Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Pratt & Whitney (PW) PW2037, PW2037M, PW2040, and F117-PW-100 model turbofan engines. This proposed AD was prompted by a report of an uncontained engine failure resulting from cracks in the knife edge of the high-pressure turbine (HPT) 2nd-stage air seal. This proposed AD would require initial and repetitive borescope inspections (BSIs), fluorescent penetrant inspections (FPIs), and visual inspections of the HPT 2nd-stage air seal assembly and, depending on the results of the inspections, replacement of the HPT 2nd-stage air seal assembly with a part eligible for installation. This proposed AD would also require replacement of the affected HPT 2nd-stage air seal assembly, depending on the engine model, at either the next engine shop visit or the next piece-part opportunity. The FAA is proposing this AD to address the unsafe condition on these products.