VFR into IMC · NTSB CEN14FA009
CESSNA 500 — Derby, KS
| Date | October 18, 2013 |
| Location | Derby, KS |
| Aircraft | CESSNA 500 |
| Purpose of flight | Business |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Enroute-climb to cruise Unknown or undetermined |
| Pilot age | 49 |
| Pilot total time | 2,605 hrs · Experienced |
| Time in type | 1,172 hrs |
| Fatalities | 2 |
Probable cause
NTSB findings
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-(general)-Capability exceeded - C
- Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to structural icing-Contributed to outcome - C
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Personnel issues-Psychological-Perception/orientation/illusion-Spatial disorientation-Pilot - C
- Personnel issues-Task performance-Workload management-Task overload-Pilot - C
- Aircraft-Aircraft systems-Indicating/recording systems-Instrument panel-Malfunction - C
- Environmental issues-Conditions/weather/phenomena-Ceiling/visibility/precip-(general)-Effect on operation - C
- Aircraft-Aircraft systems-Auto flight system-Autopilot system-Inoperative - F
- Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot - F
What happened
After climbing to and leveling at 15,000 feet, the airplane departed controlled flight, descended rapidly in a nose-down vertical dive, and impacted terrain; an explosion and postaccident fire occurred. Evidence at the accident site revealed that most of the wreckage was located in or near a single impact crater; however, the outer portion of the left wing impacted the ground about 1/2 mile from the main wreckage.
Following the previous flight, the pilot reported to a maintenance person in another state that he had several malfunctioning flight instruments, including the autopilot, the horizontal situation indicator, and the artificial horizon gyros. The pilot, who was not a mechanic, had maintenance personnel replace the right side artificial horizon gyro but did not have any other maintenance performed at that time. The pilot was approved under an FAA exemption to operate the airplane as a single pilot; however, the exemption required that all equipment must be operational, including a fully functioning autopilot, flight director, and gyroscopic flight instruments. Despite the malfunctioning instruments, the pilot chose to take off and fly in instrument meteorological conditions.
At the time of the loss of control, the airplane had just entered an area with supercooled large water droplets and severe icing, which would have affected the airplane's flying characteristics. At the same time, the air traffic controller provided the pilot with a radio frequency change, a change in assigned altitude, and a slight routing change. It is likely that these instructions increased the pilot's workload as the airplane began to rapidly accumulate structural icing. Because of the malfunctioning instruments, it is likely that the pilot became disoriented while attempting to maneuver and maintain control of the airplane as the ice accumulated, which led to a loss of control.