Airworthiness Directives; Rolls-Royce plc. RB211 Trent Turbofan Engines

This amendment supersedes an existing airworthiness directive (AD) that is applicable to Rolls-Royce plc. (RR) RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines. That AD currently requires the removal of low pressure compressor (LPC) fan blades, initial and repetitive ultrasonic inspections for cracks in LPC fan blade dovetail roots, and if necessary, replacement with serviceable parts. This amendment requires earlier initial and more frequent repetitive ultrasonic inspections of LPC fan blades, with inspection thresholds and intervals specified by engine model. This amendment is prompted by data collected by RR, that identifies the need to inspect LPC fan blade dovetail roots at an earlier initial threshold and at more frequent intervals than is required by the existing AD. The actions specified in this AD are intended to prevent possible multiple LPC fan blade failures, which could result in an uncontained engine failure and damage to the airplane.