What happened
On the afternoon of the accident, a float-equipped de Havilland DHC-2 Mk 1, registration C-GPUO, departed from Iyachisakus Lake, Quebec, bound for Mollet Lake. The aircraft was carrying a pilot and six passengers for a visual flight rules (VFR) trip to a local outfitter. While the pilot had previously reported favorable visibility and proximity to the destination, the aircraft failed to arrive at the intended dock.
An search effort initiated by the outfitter's manager located the aircraft approximately one nautical mile east of the outfitter, partially submerged in Mollet Lake. The impact left the nose of the aircraft underwater and the fuselage leaning backward. Of the seven people on board, three fatalities occurred, while four occupants were rescued from the wreckage with various injuries.
The investigation
The investigation examined the aircraft's mechanical state, the pilot's training, and the environmental conditions. The de Havilland DHC-2 Mk 1 was found to be properly maintained, with its weight and balance within legal limits at the time of the crash. Investigators noted that while a vacuum pump failure had occurred prior to the accident, the instruments driven by that pump were not required for the VFR flight being conducted.
Regarding the pilot, records showed he was qualified for the flight and had a history of careful operation. However, it was noted that his required decision-making refresher training had lapsed. The investigation also looked into the weather, noting a low-pressure system was present with variable cloud layers and snow showers, which had previously forced other aircraft to make precautionary landings in the area.
Findings
- The aircraft experienced a stall at an altitude too low to allow for recovery.
- The stall occurred during a maneuver influenced by illusions created by wind drift.
- The aircraft lacked a stall warning device, which might have provided an earlier alert of the impending stall.
- The pilot's decision to execute a right turn, rather than a standard left turn, likely placed the aircraft on a downwind track at a low altitude, making it susceptible to drift illusions.
- Potential ice accumulation on critical flight surfaces, consistent with weather reports from other aircraft in the area, may have increased the stall speed.
- The survival of the occupants was aided by the fact that the aircraft did not sink immediately, though the lack of shoulder harnesses for the front seat occupants and the inability to quickly don life jackets were noted as factors affecting the outcome.