Sydney - Shards of metal from an exploding oxygen tank shot through the fuselage of a Qantas jumbo jet and even pushed the handle of an emergency door into the opening position, news reports said Wednesday.

An exploding oxygen tank is the prime suspect in a Qantas flight Friday from Hong Kong having to make an emergency landing at Manila.

The mid-air explosion tore a hole in the plane's fuselage and prompted the pilot to make a rapid descent from 29,000 feet to
10,000 feet in about four minutes.

"It's an incredibly rare event for the oxygen tank to explode, and for it to hit the door handle and rotate it open is just eye- watering," a source told The Australian newspaper.

The controls of the 17-year-old Boeing 747 were not affected, but some computer functions and electrical systems were disrupted. Australians among the 346 passengers aboard Flight QF30 told of a big bang and then a steep descent as the pilot reduced altitude to adjust to the rapid decompression caused by the hole.

Investigators from the Australian Transport Safety Bureau said it was "most probable" that a burst oxygen cylinder caused the emergency.

Bureau spokesman Neville Blyth said that vital recordings from the cockpit voice recorder had been lost because they had been written over on the device, which operates on a two-hour continuous tape loop. (dpa)