Carl Westin

6-4 Method Study 1 125 Velocity vector Protected zone Safe zone Intruder aircraft Controlled aircraft Red no-go zone Yellow no-go zone QS OM F IGURE 6-2: Right angle conflict with heading band SSD shown for QS. The SSD’s impact on controllers’ conflict solving was expected to influence both their consistency and agreement by amplifying a particular solution in case of asymmetrical conflicts and different aircraft parameters. As such, for asymmetri- cal conflicts (Study 1), the SSD makes the biased solutions more salient (e.g., by visualizing a larger safe zone) For symmetrical conflicts (Study 2) with no biased solution, a preferred biased solution is not available. 6-4-3 Traffic scenarios and designed conflicts Scenarios and conflict parameters are provided in Table 6-2. Four baseline traffic scenarios, each with a specifically designed conflict, were created. Rotations were used to ensure that solutions would not be influenced by the recognition of repeated scenarios. Different conflict geometries were arbitrarily chosen, each consisting of a crossing between two aircraft occurring approximately in the center of the sector. All geometries were biased, meaning that aircraft parameters were not reciprocal and therefore mathematically favored a certain solution. For example, for the con- flict in Scenario 1 (shown in Figure 6-2), the closest point of approach (CPA) occurs when OM is 2.6 nmi behind QS. In terms of least additional track miles the optimal solution would be to vector OM right to go behind QS. However, additional traffic present in the sector restricted this solution and instead favored vectoring QS to the right ahead of OM. For each scenario, the following solutions were expected: • Scenario 1: vector QS to the right ahead of OM. • Scenario 2: vector PA left, or increase speed, ahead of RG. • Scenario 3: vector RG left ahead of SM. • Scenario 4: vector QS right ahead of PA.