A Japan Airlines Boeing B777 powered by PW4090 engines experienced an uncontained high pressure turbine (HPT) 1-2 seal after departing Tokyo's Haneda Airport for Naha on the island of Okinawa, Japan. The No. 1 engine’s exhaust gas temperature increased and the engine stalled while cruising at FL280. The flight crew shut down the engine and diverted the airplane to the Kansai International Airport, Osaka Japan for an uneventful landing. Ground inspection of the engine and aircraft revealed an exit hole in the high pressure turbine case, an exit penetration through the engines core cowl, and impact damage on the left horizontal stabilizer.

Teardown and metallurgical examination revealed that the high pressure compressor diffuser inner air seal had fractured allowing hot gas into the No. 3 bearing compartment. The bearing compartment temperature and pressure increased resulting in oil leaking out the rear carbon seal into the HPT and igniting, resulting in the eventual failure of the HPT 1-2 seal.

The investigation is under the jurisdiction of the government of Japan. Further information pertaining to this incident may be obtained from:

Director-General
Secretariat of the Aircraft and Railway Accidents Investigation Commission
Ministry of Land, Infrastructure and Transport
2-1-2, Kasumigaseki, Chiyoda-ku
Tokyo 100-8918
Japan

Tel.: (81) 3 5253 8813
E-mail: ARAIC@mlit.go.jp
Fax: (81) 3 5253 1677
AFTN: RJTDYAYA
Cable: KOKUKYOKU-TOKYO
Website: http://www.motnet.go.jp/araic/index.html

This report is for informational purposes only and contains only information obtained for, or released by, the government of Japan