Passengers on board a Qantas Boeing 747-400 jumbo that made an emergency landing in Singapore overnight reported hearing an explosion and seeing flames on the one of the engines minutes after takeoff.



Some passengers were screaming, while the cabin crew yelled ''crisis!'' and ordered everyone to be on their seats as the plane prepared to make a forced landing at Changi Airport.

''It was pretty scary,'' said Swedish tourist Lisa Ogden, 28. ''An engine on the wing exploded. It looked like fireworks, a pretty big one,'' she told reporters after disembarking at the airport.



''The plane jumped a bit and the cabin crew were yelling 'crisis' and they told everyone to sit down. Some were screaming, one or two got up. It felt like forever but it was one minute then the fire was out,'' she added.



''It feels good to be on the ground again.''



The Sydney-bound plane - flight QF6 - was carrying 431 people, including 412 passengers.



It was the second Qantas plane to be involved in a mid-air emergency in two days.



''We could see some flames coming out from the engine,'' Singaporean passenger Terence Sim told reporters at the airport.



''We could see quite an impressive plume of flame from the engine,'' said Australian national Andrew Jenkins, 43.



''There was a bang, not particularly loud, just loud enough to draw your attention.''



Alan Rumsey, a 60-year-old Australian, slammed his country's national flag carrier for the second incident in as many days.



On Thursday, an Airbus A380 also belonging to Qantas was forced to turn back to Singapore after one of its engines exploded minutes into the flight to Sydney, showering debris on an Indonesian town.



''It makes me wonder how reliable Qantas is since this is the second incident in two days,'' said Rumsey, adding that the airline needed to improve its maintenance.



He said the people seated on the left side of the plane who saw the fire ''got scared and started shouting''.



But Ogden, the Swedish tourist, said she did not blame Qantas.



''Things like that can happen,'' she said.



Sri Lankan-born Australian national Ranjan Sivagnanasumdaram said he also heard the bang and they were told to prepare for emergency landing, but there was no general panic.



''There was a small bang noise,'' he said.



''They basically asked for us to put our heads down and be like that for 20 minutes. They (rest of the passengers) were not panicking as such, there was not much of a chaos.''



Some passengers said the plane dumped fuel 25 minutes before the forced landing.



The Boeing 747-400 passengers' accounts were similar to the experience of those aboard the A380 who also recounted hearing a loud explosion and seeing fire on the Rolls-Royce engine.



It was still unclear what engine powered the stricken 747-400 aircraft.



AFP