Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for Rolls- Royce plc (RR) RB211-535E4-37, -535E4-B-37, -535E4-C-37, RB211Trent 768-60, 772-60, and 772B-60 turbofan engines. This AD requires removal of certain high-pressure (HP) and intermediate-pressure (IP) turbine discs before their accumulated cyclic lives have reached the revised limits. This AD was prompted by a report of an HP disc contaminated with a steel inclusion. We are issuing this AD to prevent failure of the HP or IP turbine disc, uncontained engine failure, and damage to the airplane.