With the Holiday season upon us, the Australian Transport Safety Bureau (ATSB) has encouraged air travellers to keep their seat belts fastened at all possible times.

The call coincides with the release of the ATSB report into an in-flight upset that occurred on-board a Qantas A330 aircraft en-route from Singapore to Perth in October 2008. At least 110 of the 303 passengers and 9 of the 12 crew members were injured. Of these, 51 received hospital medical treatment.

The Chief Commissioner of the ATSB, Mr Martin Dolan, said that the accident provided a salient reminder about the importance of seat belts, and he urged passengers to keep their seat belts fastened during flight whenever they are seated.

'At least 60 of the passengers were seated without their seat belts fastened. Although some of those wearing a seat belt were also injured, most of the injuries occurred when unrestrained occupants were thrown into the aircraft's ceiling. The rate and severity of injuries was much greater for those who were not wearing a seat belt.'

'Although passengers are routinely reminded on each flight to wear their seat belts when seated during a flight, some passengers do not follow this advice,' Mr Dolan said.

The in-flight upset that occurred on-board a Qantas A330 aircraft was a unique event and extremely unlikely to happen again according to the Australian Transport Safety Bureau (ATSB). During the flight, approximately 154 kilometres west of Learmonth, WA, the aircraft suddenly pitched down, due to a combination of problems involving two aircraft systems; the flight control computers and one of the aircraft's three air data inertial reference units (ADIRUs).

Due to a limitation in software design, the flight control computers commanded the aircraft to pitch down in response to a very rare pattern of incorrect angle of attack data from one of the ADIRUs.

ATSB Chief Commissioner, Mr Martin Dolan, said that Airbus had taken prompt action to reduce the likelihood of another similar accident.

'Very soon after the accident, the manufacturer issued new pilot procedures to manage the effects of any future cases of a similar ADIRU failure,' Mr Dolan said.

'The aircraft manufacturer then redesigned its software. Passengers, crew and operators can be confident that the same type of accident will not happen again.'

An extensive investigation into what triggered the ADIRU failure mode concluded that it was very unlikely to have been caused by electromagnetic interference from the Harold E. Holt Naval Communications station at Exmouth or from a personal electronic device such as a laptop or mobile phone. A range of other possible mechanisms were also discounted.

Mr Dolan stated that the ATSB investigation covered a range of complicated issues, including some that had rarely been considered in depth by previous accident investigations.

'Given the increasing complexity of aircraft systems, this comprehensive investigation has offered an insight into the types of issues that will become increasingly relevant for future investigations. It identified a number of specific lessons for the manufacturers of new, complex, safety-critical systems,' Mr Dolan says.

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Last update 19 December 2011