Abstract
While scheduled air transportation has been immeasurably aided by the provision of radio-direction facilities on the fixed airways, interruption of scheduled flying is still the rule whenever the landing field lies in an area completely inclosed by fog. The results secured by the development of instrument flying and of radio navigational aids to point-to-point flying are then nullified through the lack of means for safe landing under adverse conditions of visibility. The rigorous maintenance of scheduled flying by day or night requires the removal of this last great hazard to the reliability of air travel and transportation. This paper describes a radio system of blind landing aids, developed by the Aeronautics Research Division of the Department of Commerce at the National Bureau of Standards, which gives good promise for the solution of this difficult problem. The results already obtained with this system indicate that it will soon be ready for use under the severe conditions encountered in commercial air transportation. The system has been developed to be adaptable for use in conjunction with the radio navigational aids already being provided for point-to-point flying on the civil airways of the United States, and for this reason requires a minimum of additional equipment both on the ground and on the airplane.
