A computer glitch may have caused a Qantas passenger jet to abruptly plummet, injuring at least 30 passengers and crew, Australian air safety investigators said on Wednesday.
The Airbus A330-300, with 303 passengers and 10 crew, was cruising at 37,000 feet from Singapore to Perth on Tuesday when it suddenly gained altitude, then pitched sharply down.
Many on board were flung around the cabin or crashed against rooftop luggage compartments before the pilots regained control and made an emergency landing, passengers said.
"The pilots received electronic centralised aircraft monitoring messages in the cockpit relating to some irregularity with the aircraft's elevator control system," Australian Transport Safety Bureau safety director Julian Walshe said.
"The crew had initiated the non-normal checklist response actions. The aircraft is then reported to have abruptly pitched nose down."
The aircraft landed at a remote military and mining airstrip at Learmonth, near the port of Exmouth, around 1,100kms north of Perth, after pilots issued a "mayday" alert.
"It was horrendous, absolutely gruesome, terrible. The worst experience of my life," passenger Jim Ford told Australian radio after arriving in Perth.
The bureau said 14 people were flown to Perth by air ambulance with injuries including concussion, lacerations and broken bones. Another 30 were treated for minor bruises and did not need hospital treatment.
Qantas has declined to give details on the incident as a investigation is carried out by aviation officials. An Airbus investigator was also travelling to Australia.
Qantas has been hit by a number of incidents recently. In one, Australian air safety investigators blamed an oxygen bottle for a mid-air explosion that blew a minivan-size hole in the side of Qantas 747 last month.
The Qantas 747-400 suffered a sudden loss of cabin pressure during a flight from Hong Kong to Melbourne on July 25, forcing the aircraft to make an emergency descent before diverting to the Philippines, where it landed safely in Manila.
The pilot landed the plane manually, with help from air traffic controllers in Manila, where all 346 passengers and 19 crew disembarked safely.