Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede airworthiness directive (AD) 2013-12- 01 that applies to all Rolls-Royce plc (RR) model RB211 Trent 768-60, 772-60, and 772B-60 turbofan engines. AD 2013-12-01 requires a one-time ultrasonic inspection (UI) of low-pressure (LP) compressor blades with more than 2,500 flight cycles since new or last inspection. Since we issued AD 2013-12-01, RR determined that repetitive UIs of the LP compressor blades are needed. This proposed AD would require initial and repetitive UIs of the affected LP compressor blades. We are proposing this AD to prevent LP compressor blade airfoil separations, damage to the engine, and damage to the airplane.