After reviewing the case in detail it is clear the total duration of the 2 objects sighted or tracked was a total of about 7 minutes' duration not the 14 seconds erroneously listed, which is only the interval of the high speed final phase. The second object was detected by ground radar on the F-94's tail and the entire encounter with this 2nd object amounted to about 1.8 minutes by my estimation.
The BB file indicates the first sighting occurred at 3:20 "I" time, and the second sighting at 0325 "I" time, hence the first sighting which overlapped the second, lasted 5 minutes. The first sighting is in several pages which they removed, which would have given a fuller account. This first sighting seems to have been put in another file now lost, including p. 2 of AIIR 52-85.
But the altitude gradually increased from about 2,500 ft to 7,500 ft during these 5 minutes, or almost exactly the standard weather balloon ascent rate of 1,000 ft/min. One then has to wonder if this first object was simply a lighted balloon whose structure could not be perceived even from 50 ft range possibly because of glare from its light, though this is pretty odd. The balloon interception and shootdown reports in the file are from May 16 not May 26 and completely unrelated to this May 26 incident (BB may have stuck the May 16 report into this file in order to suggest a balloon possibility).
However, the second sighting cannot be explained so easily. The suggestion of a malfunction in the airborne radar that simulated a real target at high speed 5-10 degrees above the horizon is too convenient if not ridiculous, especially given that the radar set was checked before and after and was functioning perfectly, and given that ground radar had detected the UFO on the F-94's tail in the first place.
This was a night-time event. The time zone is NOT GMT which would be in the middle of the afternoon in Korea, but the military's Local Time designation "I" used in Japan and Korea.
This is an especially unusual case where the F-94 flight crew had their timing estimation abilities CALIBRATED afterwards and found to be quite accurate, so that when they said the UFO accelerated over 14 seconds before breaking lockon, this was found to be accurate to within perhaps a half second, i.e., 14 secs ±0.5 sec (though the pilot has cautiously smeared this out to ±1-2 secs when he says the acceleration was over 12-15 secs).
I have rewritten my BB UNKs Catalog entry as follows:
May 26, 1952. W or NW North Korea. 3:20 a.m. (local). USAF 319th FI Squadron pilot 1st Lt. John W. Martin and radar observer 1st Lt . Edward A. Monard, flying N to S from an intercept mission near the front lines of the Korean War in an F-94C jet fighter at 2,500 ft altitude saw an unidentified brilliant white or blue light above them and in front. F-94 made about 7 passes in an attempt to identify the light, first to within 600 ft distance and then succeeding passes at different cardinal directions to within 50 ft range but could not see a shape due to the brightness of the light and airborne radar could not detect object. [Possible balloon since passes occurred over 5 mins as altitude increased to about 7,000-7,500 ft or at roughly standard weather balloon rise rate of 1,000 ft/min.] At 3:25 a.m. ground radar site “Bromide” told F-94 there was an unknown target on their tail, and F-94 radar observer visually sighted an aircraft behind them, while pilot saw that the original bright light was still visible too. Pilot turned right to come around behind the new target and radar observer detected on airborne APG-33 radar and locked on the object nearly dead ahead and slightly above at about 5°-10° elevation, range 7,000 yards, overtake speed 50 knots, F-94 at 250 knots and 7,000-7,500 ft altitude now heading NE [after ~50 secs of sharp turn]. Pilot went into shallow climb, closing range to object to 6,000 yards [after ~35 secs] when object started to rapidly pull away. F-94 went on afterburner [to ~500 knots] while object steadily accelerated in shallow climb to high speed [peak velo city of ~6,700 mph at about 21 g’s] in 14 secs increasing range from 6,000 yards to 24,000 to 26,000 yards, till breaking radar lock, while F-94 accelerated on afterburner from 250 knots [to roughly 500? Knots], and object evidently still being tracked by ground radar site “Bromide.” No visual contact made with object, no exhaust observed, no evasive maneuvers other than high acceleration. Flight crew timing was calibrated afterwards and found to be about ±2 secs in 60 secs or about ±0.5 sec in 14 secs. (Sparks; Weinstein; Saunders/FUFOR Index; NICAP) ~7 mins