Air safety investigators say it appears the damaged oxygen cylinder flew about the aircraft after rupturing and fell out through a fuselage hole it created, The Australian said in its Friday edition.

The July 25 incident immediately forced the flight's pilots to land at Ninoy Aquino International Airport in Manila.

The Australian Transport Safety Bureau investigators' report released this week didn't offer a reason for the tank malfunction but said fragments of the canister were found near a door on the aircraft after the incident.

Qantas Chief Executive Officer Geoff Dixon told the Australian that the airline had conducted its own independent investigation on the matter and has found nothing wrong with its other Boeing 747-400's oxygen systems.

"Our own investigations agree with the ATSB's preliminary conclusions,'' Dixon said.