On August 11, 1994, about 1000 eastern daylight time, an Ayers S2R, N8914Q, was substantially damaged following a collision with terrain during a forced landing near Vienna, Georgia. The commercial pilot received minor injuries in the accident. The aircraft was being operated under the provisions of 14 CFR Part 137 by A&C Ag Aviation, Incorporated of Unidilla, Georgia. Visual meteorological conditions existed at the time, and no flight plan had been filed for the local, aerial application flight. The flight departed Unadilla, Georgia about 0930. The pilot stated that during an aerial application spray swath, the engine lost power. He executed a forced landing in a field. The aircraft rolled across a paved highway, and impacted the terrain on the opposite side of the highway from the original field. An examination of the engine following the accident discovered a three inch by five inch "blow-out" in the number one cylinder. The inspector who examined the engine stated that there was no evidence of over heating or abuse, and that the aircraft records reflected adequate and timely inspections.