Accident Overview
A Piper PA-31-350 Navajo Chieftain, serial number 31-7752151, collided with the ice on the Peace Reach Arm of Williston Lake, British Columbia, at approximately 1055 Pacific standard time. The pilot, the sole occupant, received serious injuries. There was no fire. The aircraft was destroyed.
The flight originated from Mackenzie, British Columbia, at about 0956 PST under an instrument flight rules (IFR) flight plan to Bear Valley, a logging camp. After transporting one passenger to Bear Valley, the pilot planned to continue to Tsay Keh under visual flight rules (VFR) to pick up seven passengers. The aircraft was reportedly operating normally up to the moment of impact.
Weather and Flight Planning
Upon arriving at Bear Valley, the pilot observed mostly cloudy conditions with patches of blue sky to the east. Visibility under the clouds was good, but a few snowflakes were falling, and a wall of dark cloud was visible to the west. The pilot was aware of the dark clouds before departure and intended to assess the weather airborne.
The planned VFR route followed the Peace Reach Arm and then northwest along Williston Lake to Tsay Keh, about 100 nautical miles. The pilot planned to fly at 800 feet above ground level, descending to 300 feet if needed to remain clear of cloud. If conditions deteriorated, he planned to return to Bear Valley.
Weather reports from Tsay Keh described overcast conditions, which would have prevented the pilot from finding clear air for descent. The only aerodrome in the area with an IFR approach was Mackenzie Airport, 50 miles away. With no IFR approaches at Tsay Keh or nearby aerodromes, the pilot's only option to complete the flight was VFR.
Impact and Examination
After encountering heavy snow and reduced visibility, the pilot executed a 180-degree turn to regain visual reference. Shortly after completing the turn, the aircraft struck the ice. Impact markings indicated the aircraft contacted the ice in a slight left bank and near-level pitch attitude on a heading of about 050 degrees magnetic. The left propeller struck first, followed by the fuselage and then the right propeller.
Examination of the wreckage by Transportation Safety Board (TSB) personnel found no pre-existing deficiencies that would have caused a loss of altitude. The weather and surface conditions made it virtually impossible to visually detect the ice surface, as the snow-covered ice was indistinguishable from the falling snow.
Findings
The TSB determined that weather conditions at the time and location were not suitable for visual flight. While attempting to regain visual flight, the pilot allowed the aircraft to descend, and it struck the ice. The weather and surface conditions made it virtually impossible to visually detect the ice surface. The pilot was appropriately certificated and instrument-rated, but no IFR approach was available at the destination.