The Transportation Safety Board of Canada says a risky manoeuvre shortly after take-off led to the air crash that killed Yukoners Chuck and Shane Buchanan.

They died in June after a float plane Shane had just purchased crashed at the airport in North Battleford, Sask.

Winnipeg-based Peter Hildebrand, a regional manager for the safety board, says the plane was only about 45 metres (150 feet) off the ground when Shane Buchanan made a steep turn to the left.

"Many of the flight manuals that I see don't recommend any significant turns below 500 feet, so that's something we've seen as a recommended practice," he says.

Hildebrand says when the plane made the turn it lost the aerodynamic lift that was keeping it in the air. He says there was not enough time for Buchanan to regain control before it crashed into the ground.

Hildebrand says the plane was also carrying too much weight. The extra 23 kilograms would have exacerbated the problem.