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TSB releases investigation report into 2022 aircraft collision with water in Pluto Lake, Quebec

Dorval, Quebec, 24 November 2023 — Today, the Transportation Safety Board of Canada (TSB) released its investigation report (A22Q0122) into the 2022 aircraft loss of control and collision with water in Pluto Lake, Quebec (Qc).

On 12 October 2022, a True North Airways Inc. de Havilland DHC-3 Otter aircraft on floats was conducting a visual flight rules flight, with one pilot on board, from Mistissini Water Aerodrome, Qc, to Pluto Lake, Qc, where it would deliver cargo and pick up passengers. At approximately 0929 (EDT), while manoeuvring for landing on Pluto Lake, the aircraft collided with the surface of the water. The pilot sustained serious injuries and the aircraft was significantly damaged.

The investigation found that due to the visual cues of the landing area that were visible to the pilot, the close proximity of the landing site where passengers were waiting, and the natural tendency to continue a plan under changing conditions, the pilot continued the approach despite visibility in the local area being below the minimum required for visual flight rules flight. Owing to the reduced visibility, the pilot’s workload while he was manoeuvring for landing, was high and his attention was focused predominantly outside the aircraft in order to keep the landing area in sight. As a result, a reduction in airspeed went unnoticed. During the aircraft’s turn from base to final, the increased wing loading, combined with the reduced airspeed, resulted in a stall at an altitude too low to permit recovery and the aircraft collided with the water.

While the aircraft was equipped with a stall warning light, it was not equipped with an auditory stall warning system. If aircraft stall warning systems do not provide multiple types of alerts warning the pilot of an impending stall, there is an increased risk that a visual stall warning alone will not be salient enough and go undetected when the pilot’s attention is focused outside the aircraft or during periods of high workload. 

After the occurrence, the company took a few safety actions, including amending its operations manual to more accurately reflect the Canadian Aviation Regulations regarding visual flight rules weather limits.

See the investigation page for more information.

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.

For more information, contact:
Transportation Safety Board of Canada
Media Relations
Telephone: 819-360-4376