On September 10, 1996, a Bell 47G-3B-1 (registration N1335X) was involved in an aviation accident near Rangely, CO. Investigators recorded the probable cause as: The pilot's excessive aft cyclic control input, which caused the tail rotor to strike vegetation, leading to a loss of directional control and a subsequent hard landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter pilot lost directional control after striking sage brush with the tail rotor while maneuvering at low altitude, resulting in a hard landing and significant structural damage.
What happened
The incident occurred during a low-altitude operation where the pilot was attempting to turn a group of horses. While executing this maneuver, the pilot applied excessive aft cyclic control input. This action caused the tail rotor to strike a large sage bush located near the ground.
Upon impact, the helicopter lost directional control and began turning to the right. Recognizing the loss of control, the pilot attempted to execute a hovering autorotation from an altitude of approximately 15 feet. The attempt resulted in a hard landing. During the impact, the main rotor blades struck the airframe and severed the tail boom. Additionally, the right skid collapsed under the stress of the landing.
The investigation
The physical examination of the wreckage revealed significant structural failures consistent with the described sequence of events. The primary damage involved the separation of the tail boom due to impact with the main rotor blades. The right landing skid was also found to be collapsed, indicating substantial force during the final touchdown.
Probable cause
The pilot's excessive aft cyclic control input, which caused the tail rotor to strike vegetation, leading to a loss of directional control and a subsequent hard landing.