Accident Sequence
The pilot lifted the helicopter to a hover and initiated a hovering turn in preparation for departure. During the maneuver, the nose of the aircraft began to rise. The pilot later stated that he could not control the aircraft. The helicopter began to descend, and the tail rotor struck a security fence surrounding the heliport. Subsequently, the main rotor struck a windsock pole, a tree, a light pole, and a concrete bench during the accident sequence.
Maintenance History
According to the investigation, the manufacturer's Service Bulletin (SB) #67-05 had been partially completed. This bulletin provided for protection against ice in the hydraulic servo by the installation of protective covers. The protective covers had been installed on the other two main rotor servos but not on the servo controlling fore and aft cyclic control.
Weather Conditions
The Omaha area experienced freezing precipitation the night before the accident. The temperature had not risen above freezing during the day, and freezing precipitation was forecast for the day of the flight. This was the first flight of the day for the aircraft.