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News release

Associated links (A19Q0015)

Runway incursion by snowplow proceeding through holding position onto active runway

Dorval, Quebec, 21 January 2020 — The Transportation Safety Board of Canada (TSB) released its investigation report (A19Q0015) today on an incident in which four snow-removal vehicles entered an active runway at Montréal/Pierre Elliott Trudeau International Airport as an aircraft was preparing to land.

On 2 February 2019, snow-removal operations were being conducted at the airport. A convoy of 7 vehicles was instructed to proceed from Runway 24R to holding bay 24L. At the same time, a Bombardier CRJ 200 operated by SkyWest Airlines was flying the instrument landing system approach and had been cleared to land on Runway 24L. A runway incursion occurred at 11:19:04 Eastern Standard Time, when the lead vehicle in the convoy, a snowplow-sweeper, crossed the runway holding position and continued onto the runway. The flight crew initiated a go-around, flying over the lead vehicle in the convoy, which had been followed by three additional snowplow-sweepers. The aircraft landed safely about 15 minutes later. The convoy subsequently regrouped and completed the snow-removal operations. There were no injuries or damage.

The TSB has identified a series of causes and contributing factors in this runway incursion. The investigation found that the convoy lead, focused on the tasks of driving, snow removal, and planning the next snow-removal pass, missed the runway holding position lighting, signage, and markings, forgot about the requirement to hold short, and proceeded onto Runway 24L. Three other vehicles in the convoy followed the lead vehicle and passed the runway holding position, which increased the severity of the incursion. The ground controller on duty was multitasking and conducting an operational phone call, which led to a breakdown of his scanning and monitoring, delayed his response, and increased the incursion’s severity.

The investigation also found that if vehicle operator training does not include runway incursion scenarios, convoy operators may not be sufficiently prepared to take necessary safety actions to reduce the associated risks. Further, air traffic control instructions that direct ground vehicles to runways and do not contain explicit instruction to hold short of an active runway can increase the potential for misunderstanding, and increase the risk of an incursion. 

Following the occurrence, Aéroports de Montréal (ADM) held meetings to raise awareness  of runway incursions, and to obtain employee feedback on the occurrence. An internal investigation within the ADM safety management system was conducted, including brainstorming/mapping and a risk analysis of the event. ADM modified procedures and employee training, and has added the issue of runway incursions to the agenda for its next meeting with NAV CANADA’s Runway Safety Action Team.

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
Email: media@tsb.gc.ca