What happened
On 04 January 2023, a Bell 407 helicopter, registered C-GTHU, was performing a tourist flight from Terrace Airport (CYXT) toward the Northern Escape Mountain Lodge in British Columbia. During the flight, the pilot received notification from lodge staff that fog had settled in the vicinity of the destination. In an attempt to continue the mission, the pilot chose to descend and navigate along the Kitsumcalum River to keep a visual connection to the terrain.
As the aircraft moved over Treston Lake, visibility worsened due to the encroaching fog. The pilot was operating at a ground speed of under 30 knots and at an altitude of less than 100 feet above the water. During this period, the pilot briefly lost all outside visual references. Consequently, the helicopter struck the frozen surface of the lake at 1136 Pacific Standard Time. While the impact caused significant damage to the landing skids, the pilot maintained control of the aircraft. The pilot subsequently climbed through the fog layer and navigated west, eventually landing at the lodge to disembark the passengers. There were no injuries resulting from the event.
The investigation
The TSB examined the flight path and the environmental conditions present during the transit. The investigation focused on the pilot's decision-making regarding terrain following and the impact of deteriorating visibility on flight safety.