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SUR? TDRWT ITA YL Engineering Division kiemorandum Report No, NCREXDeO69) p15) 26 April 199 estinate the distance, size or speed of such objects, and it waild be easy to fail to recognize then. Conclusions € it is concluded by the writer that there are sufficient psychological explanations for the reports of unidentified flying objeots to provide plausible explanations for reports not otherwise explainable. These errorg in identifying real stimli result chiefly from inability to estimate speed, distance and size, Recommendations The following recanmendations are offered: le Test the ability of pilots to estimate the course of a cnall lighted balloon while doing acrobatics with it at night. It is sugrested @ that several pilots try to fly pursuit curves and collision courses on such targets at night and report accurately their sensations, It € would be desirable, but probably impossible, to koep them fran knowing the nature of the light source. rl In all future reports of unidentified objects spooify the location of the object with reference to polar coordinates (direction and cegrees above the horizon) rather than asking individuals to estimate distance. If possible, obtain an estimate of size in terns of the visual angle subtended by the object. de In all future investigations determine the angular position of the sun with respect to the unidentified object and the observer, Also determine the approximate time during which the object was in © Sight (this information was not available for more than half the reports). CONFIDENT LAL dy Declassification Authority: NND 57565