An Air Canada flight that rolled suddenly from side to side then plunged in the air may have suffered technical problems, according to passengers interviewed after the plane was diverted to Calgary.

An injured passenger is transported to hospital after an Air Canada plane encountered trouble and made an unscheduled landing at the Calgary airport.
(Larry MacDougal/Canadian Press)

The pilot of Flight 190, heading from Victoria to Toronto, came over the intercom to say there had been a computer failure and that they were flying the plane manually, Richard Kool, a passenger from Victoria, said in an e-mail to CBC News.

Fellow passenger Jayne Harvey, a nurse from Keswick, Ont., said pilots told the flight "the computer had been knocked out.

"Some of the armrests on the aisle seat sides were bent 60 degrees from people holding on. That's how extreme it was," she said.

Health officials said two crew members and eight passengers were admitted to hospital after the Airbus A319 landed safely in Calgary at 8:30 a.m. MT.

The Calgary Health Region's Dr. Rob Abernethy said most people suffered soft tissue injuries.

All the injured passengers were released from hospital by Thursday night.

Earlier reports by Calgary EMS said six people had potentially debilitating neck and spinal injuries.

Flight 190 was diverted to Calgary on its way from Victoria to Toronto.
(CBC)

"I'm sure I speak for all the passengers when I say that the [Air Canada] folks have done a great job in dealing with what could have been a much worse incident!" Kool wrote, while waiting for a flight to continue his journey.

The Transportation Safety Board is investigating the incident, as is standard procedure.

"The aircraft was at … 35,000 feet when the event happened. Control problems were experienced by the crew. The captain declared an emergency," said board spokesman John Cottreau.

Passengers described a massive jolt that rocked the Airbus A319, saying the plane dropped several times and rolled left and right, tossing passengers and crew members around the cabin.

Passengers said the plane's sudden movement in the air lasted about 15 seconds.

"It happened really fast. One side of the plane went up sort of sideways and then came back down," one passenger told CBC News.

She said she saw her friend, who was among those taken to the hospital, "fly up" and hit the ceiling.

"All of a sudden there were three big drops," said passenger Andrew Evans. "I was in the very, very front seat of the plane and was watching dishes fly through the air.

"There was a crash. The cart tipped over and there was a lot of squealing."

Passenger Anne Norris said at one point, people thought the plane was going to turn right over.

"The whole experience was horrible," Norris said. "We thought we were going to go down. I think there's no doubt about that. We were all thrown about but we got here safely in the end."

Air Canada begins investigation into cause

An online flight path indicated that the plane appeared to change course south of Grand Forks, B.C.

Air Canada has not confirmed the cause for the flight's diversion. A spokesman said the airline will be doing a full internal investigation.

"There are a lot of factors when an aircraft is in the air and flying and it's difficult to speculate. At this point, we're just going to have to wait until the proper authorities have a chance to look at this," Air Canada spokesman Peter Fitzpatrick said.

The airline also said relatives of those on board who are seeking more information can call 1-800-961-7099.

Typical storm conditions reported at the time

Nick Czernkovich, a CBC meteorologist and a licensed commercial pilot, said turbulence might have caused the autopilot to disconnect, forcing pilots to operate the aircraft manually, or that the jolt in the sky was caused by some sort of mechanical failure.

Nav Canada's website indicates there were no aviation weather bulletins in effect at the time of the unscheduled stop. Environment Canada reported a low-pressure system with a front moving east across British Columbia on Thursday morning in what one meteorologist called a typical storm.

Bryce Paton, spokesman for the Calgary Airport Authority, said air traffic control gave priority to the plane's landing but it did not disrupt regular operations at the airport.

With files from the Canadian Press