The ATSB has released its first interim factual report into the uncontained engine failure on board Qantas Boeing 747-400 VH-OJP, noting that a number of turbine blades had separated from the engine, causing it to sustain extensive damage.
The 747 was carrying 213 passengers on August 30 when it was operating a flight from San Francisco to Sydney. Approximately 15 minutes into the flight, severe vibrations were felt through the aircraft and a number of sparks and flames were seen by passengers coming from the number four engine. As a result, the crew shut down the engine and elected to return to San Francisco, where a number of holes were found in the number four engine nacelle, indicating an uncontained engine failure. The engine was subsequently removed and sent to Hong Kong for further inspection.
According to preliminary inspections on the engine, the ATSB report notes that all of the turbine blades from the intermediate pressure turbine disk had separated, while blades from the three low pressure (LP) turbine disks were either fractured or had also separated. Additionally, the LP stage 1 nozzle guide vanes were destroyed while the remaining LP nozzle stages were substantially damaged.
The investigation into the incident is continuing, with the engine to be subject to further inspections to ascertain the factors which contributed to the engine failure, including examination of the provisions for containing debris during an engine failure.