Project Blue Book file, RB-47, July 17, 1957

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

There is reason to believe that the "unidentified" target that appeared on the scopes of the Duncanville radar sporadically between 10:48Z and 10:56Z may have been American Airlines Flt. #966. This flight from Los Angeles, via El Paso, was scheduled to arrive at the Dallas Airport (Love Field) at 6 a.m. CDT, which would be 11:00Z. If the flight was on time on July 17, the aircraft would have been making its approach to Love Field at approximately the time that Duncanville reported its "unidentified" target. Since the weather conditions were good, and pre-dawn traffic is light, Flt. #966 should have been on schedule, but 14 years after the fact it is not possible to locate original records to confirm or deny this speculation.

Recall that the RB-47 flight crew reported that the visual object (light) was located northwest of Dallas/Ft. Worth, and Duncanville confirmed this approximate location for its unidentified radar target. Love Field is situated northwest of Dallas.

The original Airborne Observer's Report has a question which asks whether the flight crew saw any other air traffic. Chase reported that he saw no other traffic and he recently re-confirmed this in response to my query. Yet if F1t. #966 was approximately on schedule there would have been at least one other aircraft in the Dallas area at the time.

If the unidentified radar target noted by the Duncanville radar was indeed Flt. #966, the explanation for its brief disappearance from the scopes at 10:50Z and subsequent re-appearance is understandable by examination of the coverage patterns of the multiple beams of the radar. (See Appendix A) At such time as Flt. #966 came within roughly 5 miles of the radar, the airliner would no longer be illuminated by any of the beams. Depending on the airliner's approach path, it could have passed through this zone of no-illumination twice if it made an outbound/inbound approach and landing--finally disappearing for good as it descended for its landing.

If the landing lights of Flt. #966 were the "visible UFO" which the RB-47 flight crew saw northwest of Dallas, and which was over-flown at 10:50Z, it seems certain that this particular airliner could not have been the "visible UFO" seen by the RB-47 crew at 10:39Z which prompted them to change flight plan and head toward Dallas/Ft. Worth.

Any attempt to identify the source of this light 14 years after the incident is a hopeless task, especially for an investigator who is not familiar with possible groundbased light sources in that region, such as industrial facilities, oil refineries, etc.

## IN SUMMARY:

The real crux of this UFO case is whether the source of the S-band signal, which had all of the characteristics of a CPS-6B/FPS-10 radar, did in fact come from such radars located near Biloxi and Duncanville, or whether the signal was being radiated by an airborne object/craft.

IF the signal was being radiated by an airborne craft, there are only three possibilities:

1. A U.S. aircraft: It makes no sense for the U.S. to go to the expense and trouble of building a CPS-6B like radar and mounting it on an aircraft. If the purpose were to mimic enemy jammers, to train our own air defense radar operators, there are far simpler and less expensive ECM equipments available for that purpose. The RB-47 UFO case file contains a letter dated Oct. 30, 1957, signed by Capt. Edwin H. Mammen of Air Intelligence, in reply to a query from Project Blue Book,