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December 9, 2016
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September 1, 1971
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A,~,,,,4, /' od,, C~'-- C-k_4_/ Vl:e~ Approved For Release 2001/04/02 : CIA-RDP81 R00560R0001 00010010-0 in UFO ENCOUNTER II Sample Case Selected by the UFO Subcommittee of the AIAA The Lakenheath England, Radar-Visual UFO Case, August 13-14, 1956 Introduction The following story-a second exam- ple of the type of observation which forms the core of the UFO issue -has been selected by the UFO Sub- committee of the AIAA for publica- tion not only because of its puzzling content, but also because of the mul- tiplicity of, observations. The author, a former member of the "Condon Committee" (University of Colorado UFO study team), discusses the case, but does not offer an explanation. The same was true for the first case, published in the July 1971 A/A, where the principal observers were highly qualified professionals making sightings in their line of duty. Both case studies are intended to give the reader a flavor of the observational residue material which underlies the UFO controversy. We hope he will give it his independent assessment as engineer or scientist. On a pleasant August evening in 1956, the night-watch supervisor at the Lakenheath, England, Radar Air Traffic Control Center (RATCC), a U.S. Air Force noncommissioned of- ficer, was startled by a telephone call fremn the Bentwaters GCA (Ground Controlled Approach) radar installa- tion (see map) asking, "Do you have I pat contact was lost about 15-20 mi. to the WNW of Bentwaters. The radar operator estimated the apparent speed of the URE as 4000 mph; but By G. D. THAYER tur was the name of the U.S. Air Force UFO investigation). At least three separate times unidentified radar echoes (UREs) were tracked by the GCA unit at Bentwaters before the telephone contact with Lakenheath; and although these are highly inter- esting events in themselves, they did not involve confirmatory visual and airborne radar contacts. A detailed account of these first three radar con- tacts can be found in an earlier paper by James McDonald (FSR 16, "UFOs over Lakenheath in 1956," 1970, pages 9-17). "Scientific Study of Unidentified Flying Objects" (Bantam Books, 1969; hereafter re- fered to as the "Condon Report") contains no account of these because the pertinent Bluebook files were ob- tained too late for inclusion. The Condon Report does contain an inde- pendent account of the primary inci- dent at Lakenheath, as reported by the night-watch supervisor, not found in the Bluebook file; this separate report forms the most coherent ac- count of the events at.Lakenheath. Following a brief description of the events at Bentwaters based on the Bluebook file, the Lakenheath inci- dent will be described here based mainly on the night-watch super- visor's account. Account of Observations The four events at Bentwaters GCA (see map for plots of these radar tracks) took this order: 1. At 2130Z a URE (No. 1 in any targets on your scopes traveling map) was picked up on the Bent- at 4000 mph?" Thus began one of waters AN/MPN-11A GCA radar the strangest and most disturbing about 25-30 mi. to the ESE. (Note radar-visual UFO episodes on record. that Z time-zero meridian time-, There is a very large, confusing re- or GMT, is also local time in the port on the Lakenheath-Bentwaters Lakenheath-Bentwaters area.) This incident in the U.S. Air Force Project URE moved steadily on a constant the transit time of 30 sec yields an estimate of 4800-6000 mph, and the operator's estimate of 5-6 mi. cov- ered by the URE between PPI sweeps (2 sec apart) gives an esti- mate of 9000-10,800 mph. "The size of the blip when picked up was that of a normal aircraft target. [It] diminished in size and intensity to the vanishing point before crossing the entire radar screen." 