On April 11, 1995, approximately 1000 Pacific daylight time (PDT), a Hiller UH-12E helicopter, N508HV, impacted the terrain about six miles west of Timber, Oregon. The commercial pilot, who was the sole occupant of the aircraft, received serious injuries, and the helicopter sustained substantial damage. The aircraft, which had just lifted off of a trailer on which it had been towed to the area, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the operator, the helicopter, which was going to be on an aerial application flight, had been towed to the area with a shipping block attached to the main rotor head. At the site of the accident, the pilot and ground crew secured the main rotor blades to the rotor head, but forgot to remove the shipping block. When the aircraft lifted off of the trailer with the shipping block still in place, the pilot was unable to maintain control.