Carl Westin

184 Conformance design A-1-1 Creation of a solution parameters framework A conformal resolution advisory was initially intended to be an exact replay of a controller’s conflict solution as recorded in the manual prequel simulation. In the manual simulation, controllers were expected to interact with only one of the aircraft in conflict, and solve the conflict with a single implementation. Furthermore, with the guidance provided by the SSD, controllers were expected to implement solution that would not cause a secondary conflict. However, these initial assumptions were challenged during early test-trials. Controllers solved conflicts in many more ways not foreseen. For instance, they sometimes solved conflicts: • through interaction with both aircraft (i.e., dual aircraft resolution); • only to later change their mind and implement another resolution; • causing a secondary conflict with a noise aircraft. These discrepancies provided a dilemma when using prequel experiment reso- lutions to create conformal resolution advisories for the conformance experiment. Exact replays of controller’s own solution for the same designed conflict were not always possible. The solution to this problem consisted of 1) quantitatively decod- ing solutions in a hierarchy consisting of five parameters, and 2) determining how far down in the hierarchy a workable solution could be found that did not violate the requirements of solving the conflict by at least two interactions and not causing a secondary conflict. For solutions that were changed (e.g., implement one solu- tion only to later change it), only the first solution was considered. The solution parameter framework is shown in Figure A-1. The five solution parameters are considered in a progressive order of conflict solution granularity. The level of solution detail increases when analyzing solutions from top to bottom in the framework. An exception to this rule is the first defining parameter of intervention time (why it is also squared and not in the shape of an arrow-like pentagon). Intervention time is a qualitatively different measure from the other parameters that define an aircraft state change. Intervention time is likely to very considerably between participants because of the precise measurement. Intervention time is an important solution parameter for several reasons. First, given a constant movement of aircraft, the passage of time will constantly change the environment and affect the options available to solve the conflict. A solution is only valid for a limited period of time. Second, the time of observable intervention might not accurately capture the time of conflict detection. For instance, a con- troller might choose to postpone intervention but continue to monitor and generate alternate solutions.