Agency: Transportation Department, Federal Aviation Administration
The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney Division (PW) Model PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines. This AD was prompted by the discovery of a quality escape involving incorrect shot peening on certain high- pressure compressor (HPC) drum rotor disk assemblies. This AD requires visually inspecting the HPC drum rotor disk assembly for incorrect shot peen coverage and, depending on the results of the inspection, replacing the HPC drum rotor disk assembly with a part eligible for installation. This AD also requires removing and replacing certain HPC drum rotor disk assemblies before reaching certain life limits. The FAA is issuing this AD to address the unsafe condition on these products.