What happened
During the approach phase of the flight, the pilot had received a weather briefing that noted an AIRMET for IFR conditions and an AIRMET for icing located just north of the flight path. Air traffic control reported that the transit portion of the flight proceeded without incident. The pilot was cleared for an ILS approach to runway 35 and subsequently received authorization to switch to the common traffic advisory frequency. Following this frequency change, the pilot ceased all communications with air traffic control.
Eyewitnesses observed the aircraft type flying at approximately 200 feet above ground level on a northwesterly heading, positioned west of runway 35. The aircraft was seen performing a climbing left turn toward the south before entering a thick layer of overcast clouds. Shortly after the plane entered the clouds, a witness noted the aircraft in a nose-down attitude of approximately 20 degrees, flying on a southeasterly heading, before the aircraft was obscured by hangars.
Upon investigation of the crash site, the aircraft type was found to have impacted the terrain in a nose-low attitude with the right wing. The landing gear and flaps were found in the extended position. There were no impact marks on the ground outside of the immediate area surrounding the engines, propellers, and wing leading edges.
Findings
Physical examination of the wreckage revealed significant ice accumulation on the aircraft. Clear ice, measuring between 1/4 and 1/2 inches, was found on the upper fuselage antenna as well as the leading edges of the horizontal and vertical stabilizers. Additionally, local responders noted a layer of ice on the leading edges of both wings. There were no mechanical failures or anomalies found in the engines or airframe that would have prevented the aircraft from operating normally. The presence of clear ice accumulation on critical flight surfaces was a notable factor at the scene.