Summary
We propose to supersede airworthiness directive (AD) 2014-16-10 that applies to all Rolls-Royce plc (RR) RB211 Trent 768-60, 772-60, and 772B-60 turbofan engines. AD 2014-16-10 requires initial and repetitive ultrasonic inspections (UIs) of the affected low-pressure (LP) compressor blades. Since we issued AD 2014-16-10, RR issued revised service information to reduce the inspection threshold. This proposed AD would retain the UIs in AD 2014-16-10 while applying the revised inspection threshold. We are proposing this AD to prevent LP compressor blade airfoil separations, damage to the engine, and damage to the airplane.