Action
Final rule.
Summary
We are superseding airworthiness directive (AD) 2014-16-10 for all Rolls-Royce plc (RR) RB211 Trent 768-60, 772-60, and 772B-60 turbofan engines. AD 2014-16-10 required initial and repetitive ultrasonic inspections (UIs) of the affected low-pressure (LP) compressor blades. This AD requires the UIs in AD 2014-16-10 while reducing the inspection threshold. This AD was prompted by revised service information to reduce the inspection threshold for UI of the LP compressor blades. We are issuing this AD to correct the unsafe condition on these products.