News release

Loss of visual reference led to 2023 controlled flight into terrain at Treston Lake, British Columbia

Richmond, British Columbia, 27 June 2024 — Today, the Transportation Safety Board of Canada (TSB) released its investigation report (A23P0003) into the 2023 occurrence involving a Summit Helicopters Ltd. Bell Helicopters Textron Inc. 407 at Treston Lake, British Columbia (BC).

On January 4, 2023, the helicopter, with a pilot and four passengers on board, was on a visual flight rules (VFR) flight from Terrace Airport, BC, to the Northern Escape Mountain Lodge when the pilot was informed that low-level fog had moved into the area surrounding the lodge. Shortly after, the pilot decided to descend and follow the Kitsumkalum River towards Treston Lake, a route he had successfully taken on previous flights when visibility was poor. As the helicopter flew over the snow-covered lake, the pilot momentarily lost outside visual reference, and the landing skids impacted the frozen surface of the lake. The landing skids were significantly damaged during the impact, but the pilot managed to recover and climb above the fog layer. Although visibility at the destination was less than the required minima, the flight was completed without further incident. There were no injuries.

The investigation determined that given the short duration of the flight, the pilot’s expectation of suitable weather conditions, a risk level that was assessed as low, and the underlying commercial pressure, the pilot decided to depart on a VFR flight with localized fog conditions that were forecast on the planned route.

The investigation also found that after the pilot decided to descend and follow the river, visibility continued to deteriorate. Several factors led the pilot to decide to continue the flight, including visual cues from the river, the close proximity to the lodge, the pilot's familiarity and past success with his strategy for flight in low-visibility conditions, and the tendency for plan continuation under all of these conditions. Once the helicopter was over the snow-covered lake, the pilot found himself in conditions of flat light, whiteout, and fog that reduced his ability to effectively assess his speed, attitude, and altitude. This ultimately contributed to the pilot’s loss of visual references and spatial disorientation, which led to the collision with the frozen surface of the lake.

Following this occurrence, Summit Helicopters Ltd. expanded the ground briefing portion of low-visibility operations in its annual training and it added this accident to the annual crew resource management training with emphasis on the topics of pilot decision making, workload management, and situational awareness. Additionally, the company discovered that it was possible to skip the flight risk assessment step when filing a flight itinerary for VFR operations. This issue has been rectified and it is no longer possible for pilots to file a flight itinerary for VFR flights without first filling out a flight risk assessment.