Summary
We propose to adopt a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-524G2-19; RB211-524G2-T-19; RB211-524G3-19; RB211-524G3-T-19; RB211-524H2-19; RB211-524H2-T-19; RB211-524H-36; RB211-524H-T-36; RB211-535E4-37; RB211-535E4-B-37; RB211-535E4-B-75; and RB211-535E4-C-37 turbofan engines. This proposed AD was prompted by an investigation by RR concluding that certain intermediate-pressure (IP) turbine discs produced before 1997 by a certain supplier may contain steel inclusions. This proposed AD would require removal of the affected IP turbine discs to inspect them for steel inclusions, and removal from service if the discs fail the inspection. This proposed AD would also require removal from service of some IP turbine discs at reduced life limits. We are proposing this AD to prevent uncontained IP turbine disc failure, engine failure, and damage to the airplane.