Incident Overview
During a low-level reconnaissance flight for the Department of Forestry, a helicopter collided with an unmarked neutral power line that was strung across a river. The purpose of the flight was to locate water holes and dip sites for future fire suppression actions. Following the initial collision with the power line, the helicopter subsequently struck the river approximately 300 feet west of the remaining power lines.
Terrain and Conditions
The surrounding terrain was mountainous and covered with dense trees and underbrush. The vegetation was in close proximity to the power line towers, which may have contributed to reduced visibility of the lines. Additionally, patchy fog and clouds were present in the area at the time of the accident.
Obstacle Visibility
According to the pilot who recovered the wreckage from the river, the remaining power lines were difficult to see and blended in with the vegetation and terrain. This suggests that the visual contrast between the lines and the environment was poor.
Mapping and Documentation
Existing maps did not indicate the presence of these power lines. Furthermore, the Department of Forestry did not maintain a "hazard map" for the area, despite such a map being required by their Aviation Procedures Manual.