DATE: January 13 1967 TIME: 2200 local CLASS:R/V ground radar/ multiple air visual
LOCATION: SOURCES: Hynek (1978) 72
Air Traffic Control Weinstein AUERVC, Vol. 4
Center, Albuquerque, N.M.
RADAR DURATION: 25 mins.
EVALUATIONS: official not specified
PRECIS: The pilot of a Lear jet flying near Winslow, Arizona, reported a red light at their 10 o'clock position that flashed on and off and several times quadrupled itself vertically, appearing to "retract into itself the lights below the original light". A National Airlines pilot in the area was queried by Albuquerque control tower, and after initially denying any sighting confirmed that they had been watching the object "doing exactly what Lear jet said" approximately 11 o'clock from their position. Albuquerque radar painted an unidentified target in a position consistent with the visual report, and for much of the 25 minutes during which the object was watched from the Lear, Albuquerque maintained radio conversation with the pilot. Whenever the red light was "on", ground radar painted a single target, but whenever it was visually "off" radar painted nothing. Radar apparently did not detect any changes coinciding with the quadrupling of the light. After a while radar showed the target closing range with the Lear, and the tower warned the pilot, who reported that the object began "cat-and-mouse" manoeuvres with his a/c involving rapid accelerations. At 2225 the object began a 30-degree ascent with great acceleration and was watched by the Lear pilot for 10 seconds until it was out of sight. At this time Albuquerque radar lost the target from their scope. Both Lear and National declined to officially report a UFO.
NOTES: Much of the significance of this case depends on details of the "catand-mouse" manoeuvres and the degree to which the radar target movements correlated during this episode. Unfortunately this information is lacking.
The downward "quadrupling" of the light is very suggestive of a multiple inferior mirage due to highly stratified atmospheric conditions, and celestial bodies can appear dramatically reddened, particularly when near setting. Since the critical grazing angle for an optical mirage is on the order of 0.5 degree this would presumably indicate a light source above the horizon for an aircraft at altitude, and would require the same (vertical) viewing angle from both aircraft. Thus Lear and National need to have been at roughly similar flight altitudes with, probably, a bright celestial body near the horizon. The visual disappearance of the object might be due to its setting below the critical angle, and the rapid "cat-and-mouse" movements of the object (in the absence of detailed description) could be due to sudden excursions of the mirage image (on the order of 1 degree) due either to movements of the aircraft relative to the refractive layer or to local discontinuities in the layer. Unfortunately we do not know the relative altitudes of the two aircraft, or the true azimuth at which the light was observed. However, it can be noted that the radar target which appeared to confirm the object near Winslow would have been due west from Albuquerque and thus not necessarily inconsistent with the azimuth of a setting star or planet viewed due west from Winslow. The same sharp inversion/lapse strata responsible for such a mirage might be expected to favour anomalous propagation of radar energy and thus the possibility of false echoes.
There are some problems with this hypothesis, however: 1) During 25 minutes of observation a celestial body above the western horizon would have declined by some 6 degrees, or at least 10 x the critical grazing angle for a mirage, and this makes some unlikely demands on the changing altitudes of the mirage layers and the two aircraft over the duration of the sighting; 2) to keep a celestial body in view for 25 mins the Lear was presumably flying a roughly straight course, during which it probably covered on the order of 100 miles at least - a great distance over which to remain in the same inversion domain; 3) the visual departure of the object, moving upwards at a 30-degree angle for ten seconds at a considerable angular rate, is inconsistent with the optical geometry of any mirage; 4) the repeated flashing of the light on and off suggests an intermittent superior mirage of a celestial body otherwise invisible below the horizon, which is at odds with the consistent downward multiplication of the image suggesting an inferior mirage of a source above the horizon.
An intermittent source would more aptly explain the flashing off and on, such as a beacon on a radio mast, which would also to some extent evade the problem of maintaining the critical mirage angle for many minutes. However, there is also the general question of the repeated simultaneous radio and optical disappearances of the source: this cannot be explained by an intermittent ground light, and optical disappearance of a celestial body due to the Lear's altitude departing from the optimum mirage angle or flying in and out of localised inversion/lapse domains cannot explain simultaneous signal loss at the radar site. In general it might be noted that the rather extreme atmospheric stratification required for the multiple mirage images would be expected to generate a great deal of AP clutter, and is not usually so anisotropic as to generate a unitary target over a narrow range of azimuths for 25 mins. In summary, the radiooptical AP hypothesis is superficially attractive but conjectural, and suffers from several serious deficiencies.
Other explanations of the radar target have to address the simultaneous radio-optical disappearances, which argue strongly for a real radar-reflective body. The object would be an anisotropic reflector and emitter - that is, an object with a high radar aspect-ratio in elevation (i.e., side-on:tail-on), zigzagging, rotating, or oscillating, and carrying a light which was visible to Lear only when it presented its greatest radar cross-section to Albuquerque. One could imagine a slowly spinning balloon with an underslung radar-asymmetrical instrument package bearing a red running light, if this could explain 25 minutes of jet-pursuit. A very large research balloon at high altitude over the horizon might be "pursued" for 25 minutes, and (improbably, given small radar crosssection at extreme range) might be painted by second-trip returns which displayed it in spurious proximity to the Lear over Winslow. But this could not explain the high-acceleration 30-degree visual ascent and disappearance, and the lights required to be carried by such balloons during night launches would hardly be prominent at the implied distant ground range and float-altitude of over 100,000'.
The illusion of a high-acceleration manoeuvre might be created by a small weather balloon near the a/c, but such a balloon could not be pursued at jet speed for 25 minutes. Furthermore weather balloon lights are not red; the quadrupling of the light would still require the superadded improbability of a rare optical mirage with a fortuitously maintained altitude relationship between the aircraft, the rising balloon and a slowly canting inversion layer; and the final radar-visual disappearance would remain unexplained and coincidental.
Visually, a reddish light could be explained as the tail-pipe of a jet, and periodic disappearance could relate to a circling or zig-zagging flight pattern which would present a changing aspect with a factor 5 or 10 fluctuation in radar cross-section (10-20 sq. m. down to 2-3 sq. m. for a small fighter). Close to the operational maximum range of the set, the returned signal might drop below the noise threshold as the a/c turned tail-on, and the distance between Albuquerque & the area of Winslow is >200 miles which would be consistent with the action occurring near the limits of an ATC surveillance radar. On this hypothesis the Lear would have been proceeding N or S with the jet ahead, tail-on to the Lear and side-on to the radar whenever it was visible. Such a jet could explain the final ascent and radar/visual disappearance by a climb and turn, tail-on to the radar and out of the pattern. This hypothesis is speculative, however, without knowing the frequency of the light's on-off cycle, the Lear's heading, the displayed speeds of the radar target, and the nature of the "cat-and-mouse" episode. 25 minutes is very a long time for a military jet to be flying at high speed (ahead of the Lear) in such an unusual fashion. Finally, the repeated quadrupling of the red light observed from two aircraft with only a single target appearing on radar is entirely unexplained without recourse to a superadded mirage phenomenon which is itself very rare and which renders the whole scenario too improbable to be convincing.
In conclusion, the raw visual description alone is strongly suggestive of mirage, although most other features of the case - qualitative and quantitative - argue against mirage as normally understood, and the simultaneous on/off radarvisual periodicity confirmed by radio between the observers as it was happening does argue quite strongly that the radar target and visual object(s) were related. The case should therefore be classified as "unknown" pending further investigation.