Life vests and quick-release doors would not have saved the lives of four people on board a float plane that went down near Tofino, B.C., the Transportation Safety Board said Tuesday.

A Cessna 185 carrying a pilot and three passengers crashed off the Vancouver Island coast in May during a six-minute trip from Tofino to the community of Ahousat.

Their deaths renewed calls for quick-release doors and for all float plane passengers to wear life vests.

The TSB has not determined an exact cause of the crash, but investigator Bill Yearwood said the accident wasn't survivable because of the speed with which the aircraft struck the water.

"This is not like the other seaplane accidents," Yearwood said in an interview. "The issues that drew a large concern of post-crash survival don't apply here."

Six people were killed after a crash off B.C.'s Saturna Island last November. A TSB investigation found four of them were able to get their seatbelts off as the plane sank, but couldn't get out of the doors.

Federal Transport Minister John Baird ordered a review of float plane safety after the Tofino accident and said officials would examine ways to improve escape from a submerged float plane.

A federal government safety review in 2006 recommended that life vests be worn and doors unlocked during takeoff and landing, but Transport Canada concluded more work needed to be done on the subject.

Yearwood said Tuesday the Tofino crash was different from others in B.C. in recent years because the four people on board died from the impact of the nosedive, not drowning.

"The fact that it hit water and was a float plane are just coincidental," he said. "If it had hit land and it was on wheels, it would have been the same result at that angle and that speed, that energy, it's not survivable."

Yearwood said he's hoping a final report on the crash will be released within a year.

The Transportation Safety Board has said drowning is the cause of death in 60 to 70 per cent of all fatal float-plane crashes.

The three passengers on the flight to Ahousat were siblings Katrina English, 22, and Edward Sam, 28, and their 24-year-old cousin Samantha Mattersdorfer.

All three passengers were young parents, and well-known in the community.

The pilot was Damon York, 33. An emotional memorial service for York in June drew 300 people.

Ahousat heredity chiefs and council presented York's family and his girlfriend with paddles, a symbol of help for people to move on after their grief.