Primary finding
Probable cause
The pilot’s inadequate performance calculations, which resulted in an overweight takeoff for the conditions and the subsequent hard impact with terrain.
Investigator assessment
Analysis narrative
Before the accident flight, the pilot asked for the weights of passengers, fueled the helicopter accordingly, and then flew to pick up the passengers. However, when the pilot arrived to pick up the passengers, they appeared to be heavier than the weights he had used for them in his preflight planning. The pilot reported that he was able to lift off and bring the helicopter to a hover, so the helicopter seemed to have sufficient power for takeoff. However, as the helicopter flew forward over a thicket, the main rotor rpm began to decrease. The pilot lowered the nose to increase rpm. The rpm did not increase, and the helicopter impacted terrain hard and sustained substantial damage when its tailboom separated. The pilot estimated that the helicopter’s weight at the time of the accident was inside the envelope for in-ground-effect operations, but was outside the envelope for out-of-ground-effect operations. The pilot reported that there were no mechanical malfunctions with the helicopter during the flight. The pilot stated that he should have requested that one person remain on the ground until more fuel was burned off.
Source record
Factual narrative
The pilot asked the weights of passengers, fueled the helicopter in reference to the passengers, and then flew to a location to pick up passengers. The passengers were heavier than expected. The pilot reported that he brought the helicopter to a hover and the helicopter seemed to have sufficient power for takeoff. As the helicopter flew forward over a thicket, the main rotor rpm began to decrease. The pilot lowered the nose to increase rpm. The rpm did not increase and the helicopter impacted terrain hard where it sustained substantial damage when its tailboom separated. The pilot estimated that the helicopter weight at the time of the accident was inside the envelope for in-ground effect operations and was outside the envelope for out-of-ground effect operations. The pilot reported that there were no mechanical malfunctions with the helicopter during the flight. His safety recommendation was that he should have requested one person to stay until more fuel was burned off.