What happened
The pilot and an observer were conducting a routine power line patrol flight. While proceeding southbound, the aircraft approached an area where the primary power lines were approximately 23 feet above ground level (AGL). These lines were crossed by another set of power lines oriented in an east-west direction. The crossing power lines were situated at approximately 45 feet AGL, with two static lines located roughly 15 feet higher, placing them at about 60 feet AGL.
Prior to reaching the perpendicular lines, a prominent marker was visible on the fourth pole north of the higher lines, warning of the crossing power lines 1,000 feet ahead. As the helicopter attempted to cross the perpendicular lines, the right skid became entangled with the north static line. The aircraft then nosed down and collided with the lower set of lines that were being inspected. The helicopter subsequently crashed to the ground and was engulfed in fire. The aircraft sustained extensive damage due to the ground fire.
The investigation
Examination of the wreckage revealed no preimpact mechanical part failure or malfunction. The sequence of events indicates that the entanglement with the static line was the primary factor leading to the loss of control and subsequent impact.