Incident Overview
On an unspecified date at approximately 0933:44 eastern daylight time, an Air Canada Airbus A320, registration C-FDRP (flight ACA513), was cleared for take-off on Runway 24 at Québec/Jean Lesage International Airport, Quebec. Sixteen seconds later, the controller instructed a Pro Aviation Cessna 172, registration C-FGIM, to taxi to position on Runway 30. At 0934:50, the controller observed the Cessna 172 rolling and taking off toward the intersection of runways 30 and 24. The controller twice ordered the Airbus A320 to abort take-off and then three times ordered the Cessna to turn left. None of these transmissions were received by the aircraft because the controller had previously disabled the transmit function of the airport control radio in an attempt to improve radio reception quality.
Approximately 1000 feet from the intersection, at rotation speed, the captain of the Airbus A320 sighted the Cessna and immediately instructed the co-pilot not to take off until they had crossed Runway 30. The Cessna flew over the Airbus A320 about 200 feet above it at the runway intersection. No injuries occurred.
Aircraft and Flight Details
ACA513, an Airbus A320 with 2 flight crew, 4 cabin crew, and 140 passengers, was operating a scheduled instrument flight from Québec/Jean Lesage International Airport to Toronto, Ontario. The captain, responsible for ATC communication, was bilingual; the co-pilot was unilingual English-speaking. The crew communicated with the controller in English.
The Pro Aviation Cessna 172 was on a visual flight rules flight to Trois-Rivières Airport, Quebec, with one pilot and one passenger. At 0934, the controller instructed the Cessna, on taxiway Charlie, to taxi to position on Runway 30. Instructions were given in French. The Airbus crew did not hear these transmissions.
ATC Communication and Radio Issues
The incident occurred in daylight with good visibility and light traffic. The controller deactivated the air frequency transmit function to address suspected radio interference, but this action prevented both aircraft from receiving subsequent abort and turn instructions. Examination of the control tower radios found no equipment malfunction; the controller's action indicated unfamiliarity with the radio system and operating procedures. The investigation also found that some controllers at Québec tower had insufficient or incorrect knowledge of the radio console operation.
Findings
The investigation determined that the Cessna 172 took off without clearance, creating a risk of collision. The controller did not instruct the Cessna to wait or advise that the Airbus A320 was taking off on Runway 24. The pilot of the Cessna interpreted the instruction to taxi to position as a clearance for take-off, suggesting a misunderstanding of ATC procedures. The controller's disabling of the transmit function prevented effective communication. Additionally, the combination of ground and air control positions contributed to the situation; had they been separate, the air controller likely could have intervened.