The characteristics and potential of VOR/DME area coverage capability

This paper describes the characteristics of the common system navigational aids, VOR and DME, as an area navigation system, and discusses methods for using them other than by flying along radials to or from the station. The use of pictorial displays and course line computers, either separtely or in combination, to achieve area navigation capability is distinctly possible. The choice of pictorial display or of the computer or of both will be made on considerations other than accuracy. Justification will have to be based on operational benefits such as least time and distance tracks, altitude availability or on air traffic control benefits. Cockpit space and chart provisioning are major problems in connection with pictorial displays, but can be overcome if cost benefits are sufficient. Flight evaluation in a live-traffic environment of the Bendix-modified Alternate Track VORTAC Computer in a united Air Lines DC-8F Cargoliner is described. Modification consisted of an additional function permitting operation parallel to radiais, in addition to phantom station mode of operation. Results were promising and indicate the track-keeping ability of a parallel course computer is consistent with existing airway criteria with little increase in pilot workload. Significant increases in traffic capacity of the existing airway system is possible with no required increase in number of VOR/DME facilities presently available.