A tank meant to supply passengers and crew with oxygen during an emergency may have exploded, ripping a hole in a Qantas jet that forced the plane to make a harrowing landing in the Philippines last week, officials said Monday.
With no signs of a bomb, the investigation into Friday’s emergency landing is focusing on the possibility that missing cylinder No. 4 may have blown a car-sized hole through the fuselage of the 747-400 jet carrying 365 people.
The theory has been bolstered by the discovery of a valve and handle fragments in the passenger compartment, a few feet from where the missing cylinder was stored, Neville Blyth, a senior investigator from the Australian Transport and Safety Bureau, told a news conference.
“We recovered ... a valve from an oxygen cylinder. It is likely that that valve is from the missing cylinder,” Blyth said, adding that the items will be tested.
He said it was possible that the valve was blown upward into the passenger cabin while the body of the cylinder went out the fuselage hole.
The 365 passengers and crew, who were not injured, reported hearing a loud bang before the plane suddenly depressurized. An eight-inch hole appeared in the floor, sending debris flying about the compartment.
Flight QF 30, which had just made a stopover in Hong Kong while en route from London to Melbourne, had to make a rapid descent from 29,000 feet over the South China Sea before landing in Manila.
It wasn’t until the plane landed and emergency crews pulled alongside did the magnitude of the problem became clear: a gaping hole where the front edge of the right wing attaches to the fuselage. The cargo hold was exposed, with luggage straining against the webbing that keeps it from shifting during a flight.
‘A bit of a twist’
Pilot Mike Glynn, vice president of the Australian and International Pilots Association, said the oxygen cylinders would have been kept along a wall in the forward cargo compartment, near where the plane’s siding was blown out.
“It’s a bit of a twist that they’re actually there to cope with a depressurization — and it looks as though they caused it in this case,” Glynn said.
Blyth said passengers who reported problems with their oxygen masks — some said they nearly passed out — will be interviewed, and he urged everyone on board to write down their recollections while they are still fresh.
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 say 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 inspected.
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 from the one being scrutinized in the Qantas emergency.
‘Very, very bad accident’
Three of Qantas’ aircraft were affected by the directive and all had been 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.
Four Australian Transport Safety Bureau specialists were inspecting the aircraft in Manila, with assistance from Boeing and the U.S. National Transportation Safety Board.
On Monday night, another Qantas jet, en route to Melbourne, Australia, was forced to return to Adelaide, shortly after takeoff, Australian media reported. Civil Aviation Safety Authority spokesman Peter Gibson told The Daily Telegraph the door above one of the plane’s wheels would not close — a malfunction he deemed on the “lower end” of the danger scale.