A Sydney-bound Qantas Airways jumbo jet has returned to Bangkok, Thailand, after an engine malfunctioned.
The Boeing 747 carrying 356 passengers had been flying for an hour after taking off from Bangkok on Sunday when "there was a bang and some vibrations were felt through the aircraft", Qantas spokesman Luke Enright said.
The pilot turned off one of the four engines as a safety precaution and the plane landed safely in the Thai capital, he said.
A passenger told Australia's Macquarie Radio that he saw sparks flying from an engine.
"There were some white sparks shooting out of the engine and then they informed us of what was going on, that the engine had been shut down and we were returning to Bangkok," said the passenger who identified himself only as David.
Mr Enright said all passengers had flown on to Sydney on other airlines.
The Australian airline, which has cancelled nearly 100 domestic flights over industrial action by maintenance crews, has taken a battering in recent years due to a series of mechanical mishaps.
The industrial action is over Australian staff concerns that the airline plans to move jobs offshore.