What happened
In the afternoon near the head of Knight Inlet, British Columbia, a Bell 206B Jet Ranger (registration C-GWUF) performed a toe-in landing at an unprepared site within a steep, narrow gorge. The pilot had arrived to pick up two forest-harvesting engineers. After the first passenger entered the cockpit, the pilot prepared for the second passenger to board.
As the second passenger moved from the ground onto the left skid, the helicopter's skids slipped backward on the loose, wet rock surface. The pilot attempted to correct the movement with simultaneous control inputs, but heavy condensation on the inside of the windows and rain on the outside caused a rapid loss of external visual reference. The aircraft became airborne, struck nearby trees, and rolled onto its side. The pilot sustained serious injuries, while both passengers suffered minor injuries.
The investigation
The TSB examined the environmental conditions, the aircraft's performance, and the impact of cockpit heating limitations. The investigation established that the landing site was a narrow, sloped ledge composed of loose debris and wet rock, adjacent to a rapid waterfall.
Investigators looked into the cockpit environment, noting that while the engine had sufficient power for the maneuver, the pilot's visibility was severely compromised. The investigation also reviewed the specific limitations found in the rotorcraft flight manual regarding the use of the cabin heater during landing operations.