Speculation about what blew a 10-foot gash in the fuselage of Qantas Flight 30 started almost as soon as the Boeing 747 made its dramatic emergency landing in Manila. Terrorism? Metal corrosion? Spilled coffee? (Yes, that's actually a theory being considered). But it looks like an oxygen tank in the cargo hold exploded.
A blown oxygen cylinder was a leading theory from the start of the investigation into Friday's mishap in part because the tank - which, ironically, provides oxygen to the cabin in an emergency - was missing from the cargo hold when when the plane landed. That theory was bolstered today when Australian investigators found a valve and metal fragments that most likely came from the missing cylinder, making it all the more likely the tank blew up and caused the hole.
"Now we know that it was the tank that exploded, and that's good," Todd Curtis, an aviation safety expert with Airsafe, told Wired.com. "But tracking down the sequence of events that led to the explosion is more important."
No one knows for sure how or why the cylinder blew. "There isn't really an easy answer," says Curtis. "I've never seen an instance where a cylinder exploded on a 747 like this. It's unusual."
Maybe so, but that's not stopping people from speculating (and keep in mind, it's all speculation at this point): the tank got too hot. Something in the hold punctured it. The regulator valve was faulty.
And then there's the back and forth about whether all the rules had been followed. In May, the FAA ordered airlines including Qantas to examine the brackets holding oxygen tanks in place and replace them as needed. The media has latched onto this with attention grabbing headlines like "FAA Warned of Oxygen Tank Damage Before Qantas Jet Hole". If those reporters had done their homework, they'd know the FAA directive didn't apply to the plane in question, and in any case Qantas had already responded to a similar safety bulletin from Boeing.
The discovery of the oxygen cylinder valve is likely to put to rest some of the other theories floating around out there. Early on, some alarmists wondered out loud if the explosion was the work of freedom-hating tourists, but investigators didn't find any bomb fragments or explosive residue in the hold.
Another slightly wacky idea is a spilled cup of coffee leaked through the floor of the plane, causing corrosion that weakened the fuselage. Curtis says that this line of reasoning "doesn't make much sense" because it would have had to been an ongoing leak, and that's highly unlikely since there are no galleys or lavatories in the area where the blast occurred.
Curtis also said that the Qantas incident bears little similarity to the 1996 ValueJet crash in the Everglades. "They both involved canisters, but the similarities end there," he says adding that the press should stop connecting the two events.
Photo courtesy of Ninoy Aquino International Airport.
