Letter from Philip J. Klass to Gordon D. Thayer
4 June 1976

Dear Gordon:

Most interested to receive a copy of your monumental hand-printed work of 5/10 and 5/25/76. These comments must be limited because I am once again working a 7-day week on a special assignment for Aviation Week that has taken me on 5 trips in the past month and will have me sewed up until early July.

Especially interesting were the comments of Perkins in his Aug. 1975 letter to Friedman, comments I presume were the result of Friedman sending him a copy of my chapter on lakenheath. It is clear to me that Perkins is reacting quite "humanly" - a bit embarassed at my pointing out some of the physical impossibilities in his original account of 1967, i.e. being able to see the UFO allegedly circle around behind the Venom using a radar that scans only once every 15 seconds. Understandably he is embarassed since he made such a big thing of the incident at the time - alerting top officials at his own base, getting RAF to dispatch two interceptors, etc. etc. Were I in his shoes, I should now be equally defensive.

But in so-doing, Perkins reveals further flaws in his recollections and in his understanding of the radar he was using at the time - the CPS-5. As you yourself note he refers to "vector scanning" instead of "sector scan".

In Perkins 1967 letter, he is unable to recall even the month in which the incident occurred, but in 1975 he recalls that the "CPS-5 was installed and a new RATCC was started in the control tower building about June 1956, or perhaps before that date." IF his 1975 recollection is correct, then the CPS-5 went into service only shortly before the UFO incident - and it wpould logically then be a new piece of equipment for Perkins and other controllers. Note in 1975 he recalls "there were several problems encountered when we started because the CPS-5 is AC&W equipment and was not designed for [ATCC] use."

In 1975 Perkins says that "I believe the vector scanning and height finding was either disconnected or simply not used after the first month or two."

I doubt that "vector scanning" or "sector scan" was ever used BECAUSE THE CPS-5 DID NOT HAVE EITHER CAPABILITY!! I base this on the Tech Order in my possession, which includes latest revisions through Aug. 31 1957, as well as some of original pages when first printed in May, 1946, plus other revisions in between.

Perkins, embarassed to discover that his slow-scan CPS-5 could not possibly have displayed what he claime he controllers saw, now improvises a solution. He writes (1975) that "The rotation of the surveillance antenna was increased to one revolution every nine seconds." BY WHOM? The CPS-5 as of Aug. 31 1957 Tech Order was still iperating at its original 4 rpm.

Perhaps Perkins and his associates at Lakenheath decided on their own to speed up the scan rate (to better track UFOs if they ever appeared?) and they personally redesigned their CPS-5, went tou and had special gears made locally and modified their radar to make it tyhe only CPS-5 in the USAF inventory to rotate at this unique RPM?? Nonsense! In so doing they would have had a major engineering job. At faster scan rate they would have had to change the pulse repetition rate to permit higher rotation rate without sacrificing long-range target detection. USAF regulations forbid such major design changes since it obsoletes spare parts in logistics supply channels.

In 1975, Perkins improvises to explain why he thought the "other" radar station that called Lakenheath was Sculthopre when we know it was Bentwaters: "I didn't take the original call on the Sculthorpe line so either just assumed it was Sculthorpe or the Bentwaters operator didn't identify which station he was calling from."

But in 1967, Perkins wrote: "I was sitting at the Supervisor's Coordinating desk and received a call on the direct line (actually I'm not sure which line it was.) Anyway, it was Sculthorpe GCA unit calling and the radar operator asked me if we had any targets on our scopes travelling at 4,000 mph. They said they had watched a target on their scopes proceed from a point 30 or 40 miles east of Sculthorpe to a point 40 miles west of Sculthorpe."

If the operator on the other end did not identify who was calling, why didn't Perkins ask?? If the station was Sculthorpe, he ought to look on the northern sectors of the CPS-5 radar displays; and if Bentwaters, he ought to look south of Lakenheath. And if one of the many other USAF/RAF stations, he ought to look elsewhere.

Even if Perkins was so incompetent that he never thought to ask, when he later discovered "mysterious blip" to SW of Lakenheath radar, one would expect him to call back the "other radar" and report his findings. If he called Sculthorpe, they would inform him it was not they who had called earlier and refer him to Bentwaters.

All of these discrepancies become explainable IF Perkins was really on the THIRD SHIFT that night, rather than the SECOND shift as he now believes. Could he have erred here - after 11 years?

