On May 14, 2001, at 1430 central daylight time, an Air Tractor AT-602, N50997, collided with the ground, and burst into flames shortly after an attempted takeoff from a dirt strip on Cagle Mountain in Dunlap, Tennessee. The agricultural flight was operated by Brandon Air Inc., under the provisions of Title 14 CFR Part 137 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane was destroyed; the pilot received no injuries. The agricultural flight departed Dunlap, Tennessee, at 1430 hours. According to the operator, the pilot was conducting an aerial application operation in the Cagle Mountain area. After reloading the airplane with chemicals, the pilot attempted a takeoff from the dirt staging airstrip. During the rotation phase of the takeoff, the pilot stated, "I got ready to rotate, it was a little slow and started to come off, and then settled back at the departure end of the strip." The airplane collided with tree stumps, which were located on the end of the dirt strip. The pilot exited the airplane after it came to a complete stop. Seconds later the airplane burst into flames.. During a telephone conversation with the owner of Brandon Air Inc, he stated there was another Air Tractor AT-602 and an Air Tractor AT-802 operating in the area and staging from the same dirt strip as the accident airplane. The other two airplanes took off immediately before N50997 without incident. The other two airplanes landed, resumed spraying operations, after the fire was extinguished and the wreckage was removed. All three airplanes were using the same fuel source, and there was no fuel contamination found in either of the other airplanes. The pilot had been flying the same airplane for two weeks before the day of the accident, and no mechanical problems were previously reported. According to the pilot, the airplane was a few hundred pounds under the maximum gross weight; there was approximately 100 gallons of fuel on board, and loaded 2/3 full with a dry fertilizer. At the time of the accident, the wind was reported as light. According to the pilot, on the takeoffs prior to the accident his ground roll was approximately 3/4 of the 2200 foot runway. At the time of the accident the density altitude was approximately 3500 feet. The pilot did not report a mechanical problem with the airplane.