What happened
In the early morning at Québec/Jean Lesage International Airport, an Air Canada Airbus A320, registration C-FDRP, was cleared for takeoff on Runway 24. Shortly after, an air traffic controller instructed a Pro Aviation Cessna 172, registration C-FGIM, to taxi to a position on Runway 30.
Without receiving takeoff clearance, the pilot of the Cessna 17 Hi began a takeoff roll toward the intersection of the two runways. The controller observed the aircraft rolling and immediately attempted to order the Airbus to abort its takeoff and instructed the Cessna to turn left. However, the controller was unable to communicate with either aircraft because the transmit function on the airport control radio had been previously disabled in an attempt to improve reception quality.
As the Airbus A320 reached rotation speed approximately 1,000 feet from the intersection, the captain spotted the approaching light aircraft. The captain ordered the co-pilot to delay liftoff until the intersection was cleared. The Cessna 172 subsequently flew over the Airbus A320 at an altitude of approximately 200 feet. There were no injuries to the 140 passengers or the crew of the Air Canada flight, nor to the two occupants of the Cessna.
The investigation
Investigators examined the controller's instructions and the technical state of the tower equipment. It was established that the controller had deactivated the air frequency transmit function, which prevented the delivery of emergency instructions to both pilots. The investigation also looked into the pilot's understanding of ATC procedures and the lack of clarity in the ATC Manual of Operations regarding departure sequencing.
Furthermore, the investigation reviewed the management of the tower, noting that the ground and air control positions had been combined, which contributed to the controller's decision to alter the radio settings. The investigation also identified discrepancies in how phraseology errors were being evaluated by supervisors and the effectiveness of the quality control programs in place at the time.