AD 2006-17-08 Airworthiness Directives; Pratt & Whitney PW4077D, PW4084D, PW4090, and PW4090-3 Turbofan Engines

This AD applies to Pratt & Whitney (PW) PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines that were: (1) Reassembled with a previously used high pressure compressor (HPC) exit inner brush seal pack, part number (P/N) 50J894-01; and (2) Reassembled with a new or refurbished HPC exit diffuser air seal inner land, P/N 55H869. (d) These engines are installed on, but not limited to, Boeing 777 airplanes.

You are responsible for having the actions required by this AD performed at the following compliance times, unless the actions have already been done. (g) Replace the HPC exit inner and outer brush seal packs with new HPC exit inner and outer brush seal packs, or replace the HPC exit brush seal assembly with a new HPC exit brush seal assembly as follows: (1) By 3,000 cycles-in-service (CIS) since a used HPC exit inner brush seal pack and a new or refurbished HPC exit diffuser air seal land were installed in the engine, or by March 31, 2007, whichever occurs later; however, (2) If on March 31, 2007, the used HPC exit inner brush seal pack coupled with a new or refurbished HPC exit diffuser air seal inner land assembly has not accumulated 3,000 CIS, then by 3,000 CIS, or December 31, 2008, whichever occurs first. (h) Use the Accomplishment Instructions of PW Service Bulletin No. PW4G-112-A72-280, Revision 1, dated March 21, 2006, to do the inner and outer brush pack replacements. Alternative Methods of

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.