Aviation Accident Summaries

Aviation Accident Summary SEA94LA183

PILOT ROCK, OR, USA

Aircraft #1

N9645A

BELL UH-1B

Analysis

THE 27000 HOUR HELICOPTER PILOT RECALLED THE AIRCRAFT ROTATING COUNTERCLOCKWISE AROUND ITS VERTICAL AXIS PRIOR TO THE CRASH. HE ATTEMPTED TO MANEUVER NEAR HIS LOGGING CREW FOR RESCUE AFTER THE IMMINENT CRASH, AND RECALLED THAT THE PEDALS WOULD NOT MOVE, OR THAT THE LEFT PEDAL APPEARED TO BE STUCK. NO EVIDENCE OF A MECHANICAL DEFICIENCY WAS DISCOVERED DURING THE POST-CRASH INSPECTION OF THE AIRCRAFT, OR COMPONENT INSPECTION OR DISASSEMBLY.

Factual Information

On July 17, 1994, at 1030 Pacific daylight time, a Bell UH-1B, N9645A, sustained substantial damage when it collided with terrain while conducting helicopter logging operations near Pilot Rock, Oregon. The pilot, who was the sole occupant, was seriously injured. No flight plan was filed for the flight, and there was no report of an ELT activation. A small fire was set by the exhaust at the crash site. The pilot had pickled a load of logs prior to the accident, when he lost directional control of the aircraft. The helicopter descended to impact near the bottom of a draw or canyon. The pilot had little recollection of the events after the accident. As his medical condition improved, he stated that he recalled that the pedals would not move, and the aircraft rotated around its vertical axis counter-clockwise. During other interviews with the pilot, his recollection of the occurrence varied, including the apparent direction of rotation, and the recollection that the left pedal was stuck. He recalled attempting to "airstream" the aircraft, but found that to be unsuccessful. He then said he recalled attempting to maneuver back near his logging crew to crash, so that he wouldn't be far from rescue. The aircraft continued to rotate until impact. The wreckage was inspected after it was moved to a salvage yard. Tail rotor control continuity was established from the tail rotor through the tail boom. The nose was crushed, precluding establishing control continuity in the cabin section of the fuselage. The tail rotor drive components were shipped to Bell for testing and disassembly. No evidence of a mechanical malfunction was found during component disassembly and inspection.

Probable Cause and Findings

DIRECTIONAL CONTROL WAS NOT MAINTAINED FOR UNDETERMINED REASONS.

 

Source: NTSB Aviation Accident Database

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