Three people have died in a plane crash involving a Simpson Air flight on Thursday evening.
The Transportation Safety Board of Canada (TSB) is sending investigators to the scene, a small lake west of Fort Simpson.
The cause of the crash, which involved a Simpson Air Cessna 206, is not yet clear. The territory's Department of Health said two others on board the aircraft survived, had been assessed, and were not injured.
Reached by phone, Simpson Air referred questions to Fort Simpson's RCMP detachment.
RCMP confirmed five people had been aboard the aircraft but could not explain why the plane had come down.
Those involved have not been identified. Police are notifying next of kin.
"Fort Simpson RCMP officers are currently on scene and assisting Transport Canada with their investigation," read an RCMP statement on Friday afternoon.
"There is very little information at this point, other than to confirm a Cessna 206 was involved in an accident in the Little Doctor Lake area yesterday at approximately 6:35pm," Chris Krepski, a spokesperson for the TSB, had earlier told Cabin Radio.
Investigators, initially expected at the scene on Saturday, are now expected to arrive on Monday. The aircraft has yet to be retrieved and remains under water at the lake.
Shane Thompson, the MLA for Nahendeh whose constituency office is based in Fort Simpson, said he believed the plane's occupants included four visitors who were not local to the community, alongside a local pilot.
Thompson, who is familiar with the staff of Simpson Air, said he had been in touch with the company.
"They’re pretty devastated," he told Cabin Radio.
"I’m trying to be as supportive as I can with the people there. It has a huge impact on their lives."
Little Doctor Lake, near the North Nahanni River, is roughly 100 km west of Fort Simpson and around 150 km north of Nahanni Butte.
Simpson Air operates two Cessna 206 aircraft, one of which serves as a floatplane during the summer months.
The company, formerly known as Arctic Air, calls itself "the longest established flying business in the Mackenzie Valley." It has offered air charters in Nahanni region since the 1960s.
"Two patients, a female pilot and female passenger, were flown to Fort Simpson Health Centre late last evening," Damien Healy, a Department of Health spokesperson, wrote in an emailed statement.
"Both survivors were assessed free of injuries ... at the Fort Simpson Health Centre."
The patients, who have been provided with counselling support, have both been discharged.
This is the second air incident in a week involving flights in the Dehcho. Earlier, a separate South Nahanni Airways flight suffered engine failure on take-off – four people on board were treated for minor injuries.
Correction: August 17 2018, 14:48 MT. Reflecting information provided by the Department of Health, this report initially stated the pilot who escaped unharmed from the crash was male. The Department of Health has since issued a corrected statement amending the pilot's gender to female, and this article has been updated accordingly.