The Haneda AFB case, Japan, August 5, 1952:

237-B. Haneda AFB (Tokyo), Japan, 5-6 August 1952, 2330-0030 LST. Weather: "exceptionally good," 0.3 cloud cover about 10 mi. north and 10 mi. south of the contact area, "excellent visibility," isolated patches of low clouds, Mt. Fuji (60 n. mi.) "clearly discernible," scattered thunderstorms in mountains northwest, temperature at Haneda 78° F, dew point 73° F. Observers saw a bright, round light (about 1 mrad arc) surrounded by an apparently dark field four times larger, the lower circumference of which tended to show some bright beading. It was low in the sky at about 30° -50° azimuth. Object appeared to fade twice, during which time it appeared as a dim point source. It disappeared, possibly becoming obscured by clouds, after about an hour. The sky at Haneda AFB was overcast by 0100 LST. One of the visual observers noted that near the end of the sighting the object seemed somewhat higher in the sky and that the moon seemed proportionately higher in elevation. The pilot of a C-54 aircraft coming in for a

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landing was directed to observe the object and he replied that it looked like a brilliant star, and he dismissed the sighting as such.

When the controller at Shiroi AFB was asked to look for target on GCI radar, he could find nothing for 15 min. He stated: "There were three or four blips on low beam but none I could definitely get a movement on or none I could get a reading on the RHI (range-height indicator) scope." A new controller taking over at 2345 LST "believed" he made radar contact with the object and an F-94 was scrambled. This officer stated: "The target was in a right orbit moving at varying speeds. It was impossible to estimate speed due to the short distances and times involved." By the time the F-94 arrived in the area of the "bogie," Shiroi GCI had lost radar contact; regaining contact at 0017 LST "on a starboard orbit in the same area as before." The F-94 was vectored in to the target, and at this point the timing becomes confused. The Shiroi controller states that the F-94 "reported contact at 0025 (LST) and reported losing contact at 0028 (LST)." The F-94 radar operator states: "At 0016 (LST) I picked up a radar contact at 10° port, 10° below, at 6,000 yd. The target was rapidly moving from port to starboard and a lock-on could not be accomplished. A turn to the starboard was instigated [sic] to intercept target which disappeared on scope in approximately 90 sec. No visual contact was made with the unidentified target." Shiroi GCI had lost the F-94 in ground clutter, and had also lost the target. It is not clear whether the GCI radar ever tracked the fast-moving target described by the F-94 crew. The maximum range of the F-94's radar is not given in the Blue Book report.

The F-94 pilot stated that the weather was very good with "exceptional visibility of 60-70 miles," yet this fast-moving UFO, obviously far exceeding the F-94's airspeed about 375 knots), was seen by neither the aircraft crew nor the observers on the ground at Shiroi GCI even though the UFO track crossed over very close to Shiroi GCI number four. There are many other inconsistencies in the

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report of the incident besides the timing and the lack of visual contact by the F-94 crew. The bright, quasi-stationary object sighted NE of Haneda AFB, and seen also from Tachikawa AFB (about 30 mi. west of Haneda AFB), should have been visible to the south of Shiroi AFB, but was never seen by any of a large number of persons there who attempted such observations. Also, at 0012 LST the object being tracked by GCI's CPS-l radar reportedly "broke into three smaller contacts maintaining an interval of about 1/4 mile." The blips on the CPS-l were described as small and relatively weak, but sharply defined.

Two things seem apparent:

the object seen at Haneda and Tachikawa AFB was much farther away than the observers realized;

the visual UFO and the target tracked by radar were not the same. The first statement is supported by the inability of the observers at Shiroi to see anything to the south; the second statement is supported by numerous inconsistencies between the visual and radar sightings. The two most important of these latter are:

During times when the GCI radar could not find the target, the visual object was in about the same location as during those times when it could be found on radar;

The visual object was seen for at least five min. after the time when the airborne radar on the F-94 indicated that the UFO had left the area at a speed well in excess of 300 mph.

The most likely light source to have produced the visual object is the star Capella (magnitude 0.2), which was 8° above horizon at 37° azimuth at 2400 LST. The precise nature of the optical propagation mechanism that would have produced such a strangely diffracted image as reported by the Haneda AFB observers must remain conjectural. Complete weather data are not available for this case, but it is known that the light SSE circulation of moist air from Tokyo Bay was overlain by a drier SW flow aloft. A sharp temperature inversion may have existed at the top of this moist layer, below which patches of fog or

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mist could collect. The observed diffraction pattern could have been produced by either

1. interference effects associated with propagation within and near the top of an inversion, or
2. a corona with a dark aureole produced by a mist of droplets of water of about 0.2 mm. diameter spaced at regular intervals as described by Minnaert (1954).

In either event, the phenomenon must he quite rare. The brightness of the image may have been due in part to "Raman brightening" of an image seen through an inversion layer.

Nor can exact nature of the radar propagation effects be evaluated, due to the lack of complete weather data. However, a substantial inference that the radar returns were of an anomalous propagation nature is derived from:

1. the tendency for targets to disappear and reappear;
2. the tendency for the target to break up into smaller targets;
3. the apparent lack of correlation between the targets seen on the GCI and airborne radars;
4. the radar invisibility of the target when visibility was "exceptionally good."

Singly, each of the above could be interpreted in a different light, but taken together they are quite suggestive of an anomalous propagation cause.

In summary, it appears that the most probable causes of this UFO report are an optical effect on a bright light source that produced the visual sighting and unusual radar propagation effects that produced the apparent UFO tracks on radar.