The advantages of a standardized avoidance manoeuvre as distinct from a late collision avoidance manoeuvre are discussed with reference to passenger comfort. The general use of plan type displays suggests the possibility of having a standard manoeuvre based upon turning one aircraft on to a new heading.

An analysis of this manœuvre was undertaken in order to obtain data as to the closest permissible approach between pairs of aircraft on various collision courses. Results show that the permissible closure is smallest if the faster of the two aircraft is manœuvred, and that little is gained by changing the heading by more than 30°. The results of this type of analysis can assist also in the programming of the computer in a future automated A.T.C. system.