Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Tay 650-15 and Tay 651-54 Turbofan Engines

الملخص

The FAA is superseding an airworthiness directive (AD) for Rolls-Royce Deutschland Ltd & Co KG (RRD) Tay 650-15 and Tay 651-54 turbofan engines. That AD currently establishes cyclic life limits for certain part number (P/N) stage 1 high pressure turbine (HPT) discs and stage 1 low pressure turbine (LPT) discs operating under certain flight plan profiles. This AD requires calculating and re-establishing the achieved cyclic life of stage 1 HPT discs, P/N JR32013 or P/N JR33838, and stage 1 LPT discs, P/N JR32318A, that have been exposed to different flight plan profiles. This AD also requires removing from service those stage 1 HPT discs and stage 1 LPT discs operated under Tay 650-15 engine flight plan profiles A, B, C, and D, and operated under Tay 651-54 engine datum flight profile, at reduced cyclic life limits, using a drawdown schedule. This AD results from RRD updating their low-cycle-fatigue analysis for stage 1 HPT discs and stage 1 LPT discs and reducing their cyclic life limits. We are issuing this AD to prevent cracks leading to turbine disc failure, which could result in an uncontained engine failure and damage to the airplane.