Bell Helicopter Textron Canada 505 N118LG accident near Ririe, Idaho

Probable cause

The pilot’s inadequate preflight planning and decision to maneuver the helicopter at a low altitude, and his subsequent failure to maintain clearance from power lines.

NTSB analysis

The pilot and passenger were maneuvering the helicopter at a low altitude over a frozen reservoir while searching for wildlife. The pilot occupied the front right seat, and the passenger was in the rear cabin area, secured with a harness. The passenger saw the power distribution lines about the same time that the pilot attempted to maneuver to avoid them. The helicopter’s main rotor blades then impacted one of the three lower phase power lines, and the helicopter subsequently descended to the frozen reservoir. The helicopter's rate of descent was likely slowed by the impacted power line, which prevented it from going through the ice. The passenger estimated that the helicopter free-fell only 30 ft, although the phase lines were about 160 ft above the reservoir surface. Impact with the ice resulted in substantial damage to the fuselage, main rotor, and empennage.

Examination of the helicopter revealed no pre-accident mechanical malfunctions or failures that would have precluded normal operation. The power lines were depicted on the visual flight rules (VFR) sectional aeronautical chart for the area. Although the investigation was unable to determine the extent of the preflight planning performed by the pilot, a thorough review of the airspace prior to conducting the low-altitude flight likely would have made the pilot aware of the power lines’ location and allowed the pilot to maintain clearance from them.

Text from the NTSB. Open the NTSB docket for WPR25FA100 for the full record.