Accident Details
The twin-engine corporate jet impacted terrain while maneuvering to land after a global positioning system (GPS) approach. The pilot reported that the airplane entered icing conditions during the approach and descended out of instrument meteorological conditions between 300-400 feet above ground level (agl). The pilot stated that his windshield had become obscured by ice accumulation during the approach and that he "had difficulty seeing the runway." The pilot elected to land the airplane instead of executing the published missed-approach procedure. The airplane impacted terrain 439 feet short of the runway threshold while in a right turn.
Ice Accumulation and Windshield Heat
After the accident, ice accumulation was observed on all booted airframe surfaces, measuring 2-4 inches wide and 1/4 to 3/8 inch thick. The upper portions of the windscreens were contaminated with ice measuring about 3/8 inch thick. The remaining airframe portions, including the heated surfaces, were free of ice accumulation. The windshield bleed air switch was selected on "High" with the pilot's side windshield heat control knob approximately mid-range. Windshield alcohol was selected "On", but the alcohol reservoir was still full upon inspection.
Weather Conditions
At the time of the accident, weather conditions included an overcast ceiling of 500 feet agl, 1-3/4 statute mile visibility with mist, and an outside temperature of -08 degrees Celsius. The published minimum descent altitude (MDA) for the GPS runway 17 approach is 500 feet agl for an airplane equipped with a lateral navigation only GPS receiver.
Pilot Information
The pilot held a private pilot certificate with multi-engine land, instrument airplane, and Cessna 500 type rating. The pilot reported having 2,200 hours total flight time and 475 hours in the same make/model as the accident airplane.
Probable Cause
The pilot's decision to continue below the minimum descent altitude (MDA) and his failure to fly the published missed-approach procedure. A factor to the accident was the pilot's improper use of windshield heat which resulted in the windshield becoming obscured with ice during the instrument approach in icing conditions.