Action
Final rule.
Summary
We are adopting 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 AD was prompted by reports 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 AD requires repetitive inspections for cracks and heat damage to the strut aft fairing lower spar web structure (a flammable fluid zone barrier), for wear to the heat shield primary seal, and, as applicable, for heat and wear damage to heat shield insulation blankets; and related investigative and corrective actions if necessary. This AD also provides optional terminating action for the repetitive inspections. We are issuing this AD to detect and correct cracks and heat damage to the strut aft fairing lower spar web structure (a flammable fluid zone barrier), wear to the heat shield primary seal, and heat and wear damage to heat shield insulation blankets, which could lead to through-cracks in the aft fairing lower web structure and heating of the aft fairing lower web structure, and consequent uncontrolled fire in the aft fairing, fuel tank ignition or possible departure of the engine.