Qantas probe focuses on oxygen tank

[July 28, 2008]  MANILA, Philippines (AP) -- Investigators found fragments that appear to bolster the theory that an oxygen tank exploded on a Qantas jet, forcing it to make a dramatic emergency landing with a car-sized hole in its fuselage, an official said Monday.

Neville Blyth, a senior investigator from the Australian Transport Safety Bureau, said a valve and other small fragments would be tested to determine if they came from the tank, which is designed to provide oxygen to passengers during an emergency.

He said the fragments were found in the passenger cabin close to where the missing tank was stored in the cargo hold, along with five other cylinders.

The Boeing 747-400 had to make an emergency landing after a quick descent from 29,000 feet (8,800 meters) Friday. The 365 passengers and crew, who reported hearing a loud bang before the plane suddenly depressurized, were not injured.

"We recovered ... a valve from an oxygen cylinder," Blyth told a news conference. "It is likely that that valve is from the missing cylinder."

If the valve and other fragments are determined to have come from the cylinder, further investigation will be required to determine why the tank burst, he said.

The aircraft flight data recorder and cockpit voice recorder arrived Monday in Australia, where officials said it will take several days to download their information.

Blyth and other officials said they are unaware of any previous cases in which an oxygen tank caused an airline accident. Qantas has ordered all oxygen tanks on its fleet of 747-400s to be urgently inspected.

Some passengers told Australian media that their oxygen masks failed to work properly during the crisis, leading some to nearly pass out.

The U.S. Federal Aviation Administration earlier warned airlines to inspect oxygen cylinders on their planes.

David Cox, Qantas' head of engineering, told reporters Monday that the FAA directive applies to a different type of oxygen system than the one being scrutinized in the Qantas emergency.

Three of Qantas' aircraft were affected by the directive and all were inspected by January 2007, Cox said.

The airline's chief executive, Geoff Dixon, said whatever caused the "very, very bad accident" was likely beyond the airline's control.

"We don't know and we can't speculate on what happened to this aircraft," Dixon told a news conference. "Obviously there is every chance it is something to do with the aircraft, and it is something that may have well been out of our control. More than likely it was."

The FAA's directive followed a report that certain oxygen cylinders' support brackets in Boeing 747-400s may not have been properly heat-treated, which the FAA said could cause oxygen leakage and subsequent fire hazards.

The plane, en route from London to Melbourne, Australia, made a stopover in Hong Kong an hour before making the emergency landing in the Philippines.

Four Australian Transport Safety Bureau specialists were inspecting the aircraft in Manila, with assistance from Boeing and the U.S. National Transportation Safety Board.

Officials have said there is no indication a bomb may have caused the incident.

[Associated Press; By JIM GOMEZ]

Associated Press writer Kristen Gelineau in Sydney, Australia, contributed to this report.

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