British Airways said on Friday a plane travelling from London to Oslo was forced to make an emergency landing after a fault in one of the engines.
Video footage on Sky News showed the plane at London's Heathrow's airport with smoke bellowing out of its right engine.
"It's right engine was on fire. This plane was coming over and suddenly the tone of the engine changed dramatically. I'd almost say it was like a blowout or an explosion," witness Clive Cook told Sky News.
The airport, Europe's busiest, closed both its runways to deal with the incident, but one has since been re-opened.
A spokesman for the London fire brigade, which attended the incident, said they believed the fire was now out.
"There has been an incident involving a BA aircraft at Heathrow airport this morning and both runways have been closed as a result," a spokeswoman for the airport said. "All passengers have been safely evacuated from the plane in question."