Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 970-84, RB211-Trent 970B-84, RB211- Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84, and RB211-Trent 980-84 turbofan engines. This AD requires inspections of the low-pressure turbine exhaust case and support assembly or tail bearing housing (TBH) to detect cracks or damage. This AD was prompted by an RR structural re-analysis indicating that the TBH may not retain full limit load capability in all fail-safe conditions. We are issuing this AD to prevent failure of the TBH, resulting in damage to the engine and damage to the airplane.