2. A "few minutes later," say roughly 2135Z, a group of 12-15 UREs was picked up on the PPI about 8 mi. SW of Bentwaters (No. 2 in map). These echoes "appeared as normal targets," and "normal checks made to determine possible malfunctions of the GCA radar failed to indicate anything was technically wrong." These URE's appeared to move as a group toward the NE at varying speeds reported as 80-125 mph. The group covered a "6-7-mi. area" on the scope. These echoes "faded considerably" at a point 14 mi. NE of Bentwaters, but were tracked to a point about 40 mi. NE of Bentwaters when they merged into a single strong echo "several times larger than a B-36 return under comparable conditions." This single echo remained stationary at do 16 in tim as t the we OP on co; in rep thi gat ma the point 40 mi. NE of Bentwaters Be for 10-15 min., then moved to the La; NE for 5-6 mi., stopped again for th 3-5 min., and finally moved out of ' he range (50 mi.) of the radar at i his 2155Z. The average apparent speed of of the URE group for the time it was the as between 290 and 700 mph (58 mi.. in? in 5-12 min-again differing from' at Approved F(orbRolease O0'b h4/62hpZhA RDP84Ra6660R 41OOi 1O0l =0 60 Astronautics & Aeronautics abAPpXpt$0 9569 Oa9Ot1lP9UO I R;90-20,000 tion or deceleration apparent-the changes varying in indicated length from 8 to 20 mi., with stationary epi- sodes of 3-6 min intervening. There were visual sightings at Lakenheath during this time, but the reports of these are confusing and inconclusive. Perhaps of greater significance are the investigating officer's statements that "two ra- dar sets [Lakenheath GCA and RATCC] and three ground observ- ers report substantially the same," and "the fact that radar and ground visual observations were made on its rapid acceleration and abrupt stops certainly lend [credence] to the report." After "about 30-45 min," or 2340 to 2355Z, the RAF "scrambled" a de Havilland "Venom" night fighter aircraft to investigate the Laken- heath UFO. (At this point, the account of the Lakenheath night-watch supervisor and that of the Bluebook report diverge. First, the watch supervisor says the aircraft was from a field near London and was picked up on the RATCC radar inbound from the southwest at a range of 30-45 mi. from Lakenheath. According to the Bluebook file, the fighter took off from Waterbeach RAF station (see' map), which is only 20 mi. SW of range-given as 50-60 mi. for targets at 5000 ft or above. Second, the watch supervisor relates that the Venom was vectored to the then stationary URE (No. 5) at a position about 16 mi. SW of Lakenheath, and that this was the aircraft's first and only contact with any UFO. Accord- ing to the Bluebook account, "the a/c flew over Lakenheath and was vectored to a radar target 6 mi. east of the field (No. 6). Pilot advised he had a bright white light in sight and would investigate. At 13 mi. west [of Lakenheath] he reported loss of target and white light [N.B. -this implies that the pilot had the unknown on his airborne radar as well as having had visual contact]. Lakenheath RATCC vectored him to (presumably) another target 10 mi. east of Lakenheath and pilot advised target was on radar and he was "locking on." This target would be URE No. 5, identified by the watch supervisor as being about 16 mi. SW of Lakenheath. Except for this discrepancy, the account of the Lakenheath watch supervisor agrees with the Bluebook file from here on in virtually every detail.) The Venom fighter was vectored by the RATCC radar to the sight of the URE, which (according to the night-watch supervisor) was station- BENTWATERS-LAKENHEATH URE/UFO CONTACTS August 13-14, 1956. 1 2130 Z Bentwaters GCA, AN / M PN-11 A. Not confirmed. 2 --2135-2155 Z Bentwaters GCA. Not confirmed. 3 2200 Z Bentwaters GCA. Not confirmed. 4 2255 Z 1. Bentwaters GCA. 2. Bentwaters control tower. Not AP. Possible AP. Not AP; possibly same as No. 4. Not AP; No. 5 could have been 3. C47 a/c at 4000 same "object." ft over Bent- waters. Appar- ently same time as radar contact. 1. Lakenheath RATCC, CPS-5. Ground observa- Not AP or radar tions not confirmed. malfunction; may 4. Pilot of Venom have been No. 4 made visual con- from Bentwaters. tact coincidental with the three radar contacts. 2. Lakenheath GCA, CPN-4. 3. Venom airborne, A-1. All coinci- dental at various times (airborne contact when a/c was on scene). 62 ft about 16 mi. SW of Lakenheath. Shortly after Lakenheath told the pilot the URE was one-half mile dead ahead of the interceptor, the pilot radioed, "Roger, . . I've got my guns locked on him." (The pilot refers to a radar fire-control system.) This pilot later told a U.S. Air Force investigator that the URE was "the clearest target I have ever seen on radar." There was a brief pause after the Venom pilot said he had gunlock on the URE and then he said, "Where did he go? Do you still have him?" The Lakenheath RATCC in- formed him that the URE had made a swift circling movement and had gotten behind the Venom. The pilot then confirmed that the target was behind him and said that he would try to shake it. Since no tail radar is mentioned, the