Abstract: A helicopter pilot was flying a helicopter, hauling pulling lines for conductors for a new transmission line. He had successfully placed the pulling lines for the three phase conductors and then began hauling the pulling line for the lightning-protection conductor. The pulling line caught between two other wraps on the tensioning drum and began to rewrap in a reverse wind. When the pulling line became taut, it sharply pulled the helicopter 90 degrees, with the rotor perpendicular to the ground. This flying position was out of the helicopter's flight envelope, and the helicopter fell approximately 75 meters, landing horizontally on the pilot's side. The pilot was crushed to death inside the cab. In the job briefing, the employees agreed that the helicopter would be flown in the freewheel mode. However, the pilot was flying in in power-out mode at the time of the accident.