On October 20, 1997, at 1300 mountain daylight time, a Helio Aircraft, Ltd. H-800, N40013, sustained substantial damage when the tail wheel separated during landing roll. The private pilot and sole occupant was not injured. The flight was a local area personal flight conducted under Title 14 CFR Part 91 and no flight plan was filed. Visual meteorological conditions prevailed. According to the FAA (Federal Aviation Administration) Inspector who examined the aircraft, the tail wheel separated during landing roll due to a weld failure in the tail wheel assembly. The skin on the aft fuselage and two aft bulkheads also sustained damage. According to the pilot, he was taking the aircraft in for an annual inspection. When he landed and the tail wheel settled to the ground, the aircraft started to "shimmy." Directional control was not possible and the aircraft ground looped and came to a stop on the runway. He said the tail wheel was locked for landing and the wind was calm. Both the pilot and an FAA inspector said that the tail wheel bracket failed at a previous repair weld joint. Examination by the FAA airworthiness inspector provided no evidence of a preexisting condition which would have contributed to the failure. Examination of maintenance records failed to reveal when a repair was made to the tail wheel assembly. The air traffic tower controller was interviewed by the FAA inspector, and said the landing appeared to be normal and the aircraft ground looped during landing roll.