What happened
On a mountain side approximately 80 nautical miles north of Mayo, Yukon Territory, a Bell 206B helicopter, registration C-GCHC, was engaged in supporting diamond drilling operations. During the mission, the pilot had been transferring heavy sling loads, including a 900-pound engine, between platforms. Following the transfer of the engine, the pilot performed an unplanned short trip to move hydraulic equipment before attempting to land at a riverbed staging area for refueling.
As the aircraft approached the refueling site, it descended toward a creek-bed area where fuel drums were positioned. During the approach, the helicopter struck a fuel pump projecting from the top of a drum. This contact triggered a dynamic rollover, causing the aircraft to tip onto its right side. The impact resulted in the death of the pilot, who was the sole occupant of the aircraft.
The investigation
Investigators examined the wreckage and the aircraft's flight configuration. At the time of the crash, the pilot had removed the right-side door to improve visibility and had stripped the aircraft of removable equipment to reduce weight. The investigation found that the longitudinal center of gravity was 1.04 inches aft of the restricted limit due to the door removal.
Technical analysis of the engine and fuel systems revealed that while the engine was capable of functioning normally, there was evidence of a potential power interruption. The investigation looked into the possibility of fuel unporting, a phenomenon where low fuel levels and aircraft attitude cause fuel to move away from the intake, leading to engine starvation. Additionally, the investigation reviewed the pilot's medical history and the structural integrity of the helmet worn by the pilot during the impact.
Findings
- The crash was caused by a dynamic rollover initiated when the helicopter's skid made contact with a fuel pump on a drum.
- A low fuel state may have caused fuel unporting, leading to a momentary loss of power during the critical landing phase.
- The pilot's open-earpiece style helmet provided insufficient side-impact protection, contributing to the fatal nature of the injuries.
- The aircraft's center of gravity was outside of the permitted longitudinal limits because the right door had been removed.