Passengers on a British Airways flight had to be evacuated after smoke poured into the cabin as it was due to land.
People were said to be laying on the floor of the plane, which was flying from London Heathrow to Valencia, to try to breathe in cleaner air as the acrid smoke appeared.
One passenger said on Twitter is was "like a horror film".
They said: "Terrifying experience on flight to Valencia. Felt like horror film. Thankfully everyone safe. Flight filled with smoke and had to be emergency evacuated."
Gayle Fitzpatrick, from Glasgow, who was on holiday with her husband Stephen, described the moment smoke entered the cabin.
She said: "It was very scary. The flight was just ending, and with 10 minutes to go the flight started descending rapidly as smoke started to fill the cabin. A detector was going off saying the cabin was filling with smoke. It was like a horrible white acrid smoke.
"There was chat it was an air conditioning unit. There were no communications from the crew, some of which started to wear full oxygen masks and protective fire wear.
"Eventually they managed to open the emergency doors and told us to go down the chutes. There were fire engines waiting and then we were all ushered into a bus then to the airport. We are still waiting to hear what happened. People were crying and hyperventilating. It was genuinely scary."
She added: "We were not told it was an emergency until we had landed and they were trying to open the cabin doors for passengers to jump down the chutes."
Mrs Fitzpatrick claimed passengers had been stuck at the airport for at least two hours "without any information at all".
She said groups of people were later told they could go and collect items from the plane.
Another passenger tweeted photos of the incident, saying: "Terrifying experience on flight to Valencia. Felt like horror film. Thankfully everyone safe. Flight filled with smoke and had to be emergency evacuated."
A statement from the airline said flight BA422 had "experienced a technical issue on its landing approach into Valencia".
The statement added: "All our customers were evacuated safely by our crew and met by the airport's emergency services.
"There were 175 customers on board the flight, with six cabin crew and two pilots. Three customers were taken to hospital as a precaution and have since been discharged.
"The safety of our customers and crew is always our highest priority.
"In addition to our team on site, other British Airways team members have arrived in Valencia to help our customers and our local airport partners with anything they need."
