What happened
During a period of reduced visibility at Calgary International Airport, a de Havill and DHC-8-102, operating as flight NCB801, crossed runway 16 while a BAE 125-800A, registration C-GMTR, was performing its take-off roll. The incident occurred at 0945 Mountain Standard Time under weather conditions characterized by freezing fog, light snow, and a low ceiling of 200 feet.
At the time, the airport was utilizing a reduced visibility operations plan with runway 16 as the sole active runway. The flight crew of NCB801 had been holding at taxiway U. After the controller issued an instruction to line up and wait at the runway threshold, the crew proceeded to cross the hold line at taxiway U. Simultaneously, the C-GMTR aircraft was passing overhead at 400 feet above ground level.
The investigation
The investigation examined the coordination between air traffic control and the flight crew, as well as the technical limitations of the airport's surveillance equipment. Investigators found that the airport controller had lost track of the exact position of NCB801 due to a significant delay between the aircraft's arrival at taxiway U and the issuance of the take-off clearance.
Furthermore, the investigation looked into the staffing levels in the tower, noting that the tower coordinator position was vacant due to personnel shortages. The investigation also assessed the functionality of the Airport Surface Detection Equipment (ASDE) and the Runway Incursion Collision Warning System (RIMCAS), which was disabled at the time of the event.