Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Rolls-Royce Deutschland Ltd. & Co KG (RRD) Trent 7000-72 and Trent 7000-72C model turbofan engines. This proposed AD was prompted by in-service experience showing that certain high-pressure turbine (HPT) blades may prematurely deteriorate to an unacceptable condition when managed in accordance with the inspection intervals in the Time Limits Manual (TLM). This proposed AD would require initial and repetitive on- wing borescope inspections (BSIs) of the HPT blades to detect axial cracking and, depending on the results of the inspections, replacement of the HPT blade set, as specified in a European Union Aviation Safety Agency (EASA) AD, which is proposed for incorporation by reference (IBR). This proposed AD would also require replacement of the HPT blade set before exceeding a specified number of flight cycles. The FAA is proposing this AD to address the unsafe condition on these products.