AVIATION/ ATSB REPORTS ON 3 SERIOUS QANTAS INCIDENTS

The Australian Transportation Safety Bureau has released one update and 2 Final Reports on 3 serious incidents involving 2 Airbus A380s and 1 Boeing 747. All Reports can be found on the ATSB website.

*QANTAS FLIGHT 32: AIRBUS A380 INCIDENT NEAR SINGAPORE ON NOVEMBER 4, 2010: Australian investigators are reviewing Rolls-Royce's quality control procedures as a probe into last November's uncontained Rolls-Royce Trent 900 engine failure on a QANTAS Airbus A380. In an update, the ATSB said it is studying how the engine manufacturer could have missed a defect in an oil feed tube, which had been identified as the cause behind an oil fire and the subsequent engine failure. On November 4, 2010, Flight 32 was on International Service from Singapore to Sydney, Australia, and was climbing out of Singapore, overhead the Indonesian Island of Batam about 20 miles south of Singapore, when the No.2 engine emitted a loud bang suffering from an uncontained failure. Debris with the Qantas logo fell onto a road in built up city district Dutamas of Batam. The crew declared an emergency, dumped fuel, returned to Singapore and landed safely about 2 hours after departure, with gear doors were open, slats retracted, flaps extended. Emergency Services immediately began spraying the engine as the aircraft stopped. No injuries onboard or on the ground in Batam were reported. Investigations into the incident so far have showed that the defect had caused a section of the oil tube to thin out and crack, leading to an internal engine oil fire which weakened the intermediate pressure (IP) turbine disc. The disc then separated from the turbine shaft, puncturing the engine case and wing structure. Together with the United Kingdom's AAIB and Rolls-Royce, the ATSB is "examining the circumstances and missed opportunities with the potential to have detected the reduced wall thickness and offset counter bore of the oil feed tube" before, during and after the manufacturing of the IP turbine module case. The ATSB is also reviewing the quality audits and quality assurance system as part of the manufacturing process and assessing how effective they are in detecting defects. Following the uncontained engine failure, Rolls-Royce initiated the removal of 53 Trent 900 engines from service due to concerns over the wall thickness of the oil feed tube. As part of the probe into the incident, investigators and Airbus are also studying the A380 and the system damage that occurred as a result of the engine failure. The A380 involved in the incident, registration VH-OQA, remains in Singapore "where repair schemes were being developed by Airbus and relevant components were being manufactured to facilitate that repair". The ATSB said it expects to complete gathering of information into the case by end-July. It then aims to complete analysis of this information by May 2012 and issue its Final Report.

*QANTAS FLIGHT 31: AIRBUS A380 INCIDENT NEAR DELHI, INDIA ON FEBRUARY 15, 2011: An oil leak in a Rolls8Royce Trent 900 engine has been identified by the ATSB as the cause behind a partial power loss on a QANTAS Airbus A280 on February 15 of this year. The leak, which led to a gradual decrease in oil quantity in the No.4 engine, prompted the aircraft's flight crew to reduce the powerplant to idle thrust during the Singapore to London Flight 31. The aircraft, registration VH-OQC, pictured, did not experience further oil level variation during the rest of the flight. Inspections after the incident showed that there was an oil leak from an external high pressure / intermediate pressure (HP/IP) oil tube at its connection to the engine case. The ATSB, in its Final Report, add that it is now conducting a "holistic investigation" into the oil leak and other reported cases of oil leaks in Trent 900 engines. Checks of the tube involved in the February incident showed that the attaching nut had less than the required torque, said the ATSB. "A torque check of the tube revealed the attaching B-nut was at 80 pound force/inch. The correct torque value for the B nut was 240 pound force/inch," it added. It is not certain how the attaching nut had less than the required torque. An uncontained engine failure last November involving another Qantas Trent 900 engine, described above, had led to inspections of all of the Airline's Trent 900s. These inspections involved the removal of the HP/IP oil tube to allow for an internal borescope inspection of the engine, said the ATSB. That inspection on the engine involved in the partial power loss was conducted 20 days before the leak developed. During this time, the engine completed 20 cycles and about 241 flight hours. There was no other maintenance carried out on the oil tube during the 20 day period. During the incident, the engine's oil quantity began decreasing 3 hours into the flight while the aircraft was cruising near Delhi, India. The quantity continued decreasing gradually to about 3.5 quarts at about 7.5 hours into the cruise. The oil pressure had dropped to 75 psi from 100 psi. The flight crew was then advised by the Qantas Engineers to reduce the engine to idle thrust for the rest of the flight, which stabilized the oil pressure at 45 psi. Upon arrival at London, only 0.7 quarts of oil remained, said the ATSB. The oil tube in the engine was subsequently replaced. The incident was not an isolated one as Qantas and another A380 operator have reported a total of 7 HP/IP oil tube leaks due to "low torque of the attachment fitting", said the ATSB.

*QANTAS FLIGHT 6: A BOEING 747 INCIDENT AT SINGAPORE ON NOVEMBER 5, 2010: The ATSB traced the cause of last November's QANTAS Boeing 747-400 contained engine failure to the engine's high pressure compressor (HPC) blade, which had broken off at the root. The aircraft, registration VH-OJD, pictured, had departed Singapore for Sydney on November 5, 2010 as Flight 6, when its No.1 Rolls-Royce RB211-524G engine failed while it was climbing through 2000 ft. The aircraft returned to Singapore after the flight crew dumped fuel. Inspections of the engine showed that the powerplant's HPC stage one blade had "liberated at the blade root", said the ATSB in its Final Report into the incident. "The liberated blade resulted in severe damage to all stages of the HPC," it added. The blade root failure and subsequent damage to the HPC were "consistent with previous HPC stage one root failures", said the ATSB. Including the November 2010 incident, Qantas hasw experienced 9 such blade root failures. Engine manufacturer Rolls-Royce had previously issued 2 service bulletins for the engine to address blade issues prior to the incident. The latest of the 3 service bulletins, issued in February 2009, had introduced a modified blade "with a revised geometry" which "could provide protection against root failures". "The revised geometry was designed to be more tolerant to stresses induced by blade tip rub," said the ATSB. However, this modified blade had not been incorporated into the engine that failed in the Qantas incident. Currently, about 18% of Qantas' RB211-524G engines have been modified to the latest standard, said the ATSB. The engine involved in the incident was subsequently replaced and the aircraft was returned to service.