What happened
The incident occurred during a solo cross-country training flight involving a student pilot. After refueling, the pilot was repositioning the helicopter for takeoff when the aircraft's tail rotor made contact with an airport windsock. The rotor blades became entangled in the fabric of the windsock structure.
As a result of this entanglement, the pilot was unable to maintain directional control of the aircraft. The loss of control led to the main and tail rotor blades striking the ground. The impact caused significant structural damage, including the collapse of the left landing skid. The helicopter came to rest in an upright position on the airfield.
The investigation
Examination of the accident site revealed that the primary mechanical failure was initiated by external contact with airport infrastructure. The tail rotor system was compromised due to its interaction with the windsock during the ground maneuvering phase. No evidence of pre-impact mechanical malfunction in the helicopter's propulsion or control systems was noted.
Findings
The sequence of events indicates that the accident was caused by loss of directional control following the entanglement of the tail rotor in a windsock. Contributing factors included the pilot's inability to counteract the asymmetric thrust and drag created by the obstruction during the critical repositioning phase prior to takeoff.