On July 17, 2018, about 1445 central daylight time, an Aero Commander S2R, N5553X, experienced multiple engine power anomalies during attempted landing at Vinton Veterans Memorial Airport (VTI), Vinton, Iowa. On final approach, the pilot was unable to reduce power and attempted a go around. During the go around, the engine experienced an uncommanded throttle decreased to idle. The pilot executed a forced landing into a cornfield and sustained substantial damage to the airplane fuselage and empennage. The commercial-rated pilot was not injured. The airplane was registered to Noe Aviation LLC and operated under the provisions of Title 14 Code of Federal Regulations Part 137 as an agricultural flight. Visual meteorological conditions prevailed for the flight, and no flight plan was filed.