19980517009629A

Acft was on test flight following maintenance, acft took off and turned right, witness stated may exp engine failure (.4)the pilot reported that he had recently installed the engine in the airplane after it had been overhauled. The purpose of the flight was a maintenance check flight and engine break-in. The pilot conducted the normal preflight and engine run-up procedures in accordance with the airplane flight manual. He reported no abnormal indications were observed. The takeoff and initial climbout were normal with no anomalies observed. At approximately 400 feet AGL, the engine sputtered and lost partial power. He established a nose down attitude to maintain airspeed. He turned to the left. He reported the engine lost complete power and he conducted a forced landing to a wheat field adjacent to the airport. A witness reported the nose pitched down about 45 degrees after the engine failure. He reported, 'the airplane continued on this -45 degree line, wings level and in control until impact.' The witness reported that during the power-on portion of the flight, no smoke or vapor trails were seen. After the engine quit, the propeller cont inued to windmill. During the inspection of the airplane,no mechanical anomalies to the airframe or engine was noted. The engine was put on a test stand and it operated nomally. (-23) aircraft fueled with 9.6 gallons 100L; took off on runway 16 with r/h turnout. Experienced engine problem and unsuccessfully attempted to return to airport. Crashed in wheat field approximately .3 mile south of Benton, Kansas airport (1K1). Flight was a test flight following engine overhaul and empanage recovering.