Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61 turbofan engines. This AD requires replacement or repair of the low-pressure (LP) compressor fan blade set before reaching a specified number of flight cycles since new (FCSN) or flight cycles since last leading edge profile blade repair (FCSLR). This AD was prompted by reports of erosion of the leading edge profile of the LP compressor blade set contributing to fan blade flutter. We are issuing this AD to prevent failure of the LP compressor blades, which could lead to an uncontained engine failure and damage to the airplane.