Unidentified Air Contact — Yellow Sea, 18 October 1951

This report details an unidentified air contact observed by a U.S. Navy PBM Mariner aircraft on 18 October 1951 over the Yellow Sea. The crew, led by Patrol Plane Commander Ensign George Gregory, sighted a light on their port side at 0333Z. The object was described as a large, silverish craft approximately 60 feet long, featuring swept-back wings and no visible empennage. It emitted a bright, conical flame that changed in color from red-orange to white-orange, suggesting the use of a reaction-type motor such as a rocket or ram-jet. The object maintained a distance of 12 miles from the patrol plane, maneuvering to stay between the moon and the observer, which hindered attempts to obtain a silhouette photograph. The object displayed high-speed flight characteristics, with an estimated speed of 530 knots, and appeared to fly at a high angle of attack, suggesting it was staggering to maintain flight at lower speeds. Radar confirmed the target throughout the encounter until the object maneuvered out of the radar beam. The encounter lasted approximately 16 minutes. The report includes detailed radar plots, sketches of the object, and diagrams of the observation geometry. The evaluating officer, Mr. Wallace R. Bush, and the preparing officer, Captain Charles J. Malven, concluded that the object was likely a conventional jet-type aircraft, possibly a MIG-15, noting that night visibility and moonlight reflections could have distorted the crew's perception of the craft's features.