On July 15, 1993, at approximately 1500 central daylight time, the pilot of an Air Tractor AT-401, N1009T, made a forced landing in a rice field approximately 4 miles north of Dermott, Arkansas. There were no injuries to the pilot, but the airplane was substantially damaged. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the aerial application flight. The following is based on the pilot's accident report. The pilot had been applying fertilizer to a rice field. He banked the airplane to return to his airstrip when the engine lost power and he was forced to land in a rice field which had been flooded. When the wheels touched the ground, the airplane sank in the water and soft ground and overturned. According to the Federal Aviation Administration (FAA) inspector who supervised the engine inspection and disassembly, there was evidence that the master rod had failed. He also found evidence of a pre-existing crack. The nature of the crack could not be determined. A review of the airplane's maintenance records disclosed the following pertinent entries: August 18, 1989 - ENGINE MAJOR OVERHAUL Tachometer - 557.0 hours Engine Total Time - 8 ,798 hours Remarks - Chrome cylinders installed. February 5, 1990 - 100-HOUR/ANNUAL INSPECTION Tachometer - 663.2 hours Engine Total Time - 8,904.2 hours Remarks - Oil drained from engine crankcase and rocker sumps. No metal contamination. Tachometer replaced. July 27, 1990 - NO. 9 CYLINDER REPLACED WITH OVERHAULED CYLINDER. Tachometer - 493.0 hours Engine Total Time - 9397.2 hours Remarks - Tachometer replaced. December 10, 1990 - ENGINE REMOVED FOR OVERHAUL Tachometer - 38.0 hours Engine Total Time - 9579.2 hours July 1, 1993 - ENGINE INSTALLED ON N1009T Tachometer - 0.0 hours Engine Total Time - 9579.2 hours