A close call involving an Air Canada jet and an unattended maintenance van at Pearson airport last year was the result of several factors, the Transportation Safety Board of Canada has concluded.  

The March 11, 2013, incident saw a van roll across a runway where an Air Canada Embraer was preparing to land. A TSB investigation has determined that the plane passed over the van at a height of about 11 metres as it made its landing.

The TSB says that a maintenance technician had been attending to a Sunwing Airlines plane and left the van parked outside a Sunwing aircraft.

The van's engine was running, and the vehicle began rolling onto an "active runway."

Air traffic controllers noticed a ground radar target on the runway and warned the Air Canada flight to go around, but the pilots couldn't hear the message because of alarms going off within their cockpit.

A second call was truncated, and the crew didn't understand that it was directed at them.

The plane, which had five crew members and 67 passengers aboard, continued and landed safely. No one was injured.

The van was later found in grass next to a taxiway, where it had become stuck against a taxiway reflector sign. Its lights and beacon were on and its engine was still running.

The TSB has since reiterated directives against leaving vehicles idling and unsecured on the "airside," or areas beyond the gates that include runways, tarmacs and taxiways.

The TSB investigation found that the van involved in the incident had an incorrect lightbulb installed in its rooftop beacon. Spot-checks have since been undertaken at the airport to ensure airside vehicles have working beacons that meet required luminosity standards.

Sunwing has also inspected its own fleet of vehicles to ensure they all meet the requirements for beacons.