Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for certain serial numbers (S/Ns) of Rolls-Royce plc (RR) RB211-Trent 768-60, 772- 60, and 772B-60 turbofan engines. This AD requires initial and repetitive on-wing or in-shop inspections of the high pressure/ intermediate pressure (HP/IP) turbine bearing support oil feed tube outer heat shield. This AD also requires installation of a revised HP/ IP turbine bearing support structure as terminating action to the repetitive inspections of the HP/IP turbine bearing support oil feed tube outer heat shield. This AD was prompted by a report of high oil consumption due to an oil leak from the HP/IP turbine bearing support oil feed tube. We are issuing this AD to prevent failure of the HP turbine disc, uncontained engine failure, and damage to the airplane.