What happened
While operating at flight level 270, the pilot established contact with the Jacksonville Center air traffic control facility. Approximately 25 minutes following this communication, the aircraft began to drift from its designated route and altitude. Air traffic controllers were unable to re-establish contact with the cockpit after several attempts.
In response to the deviation, the North American Aerospace Defense Command dispatched military fighter jets to intercept the flight. Upon approaching the aircraft, military personnel observed the plane performing left-hand circles at a high altitude characterized by low airspeed. The intercepting pilots noted that the windows of the aircraft appeared partially covered in frost. Furthermore, the crew observed that the pilot appeared slumped over and motionless within the cockpit. Despite the deployment of flares by the military aircraft to gain the pilot's attention, there was no response from the cockpit.
The aircraft continued to circle for roughly three hours before eventually descending into the Gulf of Mexico, where it sank. A search for the aircraft and the pilot was unsuccessful, and no survivors or wreckage were recovered.
Findings
An investigation into the pilot's Federal Aviation Administration medical history showed no recent health issues that would have disqualified the individual from operating the aircraft. The primary observation during the interception was the unresponsive state of the pilot and the presence of frost on the windows during high-altitude flight.