Air-borne radar

SEVERAL AIR-LINE accidents during the winter of 1945–46 focused attention on the need for some means of electronically “seeing” obstacles and avoiding them. At this time there was no satisfactory air-borne radar. Working in close conjunction with an air-line industry electronics laboratory, air-line flight engineering personnel held conferences to decide what operating requirements were needed of an air-borne electronic device to provide simple and easily interpretable cockpit presentation of collision information. The standard polar-plotted information available in the APS-10 radar was selected. The narrow-beam scanning of the APS-4 was used to confine the energy to essentially a narrow horizontal slit in the plane of flight, spilling a minimum amount of energy downward.