Troy, Missouri: Aircraft Transponder Malfunction During UAP Encounter

Incident Details On November 18, 1977 at approximately 9:17 p.m., pilot Gregory Barnett was flying a Seneca 2 aircraft at 13,000 feet between Vichy and Troy, Missouri when a bright white luminous object approached his aircraft at high velocity.

Encounter Sequence The object positioned itself alongside the aircraft and maintained a pacing pattern for approximately 3-4 minutes. During this period, Barnett's primary transponder ceased functioning while the object remained in proximity. The object maintained a distance of roughly 17 miles while flying at a higher altitude than the aircraft.

Technical Anomalies When the unidentified object departed at high speed on a 120-130 degree heading, the first transponder resumed normal operation. Barnett activated his secondary transponder, but it failed to respond. After the object disappeared from view, the secondary transponder recovered functionality. However, the primary transponder never resumed normal operation despite no other instrument malfunctions occurring.

Significance This incident represents a documented case of electromagnetic interference potentially associated with an unidentified aerial phenomenon, with direct correlation between the object's proximity and transponder malfunction.