PRODUCT: All Rolls-Royce plc RB211- Trent 970-84, RB211-Trent 970B-84, RB211-Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84 and RB211-Trent 980-84 turbofan engines. SUBJECT: Airworthiness Directive 2013-02-04 ACTION: Final Rule, Request for Comments
SUMMARY: This AD requires on-wing inspections of low-pressure turbine (LPT) disk seal fins and interstage seals when post-flight review indicates Engine Health Monitoring (EHM) vibratory maintenance-alert limits were exceeded in flight. The AD also requires in-shop inspections of the LPT disk seal fins and interstage seals to detect cracks or damage and, depending on the findings, accomplishment of corrective action.
This AD is prompted by a Trent 900 engine experiencing LPT stage 2 disk interstage seal material loss and increased low-pressure rotor vibration while in flight. The FAA is issuing this AD to prevent cracks in the LPT disk, which could result in uncontained engine failure and damage to the airplane.
DATES: This AD becomes effective February 14, 2013. Comments must be received by March 18, 2013.