A little more than 2 years ago, the laboratories of Federal Telephone and Radio Corporation became convinced that their work on radio aids to air navigation and the work of other companies and agencies engaged in this field were sadly in need of co-ordinated systems planning. The instrument landing omnidirectional range, and fixed-course range equipments, developed and manufactured by Federal and affiliate companies during the previous decade, were individually satisfactory, but the relationship of all these aids to each other and to the products made by other agencies appeared to lack basic co-ordination. Under the pressure of war needs and the impetus given to new developments by wartime discoveries, and because of anticipated increase in air-traffic densities, it was apparent that many overlapping plans were being made. As a result, a concentrated effort toward systematic planning was urgently required if the whole art of radio aids to navigation and traffic control was to be saved from chaos.