Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt 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 proposed AD was prompted by failure of the intermediate pressure (IP) turbine disk drive arm on an RR RB211 Trent turbofan engine. This proposed AD would require modification of the engine by removing any electronic engine control (EEC) that incorporates EEC software standard prior to version B7.2 and installing an EEC eligible for installation. We are proposing this AD to prevent overspeed failure of the turbine blades or the IP turbine disk, which could lead to uncontained blade or disk release, damage to the engine, and damage to the airplane.