The DHC-3 Otter was one of two floatplanes chartered for the Royal Commission on Electric Power Planning for Ontario. The final leg of the flight was from Winisk to Timmins/Porcupine Lake Water Aerodrome, Ontario, Canada. The pilot diverted to Moosonee after encountering deteriorating weather. The next day, at 12:30, the flight departed for the two-hour VFR-flight to Timmins. Because some of passengers had limited time to catch onwards flights from Timmins Airport, the pilot decided to take a direct route between the Moosonee and Timmins NDBs. He likely tried to navigate around areas of low clouds and high terrain. The aircraft followed the Abitibi River southward towards Abitibi Canyon Dam. The valley narrows and the terrain rises at this site of the power dam. It is believed that the pilot found the visibility decreasing rapidly in dense upslope fog in this vicinity. At 13:37 hours the aircraft struck the high tension electrical cables near the generating station and crashed to the ground.