Aerial-view photograph of the base camp and accident site, taken in 2013. Photo courtesy of Paycore Drilling (with TSB annotations)
A new report from the Transportation Safety Board of Canada (TSB) notes that "a perceived power fluctuation and the follow-up maneuvering" caused a Bell 206B helicopter operated by Far West Helicopters to collide with terrain near Deception Mountain, British Columbia, during a September 2016 flight.
Here is summary what occurred during the flight according to TSB investigators:
"On 2 September 2016, a Bell 206B helicopter, operated by Far West Helicopters, was returning to a remote base camp situated 3.6 nautical miles south-southeast of Deception Mountain, British Columbia. As the helicopter was approaching the base camp service pad, the pilot perceived a power fluctuation. In response, the pilot conducted a straight-in approach to the service pad. The helicopter pitched up to an extreme nose-high attitude and began to descend, eventually striking terrain near the service pad. The pilot was seriously injured and the helicopter, still running, was substantially damaged. There was no post-impact fire.
Although the precise cause of the power fluctuation could not be determined, the investigation found that, after perceiving the power fluctuation, the pilot used aggressive control inputs to position the helicopter for a straight-in approach. Attempts to reduce the rate of descent and airspeed caused the helicopter to pitch to an extreme nose-up attitude, resulting in contact between the rotating swashplate components and the cowling. Because there was insufficient height to conduct a successful autorotation to the service pad, the helicopter collided with the terrain.
The investigation also determined that the landing-gear cross-tube ruptured the fuel-cell compartment, allowing fuel to leak from the cell. The live electrical system and the running engine were potential sources of ignition. However, the fuel leaked directly into the creek, and the fast-flowing water carried it from the crash site, preventing the possibility of a fuel-fed post-impact fire. If helicopters are not equipped with crashworthy fuel cells, the risk of injury or death due to post-impact fire is increased.
During the crash, the cockpit broke open and collapsed downward, exposing the pilot's head to potential impacts. Although the pilot was wearing the 4-point seat belt and shoulder harness, he was not wearing a helmet. Other injuries prevented the pilot from exiting the wreckage on his own; however, head injuries alone could have compromised survival in the event of a post-impact fire. Helicopter pilots who do not wear helmets are at increased risk for incapacitation, serious injuries or loss of life in the event of an accident."