Primary finding
Probable cause
The pilot's failure to maintain control of the helicopter during takeoff.
Investigator assessment
Analysis narrative
The pilot stated that before lifting off from the refueling pad, he maneuvered the helicopter where the skids were still on the ground, but lightly touching and not supporting its entire weight. The helicopter made a slight yaw to the left which accelerated into a rapid spin to the left that he could not correct with right pedal input. In an attempt to arrest the spin, the pilot closed the throttle, lowered the collective, and closed the mixture control. On the fourth rotation, the tailboom struck a pole-mounted fire extinguisher, and the helicopter came to rest upright. The pilot reported that there were no mechanical deficiencies with the helicopter. He further stated that his heavy coat and boots worn to combat the unseasonably cold weather may have interfered with the flight controls.
Source record
Factual narrative
The pilot stated that he completed the before takeoff checks and got the helicopter "light on the skids" before lifting off from the refueling pad. A slight yaw to the left became a rapid spin to the left that could not be corrected with right-pedal input. The pilot closed the throttle, lowered collective, and closed the mixture control to arrest the spin. On the fourth rotation, the tail struck a pole-mounted fire extinguisher, and the helicopter came to rest upright. The pilot reported that there were no mechanical deficiencies with the helicopter, and stated that his heavy coat and boots worn to combat the unseasonably cold weather may have interfered with the flight controls.