The incident involved two Westjet Boeing 737s and a Jazz Airlines de Havilland DHC-8 on April 15, 2011.
The Transportation Safety Board report says the controller mixed up the ID of a 737 and the Jazz plane waiting to take off and ordered the 737 to take off from the same runway where the Jazz plane was waiting.
The confusion set off a delay in getting the planes off the ground, which forced an incoming Westjet plane to circle the runway.
The report says as the outgoing Westjet plane took off, it came within 213 metres vertically of the incoming Westjet plane, a violation of the minimum distance required.
In response to the incident, NAV Canada is working to change the missed-approach procedures to make sure there's a greater safety margin between planes and is revising some information around its fatigue management program.
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