield insulation blankets, which could lead to through- cracks in the aft fairing web structure and heating of the aft fairing web structure, and consequent uncontrolled fire in the aft fairing, fuel tank ignition or possible departure of the engine, and subsequent loss of the airplane. 3