It is approximately 20.15 local time at Rouyn-Noranda Airport (CYUY), Quebec when a de Havilland DHC-8-102 (Dash-8) finishes boarding the passengers for its flight to Montréal/Pierre Elliott Trudeau Airport (CYUL).
The aircraft at its final position (source TSBC report)
Due to the weather, the flight initially received a take-off slot for 22,30, which was changed to 20.45 local time. With the passengers on board the flight attendant gives the safety briefing to the passengers while the aircraft is de- and anti-iced in preparation for take-off. Whit the aircraft anti0iced the engines are started and the crew receives their clearance. Besides the weather, the crew received the latest surface condition report for the taxiways and runways.
At 20.18 local time the report for runway 26 was as follows;
the runway was covered with ¼ inch of snow over a width of 110 feet. The remaining 40-foot width was covered with 1 inch of snow. The report also indicated the presence of snow windrows on each side of the runway between the edge of the runway and the runway edge lights, specifically 5 feet from the runway edge lights and the edge of the runway.
Due to weather, no flights were accepted at Montreal and at 20.40 local time the Dash 8 returned to ramp. At 21,28 the engines are started again, and the crew is informed that the condition report from 20.18 was still valid. They taxied to runway 26 and lined up on the runway. Due to the snow on the runway, the centerline lights of the runway were covered by snow and not visible to the crew. With snow falling, and no centerline lights visible the aircraft is actually 17 feet (5.2 meters) left of the centreline of the runway and the aircraft heading is 4 º left of the runway heading.
The aircraft after recovery, damage visible to radome, fuselage and propellor
(source TSBC report)
After receiving their clearance take-off is started, the heading remains 4º left of the runway heading and the crew was unaware of this. At a speed of 80 knots, the pilot flying noticed they were near the left edge of the runway, at about the same time the left gear rolled off the runway surface and 5 feet (1.5 meters) later hit a snowbank swinging the aircraft left. A rejected take-off is initiated, however, the pilot flying mistakenly pushes the right throttle forward while pulling back the left throttle. This cause a further veer to the left hits a snowbank and comes to a stop 200 feet (60 meters) from the runway edge. The engines are shut down and ATC is informed of the situation. Emergency services transport the passengers back to the terminal (1 passenger sustained minor injuries), The aircraft sustained substantial damage to the fuselage, landing gear and propellers. The subsequent investigation by the Transportation Safety Board of Canada (TSBC) revealed no faults with the aircraft systems. Several findings were made during the investigation, these are available in the full report that can be found by clicking here. One finding showed how the perception of the location and heading on the runway was very difficult for the crew, without the centerline lights, see the pictures below. Another finding was that the pilot monitoring was head down (not looking outside) for most if not all of the take-off run
View on runway, aircraft on the centreline View on runway, aircraft 30 feet left of (both images; source TSBC report) the runway centreline