UFO Encounter II, Sample Case Selected by the UFO Subcommittee of the Aiaa.

Read from the scan by GLM-OCR; expect the odd misread word.

# Approved For Release 2001/04/02 : CIA-RDP81R00560R000100010010-0

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The AIAA now malntalns 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 Speakers 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.

--which would preclude targets that enter the radar's normal "blind zone" (if it has one).

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--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 almost 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 complicated, stop-and-go maneuvers described by the Lakenheath nightwatch 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 aircraft 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 effects, 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 observed 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 detection of an apparently stationary target while the radar was on MTI is not as surprising as it seems. A vibrating 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 contacts made coincidentally. The table on page 62 summarizes these redundancies, 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 Lakenheath 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 Bentwaters). Note that URE No. 1 was headed almost directly at Lakenheath 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 observers, 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 accounts, 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 Reflectivity of Tropospheric Layers," Rad. Sci., Vol. 5, No. 11, pp. 1295-1299.

4. Wait, J. R. (1962), "Electromagnetic Waves in Stratified Media," Pergamon Press, Oxford, pp. 85-95.