First we need to go into the basic "mathematics" of staffing a facility, such as an air traffic control center, that must be operated 7 days/week, 24 hrs/day, with minimum manpower. To do so requires FLOATING, rather than fixed shift assignments. (This I learned from Fed. Av. Admin., and was confirmed by USAF). There are a total of 21 (7 x 3) eight-hour shifts per 7 day week.

With fixed shifts, one would need 3 crews to man control center for 5 days (around the clock) and another 3 crews (total of 6) to operate it on weekends. But the weekend crews would then have to work only 2 days, get 5 days off, while other crews woold work 5 day week, get only 2 days off. Clearly an "unfair" arrangemenmt that wastes manpower. If one goes to a floating shift arrangement one can handle the job with approximately FOUR (4) crews. By floating shift we mean that you work 1st shift today, 2nd shift later in the week and 3rd shift still later. It works a bit of hardship on the personnel involved, but it is the only way to handle such a round-the-clock work arrangement.

IF we assume that lakenheath was using such an arrangement, then Perkins would accurately recall that it was a "night shift" and that he was present for the UFO incident - which began at bentwaters during the 2nd shift and which ended at Lakenheath during the 3rd shift, i.e. overlapping the two night shifts.

IF Perkins was really working the 3rd shift that night, then he would not have been on duty when the original call came in around 9:30-10 p.m. on Aug. 13. This the call would have been taken by his predecessor and this would then explain why Perkins in 1967 thought the call came from Sculthorpe when it really came from Bentwaters.

And if Perkins was on the 3rd shift that night, and if upon arriving around midnight he decided he would initiate a new search (the earlier one by his predecessor having turned up nothing unusual), only to find the "hovering" target SW of the Lakenheath radar, this would then explain why the official reports state that this target was first observed around "14::00:10," i.e. about 10 minutes past midnight on Aug. 14 - and would confirm Perkins recollection that shortly after HE AND HIS CREW BEGAN TO LOOK CLOSELY AT THEIR SCOPES, THEY SAW THE "HOVERING TARGET."

And it would explain why Perkins was "still running things" during the hectic, and extended-time period. after this discovery when he alerted base officials, alerted RAF base, vectored the first Venom, the 2nd Venom etc. etc. IF PERKINS WAS ON SECOND SHIFT, HIS THIRD SHIFT SUCCESSOR WOULD HAVE BEEN CONDUCTING THESE OPERATIONS.

And if this hypothesis is correct, we need not assume that the air intelligence dispatches were in gross error as to the date and the time that lakenheath first discovered "their radar UFOs". I find it more reasonable to believe that these reports, made within several weeks after the incident are more correct as to date and time than would Perkins recollections be some 11 years after the incident - in 1967 - especially since in 1967 he could not then recall the month or even the approximate time of year that the incident occurred.

I appreciate your willingness to concede that URE#3 and URE#4 "were in fact one and the same," reducing the Bentwaters radar-UFOs to three in total. And I recognize that you yourself, in the AIAA article, were prepared to accept the fact that URE#2 (My B-1) was probably a more traditional "angel", following in the pattern of the Borden-Vickers Fed. Av. |Admin, analysis of the 1952 Washington Airport anomalous-propagation radar-UFOs.

The important thing then is that on the night of Aug. 13-14, atmospheric conditions were such that at least one instance of anomalous-propagation radar-UFOs could exist. (As my British radar expert source indicated, A.P. is a serious problem in that region, and August is a peak-A.P.month in the Northern Hemisphere.)

Because the hour is so late (1 a.m.) I will not attempt to consider the other two Bentwaters radar-UFOs, nor the ones at Lakenheath. But when we do consider them, we must remember that the night of Aug. 13-14 was CONDUCIVE TO A.P. angels. UNDER SUCH CONDITIONS, ONE CAN GET PROPAGATION BEYOND NORMAL LINE OF SIGHT RANGES, and radars separated by more than line-of-sight distances, that usually do not pick up signals from one another, can under such conditions pick up pulses that penetrate this "line-of-sight barrier."

Before closing, let me fill you in on the radars from the Tech Orders in hand:

CPN-4: An S-band radar, for airport surveillance, with maximun range of 60 miles. Azimuth beam width (at 3 db.-down points) = 2.3 Vertical beam coverage is cosecant-squared with cosecanting up to 45. Nominal scan rate is 15 rpm. plus/minus 1 rpm - indicating antenna drive is by an induction motor rather than synchronous.

To provide clue to the cosecant-squared shaping, the T.O. quotes following minimum range vs. altitude figures against a T-33 (small jet) target.

