A Singapore Airlines (SIA) flight that left Tokyo for Los Angeles on Tuesday had to turn back because of engine trouble.
In a statement, the airline said that about 2 hours and 40 minutes after takeoff, vibrations were encountered in one of the Airbus 380's four engines.
The engine was shut down by the crew as a precaution.
A replacement aircraft has been sent from Singapore and the flight is scheduled to depart Tokyo for Los Angeles at 4.15pm Tokyo time on Wednesday.
An Airbus spokesman said the team is looking into the incident together with SIA and engine-maker Rolls-Royce.
He said: "Preliminary inspection of the engine has revealed no evidence of fire and there was no danger to passengers and crew at any time."