Accident Overview
During cruise flight, the pilot reported smoke in the cockpit to air traffic control. Subsequently, radar and radio contact were lost. The aircraft impacted the terrain in a level open alfalfa field located 9.2 statute miles and 108 degrees magnetic from the Great Bend Municipal Airport.
Witness Observations
A witness who was driving reported seeing the aircraft "diving at an angle..." and thought he "...saw smoke coming from the plane..." prior to impact.
Aircraft Examination
Examination of the control system and airframe structure revealed no anomalies that could be associated with a preexisting condition. The aft fuselage side and bottom exhibited oil streaks in the longitudinal direction.
Engine and Turbocharger Findings
Engine examination showed the connecting rod bearing surfaces exhibited evidence of distress and discoloration of the bearing material. The turbocharger had charred black deposits on its exterior surfaces. The turbocharger oil supply hose was chafed through in the area adjacent to the propeller governor control cable. No clamps were found on the turbocharger oil supply hose, and it did not have a fire sleeve jacket. In contrast, the oil supply and return lines to the oil cooler and the fuel supply hoses did have fire sleeve jackets.