A British Airways flight had to turn back to Heathrow after experiencing engine problems shortly after take-off.
The carrier said its A319 experienced an "engine surge" as it took off from the London airport at about 2100 last night.
Flight BA0364 to Lyon turned back and landed safely and will now be inspected by BA engineers.
It had been making a spluttering noise as it headed down the runway, an onlooker told the BBC.
Tom Puttick said: "I was in the petrol station opposite the airport which is when I heard the bang, so I turned around and the airplane had flames spitting out of the engine with a spluttering noise as it was taking off.
"I then watched it continue to climb and the engine was still emitting flames intermittently.
"Lots of blue lights then emerged on the airport while the plane, I guess, turned around to make an emergency landing."
BA said in a statement: "A flight experienced what's known as an 'engine surge' as it took off from Heathrow, but it has now returned and touched down safely.
"We train our pilots to the very highest standards including how to respond to these type of events, and the engine was immediately shut down.
"Of course, we gave our customers who were on the flight hotel accommodation last night and they have been rebooked to fly today.
"We have also scheduled a larger aircraft to operate to Lyon to ensure we can get all our customers there as soon as possible. We can understand how frustrating the delay to their plans must be.
"The aircraft is being thoroughly checked over by engineers. The safety of our customers, crew and aircraft is of the utmost importance to British Airways."