Basic Air Traffic Control System Concepts

The basic need for air traffic control for aircraft and missiles results from the inability of any pilot or missile control agency to digest and handle information concerning many aircraft, even if presented perfectly, since judgment must be centrally controlled. Only in wholly controlled space is separation safely handled, a system necessity. Positive Occupancy systems define occupied space most safely and economically. Area control has uniform application for universal use. The interlocking function to maintain separation can be handled most efficiently and safely by a computer, while trained controllers can expedite most economically with such automatic protection. The flight plan used for control can consist of much more limited data than those for an entire trip, a saving over methods of transmitting full plans with updating. The fundamental basis of presentation of ATC information to the pilot can be simplified by either automatic flag presentations or, for voice, equivalent short phrases. Clear distinction is necessary between the control data and monitoring data, and the two methods should be used as a cross check. Uncontrolled space, with speed restriction, is required for certain users and restricted space is required for others in certain areas. Methods of handling space on an area basis utilize all space with maximum freedom. A universal coordinate system for control has many advantages and can be easily introduced. Aircraft and missile identity numbers can contain useful additional information. Frequency, time, and space assignments are necessary considerations for control communications.