A Delta Air Lines regional jet flipped upside down upon landing at Canada's Toronto Pearson Airport on Monday amid windy weather following a snowstorm, injuring 18 of the 80 people on board, officials said.
Three people on flight DL4819 from Minneapolis-St. Paul International Airport suffered critical injuries, among them a child, a Canadian air ambulance official said, with 15 others also immediately taken to hospitals.
Some of the injured have since been released, Delta said late on Monday.
The US carrier said a CRJ900 aircraft operated by its Endeavor Air subsidiary was involved in a single-aircraft accident with 76 passengers and four crew members on board.
The 16-year-old CRJ900, made by Canada's Bombardier and powered by GE Aerospace engines, can seat up to 90 people. At least one of the two wings was no longer attached to the plane, video showed after the accident.
Canadian authorities said they would investigate the cause of the crash, which was not yet known.
The Delta plane touched down in Toronto at 2:13 p.m. (1913 GMT) after an 86-minute flight and came to rest near the intersection of runway 23 and runway 15, FlightRadar24 data showed.
The reported weather conditions at time of the crash indicated a "gusting crosswind and blowing snow," the flight tracking website said.
Toronto Pearson Fire Chief Todd Aitken said late on Monday the runway was dry and there were no crosswind conditions, but several pilots Reuters spoke to who had seen videos of the incident pushed back against this comment.
US aviation safety expert and pilot John Cox said there was an average crosswind of 19 knots (22 mph) from the right as it was landing, but he noted this was an average, and gusts would go up and down.
"It's gusty so they are constantly going to have to be making adjustments in the air speed, adjustments in the vertical profile and adjustments in the lateral profile," he said of the pilots, adding that "it's normal for what professional pilots do."
Investigators would try to figure out why the right wing separated from the plane, Cox said.
Flights have resumed at Toronto Pearson, but airport president Deborah Flint said on Monday evening there would be some operational impact and delays over the next few days while two runways remained closed for the investigation.
She attributed the absence of fatalities in part to the work of first responders at the airport.
"We are very grateful that there is no loss of life and relatively minor injuries," she said at a press conference.
The Transportation Safety Board of Canada (TSB) said it was deploying a team of investigators, and the US National Transportation Safety Board said a team of investigators would assist Canada's TSB.
Global aviation standards require a preliminary investigation report to be published within 30 days of an accident.
