Accident Overview
At 1450 CDT, while the pilot was cruising at 11,000 feet, an air route traffic control center broadcast information concerning SIGMET 17C, which warned pilots of thunderstorms with tops reaching flight level 450. At 1613, radar data showed the aircraft at 11,300 feet. When asked about his altitude, the pilot replied that he was in a cell and would be returning to his cruising altitude of 11,000 feet. He did not request assistance.
Shortly after that communication, radar data indicated the aircraft had lost 1,000 feet of altitude, and then the display entered a coast track. Later, the wreckage was found scattered over an area approximately one mile long and one-quarter mile wide. The wings and stabilators had separated during an in-flight breakup. Examination of the wreckage showed evidence that the wings had failed from positive overloads. No pre-accident part failure or malfunction was found.
Pilot and Toxicology
The pilot's body was found at 0737 CDT on October 24, 1985. A toxicology check revealed an alcohol level of 0.031 percent, but the amount of alcohol due to putrefaction was not verified.
Weather Conditions
A weather summary showed that the aircraft was in the vicinity of a very strong weather echo, with moderate to severe turbulence and up/downdrafts in the thunderstorm below 20,000 feet.
Conclusion
The aircraft broke up in flight after encountering a thunderstorm. The wings separated due to positive overloads. The exact cause of the breakup was not determined in the source material.