The hole in the fuselage of the Qantas Airways Boeing 747-400 required an emergency landing Friday in Manila. (Ninoy Aquino International Airport, Edwin Loobrera/Associated Press)A Qantas flight en route to Australia from London, England, made an emergency stop in Manila on Friday after a loud bang was heard and a hole punched in the Boeing 747-400's fuselage, officials and passengers said.

There were no injuries, but some of the 346 passengers vomited after disembarking, said Manila International Airport Authority deputy manager for operations Octavio Lina.

Australia's air-safety investigator said an initial investigation suggested "a section of the fuselage separated."

Lina said the cabin's floor gave way, exposing some of the cargo beneath, and part of the ceiling collapsed.

"There is a big hole on the right side near the wing," he said, adding it was 2½ to three metres in diameter.

An official at the U.S. Transportation Security Administration, who spoke to the Associated Press on condition of anonymity, said initial reports show that the incident was not a terrorist attack. U.S. officials have gone to Manila to take part in the investigation, along with inspectors from Boeing, Qantas and the Australian aviation safety agency.

'I presumed we were going to die'

Passengers who talked to the media at the airport in Manila described hearing an explosion, about an hour after leaving Hong Kong, before oxygen masks were released.

June Kane from Melbourne said there was a "terrific boom." She said the crew remained calm, but urged everyone to put on their masks as the aircraft made a rapid descent.

"I presumed that we were going to die at that point. I didn't think we could possibly land in that plane," she told CBC News.

Another female passenger said she felt she was going to be sucked out of the plane, according to freelance reporter Dean Bernardo in Manila.

"It was a harrowing five minutes of their lives. About 20 children who were on board started crying and panicking," Bernardo said.

The Australian Transport Safety Bureau said the aircraft made an emergency descent from 8,800 metres to 3,000 metres.

"We didn't actually fall," Kane said. "I think it was a controlled dive. The captain took us down very quickly to an altitude at which we could breathe without the masks."

Officials said no Canadians were on board the flight. There were about 50 British nationals and seven Chinese people, while the rest of the passengers were from the U.S. and Australia.

"One hour into the flight, there was a big bang, then the plane started going down," passenger Marina Scaffidi, 39, from Melbourne, told the Associated Press by phone from Manila airport. "There was wind swirling around the plane and some condensation."

She said the hole extended from the cargo hold into the passenger cabin.

"The plane kept going down, not too fast, but it was descending," Scaffidi said, adding the jetliner was over the South China Sea when the staff informed passengers they were diverting to Manila.

"No one was very hysterical," she said.

Geoff Dixon, the chief executive officer of Qantas, praised the pilots and the rest of the 19-person crew for the way they handled the accident.

"This was a highly unusual situation and our crew responded with the professionalism that Qantas is known for," Dixon said.

Qantas, Australia's largest airline and de-facto flag carrier, has a strong safety record and has not had a crash since 1951. Recently, there have been a few incidents where Qantas planes suffered damage in bad weather landings.

The airline's engineer's union, which has held several strikes to demand higher pay in the last few years, says cost cutting and an efficiency drive has compromised safety but Qantas officials deny this.

With files from the Associated Press