pilot presumably saw the UFO behind him. The pilot of the Venom intercep- tor tried numerous evasive maneuv- ers, but he was unable to lose the URE, which the Lakenheath RATCC radar continuously tracked as a distinct echo behind the aircraft echo; this implies that the separation was greater than about 500 ft. Ac- cording to the Bluebook report, "Pilot advised he was unable to `shake' the target off his tail and requested assistance." After about 10 min., the first Venom pilot, who reportedly sounded "pretty scared," said that he was returning to base- because he was running low on fuel. He asked Lakenheath RATCC to tell him if the URE followed him on the radar scopes. According to the Lakenheath watch supervisor, the URE appeared to follow the Venom only a "short distance" as the pilot headed SSW toward London [or Waterbeach], and then it resumed a stationary aspect. A second Venom was vectored by Lakenheath RATCC toward the position of the URE; but before he got close enough to pick up any- thing, he radioed that he was ex- periencing engine malfunction and was returning to his base. The fol- lowing conversation was monitored by the Lak?nheath watch supervises between the two Venom pilots: Number 2: "Did you see any- thing?" Number 1: "I saw something, but I'll be damned if I know what it was." Number 2: "What happened?" Number 1:. "He-or it-got be- could stronautics & Aeronautics Approved For Release 2001/04/02 : CIA-RDP81 R00560R0001 00010010-0 3. At 2200Z another URE (No. 3 BENTWATERS-LAKEN HEATH SIGHTINGS MAP in map) was picked up about 30 mi. CP IoE 2?E 530N east of Bentwaters and tracked to a 53?.N- point about 25 mi. west of the sta- tion; the tracking period was about SCULTMORPE ? Approx. Range of 16 sec. The radar operator estimated Bent waters GCA Radar the apparent speed of this URE to be "in excess of 4000 mph" but the First Motion to Here NORWICH n (time unknown) Sint ionary 2 time and distance figures indicated ~ a speed of roughly 12,000 mph. All 5 ? 3 5m;n the returns "appeared normal, ex- 1.0 cept for the last, which was slightly AK HH ATH / Stationary 10-15min weaker than the rest." The radar l?---~-? 6 /~ operator indicated that the "[re- - RAF STATIONI Approximate turn] disappeared by rapidly WATERBEACH o Intercept Point 011 ' BENTWATERS 2200Z 2255Z moving out of the GCA radiation CAMBRIDGE I 3.4 pattern." No further UREs are 'a r3 ~~_ Il -_ mentioned in the Bluebook uebook report `5 Lokenheoth UFO Firse ?-?----: on the Bentwaters incident; and Picked Up Here 00102 1J IPSWICH i1 2135-21552 52?N considering the confusion prevailing 52?N-' -; + ~. in reported times in Bluebook re- 2t30Z ports and the similarity of the e~?uin9 Wins reported tracks and speeds, possibly oirea"O" at this LIRE and No. 4, which insti- gated the phone call to Lakenheath, may in fact be the same. 4. According to the Bluebook re- EoNOON /~~jr port on the Lakenheath incident, the Bentwaters GCA radar, at 2255Z, picked up a URE 30 mi. east (of Bentwaters) moving to the west at an apparent speed of "2000 to 4000 mph." In the map shown at right, the track of _the URE appears identi- cal with No. 3 except for the vanish- ing point. This URE then "disap- + SI?N 51?N- i peared on scope 2 mi. east of station SCALE: and immediately appeared on scope -~ c Ic Rc FO 30 3 mi. west of station . . . it disap- l o ttEES peared 30 mi. west of station on ? XItAMETERS scope." If the word "immediately" - l means that the URE was picked up ?? top 2?E on the same PPI sweep, after 180 deg. rotation from east to west, it would imply that the apparent pilot of, a C-47 aircraft flying over less than 40-50 knots, the radar motion covered 5 mi. in 1 sec, an the station at 4000-ft altitude re- personnel could detect "no move- inferred speed of some 18,000 mph. ported a "bright light streaked under ment at all" from this URE. The At this rate the URE would have his aircraft traveling east to west at watch supervisor called the GCA covered the 60 mi. track in about 12 terrific speed." The Lakenheath unit at Lakenheath to see if they had sec (6 PPI sweeps). As pointed out, watch supervisor, although admit- the same echo on their scope and this may have been URE No. 3 from tedly skeptical of this report, "im- "they confirmed the target was on the Bentwaters Bluebook report, mediately had all controllers start their scope in the same location." As which is estimated at 12,000 mph, scanning the radar scopes ... using the Lakenheath RATCC personnel although the reported times are full MTI (moving