TIMBER, OR, USA
N508HV
HILLER UH-12E
THE HELICOPTER WAS TOWED ON A TRAILER TO THE AREA WHERE IT WAS TO BE USED FOR AERIAL APPLICATION WORK. THE MAIN ROTOR BLADES WERE THEN SECURED TO THE ROTOR HEAD, BUT THE SHIPPING BLOCK WAS NOT REMOVED. DURING HIS PREFLIGHT, THE PILOT FAILED TO NOTICE THAT THE SHIPPING BLOCK WAS STILL IN PLACE. UPON TAKING OFF FROM THE TRAILER, THE PILOT WAS UNABLE TO MAINTAIN AIRCRAFT CONTROL BECAUSE THE SHIPPING BLOCK WAS RESTRICTING THE OPERATION OF THE FLIGHT CONTROL SYSTEM. THE HELICOPTER ENTERED AN UNCONTROLLED DESCENT, AND IMPACTED THE TERRAIN.
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.
THE PILOT'S INADEQUATE AIRCRAFT PREFLIGHT DURING WHICH HE FAILED TO NOTICE THE MAIN ROTOR SHIPPING BLOCK HAD NOT BEEN REMOVED, AND THE RESULTANT RESTRICTED MOVEMENT OF THE FLIGHT CONTROL SYSTEM.
Source: NTSB Aviation Accident Database
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