Montebello, VirginiaFebruary 1963

On the night of February 6, 1963, a civilian pilot flying a C-46 cargo plane spotted a bright, spherical light in the sky near Montebello, Virginia. The pilot was about 15 miles southwest of Montebello, flying at 7,500 feet, when he first noticed the object at his one o'clock position. It appeared between 3 and 5 degrees above the horizon. Over the next 45 minutes, the object moved slowly to his four or five o'clock position while gradually rising to between 15 and 30 degrees above the horizon. The pilot described the light as varying in brightness, sometimes dim and sometimes brilliant white with a reddish glow at the edges. At its brightest, it was roughly five times brighter than the brightest star visible that night. The object then faded gradually from view on a southerly heading.

The Air Force investigation found a likely explanation. A NASA test aircraft, a Convair C-54, had been flying in the same region that night within a 25-mile radius of Quantico, Virginia. The NASA plane was equipped with landing lights and a strobe light on its underside, which it operated during much of its flight. Given the relative positions of the cargo pilot and the NASA aircraft, the Air Force concluded that the pilot had most likely seen the NASA plane's lights, particularly the strobe light, which can create unusual visual effects in darkness. The file also notes that sharp temperature inversions in the area (layers of warmer air that bend light) may have distorted the appearance of the lights.

The Air Force evaluation form indicates the case was rated as "unknown," though the senior director's analysis suggests the most probable explanation was the NASA aircraft. The full case file, reproduced below as held by the National Archives, consists of 9 pages.