Incident · 31 May 1952 · South of Chorwon (Cheorwon), Korea
Chorwon F-94 engagement
Also known as Chorwon 1952, Cheorwon 1952, Cheorwon F-94
Partly explained. Blue Book's main record card says Unknown; a second card for the ground sighting says probably a balloon with a flare or an aircraft, and FEAF intelligence suggested a light carried by a high-performance aircraft, while finding no explanation for the ground radar's failure to paint it. (Project Blue Book case files: Chorwon, Korea, May 1952)
Before dawn on 31 May 1952, during the Korean War, two airmen on guard duty at a radar site just south of Chorwon (Cheorwon) watched a glowing object descend, stop, dart back and forth and climb away, with a pulsing sound like a jet. At the same time an F-94 night fighter of the 319th Fighter-Interceptor Squadron tried to intercept a brilliant white light in the area: by the crew's account it climbed to meet them, traded head-on passes and turned with the fighter up to 30,000 feet, then outclimbed and outran it. Neither the fighter's radar nor the ground radar could paint it.
Project Blue Book filed the main sighting as Unknown, with a faint possibility of a balloon. Far East Air Forces intelligence noted that the crew's and the ground observers' accounts did not match, suggested a light carried by a high-performance aircraft, and recorded that no explanation had been found for the ground radar's failure to detect it. In the same weeks F-94 crews over Korea chased lighted balloons, and shot one down.
Source: Project Blue Book case files, U.S. National Archives (local copy)
Facts and claims
- documented At about 0350 on 31 May 1952, an airman on guard duty above a radar site south of Chorwon saw a round, glowing object, star-coloured with a blue tint, descend vertically, stop, climb, move east and back in level flight at about 100–150 mph, then climb away to the northeast at 45° and fade from view; he heard a sound like a pulse jet. A second guard, a radar mechanic, saw an oval object about the size of a fighter with a glowing outer ring “similar to white phosphorous”, which moved with “jerky movements”, reversed direction abruptly, and climbed steeply away “in a matter of 3 to 4 seconds”. He noted that the site's radar cannot pick up anything within 4 miles of the site. Source: Project Blue Book case files: Chorwon, Korea, May 1952
- documented An F-94 crew (pilot and radar operator, 21 missions or scrambles) intercepting at 0345 reported a round, brilliant white object whose shape could not be seen at close range “due to blinding light of object”. As the F-94 descended to intercept, the object climbed to meet it and silhouetted the fighter against the dawn; the F-94 lit its afterburner and traded two quartering head-on passes, neither able to get astern of the other, then a turning fight up to 30,000 feet, until the object pulled away at an estimated 400, then about 450, knots and the F-94 gave up at 0355. Source: doc-bluebook-chorwon-1952.pdf
- documented The crew reported that the object “possessed superior speed, superior climbing ability, and was able to turn equally as well as the F-94”, and that neither the F-94's APG-33 radar, in good condition, nor the ground radar station could paint it at any time, even at close range. Source: doc-bluebook-chorwon-1952.pdf
- documented Blue Book's record card marks the case “Unknown”, noting only “a faint possibility of this being a balloon”; a second card, for the ground sighting, says probably a balloon with a flare or probably an aircraft. FEAF's deputy for intelligence judged the object possibly a light carried by a high-performance aircraft, but found no explanation for the ground radar's failure to paint it. Source: Project Blue Book case files: Chorwon, Korea, May 1952
Connected files
Documents
- Project Blue Book case files: Chorwon, Korea, May 1952 (documented in)
Programs
- Project Blue Book (investigated by) — The main record card marks the conclusion “Unknown”
Mentioned in this file
- National Archives and Records Administration (Organization)