What happened
On a recent flight from Ottawa / Macdonald-Cartle International Airport to New York, a Royal Airlines Airbus A310, registration C-GRYV, was involved in two distinct separation incidents. Shortly after departing, the aircraft encountered a loss of separation with an Air Canada Bombardier Regional Jet, registration C-FZAQ, which had taken off minutes earlier. The two aircraft closed to within 3.7 nm with less than 1000 feet of vertical separation.
Shortly thereafter, the same Airbus A310 experienced a second conflict at FL230 with a Piaggio P-180, registration C-GLEM, approaching St. Hubert, Quebec. The aircraft approached within 3 nm of each other while at the same altitude.
The investigation
The investigation focused on the actions of the Valley sector controllers at the Montréal Area Control Centre. At the time of the first incident, a trainee controller was managing the sector under the supervision of an on-job instructor (OJI). The investigation examined the communication between the controllers and the flight crews, as well as the accuracy of flight progress strip updates.
Investigators looked into the specific instructions provided to the Airbus A310 crew, noting that the captain misheard a clearance to maintain FL200 and turn left, instead requesting confirmation for a climb to FL300 and initiating a right turn. The investigation also reviewed the OJI's performance, specifically regarding the monitoring of the Piaggio P-180 and the use of safety alert phraseology.
Findings
- The primary cause of the first separation loss was that the Valley controller and the OJI failed to issue timely avoidance instructions to maintain required separation between the Regional Jet and the Airbus A310.
- The OJI failed to monitor the Piaggio P-180's flight level closely enough, leading to the Airbus A310 being cleared to the same altitude.
- The trainee controller used ambiguous phraseology that lacked the necessary sense of urgency, and the OJI did not utilize the recommended safety alert phraseology during the second conflict.
- The Airbus A310 captain's error in executing a right turn instead of a left turn increased the closure rate with the Regional Jet.
- The OJI's intervention style, which allowed the trainee to manage the conflict, resulted in delays that prevented effective resolution.
- Nav Canada's radar systems at the time lacked automated conflict prediction and alerting capabilities.