(CNN) -- Australian authorities have asked the country's national airline to check every oxygen bottle in its fleet of Boeing 747s after investigators said an exploding cylinder might have ripped a hole in one of the jumbo jets while it was mid-flight.
The mid-air explosion forced the Qantas flight to make an emergency landing in the Philippines on Friday. No one was hurt.
The Civil Aviation Safety Authority asked the airline to check oxygen containers and the brackets that hold them in each of the 30 Boeing 747 that's part of Qantas' fleet, the state news agency said.
The agency thinks an exploding oxygen cylinder caused the rupture on the flight Friday because there were no signs of fire and the bottle had been in the spot that exploded, the Australian Associated Press said.
The flight was on its way from London to Melbourne with 346 passengers on board when the explosion occurred. The plane lost cabin pressure and altitude.
The crew brought the plane down from 29,000 feet (8,840 meters) to 10,000 feet (3,048 meters) and diverted the aircraft to Manila International Airport in the Philippines, where it landed safely.
Oxygen masks were deployed during the emergency. Passengers said their ears popped because of the plane's rapid descent to a lower altitude.
"There was a big bang," said one passenger. "I knew there was a hole somewhere, but I didn't know what was going on." Watch passengers talk about oxygen masks »
A U.S. Transportation Security Administration official, who asked not to be identified because his agency is not leading the probe into the incident, told CNN that a preliminary investigation found no connection to terrorism.
The damage appears to be related to a mechanical issue, based on examination of the aircraft on the ground, the official said. iReport.com: See photos of the damage
The official said a TSA representative based in Manila is assisting in the probe.
The National Transportation Safety Board also is sending investigators, and an NTSB spokesman told CNN they also do not suspect terrorism.
CNN Producer Jim Spellman contributed to this report.