On March 29, 2000, about 1000 eastern standard time, an Ayres S2R-G10, N4089Q, registered to Diversified Lenders, Inc., operated by Dry Branch Farms, Inc., collided with terrain near Leesburg, Georgia. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 137 aerial application flight. The airplane was substantially damaged and the airline transport-rated pilot, the sole occupant, sustained minor injuries. The flight originated about 10 minutes earlier. The pilot stated that the flight departed to spray a field near the "ag strip", and on the second or third spray pass, he felt a "very heavy" deceleration. He applied hard aft elevator input after observing trees ahead. The airplane cleared the trees and while climbing, he noted that the propeller stopped. The airplane then crashed into an open field on the other side of the trees. A witness reported that the airplane had made the first pass to the field and while starting the second spray pass, he noted that the "wheels" touched the ground and, "for about 300 feet the plane did not lift...." The airplane then began to climb, during which time, he observed "lots of black smoke" from under the airplane. The airplane cleared the trees then "hit the dirt." According to an FAA inspector who examined the field where the airplane came to rest, the airplane was upright on a magnetic heading of 125 degrees; both main landing gears and the spray pump were separated. The right main landing gear was in the immediate vicinity of the airplane; the left main landing gear and the spray pump were found in a field east of the field where the airplane was located. Approximately 80-foot tall trees separated the fields. Examination of the field where the left main landing gear and spray pump were found revealed damage at a 45-degree angle to the tops of several of the 6-8 inch high raised rows. Three distinct marks associated with both main landing gears and the spray pump were noted. The engine was retained for further examination. Examination of the engine at the manufacturer's facility with FAA oversight revealed rotational scoring of the propeller shaft adjacent to the propeller shaft nut. The propeller shaft coupler was noted to be fractured and damage to the inner and outer spline gear teeth was noted. The NTSB retained the fractured propeller shaft coupler for further examination. Rotational scoring was noted on the first and second stage compressor impellers. Metal spray deposits were noted on all three stages of turbine stator vanes and on the second and third stage turbine rotor blades; the first-stage turbine rotor was not accessed during the examination. Rotational scoring was noted on the blade tips of the second and third-stage turbine rotors. Functional testing of the fuel pump and control assembly and of the fuel flow divider valve was accomplished. The results are an attachment to the engine examination report which is an attachment to this report. Metallurgical examination of the fractured propeller shaft coupler by the NTSB Materials Laboratory revealed ductile dimple features typical of overstress separation. No evidence of fatigue cracking was noted. Review of the maintenance records revealed that the engine was modified/overhauled to its current configuration and installed in the newly manufactured airplane on August 24, 1999. At the time of accident, the engine had accumulated approximately 29 hours since being modified/overhauled. Federal Aviation Administration records indicate that the pilot has had a statement of demonstrated ability (SODA) since May 1967, due to having no vision in his right eye. The airplane minus the retained engine was released to insurance adjuster Harry D. Brooks, of Carson-Brooks, Inc., on May 19, 2000. The retained engine was released to insurance adjuster Tracy Reasoner of AIG Aviation, on August 30, 2000.