The Australian Transport Safety Bureau (ATSB)’s preliminary report into the Qantas Airbus A380 QF32 uncontained engine failure highlights the thorough and systematic approach the flightcrew took in responding to the inflight emergency.
The report, released on December 3, details how when the aircraft (VH-OQA) was passing 7000ft at about 250kt over the Indonesian island of Batam the crew heard two “almost coincident ‘loud bangs’ ” as the aircraft’s number 2 Rolls-Royce Trent 900 engine failed.
“The report goes on to outline the details of the actions taken by the crew in response to what you’ll understand was a very challenging situation, their methodical assessment of a range of error reports on the status of the aircraft, their professional and focussed handling of the situation, and their safe landing at Singapore,” ATSB commissioner Martin Dolan told media.
Immediately after the loud bangs, the A380’s ECAM (electronic centralised aircraft monitor) system displayed an “overheat” warning for the number 2 engine, and soon after displayed “multiple” (elsewhere reported to be over 50) warnings.
The report notes that the ECAM error messages included:
- Engines 1 and 4 operating in a degraded mode
- Low system pressure and low fluid levels for the ‘green’ hydraulic system (powered by the No 1 and 3 engines)
- No 4 engine pump errors with the ‘yellow’ (drive by engines 3 and 4) hydraulic system
- Failure of the No 1 and 2 AC electrical bus systems
- Flight controls operating in ‘alternate’ law (ie with some reduced flight envelope protections)
- Wing slats inoperative
- Partial aileron control
- Reduced spoiler control
- Multiple brake system messages
- Multiple fuel system messages
- Centre of gravity messages
- And autothrust and autoland inoperative
The crew – which comprised the captain, first officer, second officer and two check captains – discussed the options of an immediate return to Singapore, climbing or holding, “and decided that the best approach would be to hold at the present altitude while they processed the ECAM messages and associated procedures,” the report details.
After discussion with Singapore ATC the aircraft was vectored to a racetrack holding pattern east of Singapore. Over a period of 50 minutes the flightcrew worked through the procedures in response to the ECAM messages while the aircraft remained on autopilot. The crew then assessed the aircraft systems and discussed its controllability before conducting a number of handling checks at the holding speed, before making their approach for landing, and making further checks of controllability at the approach speed.
The crew were able to land the aircraft safely, despite the aircraft being 50 tonnes over its max landing weight (as the crew were unable to jettison fuel), reverse thrust being only available on the number 3 engine, and the aircraft leaking fuel and possible hydraulic fluid.
“The aircraft would not have arrived safely in Singapore without the focused and effective action of the flightcrew,” Dolan said.
The investigation into the cause of the engine failure is continuing, but has already led to the ATSB releasing a safety recommendation following the discovery of fatigue cracking in stub pipe that feeds oil to intermediate and high pressure turbine bearing structure, due to manufacturing errors.
“We are not yet at the stage where we can definitively say that the potential fatigue problem with the oil pipe that has been detected is the cause of what happened over Batam Island, but we think that it is significant enough as a safety issue that it needed to be identified and safely dealt with,” Dolan said.
The ATSB has confirmed this was only discovered in the past days, with up to that point a faulty pipe connector thought to be responsible for oil leaks discovered in Trent 900s inspected after the QF32 incident. Dolan says the ATSB can’t at this stage rule in or out a link between the two potential oil leak sources.
“We don’t have enough information at this stage to rule in or rule out that sort of relationship. Our best assessment at this point is that there are two potential points of oil leakage, one relates to a fitment of an oil tube … the second relates to this potential fatigue cracking.”
Dolan also used the report’s release to highlight the “very effective” cooperation with the investigation from Rolls-Royce.
Meanwhile, Qantas says the first of its two A380s currently in service to undergo inspection following the ATSB’s safety recommendation has been checked with “no issues as outlined by the ATSB … found”. That aircraft is due to operate a Sydney-Singapore-London service tonight as scheduled, while inspection of the second A380 is now underway.
“Qantas will continue to operate a full international and domestic schedule and expects to make further announcements about the return to service of more A380s, before Christmas, in the near future. In addition to the two aircraft that are back in service, two new A380s will be delivered and enter service in coming weeks, and another two are due for delivery in early 2011,” the airline said in a statement.
“The aircraft involved in the QF32 incident will remain in Singapore for some time while Airbus develops and then undertakes a significant repair program. Sixteen Qantas engines require either modification to the latest standard or full replacement. Five of these have been replaced to date and all airworthiness directive and CASA requirements are being met.”