What happened
Shortly after departing under IFR conditions, the pilot of a Cessna 414 declared an emergency, requesting to return to the airport under visual flight rules. During the communication with air traffic control, the pilot noted an inability to maintain sufficient airspeed. At the time, the airport was experiencing a snow shower with visibility reported as low as 0.5 miles.
Witnesses observed the aircraft flying at a high speed and low altitude, noting that both engines appeared to be operational. The aircraft was seen entering a snow shower before turning back toward the airfield. Observers described the plane as having a steep bank angle between 80 and 90 degrees with a 20-degree nose-down pitch. Just prior to the impact in a snow-covered field, the aircraft was seen leveling its wings. The accident resulted in two fatalities.
Findings
Investigation into the incident determined that pitot tube covers had not been utilized during servicing prior to the flight. Although approximately 1.5 inches of snow had accumulated on the airframe while the aircraft was being refueled, the snow was brushed off the exterior. However, manufacturer guidelines specify that onboard ice protection systems are not intended to clear snow from an aircraft that has been parked. Furthermore, the manufacturer advises using heated hangars or specific deicing fluids to prevent internal buildup within the pitot-static system ports, suggesting that internal ice or snow accumulation may have contributed to the loss of airspeed.