Cargo door issue in fatal N.W.T. plane crash 'easily fixable,' says expert

The deaths in a plane crash near Fort Simpson, N.W.T., in August 2018 may have been due to the cargo door being blocked, says a safety advisory from the Transportation Safety Board of Canada.

The float plane, a Cessna 206, operated by Simpson Air, went down when it was coming in for a landing on Little Doctor Lake on Aug. 16, 2018.

According to the TSB, the pilot lost control during the touchdown and the right float dug into the lake, causing the right wing to hit the surface of the water. The aircraft suddenly nosed over and landed upside down on the lake.

"The pilot and one passenger escaped the submerged fuselage and climb up onto the floats," the TSB advisory reads. "The three remaining occupants were unable to exit the aircraft and drowned; they were found inside the cabin with their seatbelts undone."

Everyone had been wearing seat belts and no one received injuries that would have immobilized them, the advisory says.

Doors difficult to open

The pilot dove under water to try to help the remaining passengers but was unable to open the doors from the outside because they were locked from the inside, the advisory says.

The TSB says it's unknown whether the other passengers tried to exit the plane but it is known that the Cessna 206 series aircraft with double cargo doors can be difficult to open when the flaps are extended.

"In that configuration, the forward half of the door can only be opened approximately 8 cm before coming into contact with the flap," the advisory reads.

I'm getting tired about reading about people drowning [in float planes] because this should be easily fixable.- Jock Williams, retired safety officer with the TSB

A placard above the door lists the procedure to open the door when the flaps are down. The TSB said the post-accident examination found the instructions were in place in this aircraft and all doors and latches were functioning normally.

But even with those instructions in place, opening those doors becomes significantly harder in an emergency, explained Jock Williams, a retired Air Force fighter pilot and retired safety officer with the TSB.

"It's real easy to open if you're sitting there and there's nothing going in. If you're not upside down in the water, you can open it no problem," Williams said.

"Sadly that's not when you need to be able to open it," he said. "You need to be able to open it when you're upside down in the water. A lot of people have failed to do that." 

Problem first identified in 1991

Since 1989, there have been five accidents where the flaps blocked the door, resulting in eight fatalities, the advisory says.

This problem with the cargo doors was first identified in 1991 when Cessna released a service bulletin calling for changes to the cargo door that would make it easier to open.

In 1997, Transport Canada issued an alert that strongly recommended owners incorporate Cessna's recommendations, though it was not mandatory under the Canadian Aviation Regulations.

The aircraft involved in this accident did not have the recommended changes.

"As shown in this occurrence, without functional exits, the time required to exit the aircraft may increase, which in turn increases the risk of death in time-critical situations, such as when the aircraft is submerged or there is a post-impact fire," the advisory says.

The problem could easily be solved with doors that could break away from an aircraft by pulling on a lever, removing the pins connecting the door to the plane — something that's common in planes used for skydiving, Williams said. 

"I'm getting tired about reading about people drowning [in float planes] because this should be easily fixable," he said.

"There should be an easily identifiable, easily operated single handle. That's all you need." 

Geoffrey Dean, 33, from Castor, Alta., and Jean and Stewart Edelman, both 72, from Saskatoon were killed in the crash. Two people survived the crash, the pilot and one passenger.

The TSB said the investigation into this accident is ongoing.

A spokesperson from Transport Canada, meanwhile, declined an interview request from CBC News, but said the department would issue a response to the TSB's advisory letter within 90 days. 

• Read more articles by CBC North, like us on Facebook for updates and subscribe to our CBC North newsletter for the day's news at a glance.