On September 9, 1999, approximately 1800 central daylight time, an Aeronca 11AC tail-wheel equipped airplane, N9044E, was substantially damaged during a precautionary landing near Van Horn, Texas. The commercial pilot, 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 cross-country flight. The airplane initially departed from Brenham, Texas, and was being ferried to Tulare, California. The last re-fueling stop was at Fort Stockton, Texas, approximately 2 hours prior to the accident. During a telephone interview conducted by the NTSB investigator-in charge, the 17,000-hour pilot, who was the new owner of the airplane, reported that the previous owner stated that the 8-gallon auxiliary fuel tank had not been used during the time he owned the airplane. The pilot filled the auxiliary fuel tank prior to his departure and sumped the fuel tank to check for sediment and/or water and found none after the second sump. During the first leg of the flight, the pilot transferred approximately one gallon of fuel from the auxiliary fuel tank to the 15-gallon main fuel tank. During the second leg of the flight, the pilot transferred approximately 1.5 gallons of fuel from the auxiliary fuel tank to the main fuel tank. On the third leg of the flight, the pilot had to deviate from his planned course to avoid thunderstorms in the area. The pilot stated that he noticed that the main fuel tank quantity decreased to approximately a quarter of its capacity and appeared to stay at that level. The pilot added that he kept monitoring the fuel quantity of the auxiliary fuel tank; however, it did not appear to be decreasing. The pilot estimated that he had 1-2 gallons of fuel remaining in the main fuel tank and approximately 8 gallons of fuel remaining in the auxiliary fuel tank, when he elected to make a precautionary landing in an open area. According to the pilot, during the landing roll, at about 15 miles per hour, the main landing gear impacted a rut made by 4-wheel drive vehicles. The left main landing gear folded aft and the right main landing gear collapsed, damaging the landing gear-to-fuselage attaching points on the right side of the airplane. The left aft wing strut was dented, the left wing tip was dented, and one of the propeller blades separated. According to a mechanic, who helped recover the airplane, the fuel from the auxiliary fuel tank had drained into the main fuel tank by the time they recovered the airplane, which was a few days after the accident.