target indicator), watched this URE, it suddenly began different. which eliminat?d entirely all ground moving in a NNE direction at a At this point, someone at the returns." speed that they subsequently calcu- Bentwaters GCA station called the Shortly after this search began, lated to be 400-600 mph. In their Lakenheath RATCC station asking one of the controllers noticed a sta- words "there was no . .,. build-up to the night-watch supervisor there if tionary echo on the scopes at an this speed-it was constant from the he had any "4000-mph targets" on indicated position 20-25 mi. SW of second it started to move until it his scopes and describing the track Lakenheath (No. 5 in map). Note stopped." of URE No. 4. The caller stated that the position of this initial cont,-ct on The watch supervisor contacted the control tower at Bentwaters had the map; it is almost directly in line local AFB command personnel and reported seeing "a bright light pass- with the path of UREs 3 and 4 from kept them informed of the happen- ing over the field from east to west the Bentwaters report. Although the ings from this point on. The URE ave altitG PP S E of tiic ur g 4ehaase 20QTTI~O should 4nC AgR?1a6~O0586R00010 064100''?-fi~waysl at made several changes in direct September 1971 61 to get bdhlPc i9t vagfPI F0qfdRe)gasetg9AJJQ"2's: (q4 -RpFtaSjsRO@56GR0>OD100&40a -Overe lmost o - ith i l the damnedest thing I've ever seen." sighted visually and by radar, the The pilot of Venom. Number 1 meteor hypothesis must be ruled _1 I$ also stated that he had radar gun- lock for several seconds so "there was something there that was solid." Following this strange "chase," the URE did not immediately disap- pear from the Lakenheath RATCC radar. In the words of the night- watch supervisor, "The target made a couple more short moves, then left our radar coverage in a northerly direction-speed still about 600 mph. We lost target outbound to the north at about 50-60 mi., which is normal if aircraft or target is at an altitude below 5000 ft (because of the radiation lobe of that type radar [a CPS-5])." The time of loss of contact was not given by the watch supervisor; according to the Blue- book file the time was about 0330Z. The night-watch supervisor also stated "all speeds in this report were calculated speeds based on time and distance covered on radar. This speed was calculated many times that evening...." Discussions The interpretations and analyses that have been made of this intrigu- ing UFO incident are almost as numerous as the investigators them- selves. The investigating U.S. Air Force officer wrote: "My analysis of the sightings is that they were real and not figments of the imagination. The fact that three radar sets picked up the targets simultaneously is certainly conclusive that a target or object was in the air. The maneuv- ers of the object were extraordinary; however, the fact that radar and ground visual observations were made on its rapid acceleration and abrupt stops certainly lend [cre- dence] to the report. It is not be- lieved these sightings were of any meteorological or astronomical ori- gin." We quote this statement, although these are hardly the words of a careful, scientific investigator. J. Allen Hynek, the well-known UFO consultant to the Air Force, wrote in part: "It seems highly unlikely, for instance, that the Per- seid meteors could have been the cause of the sightings, especially in view of the statement of observers that shooting stars were exception- ally numerous that evening, thus implying that they were able to dis- tinguish the two phenomena. Fur- ther, if any credence can be given The Condon Report in its analysis of this incident states: "In conclus- ion, although conventional or na- tural explanations certainly cannot be ruled out, the probability of such seems low in this case and the proba- bility that at least one genuine UFO was involved appears to be fairly high." The meaning of this last statement (by the present author) has puzzled some later investigators; in this context a "genuine UFO" was meant to imply precisely that; there was a material object, it was flying (in the sense of moving through the air), and it was (ob- viously) unidentified. Hence, the conclusion that there was a "genuine UFO" was not meant to imply, for example, that the UFO was neces- sarily of extraterrestrial origin. In Chapter 5 of the Condon Re- port, "Optical and Radar Analyses of Field Cases," the analysis of this report concludes with: "In sum- mary, this is the