What happened
On a mountain afternoon near Golden, British and Columbia, a Bell 212 helicopter, registered C-GERH, struck a mountainside while attempting to land at a designated drop-off site. The aircraft, operated by Sequoia Helicopters Ltd. for Purcell Helicopter Skiing, was transporting a group of seven skiers and two guides to the Whitehorn ski run. Due to a snow squall at the intended destination, the flight path had been diverted to an alternative site.
As the helicopter approached the landing area, the main rotor blades made contact with the terrain. The impact caused the main rotor to separate from the aircraft and strike the fuselage. The helicopter remained upright following the impact. The pilot sustained fatal injuries, while a ski guide in the front seat suffered serious injuries. The passengers and the second guide in the rear of the cabin were uninjured. Following the crash, the uninjured guide successfully deactivated the fuel valves and battery switches, preventing a fire.
The investigation
Investigators examined the flight history and the aircraft's performance parameters. On the day of the accident, the helicopter had completed 28 successful flight legs. The investigation noted that the aircraft was lighter than previous flights due to having fewer passengers and a minimal fuel load. Environmental conditions included an uphill wind and low density altitude, which had increased the helicopter's rate of climb during the enroute portion of the flight.
Technical analysis of the GPS-based tracking system showed that the last nine minutes of flight data had not been transmitted via satellite link, though the data was recovered from the unit. The investigation also looked into the visibility conditions, noting that the sky was overcast, creating a flat light effect that eliminated shadows and visual depth on the snow-covered terrain. The aircraft showed no mechanical defects that would have contributed to the event.
Findings
- The primary cause of the accident was the main rotor blades contacting the mountainside during the landing approach.
- Poor visibility, characterized by flat light and blowing snow, likely prevented the pilot from maintaining adequate distance from the terrain.
- The approach to the drop-off site was flown at a lower altitude and a flatter profile than previous successful approaches made that day.
- A sudden decrease in upflowing air or a reduction in rotor efficiency due to low airspeed may have caused the aircraft to descend into the slope.
- The actions of the guide in shutting off the fuel and electrical systems helped prevent a post-crash fire.