What happened
On a morning in British Columbia, a Bell 407 helicopter, registered C-GNVI, departed Stewart Airport carrying a pilot and two passengers. The flight was destined for a geological exploration site located approximately 14 nautical miles north of Stewart, near the Nelson Glacier. After an initial landing on a mountain ledge to allow a passenger to retrieve a climbing rope, the aircraft took off again at 1001 PDT.
During subsequent maneuvers near the mountain face, the aircraft's GPS tracking ceased at 1004 PDT. Approximately six hours later, the wreckage was located scattered down a steep mountainside. There were 3 fatalities and no survivors. While the aircraft's emergency locator transmitter activated, a damaged antenna and cable prevented the signal from reaching the Canadian Mission Control Centre.
The investigation
Investigators utilized data from the electronic control unit (ECU), a portable GPS, and various handheld cameras to reconstruct the flight. The investigation found that the helicopter was performing maneuvers in close proximity to the rock face when the main rotor blades struck the terrain. This impact caused a sudden reduction in rotor speed and a surge in torque, leading to the severing of the driveshaft between the engine and transmission. This mechanical failure resulted in a total loss of control and the subsequent collision with the mountain.
Regarding the response, the investigation examined the breakdown in flight-following procedures. The pilot's verbal flight plan lacked a specific return time, and the absence of a documented operational plan led ground personnel to assume the aircraft had simply landed to wait out weather conditions. Furthermore, the failure of the ELT signal and the lack of an automated emergency notification from the GPS system delayed the initiation of the overdue-aircraft response plan and the notification of the Joint Rescue Coordination Centre.
Findings
- The main-rotor blades made contact with terrain while the aircraft was maneuvering near a steep rock face, causing a loss of control.
- A gap between established operator procedures and actual practice increased the risk to the crew.
- Delays in notifying the Joint Rescue Coordination Centre placed the occupants at higher risk due to postponed search-and-rescue efforts.
- Damage to the ELT antenna prevented the detection of a distress signal.
- The use of unfastened seat restraints during flight operations increased the risk of injury during maneuvers.
- The lack of cockpit or flight data recorders limited the ability to identify specific safety deficiencies.