Incident Overview
A pilot conducting a practice autorotation with a power recovery reported that the maneuver was attempted with the helicopter as the sole occupant. According to the pilot's account, power was reintroduced at an altitude of 200 feet above ground level (AGL). During the subsequent flare, the pilot initiated the flare at an altitude lower than intended. As a result, the tail rotor system contacted the soft ground adjacent to the planned landing area.
Damage Assessment
The helicopter sustained substantial damage. Specifically, the tailboom, the tail rotor driveshaft assembly, and the tail rotor system were affected. The pilot verified that no preimpact mechanical failures or malfunctions with the airframe or engine had occurred that would have precluded normal operation.
Relevant Guidance
The Federal Aviation Administration (FAA) has published Advisory Circular (AC) 61-140, titled "Autorotation Training" (2013). This circular discusses the flare portion of autorotation training, noting that "every autorotational flare will be different depending on the existing wind conditions, airspeed, density altitude, and the aircraft gross weight." Additionally, the AC lists common errors during autorotation training, including "improper flare (too much or not enough)" and "flaring too low or too high (AGL)."