What happened
A Part 135 air taxi operation departed from Denver, Colorado, bound for Columbus, Nebraska. The flight was operating under weather forecasts that predicted icing conditions throughout the intended route. During the flight, air traffic control notified the pilot of reported icing ahead, prompting the pilot to climb to 19,000 feet to avoid the cloud layer.
During the flight, the pilot reported issues regarding the aircraft's alternators and requested a diversion to North Platte, Nebraska. Due to weather conditions at the North Platte airport, the pilot subsequently decided to divert to McCook, Nebraska. During this diversion, communication between the pilot and air traffic control was lost.
Observers near the McCook Airport reported seeing the aircraft circle the field twice. According to witness accounts, the plane entered a 45-degree bank and subsequently stalled. The aircraft then impacted a stand of trees, traveling approximately 190 feet through the vegetation before coming to a stop.
Findings
Post-accident observations indicated that the aircraft was covered in ice, with a measurement of one-half inch of mixed ice found on a portion of the windshield. Investigation into the electrical system revealed that both alternators had a short in one phase of the stator winding, which contributed to the reported electrical malfunctions.