Carl Westin

A-1 Introduction 185 Solutions parameter Intervention time Aircraft choice Resolution type Direction Directional value Description Time after scenario start that conflict aircraft are interacted with. Aircraft interacted with. Type of resolution command. Direction of resolution type. Value of resolution command. Measure Seconds (s). Aircraft call sign. Heading (H); Speed (S); or Combination of H and S (C). Heading right (R); Heading left (L); Speed increase (I); Speed decrease (D); Combinations (RI); (LI); (RD); or (LD). Deviation from original state value in degrees heading, knots speed, or combination. F IGURE A-1: Solution parameter framework If excluding intervention time, the initial solution parameter is aircraft choice . To solve the conflict, the controller will choose one aircraft to interact with. Even if both aircraft are interacted with, one will be chosen first. Next is the resolution type , which refers to the general category of control maneuver(s) chosen: heading, speed, or a combination of both. Note that vertical and time control (i.e., issuing an aircraft to reach a specific position at a certain time) maneuvers are not included as they (for reasons of experimental control) are not available in the simulation. The third step in the framework further defines the resolution type by assigning direction . A turn, for example, can be made either left or right. In the final step, the exact directional value of the conflict resolution is determined by the deviation from the aircraft’s current directional value. For instance, aircraft A may be turned 30 degrees to the left to solve the conflict. Note that these four solution parameters later were defined as decision stages 2 to 4 in the Consistency study (the first decision stage being defined by three different solution classifications). Controllers’ solution variation was expected to increase for each lower step in the solution hierarchy. For example, while a large number of controllers may choose aircraft A for solving the conflict, they may opt for different resolution types. A few controllers may prefer to solve the conflict by turning aircraft A to the right, in contrast to the majority who to turn it left. A third group may solve the conflict by speed, issuing either a speed increase or reduction.