La Verde Piper engine surges during UFO observation — August 31 1958

On August 31, 1958, a Piper light aircraft near La Verde, Argentina, was associated with a UFO observation. While the object was present, the aircraft engine’s revolutions increased abnormally. After the object left, the engine returned to normal operation. The surviving chronology does not preserve the witnesses, object appearance, flight path, duration, distance, or aircraft registration.