On January 29, 1998, about 0800 eastern standard time, an Air Tractor AT-602, N50929, registered to Everidge Aerial Farming, Inc., crashed into a field shortly after takeoff from a private airstrip near Wrightsville, 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 commercial-rated pilot, the sole occupant, sustained serious injuries. The flight was originating at the time of the accident. The airplane was left outside overnight facing the west so as to have the sun contact the wings in the morning to eliminate the anticipated frost. The pilot stated that he arrived at the airstrip about 0700, performed a preflight of the airplane, and started the engine, then had the fertilizer loaded into the hopper. The engine remained running for about 45 minutes while he reviewed maps, and also to eliminate the moderate frost on the wings. He then cycled the propeller three times and initiated the takeoff run. About 1/2 way down the runway he noticed that the airplane was not accelerating as it had the day before; and at that location, the airplane was too far down the runway to abort. He continued the takeoff and at rotation, the airspeed was slower than he wanted. The airplane then rolled to the left, impacted the ground nose and left wing low, and rolled inverted. The pilot stated that he pulled on the emergency release handle perpendicular to the fuselage to exit out the left cockpit door, but was only able to release the pin from the forward hinge. The pin for the rear hinge did not release. According to the pilot's father, he arrived on scene shortly after the accident and noted that the right cockpit door was open. Using a pair of pliers from outside the airplane, he pulled on the cable of the emergency door release for the left door and was successful in releasing the aft pin. He then bent what was the bottom portion of the left cockpit door down to the ground and pulled the pilot from the airplane. The pilot also stated that he could have exited out the right cockpit door which was open. Examination of the engine revealed control cable continuity from the cockpit. Additionally, about 1 teaspoon of water was noted in the fuel filter bowl area; the fuel was clear in color. Examination of the airframe revealed that the emergency dump valve handle was in the "open" position and according to a witness who was the pilot's father, he observed chemical dumping just before the impact. The engine was removed from the airplane and shipped to the manufacturers facility in Canada for further examination. Examination of the engine revealed no evidence of preimpact failure or malfunction. Bench testing of the propeller overspeed governor, fuel pump, fuel control, bleed valve, oil to fuel heater, and propeller governor were accomplished. The results are an attachment to this report. According to the sheriff's department deputy who talked with a person who identified himself as the pilot's brother, there was frost on the wing tips of the airplane that morning. The deputy also stated that on the morning of the accident, at about 0540, he had frost on the vehicle that was parked at his house, which was located about 1 mile from the crash site. The airplane minus the retained engine was released to Mr. Les Sychak, of AIG Aviation, on May 8, 1998. The retained engine was also released to Mr. Les Sychak, on October 22, 1998.