Analysis of Long-Range Air Traffic Systems: Separation Standards — I

Abstract

This paper was first published in Volume 19, p. 88, in 1966. Parts II and III were included in following issues of the Journal. The paper is Crown Copyright and is reproduced with the permission of H.M. Stationery Office. It is followed by comments from Stanley Ratcliffe.The main task of air traffic controllers is to plan traffic flows so that aircraft are allotted sufficient separation to absorb not only systematic differences in speed but also the imperfections of navigation and piloting, which we term flying errors. To this end, they usually work with three separation standards, to be applied in, respectively, the along-track, across-track and vertical dimensions of space. The separation standard for any one dimension is the minimum intended (i.e. planned) separation permitted in that dimension when the intended separations are less than standard in the other two. The problem is to choose standards which are safe enough, but not so large as to lead to unnecessary traffic delays and deviations.