Incident Overview
A helicopter on a training flight experienced a series of downdrafts while descending for an off-airport pinnacle landing, resulting in structural damage to the tailboom.
Sequence of Events
During the descent, when the helicopter was approximately 75 to 100 feet above ground level (AGL), it encountered a downdraft. The pilot receiving instruction responded by increasing the collective. The flight instructor then advised the trainee to apply less aggressive collective inputs as the approach continued. As the helicopter descended further, to an altitude between 10 and 25 feet AGL, a second downdraft was encountered. The pilot receiving instruction again increased collective, which led to a decrease in rotor RPM. Subsequently, the flight instructor took control of the helicopter. The aircraft contacted the ground and then became airborne again. It yawed to the right before landing upright on sloping terrain.
Inspection Findings
A post-flight examination of the helicopter revealed that the tailboom had sustained structural damage just aft of the fuselage attach point. The pilots reported no preimpact mechanical malfunctions or failures that would have precluded normal operation.