Qantas Dive Was Caused by Faulty Computer Component

As I noted last week, Qantas flight QF72 traveling from Singapore to Perth last Tuesday was forced to make an emergency landing in at Learmonth air base in Western Australia (about 1,100 kilometres northeast of the state capital Perth) after it unexpectedly and rapidly climbed and then lost altitude. Some 70 plus passengers and crew were injured, 14 severely.

Speculation for the cause ranged from air turbulence to possibly a passenger's wireless laptop computer interfering with the aircraft's avionics. Both of those have been ruled out.

The Australian paper Sydney Morning Herald reported that investigators found during the analysis of flight data that the plane's air data inertial reference unit - the device responsible for supplying data on air pressure, temperature and acceleration - had failed.

The failure caused incorrect wrong data to be sent to the aircraft's flight control system.

Australian Transport Safety Bureau's director of aviation safety investigation, Julian Walsh said that, "Because of the fault â'¿ [the component] has indicated to the flight control computer that the angle of attack of the aircraft was higher."

"So the flight computer has considered that it needed to nose the aircraft over."

"About two minutes later â'¿ the flight control computers commanded a nose-down movement," Mr Walsh said. "The inertial reference unit continued to generate random spikes and a second nose-down aircraft movement was encountered."

The component that malfunctioned is used on A330-300s, A330-200s, A340s and non-Airbus aircraft.

A preliminary report by the Australian Transport Safety Bureau is scheduled to be out one month from the date of the flight. This is the latest information from the bureau on the incident.


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Robert Charette
Spotsylvania, Va.
Willie D. Jones
New York City