On September 3, 1999, at 1215 central daylight time, a Cessna 170A tail-wheel equipped airplane, N3865V, was substantially damaged when it impacted a dirt mound while taxiing at the Curtis Field Airport near Brady, Texas. The commercial pilot, who was the owner and operator of the airplane and the sole occupant, was not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight originated from the Eastland Municipal Airport, Eastland, Texas, at 1120. According to the pilot, the asphalt runway at Curtis Field Airport was under construction and there were dirt mounds adjacent to it, therefore, he elected to land on the grass runway. The pilot stated that as he was taxiing off of the grass runway, he misjudged his distance and speed, and the airplane impacted one of the dirt mounds with the left main landing gear and left wing. The FAA inspector, who visited the accident site, stated that the left main landing gear attachment assembly was structurally damaged, and the left wing spar was bent up outboard of the wing flap.