SYDNEY—Qantas Airways Ltd. said the cause of an engine problem on a flight from Bangkok to London that prompted an unscheduled landing is similar to the causes of other recent incidents involving Rolls-Royce Group PLC engines.

The Boeing 747 turned around and landed safely back in Bangkok on Friday morning as a precautionary measure after there was "an increase in vibration" and "high temperatures" from one of its four engines, a Qantas spokesman said.

"We...