Accident Overview
A helicopter collided with power lines while conducting a downwind approach to a helipad. According to witnesses, the helicopter was traveling perpendicular to an electrical transmission line at approximately 60 knots when it struck the top of a two-wire set at about 30 feet above ground level (AGL). Paint transfer from the tail rotor (T/R) skid was found on the damaged power line.
Tail Rotor Separation
After striking the wire, the tail rotor separated at the gear box mounting flange. Small pieces of the tail rotor blade were found on the ground below the point of initial wire contact.
Pilot Statement
The pilot stated that during the downwind climbing turn after takeoff, while passing over a gully near a 6,200-foot ridge, he encountered windshear at 230 feet AGL. This encounter resulted in a loss of 200 feet of altitude and the subsequent collision with the power lines.
Investigation Findings
The existence of the reported windshear, or a possible downdraft, could not be verified.