On March 13, 1998, approximately 1030 Pacific standard time, a Snow Model 600-S2C agricultural aircraft, N1640S, operated by Bonnys Valley Air Service of Sunnyside, Washington, experienced a loss of engine power and forced landing during a 14 CFR 137 agricultural aerial application flight near Bickleton, Washington. Damage to the aircraft sustained in the forced landing was determined to be substantial, and the accident was reported to the NTSB by the FAA on March 26, 1998. The commercial pilot-in-command of the aircraft was not injured in the accident. Visual meteorological conditions prevailed and no flight plan had been filed for the flight. The pilot reported that he took off between 0930 and 0940 (50 minutes to 1 hour before the accident) with 74 gallons of fuel aboard. The pilot stated that prior to the accident, he was spraying a field approximately 3 miles southwest of Bickleton. The pilot reported: "On my last pass, after having pulled up...the [Pratt & Whitney R-1340-AN1] engine quit in a left turn. Being low on airspeed and low, I did not have much time to pick a good spot and land; the ground being uneven and rocky caused [a] pretty rough touchdown...." The pilot reported that during the landing, the left wing hit a hill and broke, and that the airplane then nosed over. According to the FAA type certificate data sheet (number 2A7) for the model 600-S2C, the aircraft's fuel capacity is 66 gallons, consisting of one 33-gallon tank in each wing, of which 53 gallons are usable. The aircraft salvage crew which recovered the accident aircraft reported to the NTSB on March 18, 1998, that at the time they recovered the aircraft, the left tank contained 3 gallons of fuel and there was no fuel in the right tank.