most puzzling and unusual case in the radar-visual files. The apparently rational, intelligent behavior of the UFO suggests a mechanical device of unknown ori- gin as the most probable explanation of this sighting. However, in view of the inevitable fallibility of wit- nesses, more conventional explana- tions of this report cannot be en- tirely ruled out." Philip Klass (private communica- tion) believes that the Lakenheath RATCC radar was malfunctioning because of a faulty MTI unit; he feels that once the radar evidence has been explained, the rest can be accounted for by either confusion of witnesses or conventional causes. The reader may draw his own conclusions as to which of the above "explanations" seems the most likely. However, a few things are worth pointing out in summary: 1. The possibility that meteors might have accounted for these events seems to be easily ruled out, and it was so discounted by early investigators. 2. Visual mirage is ruled out by the large angles (i.e., simultaneously seen over a control tower and under an aircraft) at which the UFOs were observed and by the manner and directions of movement. 3. Anomalous propagation of radar seems equally unlikely as an over-all explanation. All but No. 2 p er a ng e y mov apparent posite to or across the prevailing winds, ruling out ground objects seen by partial reflections from moving elevated inversions (or other layered structures). Such re- flections produce false targets that appear to be at twice the range and twice the height of the reflecting layer, and appear to move in the direction of the prevailing wind but at an apparent speed twice as great. Thus the group of echoes (No. 2) observed from 2135 to 2155Z moved generally from the SW (exact azi- muth not given) at "80-125 mph," commensurate with winds of 40-63 mph from the same direction. The actual winds are given as 260 deg/ 45 mph at 10,000 ft and 260 deg/ 63 mph at 16,000 ft. Although the reported stationary episodes of the merged echoes at the two points shown on the map would, taken at face value, rule out the moving- layer reflection hypothesis, there remains a possibility that this may have been the cause of the No. 2 URE contact at Bentwaters. This hypothesis can be ruled out, how- ever, for the other URE episodes at Bentwaters, and particularly for those at Lakenheath. The "disappearance" of URE No. 4 as it overflew the Bentwaters GCA station was mentioned in the Con- don Report as being "suggestive of AP" [anomalous propagation], and so it is. The elevated-layer partial reflection phenomenon that causes this type of AP involves a reflection coefficient that is typically propor- tional to the inverse sixth power of the elevation angle of the radar beam (cf. Wait, 1962; Thayer 1970). Thus caused by a moving layer, if such a false target appears to ap- proach the radar site, the signal will drop below the noise level when the beam elevation exceeds some critical angle; the false target will often re- appear on the other side of the radar when the beam angle once more drops below the critical value. With a fixed-elevation PPI display radar, this results in a "zone of invisibility" around the site with a radius on the order of 5-15 mi. in which the target disappears. Two additional factors seem to point to AP as a possible cause for URE No. 4: 1. Radar operators who are fa- miliar with their sets will not norm- ally report the "disappearance" of a target unless they do not expect it, Septem" bDrQrQved For Release 2001/04/02 : CIA-RDP81 R00560R000100010010-0 Approved For Release 2001/04/02 : CIA-RDP81 R00560R0001 00010010-0 Going abroad? ..think of us! The AIAA now maintains two fully chartered student branches In Europe- one at the Von Karman Institute In Brussels, and the other at the Institute of Aerodynamics at the University of Naples. In addition, we are now forming additional branches In Europe, Asia and Africa. In order to provide more services to these student branches, we are establishing an International Speak- ers Bureau. We are asking all AIAA members who are planning to be abroad during the next six months and who are willing to speak to a college audience about a technical or general aerospace topic to complete and return the following form. AIAA INTERNATIONAL SPEAKERS BUREAU REGISTRATION FORM Return to: AIAA Student Programs 1290 Avenue of the Americas New York, New York 10019 LANGUAGES OTHER THAN ENGLISH (SPOKEN) I WILL BE ABLE TO ADDRESS STUDENT GROUPS IN: A. THE CITIES I AM NOW SCHEDULED-TO VISIT 0 B. OTHER CITIES IN THE SAME GENERAL AREA ^ SIGNATURE w~?.ew-no MW an?