Investigators probe cause of Toronto Delta plane crash

Investigators are looking into what made a Delta plane crash land and flip over at Toronto's Pearson Airport on Monday, an incident all 80 people on board survived.

Officials have yet to say what caused the crash. Toronto was hit by a major snow storm over the weekend, but authorities said the runway was dry at the time of landing and that there were no cross-wind conditions.

The Delta Air Lines flight from Minneapolis skidded along the runway with flames visible before it came to a halt upside down.

Twenty-one people were injured, but only a small number are thought to be seriously hurt, a fact described as miraculous by analysts.

Passengers on board said they were hanging upside down in their seats and had to release themselves, falling on to the ceiling before clambering out on to the snow-covered tarmac. Firefighters quickly came to the rescue.

"We were upside down hanging like bats," passenger Peter Koukov told CNN.

In a statement on Tuesday morning, Delta Air Lines said 19 of 21 injured passengers taken to hospital had been released.

A child was among the injured but was in good condition as of Tuesday morning, the Hospital for Sick Children in Toronto told the BBC's US partner CBS News.

There were 76 passengers and four crew on board the 16-year-old CRJ900 aircraft, made by Canada's Bombardier company.

Airport authorities have released few details on what may have caused the crash.

They said the runway was dry at the time of landing, despite the wintry conditions in the city. There were also no cross-wind conditions at the time of landing, said Toronto Pearson's fire chief Todd Aitken at a news conference on Monday evening.

Cross-wind conditions refer to when wind blows opposite to the direction of travel which could affect vehicles and aircraft by pushing them sideways and requiring corrective action to maintain control.

Before the crash, authorities said snow had stopped and "frigid temperatures and high winds [were] moving in".

Audio recording from Pearson's air traffic control tower, reported on by the Canadian Press, shows the flight was cleared to land shortly after 14:00 on Monday, and that the tower had warned the pilots of a possible air flow "bump" in the glide path from a plane in front of it.

Analysts say it is possible the plane may have struck an item on the runway such as a light when it landed.

Experts told the BBC it was miraculous that everyone survived the crash, adding that the swift response of flight attendants and emergency crews helped save people, as well as plane safety improvements.

The crash is at least the fourth major aviation incident in North America in the past month, including an American Airlines plane in Washington, DC, that collided with a US Army helicopter, killing all 67 people on board.

Two runways at the airport remain closed as the investigation continues. It is being carried out by the Transportation Safety Board of Canada, with some assistance from its US counterparts.