News release

Today, the Transportation Safety Board of Canada (TSB) released its investigation report (A23W0122) into a runway incursion involving two ground vehicles operated by Airport Terminal Services and a departing aircraft at the Calgary International Airport, Alberta.

On October 6, 2023, two aircraft tugs inadvertently entered an active runway while a Jazz Aviation DHC-8-402 aircraft was accelerating for takeoff. The flight crew saw the vehicles ahead on the runway, but given their distance, elected to continue the takeoff. The aircraft became airborne and flew over the ground vehicles at an altitude of approximately 350 feet.

The investigation determined that procedural drift over time resulting from a lack of recurrent training and oversight was an underlying factor in the incursion. In this occurrence, the tug driver misinterpreted the ground controller instructions and entered the active runway. This misunderstanding stemmed from differing mental models: the ground controller expected the driver to follow the intended taxi route, while the driver, who was positioned near the holding line, believed entering the runway was the only way to proceed. As a result, the tugs entered the runway while a departing aircraft was accelerating for takeoff, creating a risk of collision.

At the time of the occurrence, the airport’s advanced surface movement guidance and control system had been temporarily shut down for a scheduled update, limiting surveillance and visual aids available to controllers.

Following the occurrence, NAV CANADA took action to clarify controller phraseology around when takeoffs should be aborted.

Runway incursions remain a key safety issue on the TSB’s Watchlist.

See the investigation page for more information.