Tehran, Iran, May 1953May 1953

On May 11, 1953, Lieutenant Colonel Dayton C. Casto Jr., a U.S. Air Force officer stationed in Tehran, Iran, reported sighting an unidentified flying object over the city. The object appeared at approximately 1500 (3 p.m.) local time, flying at an estimated altitude of 20,000 to 25,000 feet above a cloud layer that sat at 13,000 to 15,000 feet.

Casto's wife saw the object first. She was on the roof of their home and spotted five objects in a trail formation flying together. When she called her husband to look, he arrived just in time to see only one object remaining visible. He described it as definitely an aircraft, roughly the size of a B-45, metallic in color like aluminum, and traveling at an estimated speed of 500 to 600 miles per hour. The object rolled from side to side during its flight, similar to a coordination exercise. It made no noise, left no contrails or exhaust, and disappeared from sight in the distance toward Mount Demavand.

The Air Force investigation reviewed the sighting and initially considered whether the object might have been a foreign aircraft. Intelligence analysts noted that Soviet IL-28 aircraft were based in the region and had sufficient range to overfly Tehran. The observers' assessment that the object was definitely an aircraft strengthened this possibility, though the file notes this was a tentative evaluation rather than a definitive conclusion.

The full case file, comprised of 24 pages as held by the National Archives, is reproduced below.