On May 19, 2015, at 1830 central daylight time, a Piper PA-22 airplane, N118U, collided with the terrain during an off airport landing following a loss of engine power while on approach to land at the St. Charles County Smartt Airport (SET), St. Charles, Missouri. The private pilot and passenger were not injured. The airplane was substantially damaged. The aircraft was registered to a private individual and was operated under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which not operated on a flight plan. The flight originated from the Tuscola Airport (K96), Tuscola, Illinois, at 1720. The pilot reported that he switched from the right fuel tank, which contained about 7 gallons of fuel, to the left fuel tank, which contained about 12 gallons of fuel, when he was about 15 miles from the destination airport. While approaching the airport, he turned on the fuel boost pump, reduced the throttle to 20 inches of manifold pressure, applied carburetor heat, and began the descent to traffic pattern altitude. While on downwind, he reduced the engine power to idle and applied flaps. On base leg, he advanced the throttle; however, the engine stayed at idle power. He turned off the carburetor heat, adjusted the throttle, and cycled the boost pump, but was unable to gain engine power. Unable to make it to the runway, the pilot chose a plowed field in which to land. The airplane contacted a ditch at the end of the field, crossed over a road, and came to rest in another field. The right main gear collapsed resulting in substantial damage to the fuselage and right main wing struts. A postaccident examination of the engine was conducted under the supervision of the Federal Aviation Administration (FAA). The inspector reported the fuel level in the right fuel tank was low and the left tank was about ½ full. The bent propeller was replaced with a serviceable one. The engine was started and it ran normally. The temperature and dewpoint reported at SET at the time of the accident were 63 degrees Fahrenheit and 46 degrees Fahrenheit respectively. According to the FAA SAID CE-09-35 "Carburetor Icing Prevention" chart, serious carburetor icing could be expected at glide power. However, the pilot reported that he had applied carburetor heat during the descent and that it was on when the engine would not regain power.