Airworthiness Directives; Rolls-Royce plc Turbofan Engines

We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211 Trent 875-17, 877-17, 884-17, 884B-17, 892- 17, 892B-17, and 895-17 turbofan engines. This AD requires modification of the engine by installing upgraded software in the electronic engine control (EEC) or by removing any EEC that incorporates a software standard prior to B7.2 and installing an EEC eligible for installation. This AD was prompted by failure of the intermediate pressure (IP) turbine disk drive arm and subsequent overspeed and burst of the IP turbine disk on an RR RB211 Trent turbofan engine. We are issuing this AD to prevent overspeed of the IP turbine disk, resulting in failure of the turbine blades or the IP turbine disk and subsequent uncontained release of the turbine disk and/or blades, which could lead to damage to the engine and damage to the airplane.