A Sydney-bound Qantas Airways Boeing 747 jumbo jet returned to Bangkok due to an engine problem, the airline said Monday.
The plane 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 back at 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.
Enright said all passengers had flown on to Sydney on other airlines by Monday.
The Australia-based airline has canceled almost 100 domestic flights last week from Monday due to an industrial action by maintenance crews.
Qantas image has taken a battering in recent years due to a series of mechanical mishaps and flight cancellations due to industrial action over Australian staff concerns that the airline plans to move jobs offshore.
(This version CORRECTS Corrects dateline from Sydney to Canberra, upgrades attribution and adds details. For global distribution.)