Malmstrom AFB, MontanaAugust 1958

On the night of August 4, 1958, an airman on roving patrol at Malmstrom Air Force Base in Montana saw an unusual object in the sky. The witness described it as shaped like a flying wing or delta, about the size of a volleyball held at arm's length, with a bright silver color and a solid appearance. The object made no conventional sound like a jet engine. Instead, it produced a varied pitch whistling noise that faded and rose about every five seconds, quieter overall than a typical jet aircraft.

The object moved in a straight, level course toward the north and disappeared after roughly 30 seconds. The witness spotted it directly overhead, at about 98 degrees (looking roughly east), and last saw it at a 30-degree angle above the horizon as it departed. The sighting occurred on a clear night with excellent visibility.

The Malmstrom Air Force Defense Command (ADC) radar facility picked up an unidentified target moving along a similar flight path for about the same duration as the visual sighting. However, the ADC radar in close proximity to the object's path did not detect it, raising questions about what was seen. The Air Force base's control radar did track an unidentified target for several sweeps. The description of the object's lights and flight path differed from any locally assigned aircraft that operators would have recognized.

The Air Force evaluation noted that the object's characteristics, including its unconventional appearance and the radar correlation, did not match any known aircraft. In internal correspondence, an ATIC (Air Technical Intelligence Center) officer criticized the fighter interceptor unit for failing to attempt an intercept despite having the resources and proximity to do so. The officer flagged the case as an example of non-compliance with Air Force UFO reporting directives. No final determination of the object's identity appears in the file.

The complete case file is reproduced below as held by the National Archives, containing 22 scanned pages.