An airline mechanic walks past the damaged right wing fuselage of a Qantas Airways Boeing 747-400 passenger plane following an emergency landing at the Ninoy Aquino International Airport Friday in Manila, Philippines. The plane, with about 350 passengers and 19 crew, was enroute to Australia from London when an explosion punched a hole in the right wing fuselage, passengers said.

Manila, Philippines ? The 346 passengers were cruising at 29,000 feet Friday when an explosive bang shook the Qantas jumbo jet. The plane descended rapidly. Oxygen masks dropped from the ceiling as debris flew through the cabin from a hole that had suddenly appeared in the floor.

It wasn’t until they were safely on the ground after an emergency landing that they realized how lucky they had been: A hole the size of a small car had been ripped into the Boeing 747-400’s metal skin and penetrated the fuselage.

The eerie scene aboard Flight QF 30, captured on a passenger’s cell phone video-camera, showed a tense quiet punctuated only by a baby’s cries as passengers sat with oxygen masks on their faces. The jerky footage showed a woman holding tightly to the seat in front of her as rapidly approaching land appeared through a window. Loud applause and relieved laughter went up as the plane touched down.

There were no injuries and only a few cases of nausea, airline officials said. An official of the U.S. Transportation Security Administration said initial reports indicated no link to terrorism.

The passengers and crew arrived in Melbourne on a different plane this morning and were greeted by hundreds of relieved family members.

Investigators appeared to be focusing on a structural problem.

“From the pictures that we’ve seen out of Manila during the course of the day, it would seem that one of the panels to the outer skin of the aircraft has literally come away from the rest of the fuselage,” Chris Yates, an aviation expert at Jane’s Aviation, told The Associated Press.

“As a consequence of this, the aircraft experienced rapid decompression,” he said.

While it is not uncommon for metal panels to be lost from aircraft in flight, he said: “It’s relatively rare that when a bit falls off the airplane it causes the sort of instance that we saw in relation to Qantas. In other words that it causes the aircraft cabin to depressurize.”

Yates said investigators will examine closely the fracture points that showed up on the skin of the aircraft to determine whether metal fatigue or manufacturing defect caused the panel to peel away.

The passengers, on a flight from London to Melbourne, had just been served a meal after a stopover in Hong Kong when they described hearing a loud bang, then their ears popping as air rushed out the hole. The pilots put the plane into a quick descent to 10,000 feet, where the atmosphere is still thin but breathable.