Analysis of observed aircraft-to-aircraft separations

As air traffic demand continues to increase in the coming years, the need for concepts, procedures and tools that can improve airspace efficiency will likewise increase. Reduction of terminal and en-route separation minima has been the focus of many of the concepts and emerging technologies developed to respond to this need. Horizontal separation distances consist of two major elements: lateral separation (i.e. track-to- track) influenced by the spacing of parallel or converging routes and individual aircraft route conformance; and longitudinal separation (i.e. along-track) influenced by both Federal Aviation Administration (FAA) Orders regarding standard separations minima and an additional spacing buffer which reflects controller comfort with position variability and work load. This paper presents the preliminary results of an investigation of current terminal and en-route separations observed on conventional and Area Navigation (RNAV) routes and procedures. This analysis has been undertaken to determine the magnitude of spacing buffers as they are applied today, and then model a future throughput capability that could result from reducing the currently applied separations toward the established minimums.