AD FAA-2012-0482

We are adopting 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 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 AD requires removal of the affected IP turbine discs to inspect them for steel inclusions, and removal of the affected discs from service if they fail the inspection. This AD also requires removal from service of some IP turbine discs at reduced life limits. We are issuing this AD to prevent uncontained IP turbine disc failure, engine failure, and damage to the airplane.