On August 22, 2003, at 1825 central daylight time, an Air Tractor AT-502B, N5007G, piloted by a commercial pilot, was substantially damaged during a forced landing following a loss of engine power near Westside, Iowa. The agricultural application flight was operated under 14 CFR Part 137 and was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot reported minor injuries. The local flight departed the Arthur N. Neu Airport (CIN), Carroll, Iowa, at 1620. In his written statement, the pilot reported completing a final agricultural application pass and was planning to return to the airport when the engine abruptly lost power. The pilot stated: "There was no place to land, I hit the fuel boost pump and the [aircraft] powered up again for 1 or 2 seconds." This allowed the pilot to clear a farm house and set-up for a forced landing in an alfalfa field. The pilot noted that the aircraft "was descending quite fast." It subsequently impacted an "up sloping draw ... a terrace and went into a steep gully," according to the pilot. A post-accident examination found no evidence of fuel on-board. Both fuel tanks were empty and there was no sign of fuel on the ground in the vicinity of the aircraft. The fuel lines and fittings were intact. No indication of leakage at the fuel caps or within the fuselage in the vicinity of the fuel selector was present. The pilot reported no malfunctions with the aircraft prior to the loss of engine power. No anomalies associated with a pre-impact failure were observed during the post-accident inspection. The pilot reportedly had a standing request with the fixed base operator that the aircraft be filled to the 3/4 tabs each time it was fueled. The 3/4 tabs equated to 162 gallons or about 3 hours-10 minutes endurance, according to the pilot. The pilot stated that the fuel gauges "have been very undependable this summer," so after each refueling he would enter 162 gallons into the fuel flow meter. Due to his lack of confidence in the fuel gauges, the pilot was using the fuel flow meter to monitor his in-flight fuel status. After the accident flight, the pilot noted the fuel flow meter indicated 104 gallons had been used. Review of the airport fuel records indicated the accident aircraft was refueled twice on the day of the accident. The first was with 70.5 gallons and the second with 108.0 gallons. The previous flights that day lasted 2 hours to 2-1/2 hours, according to the pilot. He noted that after the first flight he would have expected about 110 gallons would have been needed to fill the tanks to the 3/4 tabs, instead of 70.5 gallons. The pilot stated that he did not visually verify the fuel quantity after refueling prior to the accident flight.