South Korea.Korea · a fighter chases a light; radar spots something behind it

In the early hours of Monday, May 26, 1952, an F-94 night fighter of the U.S. 319th Fighter-Interceptor Squadron took off from K-13 (Suwon) to patrol the central sector of the Korean front. It carried two men: the pilot and, behind him, an operator who ran the aircraft's radar, whose screen showed what lay ahead. A controller on the ground, call sign "Bromide", guided them; he watched the sky on a larger radar and sent fighters toward whatever appeared on his screen. Bromide told them about an unknown contact and asked them to investigate. According to the pilot, they came down to about 2,500 feet and saw, in the glare of the front-line searchlights, a small plane below them, but the terrain kept them from descending further to identify it. Bromide told them to drop it and take up a southerly heading.

As they turned they saw a brilliant object above and ahead. With the controller's permission they flew past it first from north to south, at about 600 feet, and then from the four cardinal points, down to about 50 feet, without making out any outline because of the glare. The operator, whose name is blacked out, adds details. It was the pilot, whom he calls "Martin", who spotted the light; he himself could not pick it up on his radar, although the controller said he had it on his screen ("I can not understand how GCI was painting this target and I could not pick it up"). They flew past it about seven times, and when he looked up from the screen it appeared to be "a bright blue light".

The two statements tell what happened next in a different order. According to the operator, after the last run past the light, at about 7,000 feet, the controller announced that they had something on their tail; he turned and thought he saw a plane, without being sure, because it lasted a second. According to the pilot, it was the operator who, on that last run, looked back and said he thought he saw something behind them, and he gave it little credence until the controller called to say he could see something behind the fighter on his screen.

The pilot asked the controller to steer him toward it and, with the light still in sight, turned right. On a northeasterly heading, the fighter's radar picked up something at 7,000 yards (about 6.4 km), nearly dead ahead and slightly above, and the fighter began to close at 50 knots faster than the object. At 6,000 yards the thing began to pull away. The pilot lit the afterburner, which gives the engine extra thrust, from about 250 knots, and followed it in a gradual climb, past 10,000 feet, with the blip nearly centered on the screen, while the range opened at a steady rate: to about 26,000 yards in 12 to 15 seconds, according to the pilot, or about 24,000 in about 14, according to the operator. There the radar lost it, and they did not find it again for the rest of the mission. Neither man saw any evasive maneuvere or exhaust. The operator added that, in his view, this was what the controller had had on his screen all along, while they were flying past the light.

The next day the Fifth Air Force intelligence summary recorded the two episodes separately and at two different points on the map: at 0320 and 7,500 feet, the radar chase of an "unidentified aircraft"; at 0325 and 7,000 feet, an "unidentified aircraft" with a very strong light, visible from more than 5 miles, which the crew said was "definitely" not a balloon; "No outline was visible because of the brilliant light". Those times put the chase before the light, the reverse of the statements.

On May 29 both crewmen signed their statements (the pilot's before Captain Fielder C. Slingluff III; in the operator's, the witness's name is blacked out). On the 31st Captain Vincent A. Goskey, of an air intelligence unit, sent a report with the answers to a questionnaire from the intelligence staff of Far East Air Forces (FEAF), the U.S. air command in the region. The fighter's radar was checked before and after each mission and was working "very good"; the operator never took his eyes off the screen; the time was measured by counting aloud, with an error the report puts at no more than two seconds a minute. The report adds that what the radar tracked was never seen for certain ("no actual ascertainable visual observation was made") and that the light was only seen, never caught on radar. Someone wrote a "?" in the margin beside those two underlined sentences. Page 2 of the four-page report is missing, and in the FEAF extract someone asked by hand where the rest was.

Brigadier General Charles Y. Banfill, FEAF's head of intelligence, did the arithmetic: about 68,500 feet covered, an acceleration of 650 feet per second squared, about 20 times the force of gravity, and a final speed of about 5,580 knots; even if the timing or the calibration were off by 50%, it would still exceed any known missile. He added that the Bromide controller had not yet sent anything on what his radar had recorded, and concluded that the acceleration led to the belief that the fighter's radar was not working properly at the time of contact, despite the checks. The Blue Book record card summarizes the case as "Ground Radar, Air Radar, Air Visual Combined Sightings", gives as its solution a possible fault in the fighter's radar and ticks "Possibly Balloon", with "Was Aircraft", "Probably Aircraft" and "Unknown" crossed out; Blue Book's 1952 index lists it as "BALLOON WITH FLARE".

The documents tell two different things and the Blue Book record card blends them. Its summary says that, while the fighter's radar was tracking the object, the pilot and the operator saw a brilliant white light straight ahead and that it was this light that pulled away. The signed statements and Goskey's report say otherwise: the light was a first object, which the fighter's radar did not pick up although the ground controller said he had it on his screen, and what drew away on the fighter's screen was a second object that nobody saw clearly.

Read this way, each part has its proposed explanation. The light, with no outline, which they could fly past from the four cardinal points, fits the lighted balloons that F-94 crews shot down ten days earlier in the same area of the military map. That day they shot down two, one of them with a white light, "Very powerful", that "was still burning as the balloon fell". FEAF's Air Technical Intelligence Liaison (ATIL) Office commented that these balloons could explain many of the sightings over that area of Korea. They were enemy balloons: the FEAF summary of June 13, headed "Enemy balloons", tells how a forward observer saw a balloon raised and lowered on a cable near the front and notes that it "could possibly be a method of communication". The same extract records reports of enemy aircraft carrying searchlights over northwest Korea, though none in that area. The crew denied it was a balloon because they had flown directly beneath it several times at 50 feet ("as several passes were made directly beneath at 50 ft range").

The radar part is what gives the case its weight. There is a warning from the ground radar, a track on the fighter's radar by an operator who signed what he saw on his screen, and a timing that the report itself explains. FEAF's explanation, a fault in the fighter's radar, is not refuted, because a check before and after the flight does not rule out a failure during the contact; but it does not explain why the ground controller saw something on the fighter's tail before the onboard radar picked it up either. The data from that ground radar, which would have allowed a check, never reached Blue Book's files.

The place matters too. The record card and Goskey's report say "North Korea", and positions are given in the military map grid of the period; the investigating officer wrote that the light was beyond the bomb line, on the enemy side of the front, and the fast object was "to the rear of our front lines", in territory that today belongs to South Korea.