On February 27, 1996, approximately 0720 central standard time, a Rockwell International S-2R, N431BL, registered to, and operated by MS&T Flying Service under Title 14 CFR Part 91, was substantially damaged during a forced landing following a loss of engine power, near Winchester, Arkansas. No flight plan was filed and visual meteorological conditions prevailed. The flight departed from a private agricultural airstrip about 5 minutes prior to the accident. According to the pilot, the flight was intended to "rinse and clean the airplane and spray system with water." He reported that, after he "rinsed" the aircraft and "pulled" up from a swath run, "the engine stopped, causing [the] propeller to stop." During the ensuing forced landing, the pilot "had to go under a power line" to land the airplane in a field. Upon landing, the airplane "came to [a] complete stop after hitting [a] tree with the right wing. The right wing was found partially separated from the fuselage and was structurally damaged. Examination of the engine by a FAA inspector and the operator's mechanic, revealed a "broken" master rod and a "hole" in the #5 cylinder. A review of the maintenance records by the FAA inspector, did not reveal any anomalies or uncorrected defects that would have contributed to the loss of engine power.