He said the hole in the fuselage caused another hole to open up in the cabin floor and debris was sent flying through the plane.
"It was just like it was snowing in the cabin," he said.
Back in Manila four offices from the Australian Transport Safety Burea and other investigators are looking over the aircraft to identify what caused the problem.
Experts were focusing on two theories - that an explosion inside some luggage or a broken panel created the hole in the aircraft.
An unnamed source told the AFP news agency: "They were very lucky. While it is too early to say what actually caused the hole, we will be looking at two possibilities ... something exploded in one of the bags or a panel came loose on the fuselage."
The explosion could have been caused by a pressurised container. He said a bomb was unlikely.
No one was hurt in the incident which happened after the flight from London to Melbourne had departed from a stop in Hong Kong. Some passengers praised the 19 crew members for their handling of the problem.
Qantas says that it has never lost a jet through an accident.