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Aitor the range, . to detect its - 115 - .. PROBABLE CAUSE On the basis of the foregoing findings of fact and upc. all of the evi- dence arailable at this time, we find that the probable cause of the accident to aircraft NC 16086 (United's s Trip 16). on November 4, 1940, was the malfunc- tioning of the Salt Lake radio range and that substantial contributing fac- tors to the accident were: (1) The failure of the communications operators at Tintic, Plymouth, and Salt Lake City, Utah, whose duty it was to malfunctioning and immediately notify those, concerned; and (2) The failure of the pilot of Trip 16 to follow to the fullest extent established radio range technique in accordance with the requirements of the procedure established by United and approved by the Civil Aeronautics Adminis. tration. RECOMMENDATIONS We present the following recommendations pertaining to safety in air navigation with respect to most of which we understand the Administrator of Civil Aeronautics to have already initiated action, Radio Range Transmission We recommend that a study be made by the Civil Aeronautics Administra- tion of the components of the Salt Lake City range in order to determine the reason for the demonstrated effects of particular atmospheric conditions upon the functioning of the range; and that the knowledge gained from such study be used to improve the stability of the Salt Lake range and any other range where similar conditions exist.
