On July 3, 1995, at 1030 central daylight time, a Cessna A188B, N6296G, collided with terrain during a precautionary landing in a field near Decatur, Alabama. The commercial instrument pilot was not injured, and the aircraft was substantially damaged. The aerial application flight operated under the provisions of 14 CFR Part 137 with no flight plan filed. Visual meteorological conditions prevailed at the time of the accident. The flight originated from Decatur, Alabama, at 1000 hours According to the pilot, before departing Pryor Field in Decatur, Alabama, he loaded the aircraft with 50 gallons of chemical spray. He performed a run up prior to departure, and noticed that the fuel flow indication was a bit high. He leaned the mixture slightly to bring it within the green arc, but it still did not look normal on the exhaust gas temperature gauge (EGT). The pilot stated that the airplane seemed to have a longer takeoff roll than normal. Upon approaching the field, the pilot began making passes in a race track type pattern. He noticed on the first pass over the field that all of the engine gauges looked normal. When he had finished his fourth pass over the field, the pilot noticed that the plane did not feel as "solid" as it should. As he turned back toward the field, he realized that he may have a real problem with the aircraft, because the ground speed then began to slow. The pilot stated that he began looking for a precautionary landing site. The engine continued to produce power throughout the precautionary procedure. The pilot stated that just as he was lined up with a field that was adequate for precautionary landing, he heard a "whaaaa" noise, followed by a wing shutter. Upon touchdown, the landing gear collapsed. An examination of the engine was completed, and no mechanical malfunctions were found. During the subsequent engine test run, the engine started immediately, and produced rated power during the test run (see attached engine examination).