Expediente Número 690513: Avistamiento de Fenómenos Extraños en Base Aérea de Reus

This document is a declassified military file (Expediente 690513) from the Spanish Air Force (Ejército del Aire) regarding an unidentified aerial phenomenon observed on May 13, 1969, at the Reus Air Base. At 11:40Z, the duty controller at the Reus control tower observed a bright, stationary object while monitoring the takeoff and ascent of a Boeing 727. The object was described as circular, similar in apparent size to a 5-peseta coin, and featured horizontal, yellowish, elongated spots. Five other personnel, including a relief controller, radio mechanics, and soldiers, also witnessed the phenomenon. The object was observed through binoculars, disappeared when it overlapped with the aircraft's exhaust gases, and reappeared two minutes later at a lower altitude before vanishing. The investigation included inquiries into potential scientific balloon launches from the French L'Adour center, but the National Commission for Space Research (CONIE) confirmed no such launches occurred on that date. Other aircraft in the vicinity, including five Portuguese planes and a light L-9 aircraft, did not report seeing the object, despite the L-9 pilot being alerted by the tower. The final assessment by the Air Force Intelligence Section suggested that the sighting was likely a refraction phenomenon caused by the interaction of the aircraft in the air and the near-vertical position of the sun, noting that the lack of conclusive data made it impossible to classify the event as a genuine unidentified object of concern.