Primary finding
Probable cause
The pilot's improper decision to fly at low altitude while maneuvering in mountainous terrain in a canyon and inadvertently exceeding the climb capability of the helicopter. Contributing to the accident were a high density altitude, mountainous terrain, and a tailwind encountered during the attempted course reversal.
Investigator assessment
Analysis narrative
While en route to her destination, the pilot elected to fly the helicopter up a canyon toward rising terrain. Soon after making a low pass over a ridge above 8,000 feet mean sea level, the pilot increased collective in order to climb over upcoming higher terrain. As the collective was increased, the rotor rpm started to drop. The pilot immediately increased throttle, reversed course to fly downhill, and lowered the collective. During the turn, the helicopter encountered a quartering tailwind and began to settle toward the snow-covered down-sloping terrain. Soon thereafter the helicopter contacted the terrain, bounced back into the air, and a main rotor blade severed the tail boom. The helicopter rotated 180 degrees, impacted the terrain, and rolled over. According to the pilot there was no evidence of an engine power loss or any anomaly with the flight control system.
Source record
Factual narrative
While en route to her destination, the pilot elected to fly the helicopter up a canyon toward rising terrain. Soon after making a "low pass" over a ridge above 8,000 feet mean sea level (MSL), the pilot increased collective in order to climb over upcoming terrain. As the collective was increased, the rotor RPM started to drop. The pilot immediately increased throttle, reversed course to fly downhill, and lowered the collective. During the turn, the helicopter encountered a quartering tailwind and began to settle toward the snow-covered terrain. Soon thereafter the helicopter contacted the terrain, but bounced back into the air. Immediately thereafter a main rotor blade severed the tail boom, and the helicopter impacted the terrain. According to the pilot, there was no evidence of an engine power loss or any anomaly with the flight control system.