Pilots in fatal mid-air crash near Fort McMurray didn't see each other, TSB finds

A fatal mid-air collision near Fort McMurray last year was another example of why small aircraft should be equipped with technology that alerts pilots when other planes get too close, according to an investigation report from the Transportation Safety Board of Canada.

Pilots in small planes use visual flight rules instead of instruments when they fly in good weather, meaning they have to rely on their eyes to avoid collisions with other aircraft

But visual scanning can be unreliable due to the limitations of human vision. When pilots are landing a plane or teaching a student, their attention is focused on the task at at hand, meaning the range of their peripheral vision decreases, leaving them with "tunnel vision."

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Flight instructor Nabeel Chaudhry, 33, and his student Amjed Ahmed, 32, died when the Cessna 172P they were in collided with a Cessna A185E float plane about 21 nautical miles northeast of Fort McMurray on June 21, 2015. The plane broke up in flight.

The pilot of the float plane survived after crash-landing his plane at the Fort McMurray airport. His plane lost its right float in the collision. 

In its report, the TSB repeats an earlier call for small planes to be equipped with aircraft collision avoidance systems, which are not required by regulation.

"If used, these technologies offer the potential to significantly reduce the risk of mid-air collisions," the report states.

"If visual flight rules aircraft are not equipped with aircraft collision avoidance systems, it is highly likely that accidents will continue to occur due to the inherent limitations of the see-and-avoid technique of collision avoidance."

In the incident, the instructor had three opportunities to see the other plane, but factors such as the position of the wing while he was making a turn, and the colour of the other plane against an overcast sky, could have impeded his ability to see it.

"Even though the two aircraft flew in close proximity to each other for a number of seconds, it was unlikely that the instructor would have picked up the traffic peripherally due to the increased workload while instructing," the report states.

The other pilot was tied up talking to the tower controller at the Fort McMurray airport and performing other cockpit duties in preparation for landing.

"This may have rendered his peripheral vision ineffective," the report says.

"In summary, neither pilot saw the other aircraft in time to avoid a mid-air collision, due to the inherent limitations of the see-and-avoid principle."

Investigators also found that the two planes never established radio communications with each other, which also increased the risk of a collision in an uncontrolled airspace.

Weather conditions were good at the time of the 7:17 p.m. crash and both planes were certified, equipped and maintained properly. Investigators didn't find any evidence of airframe failure or system malfunction.