Carl Westin

6-3 Towards a conflict solution framework 123 6-3-3 Solution geometry classification The solution geometry classification is derived from an exocentric assessment con- sidering a solution’s resulting spatial geometry. It acknowledges that a conflict so- lution is based on the relationship between two or more aircraft and their constraints as they evolve over time, rather than on discrete information about aircraft state and position. 229 The first DS identifies the resulting spatial relationship between the conflicting aircraft. Only four alternatives exist, with aircraft A situated behind B, B behind of A, A above B, or B above A. Note, however, that each relationship can be framed in two ways. For example, vectoring aircraft A ahead of B is considered the same as vectoring aircraft B behind A. The resulting relationship can be framed as aircraft A situated ahead of B, alternatively as aircraft B situated behind A. Im- portantly, this stage disregards number of interactions, aircraft choice, and which aircraft that is controlled. 6-3-4 Mutually exclusivity and consistency At the highest decision stage, the three classifications represent three contrasting perspectives of conflict solving for which consistency is affected differently. For example, consider the following repeated situation: a right angle conflict between aircraft A and aircraft B, solved once by vectoring A left behind B, and once by first vectoring B to the right and then vectoring A to the right so that B passes behind A. The solution parameter hierarchy defines the two solutions as different because in the first situation only aircraft A was interacted with, while in the second situa- tion both aircraft were interacted with. The control problem classification initially disregards number of interactions (only considers the first interaction) and specific aircraft choice, meaning that the first solution is considered the same the second solution. In both situations, one aircraft is vectored behind the other. According to the solution geometry classification, however, these two solutions would create two different geometries: one with aircraft B in front of A, and the other with aircraft A in front of B. However, there is one exception for which the classifications overlap so that a participant can be found consistent according to all three. This occurs when two (or more) solutions are identical according to the first two DS in the solution pa- rameter hierarchy. Say, for instance, that both solutions consisted of vectoring A left behind B. According to the control problem classification this would be defined as a consistent control action (always behind). According to the solution geometry classification the same spatial relationship has been accomplished in both solutions.