Airworthiness Directives; Rolls-Royce plc 524 Series and Trent 768-60 and 772-60 Turbofan Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) RB211-524G2-T-19; RB211-524G3-T- 19; RB211-524H2-T-19; RB211 Trent 768-60; and RB211 Trent 772-60 turbofan engines. This AD requires the replacement of the joint bolt assemblies that secure the high-pressure compressor (HPC) to the high- pressure turbine (HPT) of the RB211-524 series and Trent 768 and 772 series turbofan engines. This amendment is prompted by six incidents of bolt failure, one of which resulted in a damaged stage 6 HPC disk following an impact with a separated bolt head. The actions specified in this AD are intended to prevent failure of the HPC-to-HPT joint bolt assemblies, which could result in a cracked stage 6 HPC disk, possible uncontained engine failure, and damage to the airplane.