Incident Overview
A pilot reported that while maneuvering a helicopter for a turnaround over trees after completing the first swath run, the aircraft encountered a sudden wind change. The pilot indicated that the wind originated from a cumulus cloud buildup, resulting in a tailwind condition.
Sequence of Events
As the pilot completed the turn with near zero airspeed, the helicopter began to settle with power. Attempting to recover, the pilot tried to fly out of the situation, but the tail rotor struck a tree limb and separated from the helicopter. The loss of the tail rotor caused the helicopter to spin.
Pilot Actions and Outcome
The pilot responded by rolling off the throttle in an attempt to perform an autorotation. Subsequently, the helicopter touched down hard.