SUMMARY THE AIRBORNE SYSTEM OlX?ratiOnabfU!tional requirements (from navigation using enroute aids to navigation using approach guidance) are examined for the transitional phase of an aircraft flight. In this paper the automated navigation system (based nominally on enroute aids) and the ILWMLS system capabilities are described, and the complementary nature of each is treated. To achieve the full potential benefits of proposed landing system operations, it is suggested that on-board enroute navigation systems will be an important aid to exploit fully the resulting operational capabilities. Proposed microwave landing system capabilities suggest new operational procedures for predefmed maneuvers in the terminal area such as close-in captures and complex approach paths. These operational procedures, although only partially available at this time, can be expanded upon based on the operational advantages of the system. Equipment configurations are presented to demonstrate the system requirements.