Passengers drowned after door design impeded exit in fatal NWT plane crash: TSB

In the advisory, the board notes the five-passenger, float-equipped plane was on a sightseeing trip from Fort Simpson, N.W.T., to Virginia Falls in Nahanni National Park last August when the pilot lost control while trying to land on a lake. The right wing hit the water, the plane flipped and came to rest upside-down and partially submerged.

The pilot and one passenger got out safely and were quickly rescued. The pilot dove back in to try to free the others inside but was unsuccessful.

“The three remaining occupants were unable to exit the aircraft and drowned; they were found inside the cabin with their seatbelts undone,” says the document.

“The impact forces were well within the range of human survivability. The investigation was unable to determine what egress action, if any, was taken by the passengers who were unable to exit the aircraft.”

Killed were 33-year-old Geoffrey Dean of Castor, Alta., and Stewart and Jean Edelman of Saskatoon, who were both 72.

The Cessna 206 is equipped with two adjoining cargo doors.

The board found that the front door was blocked by the extended flap of the right wing, which stopped the door from opening past eight centimetres. In that position, the rear door can only be opened by actions described on a placard above the handle.

“Without functional exits, the time required to exit the aircraft may increase, which in turn increases the risk of death in time-critical situations,” the board says.

The problem has been understood since 1989. In 1991, Cessna released a bulletin to plane owners recommending installation of a spring assembly to automatically retract the rear handle and get that door to open.

Transport Canada strongly recommended the spring in 2007, but it wasn’t made mandatory. Simpson Air, the company that owned the crashed Cessna 206, hadn’t installed it.

No one from Simpson Air was immediately available to answer questions.

Board spokesman Eric Collard said in an email the door problem can’t be linked definitively to the fatalities.

“The (board) has not conducted any analysis to determine differences between operating doors equipped with or without the spring.”

The investigation into the accident is continuing, Collard said. No recommendations have been issued to Transport Canada, although the advisory says “(Transport Canada) may wish to reassess the suitability of the rear double cargo door as an emergency exit.”

Department spokesman Simon Rivet said Transport Canada is reviewing the advisory.

“The department will provide its response to the Transportation Safety Board of Canada’s advisory letter within 90 days,” he said in an email.

Aviation regulators in Canada and the United States had discussed the problem extensively with Cessna between 1999 and 2003. Transport Canada looked at it again in 2005 and commissioned a report on exiting submerged float planes.

No action was ever taken.

“Results of the studies indicated there were no suitable design changes that could feasibly be applied to the entire Cessna 206 fleet,” the advisory says. “By May 2008, the file was put on hold due to other priorities and the absence of a clear way forward.”

The board says five accidents resulting in eight deaths have occurred since 1989 in the United States and Canada in which extended flaps blocked the rear double-door.

There are more than 250 Cessna 206 planes licensed in Canada for commercial and private use.

— By Bob Weber in Edmonton. Follow @row1960 on Twitter

The Canadian Press

by Canadian Press

Passengers drowned after door design impeded exit in fatal NWT plane crash: TSB

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