The pilot escaped before the chopper ignited, said Transportation Safety Board accident investigator Mike Tomm.
"I guess they had a fuel leak," he said.
The pilot was picking up passengers he dropped off earlier that day at Horne Plateau, said Tomm. The passengers were on the ground waiting to be flagged into the helicopter. They called for help on a satellite phone. Horne Plateau is about 110 kilometres southeast of Fort Simpson.
Tomm said this kind of accident is rare.
Adam Bembridge, CEO of Great Slave Helicopters, would not comment. He said the company is planning an investigation.