Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) RB211 Trent 875, Trent 877, Trent 884, Trent 892, Trent 892B, and Trent 895 turbofan engines with high pressure (HP) compressor rotor rear stage 5 and 6 discs and cone shafts, part numbers (P/Ns) FK25230 and FK27899 installed. This proposal would require removal from service of these HP compressor rotor rear stage 5 and 6 discs and cone shafts, before reaching newly reduced life limits. This proposal is prompted by three reports of crack indications in the stage 5 and stage 6 blade loading slots, found during engine overhaul. The actions specified by the proposed AD are intended to prevent crack initiation and propagation leading to uncontained disc failure and damage to the airplane.