Accident Sequence
The pilot conducted low altitude flight within a gorge, which was not in accordance with the assigned mission profile. After entering the canyon, the pilot proceeded upslope towards rising terrain. The pilot's extensive flight experience was predominantly in helicopter aircraft, comprising 87% of total hours, while he had accumulated only an estimated 13 hours in the accident make and model at the time. The aircraft was slightly over its gross weight, and high density altitude conditions prevailed.
During an attempt to reverse direction at the end of the gorge, the aircraft stalled, resulting in a loss of control. A stall/spin maneuver ensued, placing the aircraft in an uncontrolled descent into the terrain. All six occupants were killed in the impact.
Findings
Official investigation findings identified the following factors: improper in-flight planning and decision-making by the pilot in command; rising terrain conditions; high density altitude weather; misjudged clearance by the pilot; the aircraft weight and balance being exceeded by the pilot; airspeed not being maintained by the pilot; and the pilot's lack of total experience in the type of aircraft. The loss of control occurred during a maneuver to reverse direction, leading to a stall/spin and subsequent uncontrolled descent into terrain.