What happened
On a day involving active wildfire suppression, an aircraft registered CF-HTN finished a water drop at 60° 33' N and 113° 03' W. Following the drop, the crew flew toward the site of a helicopter crash located roughly 1.5 miles west of the fire. While circling the wreckage to the right, the pilot reported the earlier accident to Fort Smith aeradio via VHF radio.
During its final circuit around the helicopter wreckage, CF-HTN widened its path toward the northwest, moving on a trajectory that took it directly over the site from the north. Simultaneously, another aircraft, a Canadian Vickers PBV-1A Canso registered as CF-IDS and operated by North Canada Air (Norcanair), approached the same fire from the south. After completing its own water drop, the Canadian Vickers PBV-1A Canso entered a climbing left turn.
As the flight paths intersected, the two aircraft collided. The impact involved the left wing of CF-HTN and the right wing of CF-IDS. The collision caused the right wing of CF-IDS to lose a portion of its structure, leading the plane to roll right and crash. The contact also severed the outer third of the left wing on CF-HTN, while debris from the Canadian Vickers PBV-1A Canso struck the stabilizer and elevator of CF-HTN, breaking those controls away. Both aircraft subsequently rolled and crashed. There were 4 fatalities among the crews, and both airframes were destroyed.
Findings
Investigations determined that neither aircraft experienced mechanical failure prior to the impact. Evidence from witnesses and a lack of distress calls supported the conclusion that no malfunctions occurred. The collision was driven by the fact that the two bombers were on converging paths after one crew altered their flight pattern to investigate the previous helicopter crash site.