A tired air traffic controller is getting the blame for a mix-up in the sky near Vancouver Airport.

It happened in April 2011.

An Air Canada Jazz plane took off from runway 26 left, followed by a Westjet 737.

There was also an arriving Westjet, looking to land on the same runway.

The air traffic controller directed the arriving flight to carry out a “go-around,” during which the two Boeings came within 213 metres of each other.

An investigation by the Transportation Safety Board has determined the controller was tired, making it difficult for him to recognize the developing situation and to take timely corrective action to ensure proper seperation was maintained.