What happened
An Air Canada Boeing 747 was climbing from flight level 370 to 410 while traveling from Vancouver to Toronto. At the same time, an Airbus A319 was traveling on a reciprocal track from Montreal to Vancouver at flight level 390. The aircraft were under the control of the Lumsden sector within the Winnipeg Area Control Centre.
After the Boeing 7ually 747 requested a climb, the controller issued the clearance. However, the aircraft's actual rate of climb was slower than the controller anticipated. As the two aircraft approached each other, they eventually passed with only 1100 feet of vertical separation and zero horizontal separation, failing to meet the required minimum of 2000 feet vertically or 5 nautical miles horizontally. The conflict was first identified by the crews via their TCAS traffic alerts, and the aircraft subsequently passed each other without a collision.
The investigation
The investigation focused on the air traffic controller's actions and the operational environment at the time of the incident. The controller was managing both the radar and data positions simultaneously, a common practice during low traffic periods. During the period in question, the controller was also managing the arrival of a Fokker F28 and performing various administrative tasks, such as processing flight progress strips and managing non-pertinent data.
Investigators examined the radar indicator module (IM) and the use of flight progress strips. It was noted that the vertical motion indicator on the radar display did not show a climb rate exceeding 600 fpm, which would have signaled the slower-than-expected performance. Additionally, the investigation looked into the lack of automated conflict-alerting software, which was not operational in the Canadian airspace at the time of the occurrence.