SINGAPORE – Qantas grounded its Airbus A380 fleet after one of the superjumbo jets blew out an engine Thursday, shooting flames and raining large metal chunks before making a safe emergency landing in Singapore with 459 people aboard.

It was most serious midair incident involving the double-decker A380, the world's largest and latest airliner, since it debuted in October 2007 with Singapore Airlines flying it to Sydney — the same route that Qantas flight QF34 was flying when it was stricken.

Qantas said there had been no explosion, but witnesses aboard the plane and on the ground reported blasts. Officials in Indonesia said the engine trouble could not have been related to recent volcanic eruptions of Mount Merapi, some 800 miles (1,300 kilometers) to the east.

After the plane touched down in Singapore, the engine closest to the fuselage on the left wing had visible burn marks and was missing a plate section that would have been painted with the red kangaroo logo of the airline. The upper part of the left wing also appeared damaged.

One passenger, Rosemary Hegardy, 60, of Sydney, told The Associated Press that she heard two bangs and saw yellow flames from her window.

"There was flames — yellow flames came out, and debris came off. ... You could see black things shooting through the smoke, like bits of debris," she said.

Although it was nearly 90 minutes from the time of the explosion to the plane landing, there was no panic inside the aircraft, she said.

The captain addressed the passengers immediately by saying "'I'm sure you realize there's a problem. We have to find out what the problem is,'" she said. Shortly after that, the captain explained that an engine had failed and needed to dump fuel before landing.

"The crew were fantastic, really — I am so amazed that everyone stayed calm," she said. "We were all sort of really shaken up, but what could you do?"

In another seat, Tyler Wooster watched as part of the skin of the wing peeled off, exposing foam and broken wires.

"My whole body just went to jelly and I didn't know what was going to happen as we were going down, if we were going to be OK," Wooster told Australia's Nine Network news.

Residents on the western Indonesian island of Batam, near Singapore, helped authorities pick up more than 100 pieces of debris scattered in 15 locations in Batam. The pieces, mostly small, torn metal but some the size of doors, were brought to police headquarters for the investigation.

The trouble with one of the plane's four engines happened 15 minutes after takeoff from Singapore at 9:56 a.m. The plane landed after one hour and 50 minutes.

"The shutdown of the Qantas engine had no connection with Mount Merapi," said Bambang Ervan, a spokesman for Indonesia's Transportation Ministry. "It was too far from the volcano — the sky over Singapore and Sumatra island is free of dust."

The flight is a regular service that flies between Sydney, Singapore and London. Qantas' A380s can carry up to 525 people, but flight QF34 was carrying 433 passengers and 26 crew, all of whom were evacuated by a stepladder in an operation that lasted two hours.

Qantas spokeswoman Emma Kearns in Sydney said there were no injuries or an explosion on board. The airline described the problem as an "engine issue" without elaborating.

"We will suspend those A380 services until we are completely confident that Qantas safety requirements have been met," Qantas CEO Alan Joyce told a news conference.

Joyce appeared to blame the engine, made by Rolls-Royce.

"This issue, an engine failure, has been one that we haven't seen before. So we are obviously taking it very seriously, because it is a significant engine failure," he said.

Singapore Airlines later said in a statement it would be "delaying all flights operating our A380 aircraft" after Rolls-Royce and Airbus advised it to conduct precautionary technical checks.

Experts said the problem appeared to be an "uncontained engine failure," which occurs when turbine debris punctures the engine casing and the light cowling that covers the unit.

Aviation expert Tom Ballantyne told the AP that Thursday's troubles were "certainly the most serious incident that the A380 has experienced since it entered operations."

But "it's not like the aircraft is going to drop out of the sky," Ballantyne, Sydney-based chief correspondent at Orient Aviation Magazine, said by telephone from Brunei.

He said the engine shutdown couldn't have caused a crash. The planes are designed to fly on just two engines, and the pilots are trained to handle engine failures, he said.

Rolls-Royce said it was aware of the situation, noting that the investigation was still at an early stage. Its shares were 4.5 percent lower at 625 pence ($10.16) in midday trade on the London Stock Exchange.

Airbus said in a statement that it was providing all necessary technical assistance to the investigation and a team of specialists from Airbus was being dispatched to Singapore.

Martin Fendt, a spokesman for the consortium, declined to comment on Qantas' grounding of all its A380s, but he said no airworthiness directives have been issued mandating a halt to flights by the superjumbo.

Still, the incident is likely to raise safety questions about one of the most modern aircraft, which has suffered a series of minor incidents.

In September 2009, a Singapore Airlines A380 was forced to turn around in mid-flight and head back to Paris after an engine malfunction. On March 31, a Qantas A380 with 244 people on board burst two tires on landing in Sydney after a flight from Singapore.

Last August, a Lufthansa crew shut down one of the engines as a precaution before landing at Frankfurt on a flight from Japan, after receiving confusing information on a cockpit indicator.

The other issues with the A380s have all been relatively minor, such as electrical problems, Ballantyne said.

Qantas' safety record is enviable among major airlines, with no fatal crashes since it introduced jet-powered planes in the late 1950s.

But there have been a run of scares in recent years across a range of plane types. The most serious — when a faulty oxygen tank caused an explosion that blew a 5-foot hole in the fuselage of a Boeing 747-400 over the Philippines — prompted aviation officials to order Qantas to upgrade maintenance procedures.

Airbus has delivered a total of 37 A380s so far. Thirteen are in service with Emirates, 11 with Singapore Airlines, six with Qantas, four with Air France and three with Lufthansa.

Emirates airlines, which has 13 A380s in operation, said all of them are flying as scheduled. It noted that its planes are powered by Engine Alliance GP7200 engines.

Thursday's incident appeared unrelated to mail bombs sent recently on cargo planes, allegedly from Yemeni militants.