Airworthiness Directives; Rolls-Royce plc Turbofan Engines

We propose to supersede Airworthiness Directive (AD) 2017-03- 02, which applies to certain Rolls-Royce plc (RR) RB211 Trent 768-60, 772-60, and 772B-60 turbofan engines. AD 2017-03-02 requires initial and repetitive ultrasonic inspections (UIs) of the affected low- pressure (LP) compressor blades. Since we issued AD 2017-03-02, RR issued revised service information to reduce the inspection threshold for UIs of the affected blades. This proposed AD would retain the UIs in AD 2017-03-02 while reducing the inspection threshold. We are proposing this AD to address the unsafe condition on these products.