Accident Sequence
The pilot was approaching a narrow ridge. At about 25 feet above ground level, he ran out of left pedal input and the helicopter began an uncommanded right turn. The pilot attempted to gain altitude to remain on the ridge. Subsequently, he entered an autorotation and the aircraft impacted the ground in a level attitude, then rolled onto its left side.
Maintenance History
Review of maintenance records revealed that on October 30, 1998, the maintenance facility had removed the tail rotor hub and blade assembly from the accident helicopter and replaced it with an assembly from a Bell 206L-1. This was the first flight since the replacement. The Director of Maintenance reported that the maintenance technician did not perform a rigging check after installing the new assembly because he assumed that the same assembly did not require a check.
According to the maintenance records, the tail rotor pitch links installed on the accident aircraft were part number 206-010-795-101. The maintenance manual specifies that pitch links for a Bell 206L-3 should be part number 206-010-795-105. A representative from Bell Helicopter Textron stated that all parts from the tail rotor hub and blade assembly are compatible between the Bell 206L-1 and Bell 206L-3, except for the tail rotor pitch links. He further noted that the pitch links on the Bell 206L-1 are smaller than those on the Bell 206L-3, resulting in reduced tail rotor authority for the pilot.