U.S. & World

MANILA, Philippines (CBS) ― A Qantas flight en route to Australia from Hong Kong made an emergency stop in Manila on Friday after something punched a hole in the Boeing 747-400's fuselage, officials and passengers said.

There were no injuries, but some of the 350 passengers vomited after disembarking, said Manila International Airport Authority deputy manager for operations Octavio Lina.

The flight originally departed from London, but had left for its final destination in Australia after a scheduled stop in Hong Kong.

In a statement from Sydney, Qantas confirmed the hole in its fuselage and said it was being inspected by engineers.

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 2.5 to 3 yards in diameter.

David Learmount, operations and safety editor of Flight International magazine and an expert on aviation, told CBSNews.com after seeing photos of the Qantas aircraft that the actual hole in the fuselage was much smaller than that - about one yard across.

Learmount said there were two visible layers of damage to the 747 - a missing exterior layer of light-weight "filleting," which serves only to blend the shape of the fuselage with the base of the wing for aerodynamics, and the smaller area of damage, the hole, in the pressurized fuselage.

"Most of what's missing doesn't really matter very much," said Learmount, adding that numerous passenger jets have landed safely with far more serious structural damage.

He said the most likely root of the incident was internal damage to the freight bay, caused by the inadvertent action of handlers or by corrosion from a leak that had gone unnoticed.

Learmount indicated to CBSNews.com that there was no evidence to suggest any explosion had occurred inside the plane's cargo hold, but there was "no way I'd rule that out."

Passengers who talked to the media at the airport described hearing an explosion just before oxygen masks were released.

Learmount said such a noise would be expected if a hole were to appear suddenly in the pressurized cargo hold of an aircraft, with or without any actual explosion.

An explosives expert in London said whatever caused the hole to appear, it was definitely not "a significant high-explosive event," reported CBS News correspondent Elizabeth Palmer

The expert said the lack of fragmentation or any sign of heat around the hole ruled out the possibility of a large bomb having gone off, but it could have been caused by a "secondary effect" incident. He said that could mean a grenade-sized device going off in the baggage area, or a larger device on which only the detonator exploded, but the rest of the explosive chain did not function.

"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.

The passengers will be given hotel accommodation while the aircraft is being repaired, said Alfonso Cusi, the airport's general manager.

(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)