=W which would preclude targets that enter the radar's normal "blind zone" (if it has one). 2. The target was "lost" at 2 mi east but reacquired at 3 mi. west, an asymmetry that is possible with AP but not usual with radar "blind zones." However, a strong factor argues against the AP hypothesis in this instance: the URE was moving al- most opposite to the prevailing winds. In addition, because of the apparent speed of the URE, it should have reappeared about 3.5 mi. west of the radar on the second PPI sweep after "losing" it 2 mi. east (on the first sweep it should have been almost over the radar, and probably not visible to it) , so that the "asymmetry" can be assigned to the "digital" sampling by the PPI sweep-scan display. It is therefore most unlikely that URE No. 4 was caused by AP, a conclusion also reached in the Condon Report. The Lakenheath episode (URE No. 5) is even more unlikely to have been caused by AP. That the com- plicated, stop-and-go maneuvers de- scribed by the Lakenheath night- watch supervisor could have been caused by AP returns, and at that on two different radars operating on different frequencies and scan rates, is almost inconceivable. Ghost echoes have often been observed that will appear to "tail" an aircraft echo -sometimes the radar will even track a jet-exhaust plume-but such echoes never stop following the air- craft and become stationary, as did the Lakenheath URE. In summary, although AP may possibly have been a factor in the No. 2 Bentwaters sighting, it is not possible to assign the rest of the events reported to propagation ef- fects, even aside from the visual confirmations. Possible malfunction of radar equipment, and especially possible malfunction of the MTI on the Lakenheath RATCC radar, has been suggested as a cause of these UREs. It is true that a malfunctioning MTI unit could conceivably produce false echo behavior similar to that ob- served at Lakenheath. However, the coincident observation of the URE by the Lakenheath GCA radar, a different type, and later by the Venom's airborne radar, seems to rule out this hypothesis. The detec- tion of an apparently stationary tar- get while the radar was on MTI is not as surprising as it seems. A vi- brating or rapidly rotating target will show up on MTI radar even if it is not otherwise in motion. Thus, none of the conceivable "simple" explanations for the events at Bentwaters and Lakenheath seems to hold up under investigation. Moreover, the credibility of the accounts is increased by the number of redundant radar and visual con- tacts made coincidentally. The table on page 62 summarizes these re- dundancies, which are seen to be present primarily for events No. 4 and 5 (Bentwaters URE-UFO No. 4 and the Lakenheath UFO). One slightly disturbing aspect of these contacts is that the Laken- heath RATCC radar operators failed to "pick up" Bentwaters UREs 1 through 4, even though they should have been well within range. (A target at 5000 ft, for example, should have been visible anywhere west of the coastline in the vicinity of Bent- waters). Note that URE No. I was headed almost directly at Laken- heath at the time it was lost by Bentwaters GCA. Of course, it is possible that the radar did pick up these objects and that, for various possible reasons, the operators did not notice or report them. Conclusions In conclusion, with two highly redundant contacts-the first with ground radar, combined with both ground and airborne visual observ- ers, and the second with airborne radar, an airborne visual observer, and two different ground radars- the Bentwaters-Lakenheath UFO incident represents one of the most significant radar-visual UFO cases. Taking into consideration the high credibility of information and the cohesiveness and continuity of ac- counts, combined with a high degree of "strangeness," it is also certainly one of the most disturbing UFO incidents known today. Bibliography 1. Condon, E. U., Project Director, and D. S. Gillmor, Editor, "Scientific Study of Unidentified Flying Objects," Bantam Books, New York, 1968. 2. McDonald, J. E. (1970), "UFOs over Lakenheath in 1956," Flying Saucer Review, Vol. 16, No. 2, pp. 9-17. 3. Thayer, G. D. (1970), "Radio Re- flectivity of Tropospheric Layers," Red. Sci., Vol. 5, No. 11, pp. 1293-1299. 4. Wait, J. R. (1962), "Electromag- netic Waves in Stratified Media," Per- gamon Press, Oxford, pp. 85-95. IN 64Approved For Release 2001/04/02 : CIA-RDP81 R00560R00010O&$ .AIeronautics