On July 19, 1996, at 2020 central daylight time (cdt), a Grumman- Schweizer G-164A, N9544, registered to Mid-Continent Aircraft, Corp., of Hayti, Missouri, was substantially damaged following a partial loss of engine power and subsequent forced landing in a farmer's field. The airline transport rated pilot reported no injuries. The 14 CFR Part 137 aerial application flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The flight departed Dighton, Kansas, at 2018 cdt. According to the pilot's written statement, he loaded the airplane with 190 gallons of insecticide and a full tank of avgas (64 gallons). The takeoff and climb out were normal. The airplane cleared the powerlines a quarter of a mile north of the runway, without any problems. Southeast of the field to be sprayed, the pilot noticed that the airplane began to settle. The pilot noticed that there were powerlines running east to west ahead of him so he turned to the west to parallel them. The pilot stated, "As I leveled my wings, the aircraft seemed like it might fly out of the dead air, which I thought was the problem. But, it soon began to settle again, slowly losing altitude. I saw a corn field ahead of me and added full power (I was already very close to this setting) and began to dump the load. Neither the power nor dumping helped the situation and the aircraft went into the corn field and flipped over on its back." A Federal Aviation Administration (FAA) Inspector represented the NTSB during the on-scene investigation. The Inspector's visual inspection did not reveal any mechanical problems that would have resulted in a partial power loss. The FAA Inspector compared the airplane's weight with the high density altitude and high outside air temperature and determined that the airplane was overweight for those conditions.