On October 27, 1994, at 1115 central daylight time, a Bell 206L-3, N206SF, was substantially damaged during autorotation near Ruston, Louisiana. The helicopter, flown by an airline transport rated pilot, was on a personal flight that had originated in Meridian, Mississippi. No flight plan was filed and visual meteorological conditions prevailed. The solo pilot was uninjured. According to the pilot, he had just completed two practice autorotations, recovering with power each time. The third autorotation was entered at 1,000 feet above the ground and the flare initiated about 100 feet above the ground at 70 knots. The pilot added power; however, he did not notice torgue change or yaw. He took this as evidence of a loss of power. Due to low rotor rpm, pitch pull was delayed and touchdown was at a "higher than desired forward speed." During the landing slide a main rotor blade contacted the right vertical stabilizer, collapsing the tail boom to the right side of the helicopter. The Federal Aviation Administration inspector (statement enclosed) examined the engine. "All checks indicated the engine was functioning normal."