Mid-air explosion on Qantas plane

QANTAS will fly a replacement aircraft engine to the United States after a mid-air explosion forced one of its 747s carrying 230 people to make an emergency landing.

The 747-400 departed San Francisco about 11.30pm local time on Monday (Tuesday afternoon AEST) with 212 passengers and 18 crew on board.

About 15 minutes into the flight, an apparent explosion in one of the aircraft's engines ripped a hole through its outer shell.

"We felt and heard a bit of an explosion and flames coming out of the engine, the number four engine, which lit up the whole side of the plane," a passenger, Darren, told ABC Radio in Melbourne.

"I could see the flames and all these sparks coming off it, and also felt the eruptions when it exploded."

Flight attendants rushed to the front of the plane as the engine surged and sent sparks and flares stretching all the way to the tail of the aircraft, he said.

Passengers said it took the captain about five minutes to shut down the engine before he started dumping fuel to prepare for an emergency landing.

"Everyone remained pretty calm and the captain kept us all up to date with everything. I've really got to say they did a fantastic job," he said.

A Qantas spokesman said San Francisco air traffic control was quickly told of the problem and the flight returned to the city and made a normal landing.

Passengers were not required to assume the emergency brace position, the spokesman said.

Qantas will fly the replacement engine to San Francisco on Wednesday.

Affected passengers have been offered seats on any of three Qantas flights scheduled to depart Los Angeles on Tuesday evening local time (Wednesday afternoon AEST).

But passengers complained of having to wait for five hours for a shuttle bus to a motel and then returning to the airport to find no one there to help them.

"There was no Qantas representative here to help anybody out at all," said Darren.

"There were a lot of arguments happening and also a lot of elderly people being left to fend for themselves. So in my view it was quite appalling considering the circumstances."

Darren is now waiting in Los Angeles for a midnight (local time) flight to Sydney.

The Federal Aviation Administration (FAA) in the US said Qantas will prepare a report on the incident for the FAA and the National Transportation Safety Board.

"Whatever Qantas does is going to have to meet with our approval too," an FAA spokesman told AAP.

"The bottom line is we want to make sure and know that aircraft is airworthy when they are saying they want to put it back on line."

Qantas said the Australian Transport Safety Bureau will also receive a report on the incident.