Incident Overview
A helicopter pilot was conducting a series of low-altitude passes for a ground-based camera. The aircraft flew at approximately 350 feet above ground level with an indicated airspeed of 20 to 25 knots. The first three passes were performed into the wind without any issues.
Loss of Control
During the fourth pass, the pilot observed that the wind direction had changed from a headwind to a left crosswind of about 10 to 15 knots at a 90-degree angle. Simultaneously, the helicopter's nose began to drift to the right. The pilot was unable to regain control before the aircraft impacted the ground.
Contributing Condition
A review of the FAA Advisory Circular on Unanticipated Right Yaw indicated that the change in wind conditions placed the helicopter in a situation where it was susceptible to loss of tail rotor effectiveness (LTE).