Incident #183 Sighting Report — Fukuoka Area, Japan, 15 October 1948

On the night of 15 October 1948, at approximately 2305 hours, a 68th Fighter Squadron F-61 interceptor, piloted by 1st Lt. Oliver Hemphill Jr. with radar observer 2nd Lt. Barton Halter, encountered an unidentified aerial object while on a routine airborne alert mission northwest of Fukuoka, Japan. The crew made six separate radar contacts with the target over a ten-minute period. Initially, the crew assumed the target was an F-51 aircraft, but the object demonstrated performance capabilities far exceeding conventional aircraft, including a tremendous burst of speed and rapid acceleration. The object was described as having a stubby, clean-lined silhouette, approximately 20-30 feet long, with no visible exhaust trails or flames. During the interception attempts, the object executed rapid maneuvers, including diving beneath the F-61 and pulling away at speeds estimated between 200 and 1200 MPH. The F-61 crew attempted to follow the target, but were unable to maintain contact. Notably, the target was never detected by ground radar stations in the area, despite those stations tracking the F-61 throughout the mission. The crew, both experienced pilots and trained observers, stated that the object did not resemble any aircraft they were familiar with, noting it was not a German ME-262 or similar jet. The official Air Materiel Command conclusion was that there is no apparent explanation for the incident, highlighting the discrepancy between the airborne radar contacts and the lack of ground radar detection.