Accident Overview
A helicopter conducting a powerline patrol experienced a loss of directional control while maneuvering at low speed. The pilot had maneuvered the aircraft at the request of observers to allow a closer look at a tower. During the flight, the wind was from the west to northwest at 10 knots, with gusts from 15 to 20 knots. While flying westward, the pilot inadvertently reduced airspeed to 20 knots.
Sequence of Events
As the pilot applied power and left pedal input, the helicopter began a right rotation. The pilot was unable to regain directional control and was forced to perform an autorotation into unsuitable terrain. During the descent, the tail rotor struck a tree. Upon touchdown, the skids were driven up into the fuselage.
Flight Manual Information
According to a chart in the helicopter's flight manual, the critical wind azimuth area for this aircraft was from 050 degrees to 210 degrees. The reported wind direction and speed, combined with the low airspeed, placed the helicopter within this critical area, contributing to the loss of control as described in the manual.