On August 21, 2010, at 1147 central daylight time, an experimental amateur-built Ashcraft DR107, sustained substantial damage on impact with terrain during landing on runway 27 at Aurora Municipal Airport, Aurora, Illinois. The pilot was attempting a landing with a separated tail wheel spring that had fractured during a previous landing attempt. The airplane then veered off the runway and nosed over. The 14 Code of Federal Regulations Part 91 personal flight was not operating on a flight plan. The airline transport pilot was uninjured. Visual meteorological conditions prevailed at the time of the accident. The local flight originated at 1130. The pilot stated that during the second landing of the flight, he felt/heard something "give way" in the rear of the airplane. The tail of the airplane also "felt lower" than it should have been during the landing. He aborted the landing and contacted the airport's air traffic control (ATC) tower asking them to check the tail wheel. The ATC tower controller reportedly told the pilot that the tail wheel was hanging by a cable. The pilot returned and attempted a landing on runway 27 (6,501 by 100 feet, concrete) by keeping the tail off the runway surface until the airspeed decreased. When the tail/rudder contacted the runway surface, the airplane veered off the runway and ground looped. The left main landing gear collapsed and the airplane nosed over. The tail wheel spring had a reported total time in service of 81.8 hours. Examination of the tail wheel spring revealed low cycle fatigue fracture. The tail wheel spring was originally designed with a bent tail wheel spring from heat treated 17-4 steel. The spring was 3/4 inch square, transitioning to just under 3/4 inch round, tapering to just under 5/8 inch at the tail wheel. The tail wheel spring was redesigned since the accident with the prototype spring being 7/8 inch round, 24 inch long and straight, and tapering towards the end down to 5/8 inch to fit the tail wheel.