At 2,000 ft. altitude, at least 20 naut. mi. range
At 6,000 ft., at least 25 naut. mi.
At 10,000 ft., at least 30 naut. mi.
At 25,000 ft., at least 35 naut. mi.

MPN-11: This is a complete GCA, consisting of the CPN-4 airport surveil. radar PLUS an associated blinding landing radar for talk-down. Latter consists of two fixed antennas, one aligned with runway to provide azimuth guidance while other is angled upward to provide vertical guidance. Each is electrically scanned at a rate of TWO SWEEPS PER SECOND (to answer your question on page 23.) Az. beam scans 10 either side of runway centerline while vertical beam scans through angle of 7 total

CPS-5: L-band, very long range radar, operating at approx. 1.3 gc freq. Antenna is 25 feet wide, 14 ft. high. (You figure beam width - my handy-dandy sliderule is at office and am too weary to compute.) T.O. does not state, but from antenna shape this almost certainly also has a cosecant-squared vertical beam pattern.

IMPORTANT for computing coverage: T.O. says CPS-5 antenna mounts either atop a 25 ft. platform or a 75 ft. tower. No clue as to what was used at Lakenheath.

As to whether there were two or a single T-33 that performed search near Bentwaters, there is the Nov. 7 letter from AF Intelligence, signed by Henry A Miley, to Col. Hoffman, which speaks of search by "a local intercept squadron." And letter from Capt. Gregory of Blue Book to Hynek, Nov. 26, 1956, which says search was conducted by "American airplanes."

T-33 originally was developed as a trainer, to carry instructor plus student. But it quickly became an easy-to-fly jet used by pilots to log flight time to qualify for flight pay and keep up proficiency. If the original purpose of the flight was to acquire flight time, then there would be two aircraft so both pilots could achieve max. flying time for invested hours. But I agree that this point is ambiguous - but not really essential. In any event, we do know that two pilots were vectored to where Bentwaters had radar-UFOs, they performed a visual search, and saw nothing - despite the fact that ground observers had reported seeing "visual UFOs." Clearly if UFOs were visible to ground observers they should have been visible to T-33 pilots.

As to your suspicions that the presence of U-2 at lakenheath may have prompted USAF officers there to try to "cover-up" in their classified, secure report to their superiors, I would simply say there was no need to attempt same. While the true mission of the U-2 was deep secret, the existence of the airplane and the fact that it would be seen flying out of USAF bases around the world was far, far from secret. On Apr. 30, 1956, NACA (predecessor to NASA) put out a press release saying that it would be flying U-2 out of USAF bases around the globe to gather high-altitude weather/gust data to be used in design of future civil and military aircraft. To have even attempted a "cover-up" would have implied that the U-2 had a very secret mission which was contrary to the announced mission - and would have defeated the very intent of the "cover story".

When I come to Boulder, I will bring along my complete "dupe" of the Lakenheath file as obtained from Air Archives. You will be free to make photo-copy of anything I have, including the Tech. Orders.

As for your invitation to do a detailed, intensive investigation on this case, it is my feeling that that might have been done in the fall of 1956 - but 20 years, later the trail is much too "cold" to extract very much if any new data on the case.

It is clear to me from Joint Messageform BOI-485 & IDO 7-3351 (date not shown) which was sent to DIRECTOR OF INTELLIGENCE, USAF HEADQUARTERS, WASH. with copy to Norad and Comdr. in chief of USAF in Europe, that the author of that dispatch concluded that the incident was the result of atmospheric conditions conducive to angels, to the then prevailing meteor shower, and to over-active imaginations.

Note that this dispatch ends by saying that if this conclusion "prove unsatisfactory as to probable nature of sightings, detailed information outlined in Part 1 above will then be required to pursue a more thorough course of evaluation."

There is no evidence in the file that the USAF Hdqtrs. Director of Intelligence then believed that any more thorough investigation was required.

Had I been in his position, knowing what I now know, I would have reached the same conclusion. Case closed!

But I would pose the following question to you: Recognizing that you had scant time during your original U. of C. investigation in 1967-68, IF you found the case so intrigueing and impressive, WHY DID YOU NOT LAUNCH A PERSONAL INVESTIGATION with your own time and resiurces in 1969, 1970 - while the trail was still slightly warm?

If this case had the potential for demonstrating beyond all doubt that there were hypersonic craft of unknown source operating in our airspace, surely that would be a discovery and effort worthy of your spare time. Why have you waited so long?

And on that note - it being past 2 a.m. - I end and take off for slumberland.

Cordially

s/ Phil Klass

cc: Stanton Friedman