Primary finding
Probable cause
The failure of the temporary hoist holding the powerline wire which resulted in a brief loss of control and main rotor blade impacts with the tower.
Investigator assessment
Analysis narrative
The helicopter was conducting an electrical power line construction operation with a lineman standing outside on the skid. The wire was temporarily suspended by a hoist and the lineman was inserting a fiber shoe to attach the wire to the arm of the tower. While the helicopter was hovering next to the wire at about 200 feet above ground level the hoist slipped and the wire fell onto the top of the helicopter's skid. Control was briefly lost and four of the helicopter's main rotor blades impacted the tower resulting in substantial damage to the main rotor blades. The pilot quickly regained control and made an emergency landing in tall corn about 200 feet from the accident location.
Source record
Factual narrative
The helicopter was conducting an electrical power line construction operation with a lineman standing outside on the skid. The wire was temporarily suspended by a hoist and the lineman was inserting a fiber shoe to attach the wire to the arm of the tower. While the helicopter was hovering next to the wire at about 200 feet above ground level the hoist slipped and the wire fell onto the top of the helicopter's skid. Control was briefly lost and four of the helicopter's main rotor blades impacted the tower resulting in substantial damage to the main rotor blades. The pilot quickly regained control and made an emergency landing in tall corn about 200 feet from the accident location.