Oxygen Bottle Blamed for Hole in Qantas 747

On July 25, 2008, Qantas flight QF30 made an emergency landing in Manila after the Boeing 747 Jumbo Jet suffered a mid-air cabin decompression caused by a gaping hole on the right lower fuselage. Investigations by the Australian Transport Safety Bureau (ATSB) have shown that the hole was caused by an exploding oxygen bottle.

Gaping hole on the 747′s fuselage. Photo courtesy: Getty images via NYTimes.com

The 4th oxygen cylinder out of 7 on the right side of the cargo hold ruptured, sending the main part of the bottle out of the aircraft, causing the hole in the cargo area of the fuselage. Another part was blasted up through the cabin floor, hitting a door frame, hitting a door handle and pushing it to the open position, and finally hitting the overhead panel. Parts of the valve could be found in the cabin but the part of the bottle that blasted out from the fuselage is probably lost at sea.

The rupture caused the rapid decompression and it also ripped away the first officer’s aileron cables and electrical wiring. All three instrument landing systems, the left VHF omnidirectional radio-range navigation instrument, the left flight management computer and the aircraft anti-skid braking system were affected. The photos below will give a better understanding of how the bottle traveled through the aircraft.

This is how an oxygen bottle looks like. It is made out of metal and it is heavy so it can deal a lot of damage if it travels through the aircraft at high speeds.

Fuselage skin ripped away by the main part of the oxygen bottle.

Close view shows the stringers ripped apart and skin torn back. Also visible inside is the other green oxygen bottle.

Damaged wiring. On the upper right hand corner you can see the internal honeycomb construction of the composite fairing that was partly blown away also.

The red circle on the right shows where the ruptured oxygen bottle was supposed to be.

Red circle shows missing bottle.

The other part which has the valve shot through the composite floorboards. I’ve worked with floorboards and they’re very strong. It would require a lot of energy to propel the valve through it.

Went through the floorboard and hit the door frame.

It also hit the door handle, moving it from close to open. But because of a safety lock that prevented the door from opening during a flight, the door handle shaft was sheared. The door locks remain locked.

After hitting the door handle it smashed into the overhead panel.

As to why the oxygen bottle failed during flight, the ATSB have no clear explanation. The tank was part of a batch of 94 cylinders made in February 1996, and had undergone regular three-yearly checks. It was serviced and refitted to the plane six weeks before it failed.

I was attached to the hydrostatic workshop before this and I have observed the testing of oxygen bottles. The bottle to be tested is placed in a jacket of water for safety and then water is pumped into the bottle until the certain testing pressure is reached. The testing pressure is higher than the operating pressure so if it passes the test, it should not fail during operation. The bottles are tested according to fixed intervals and after each test, a date of test stamp is punched onto the bottle. So if the test of the bottles are carried out properly, they shouldn’t fail.

“There’s nothing at this stage that the ATSB can identify that could have been done to prevent this,” says investigator Julian Walsh. “We don’t really know why the bottle failed. That’s the key question for the investigation.” And so the investigation continues.

Sources: Reuters, AviationNow, Yahoo!, and Telegraph.

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