Primary finding
Probable cause
the helicopter's encounter with loss of tail rotor effectiveness while hovering out-of-ground effect, and the pilot's failure to maintain control. A contributing factor was the soft terrain condition.
Investigator assessment
Analysis narrative
The pilot made an approach to a high hover due to the rough/uneven terrain. As the pilot was hovering the helicopter to a level area at 40 feet agl, the helicopter began to yaw to the right. The pilot stated that he hover taxied through his "rotor wash," and the helicopter encountered "loss of tail rotor effectiveness." The pilot increased collective in an attempt to takeoff, and the helicopter made "two quick revolutions." The pilot stated that he elected to land the helicopter instead of continuing with the takeoff due to power lines and rising terrain. The pilot initiated an autorotation, and the helicopter touched down on the soft ground while still rotating, collapsing the left landing skid. Subsequently, the tail rotor and main rotor blades struck the ground. The helicopter came to rest leaning toward its left side.
Source record
Factual narrative
On March 2, 2001, at 1500 central standard time, a Hughes 369D helicopter, N8356F, was substantially damaged following a loss of directional control while landing near Canadian, Texas. The helicopter was owned and operated by a private individual. The airline transport pilot and both passengers were not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 business flight. The flight had originated from a private helipad near Amarillo, Texas, approximately 1415. According to the pilot, he made an approach to a high hover due to the rough/uneven terrain. As he was hovering the helicopter at 40 feet agl to a level area, the helicopter began to yaw to the right. The pilot stated that he hover taxied through his "rotor wash," and the helicopter encountered "loss of tail rotor effectiveness." He increased collective in an attempt to takeoff, and the helicopter made "two quick revolutions." The pilot stated that he elected to land the helicopter instead of continuing with the takeoff due to power lines and rising terrain. The pilot initiated an autorotation, and the helicopter touched down on the soft ground while still rotating, collapsing the left landing skid. Subsequently, the tail rotor and main rotor blades struck the ground. The helicopter came to rest leaning toward its left side. Examination of the helicopter by the FAA inspector revealed that the tail rotor drive shaft was twisted and separated about 6 inches forward of the tail rotor gearbox. The tailboom was bent and one tail rotor blade was found separated. Control continuity was confirmed from the anti-torque pedals to the tail rotor pitch change links. All five main rotor blades were damaged.