ATSB Second Interim Factual Report into the Qantas Airbus A330-303 in-flight upset
18-Nov-2009 The Australian Transport Safety Bureau has released a second Interim Factual Report into the accident involving the Qantas Airbus A330-303 in-flight upset, 154 km west of Learmonth WA, on 7 October 2008. The report summarises new activities conducted since the first Interim Factual Report that was released on 6 March 2009, and it should be read in conjunction with that previous report.
The aircraft (registered VH-QPA) was being operated on a scheduled passenger service (QF72) from Singapore to Perth. At 1240, while cruising at 37,000 ft, the aircraft experienced two uncommanded pitch-down events. The flight crew were able to quickly return the aircraft to level flight on each occasion and diverted to Learmonth, WA for a safe landing.
One flight attendant and 11 passengers were seriously injured, and eight other crew members and at least 99 other passengers received minor injuries. The injury rate and severity of injuries was significantly greater for those passengers who were not seated or not wearing seatbelts at the time of the first in-flight upset.
At least 60 of the 303 passengers were seated without their seatbelts fastened. Although there are legitimate reasons for passengers leaving their seats during a flight when the seatbelt sign is not illuminated, passengers are reminded to wear their seatbelts at all times when seated during a flight.
In addition to the initial procedures-based safety action taken by the aircraft manufacturer in response to this accident, Airbus is modifying the flight control primary computer (FCPC or PRIM) software used in the A330/A340 fleets to prevent any future similar problems leading to an uncommanded pitch-down event. An interim modification to the FCPC software standard is being installed in the operator's fleet, and the installation is expected to be completed by the end of November 2009. A later FCPC software standard to improve the treatment of all ADIRU parameters will be certified in mid to late 2010, and will then be retrofitted to the world-wide fleet of A330/A340 aircraft.
There has been speculation of a potential link between the QF72 accident off Learmonth on 7 October 2008 with the AF447 accident that occurred on 1 June 2009 on a flight from Rio de Janeiro to Paris. Although each of the accidents involved the same basic aircraft type, there are several important differences between the two accidents:
* The ADIRUs on the two aircraft were different models, and constructed by different manufacturers.
* The cockpit-effect messages and maintenance fault messages from both flights showed a significantly different sequence and pattern of events. For example, a series of maintenance messages that were transmitted by AF447 prior to the accident showed inconsistencies between the measured airspeeds and the associated consequences on other aircraft systems. No such messages were recorded by QF72. The airspeed sensors (pitot probes) on the two aircraft were different models made by different manufacturers.
* The ATSB expects to release a final report into this accident in the second quarter of calendar year 2010. However, the ATSB will immediately bring any critical or significant safety issue(s)s to the attention of the relevant organisations best placed to address them, should any such issues arise. The ATSB will also publish details of any such issue(s).