of the problems involved and assumed the job to be easierthan it actually was. sult, the specification of data requirements may havebeen inadequate. As a re- The other groups concerned also as3umedthe job to be routine, and as a result, everyone was inadequately briefed. , . . co, _ The disappointing data from the first shot pointed up the problem and led to corrective measures. Twoplanes furnished sketchy information, starting after the useful photography was completed, and the other two sets of data contained obvious errors and inconsistencies. _ Some of the navigators performed consisten‘ly better than others thereafter, although the data still contain obvious gross errors: one log had the plane remaining in the same position . . for 3 minutes; in other cases the aircraft backed up, went sideways, or ran at 700 miles per hour. It is believed that the navigators did the best job they could, adequate for the routine baer running of the plane, but that the added requirements of this program lec to the sort of human errors that everyone can make when working under extremestress. _ On the last two shots, supporting navigational data were furnished by the Air Operation Center aboard the USS Estes. Comparison of these results with those logged by the aircraft navigatorsshows that the probable uncertainty in distance is of the order of +2 nautical miles, and in angular bearing of the order of +4 degrees. (Extreme discre~ pancies of 26 miles and 14.degrees were actually reported.) — It is believed that the data are generally good as regards distance from plane to ground zero but that the bearings are too poorly known to give any accuracy in triangulating on the cloud. This conclusion, together with the limited photography coverage, restricts the interval of measurement to about the first 10 minutes, before wind drift becomes appreciable. Thus the third, and least important, objective of the program was not satisfied, with the exception of several measurements of stem didmeter at about 30 minutes. The two major objectives, however, were met with reasonable precision. a 16 ” SECRET — ns eeae QaRey ata aS a