What happened
After receiving a weather briefing at 0615, the pilot departed on a flight where an AIRMET for icing and instrument meteorological conditions was in effect along the route. Although the pilot initially believed reports of light icing were minimal, the aircraft began accumulating light mixed ice on the wings approximately thirty minutes after takeoff.
As the aircraft attempted to climb to its intended altitude of 11,000 feet, the airspeed dropped to 130 knots, and the plane became unable to maintain the climb. The airspeed further decreased to 120 knots, prompting the pilot to divert to a nearby airport for a GPS Runway 27 approach. During the approach, while flying at 3,000 feet and 120 knots, the pilot extended the landing gear and selected 10 degrees of flaps. At approximately 500 feet above ground level, the aircraft began to buffet, and the pilot lost directional control. To avoid an attempt to turn toward the runway, the pilot executed a forced landing in a field located roughly 100 yards south of Runway 27. The stall warning horn sounded immediately before the aircraft impacted the ground. The impact resulted in substantial damage, including the landing gear being sheared off and the propeller striking the ground. The pilot was not injured.
The investigation
Witnesses on the ground observed significant ice accumulation on the aircraft. One witness specifically noted large amounts of ice present on the antennas, wings, and other portions of the airplane. The aircraft featured a placard stating it was approved for VFR, IFR, day, and night non-icing flight when equipped in accordance with FAR 91 and FAR 135.