Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Pratt & Whitney (PW) Model PW2037, PW2037M, and PW2040 engines with a certain high-pressure turbine (HPT) 2nd stage blade assembly installed. This proposed AD was prompted by an in-flight shutdown (IFSD) caused by the fracture of HPT 2nd stage turbine hub assembly lugs, which resulted in blade liberation and a titanium fire in the high-pressure compressor (HPC). This proposed AD would require a visual inspection of the HPT 2nd stage blade assemblies for missing contact marks, a dimensional shadowgraph inspection of the HPT 2nd stage blade assemblies for blade root profile dimensional inspection, and an eddy current inspection (ECI) of the HPT 2nd stage turbine hub assembly for conforming slot flatness. This proposed AD would also require removal and replacement of any HPT 2nd stage turbine hub assembly or HPT 2nd stage blade assembly that does not pass any inspection. The FAA is proposing this AD to address the unsafe condition on these products.