Airworthiness Directives; Pratt & Whitney PW4077D, PW4084D, PW4090, and PW4090-3 Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for Pratt & Whitney (PW) PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines that were reassembled with certain previously used high pressure compressor (HPC) exit brush seal assembly parts and certain new or refurbished HPC exit diffuser air seal inner lands. This AD requires replacing the HPC exit inner and outer brush seal packs with new brush seal packs, or replacing the HPC exit brush seal assembly with a new HPC exit brush seal assembly. This AD results from a report of oil leaking into the high pressure turbine (HPT) interstage cavity and igniting, leading to an engine case penetration and engine in- flight shutdown. Although liberated engine parts did not penetrate the engine nacelle, we are issuing this AD to prevent uncontained engine failure, damage to the airplane, and injury to passengers.