Narrative
The helicopter had departed from the airport for the second surveillance flight of the day. Shortly after departure, a ground crew member contacted the pilot and reported that a 55-gallon fuel barrel had been knocked over during the helicopter's departure. In response, the pilot elected to return to the airport and inspect the helicopter for possible damage that may have occurred.
The pilot executed a normal approach to the airport and established the helicopter in a hover taxi. At that point, the helicopter suddenly began to descend. The pilot stated that he increased the collective without any response. He then pulled full up-collective, but the helicopter continued to descend. The helicopter subsequently impacted terrain in a slightly nose-low attitude.
After contacting the ground, the pilot released the collective. The main rotor blades then struck and severed the tail boom assembly. The helicopter canted to the left and partially rolled to one side.
Operating Conditions
At the time of the accident, the helicopter was operating near gross weight at an elevation of 3,835 feet mean sea level (MSL).