TSB has completed this investigation. The report was published on 8 January 2026.
Controlled flight into terrain
Air Tindi Ltd.
De Havilland DHC-6 Twin Otter Series 300, C-GMAS
Diavik Aerodrome (CDK2), Northwest Territories, 7 NM SE
The occurrence
At 1205 Mountain Standard Time on 27 December 2023, the wheel-ski equipped Air Tindi Ltd. De Havilland Inc. DHC-6 Twin Otter Series 300 (registration C-GMAS, serial number 438) aircraft departed Margaret Lake, Northwest Territories, as flight TIN601, on a visual flight rules flight to Lac de Gras, Northwest Territories, with 2 flight crew members, and 8 passengers on board.
Upon arriving over the Lac de Gras road camp, the flight crew conducted 4 approaches toward the desired landing area on the frozen lake surface, descending at times to heights below 50 feet above ground level. During the 4th and final approach attempt, the aircraft descended to below 50 feet above ground level, and the flight crew lost visual contact with the terrain. At 1245 Mountain Standard Time, the aircraft impacted the terrain 1 nautical mile southeast from the desired landing site. Two passengers were seriously injured and were unable to egress. The remaining occupants, including one passenger who was ejected, sustained minor injuries. The aircraft was substantially damaged from the impact forces. There was no post impact fire. The emergency locator transmitter activated, and search and rescue personnel from the Canadian Armed Forces and a volunteer search party from Diavik mine, Northwest Territories, arrived on the scene 8 hours after the occurrence. The following morning, all but the volunteer search party were flown to Diavik Aerodrome (CDK2), Northwest Territories, and subsequently to Yellowknife Airport (CYZF), Northwest Territories.
Investigation information
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Class of investigation
This is a class 3 investigation. These investigations analyze a small number of safety issues, and may result in recommendations. Class 3 investigations are generally completed within 450 days. For more information, see the Policy on Occurrence Classification.
TSB investigation process
There are 3 phases to a TSB investigation
- Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
- Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
- Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.
For more information, see our Investigation process page.
The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.