What happened
During a daytime flight under instrument flight rules, a private pilot encountered significant difficulties while navigating through active weather. After communicating with an air route traffic control center, controllers observed the aircraft performing altitude changes that deviated from assigned levels. When questioned, the pilot reported an issue with the autopilot and subsequently requested permission to climb to avoid weather.
At the time of the incident, the region was experiencing rapidly developing convective activity, including supercell-type storms with cloud tops reaching approximately 48,000 feet. While weather advisories regarding severe turbulence, hail, and high winds were being broadcast on the frequency, the controller did not provide specific updates to the pilot. Radar tracking later showed that the aircraft turned directly into the intense weather cells rather than away from them. The pilot eventually declared a mayday, reporting a loss of visual reference and that the aircraft was in a spin. The impact with the ground was consistent with a flat spin at a level attitude.
Findings
Investigators examined several potential contributing factors. While the pilot reported an autopilot malfunction, no mechanical anomalies were found that would have prevented the aircraft from operating normally. It remained unclear if a true mechanical failure occurred or if the severe weather created the perception of an autopilot issue.
Regarding the pilot's health, an autopsy revealed coronary artery disease; however, investigators determined this was unlikely to have impaired decision-making during the flight. Toxicology results showed the presence of zolpidem and tetrahydrocannabinol in the pilot's blood. While the use of zolpidem was not deemed a likely contributor, the investigation could not rule out the impact of marijuana use on the accident.