Incident Details
On October 10, 2010, a Korean Air Boeing 747-400, registered in Korea as HL7489, was operating as Flight KE023 from Seoul to San Francisco, California. Approximately 40 minutes after departure, the flight crew observed engine vibrations and oil pressure indications, followed by a high exhaust gas temperature reading on the No. 3 engine, a Pratt & Whitney PW4056. The crew shut down the affected engine and returned to Seoul without further incident.
Post-Landing Examination
After landing, examination of the No. 3 engine revealed that the exhaust sleeve was missing. A large hole was found in the low pressure turbine case, exposing extensive internal damage to the engine. The failure was characterized as an uncontained release of turbine material.
Investigation
The incident is being investigated by the Korean Aviation & Railway Accident Investigation Board (ARAIB). The U.S. National Transportation Safety Board (NTSB) has designated a U.S. Accredited Representative to participate in the ARAIB's investigation, in accordance with ICAO Annex 13, as the state of manufacture of the airplane and engine. No cause has been stated in the initial report.
Injuries and Damage
There were no reported injuries to the passengers or crew. The aircraft sustained engine damage but no other structural damages have been noted. The incident did not result in any further operational issues.