TORONTO (AP) – Investigators trying to determine why an Air France jet skidded off a runway said Saturday that only four of the aircraft’s eight doors and emergency exits were used to escape the burning jetliner, and that two emergency slides malfunctioned.

Real Levasseur of Canada’s Transportation Safety Board said one of the four exit doors used by the 309 passengers and crew in their rush to disembark was difficult to open, and that the fire after the crash last Tuesday may have prevented access to the other doors.

Levasseur also said two of the slides used failed to work, even though they are supposed to automatically unfold when the emergency doors are opened.

The discovery confirms comments by many passengers and witnesses who said some of the slides and emergency exists were not functioning, forcing people to jump from as high as 4 or 5 yards. Some aviation experts have surmised that the impact of the Airbus A340, which slammed into a ravine, might have damaged the exit doors and chutes.

Levasseur said two experts from the U.S. manufacturer of the chutes, Goodrich Corp., and one from the U.S. National Transportation Safety Board were on site looking at why the slides and doors failed to work.

Air France Flight 358 landed at Lester B. Pearson International Airport amid heavy thunderstorms, skidding off the east-west runway some 218 yards and then slamming into a ravine.

Remarkably, none of the 309 passengers and crew members died, though at least 43 people were injured and several remained hospitalized Saturday.

Veronique Brachet, an Air France spokeswoman, said the pilot was still hospitalized with compressed vertebrae.

Meanwhile, a passenger has filed a class-action lawsuit against Air France, Toronto airport authorities and a Canadian private air navigation service, accusing them of negligence, the Toronto Star reported. The suit, filed Friday, asks for $62 million. An Air France spokesman declined comment on the lawsuit.

The plane’s flight data and voice recorders were found intact and investigators said they should have details within days to help them determine what caused the late afternoon crash. There have been questions about whether the 9,000-foot runway is long enough and whether it is safe to have the ravine at its end.

Lucie Vignola, a spokeswoman for the federal transportation ministry Transport Canada, said a plan to require clear, nearly flat runway extensions was under consideration before Tuesday’s accident.

She said Transport Canada decided to go ahead with the plan after it became clear that international standards are shifting to require additional room at the end of runways. The department has not determined how long the safety areas would be, Vignola said.

The Air Line Pilots Association said Pearson does not have sufficient safe areas at the end of runways, including the one on which Flight 358 attempted to land.

“This runway is not as long as what you find at most international airports, so the important of an adequate overrun is increased, and this accident is an example why,” said Capt. Tom Bunn, a retired commercial airline pilot of 30 years for Pan and United Airlines, who now runs fear-of-flying courses.

The gully at the end of the runway has also been a source of contention. A coroner’s jury recommended filling in the gully, or extending a causeway over it, after a 1978 incident in which an Air Canada DC9 aborted takeoff and ended up in the gully, killing two passengers.

Steve Shaw, a spokesman for the Greater Toronto Airports Authority, said that after the 1978 accident, the gully was graded so the slope was not so severe, but it was not filled in.

AP-ES-08-06-05 1928EDT