Computer glitch may have caused Qantas plunge

A computer glitch may have caused a Qantas jet to plunge mid-flight, an investigator said Wednesday as passengers told how they were slammed against the cabin roof in the terrifying drama.

Health officials said 51 passengers and crew received medical treatment, some for broken bones, cuts and serious spinal injuries, when the Australian Airbus A330-300 suddenly began dropping Tuesday, forcing an emergency landing.

The plane was cruising at 37,000 feet (11,200 metres) when pilots received an automated warning of an "irregularity with the aircraft's elevator control system," an investigator told reporters in Canberra.

"The aircraft departed normal flight and climbed 300 feet," said Julian Walsh, director of aviation safety with the Australian Transport Safety Bureau (ATSB).

"The aircraft did that of its own accord and then, whilst the crew were doing the normal actions in response to that not normal situation, the aircraft then pitched down suddenly and quite rapidly," he said.

Qantas, which has been plagued by incidents in recent months, said it was too early to speculate on the cause of the "sudden change in altitude" of flight QF72 bound from Singapore to Perth carrying 313 passengers and crew.

But it confirmed that the plane climbed 300 feet before "the nose dropped momentarily and the flight crew declared an emergency."

"As always we will cooperate fully with the ATSB, as well as conducting our own investigation into the incident," Qantas chief executive Geoff Dixon said in a statement.

News reports had speculated that clear air turbulence may have caused the plane to plunge, hurling passengers at the rear onto the roof, smashing ceiling panels and luggage lockers.

"It was horrendous, absolutely gruesome, terrible, the worst experience of my life," said Jim Ford, of Perth, who said he thought he was going to die.

Several passengers said the plane fell 2,000 metres (6,500 feet) while cruising over the Indian Ocean just off the northwest coast of Australia.

"Basically the plane just fell out of the sky," another passenger told Sky News. "It must have lasted 10 or 12 seconds, it just went straight down," he said.

The jet made an emergency landing at an air force base near Exmouth in remote Western Australia when it became clear that there were serious injuries on board.

Numerous passengers and crew were taken off the jet by emergency services on stretchers and in wheelchairs.

Some 14 of the seriously injured were flown to Perth for treatment, while Qantas planes were sent to pick up the remaining passengers, many of whom were treated locally.

Qantas said Australians accounted for 131 of those onboard the plane which was also carrying 53 Britons, 40 Indians and 38 Singaporeans.

ATSB investigators examining the grounded aircraft in Exmouth had removed its black box flight recorders to establish the cause of the incident, Qantas said.

An investigator from the French Bureau d'Enquetes et d'Analyses (BEA), which probes air incidents, and another from the European aircraft manufacturer Airbus will also join the probe, Walsh said.

The investigation could take up to six months, but a preliminary report could be ready within 30 days, he said.

The incident is the fourth involving Qantas planes in two-and-a-half months and comes as a survey published Tuesday showed that 63 percent of Australians believe the safety standards of their flag carrier have slipped.

On July 25, an exploding oxygen bottle punched a huge hole in the side of a Qantas Boeing 747-400 during a flight from Hong Kong to Melbourne, forcing an emergency landing in the Philippines. No one was injured in the mid-air drama.

Just three days later, a Qantas Boeing 737-800 returned to Adelaide after a landing gear door failed to retract. And in early August a Boeing 767 bound for Manila turned back to Sydney after developing a hydraulic fluid leak.