Project Blue Book Case #1584. On July 24, 1952, two Air Force officers — Lieutenant Colonel John McGinn and Colonel John Grubb — observed three bright, silver-colored objects while flying a B-25 bomber over the Carson Sink area of central Nevada. This case became one of the most cited Blue Book unknowns due to the exceptional credibility of the witnesses and the quality of the observation.
The two colonels, both experienced military pilots, spotted the objects in a V-formation, flying at high speed across the desert landscape below their aircraft. The objects appeared to be delta-shaped or circular, bright silver, and were estimated to be moving at approximately 1,000 mph — well beyond the capability of any known aircraft in 1952. The objects were visible for approximately 30 seconds before disappearing.
Carson Sink is a vast dry lake bed in Churchill County, Nevada, within the military's extensive western test range complex. Nellis Air Force Base, the Naval Air Weapons Station at Fallon, and various restricted test areas surrounded the region. Despite this concentration of military aviation, the objects did not match any known aircraft type or test vehicle.
The case was prominently featured in Captain Edward Ruppelt's book "The Report on Unidentified Flying Objects" and was considered by Blue Book to be among its most credible reports. The witnesses' rank and experience, the daylight conditions, and the relatively close observation distance made conventional misidentification extremely unlikely.
The case was classified "Unknown" — one of the Blue Book cases most often cited by proponents of the phenomenon's reality.