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 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.
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," said Chris Yates, an aviation expert at Jane's Aviation.
"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.
The Manila airport authority, quoting pilot John Francis Bartels, said the plane suffered an "explosive decompression."
"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 the airport. "There was wind swirling around the plane and some condensation."
She said a hole extended from the cargo hold into the passenger cabin.
After the pilots' initial rapid descent, "the plane kept going down, not too fast, but it was descending," Scaffidi said, adding the staff informed passengers they were diverting to Manila. TV screens on the backs of seats allowed them to track their route to the Philippine capital.
"No one was very hysterical," she said.
June Kane of Melbourne agreed, telling Australia's ABC radio: "It was absolutely terrifying, but I have to say everyone was very calm."
Amazingly calm, in fact.
Video footage showed people looking almost as if nothing was wrong as they glanced from side to side, their nearly untouched meals still in front of them. The cabin crew continued to work, smiling as they walked down the aisles to reassure nervous passengers.
After the plane touched down safely amid applause, one of the pilots could be heard saying over the intercom: "Fire vehicles and emergency vehicles are going to take a look at us."
What they found was a stunning sight. A 9-foot-wide hole gaped at the joint where the front of the right wing attaches to the plane. Luggage from the cargo hold strained against the webbing used to keep it from shifting during a flight.
A curved line of rivets was still visible on the plane's body at the front edge where the missing sheet once was; a straight line of rivets was along the other.
Boeing spokeswoman Liz Verdier said it was too soon to determine what caused the hole, but the company was providing technical assistance as part of an investigation led by the National Transportation Safety Board.
"We are dispatching four personnel from Boeing, an investigator and three engineers," who were leaving immediately, she said.
The probe into the 17-year-old aircraft was likely to be lengthy, Verdier said, and the Boeing team expects to interview the crew and examine the structure of the plane, among other things.
Friday's incident carried some echoes of a 1988 case in which a large section of an older Aloha Airlines jetliner was torn off over Hawaii because of metal fatigue. Although the pilots were able to land, a flight attendant died and many of the 89 passengers were seriously injured.
Geoff Dixon, the chief executive officer of Qantas, Australia's largest airline, praised the pilots and the rest of the 19-member crew for how they handled Friday's events.
"This was a highly unusual situation and our crew responded with the professionalism that Qantas is known for," he said.
The passengers were taken to several hotels in Manila, then left just before midnight on another plane to Melbourne.
Qantas boasts a strong safety record and has never lost a jet to an accident, although there were crashes of smaller planes, the last in 1951. Since then, there have been no accident-related deaths on any Qantas jets.
However, the airline has had a few scares in recent years.
In February 2008, a Qantas 717 with 84 passengers on board sustained substantial damage in a heavy landing in Darwin, Australia. And the year before, Qantas acknowledged that an unlicensed mechanical engineer had conducted safety checks on more than 1,000 international flights over a 12-month period at Sydney airport.
In September 1999, a Qantas Boeing 747-400 with more than 400 people on board overshot a runway in Bangkok, Thailand, during bad weather.
Union engineers -- who have held several strikes this year to demand pay raises -- say that safety is being compromised by low wages and overtime work.
As of December 2007, Qantas was operating 216 aircraft flying to 140 destinations in 37 countries, though in recent months it has announced it will retire some aircraft and cancel some routes -- as well as cutting 1,500 jobs worldwide -- due to skyrocketing fuel prices.