Carl Westin

98 Automation transparency effects 5-5 Method 5-5-1 Participants The study used a sample of nine Swedish air traffic controller trainees (three females and six males, mean age 26 years) with their basic training completed and one year on-the-job training remaining. All had undergone the entire training together as part of the same student group. Participation was voluntary. Trainees were chosen because earlier empirical research has shown that the SSD benefits novices more than experienced controllers. 102 Furthermore, while active controllers have been used in a previous study, 101 this study sought to investigate whether conformance effects applied to trainees as well. The strategic conformance of decision support may be less effective with inexperienced novices who lack well-developed problem- solving styles after which conformance can be modeled. 155 5-5-2 Simulator The ATC simulator environment and scenarios were programmed in Java with an OpenGL binding for the graphics. It provided a classic plan view display, providing a top-down sector presentation similar to current ATC. The simulator ran on a laptop connected to an external monitor with a resolution of 1600 x 1200 pixels. To reduce simulation time and induce additional time pressure, the simulation was increased to 2x real speed. Aircraft plots were updated every second to simulate a 1 Hz radar update frequency. 5-5-3 Task There were two main tasks: 1) direct traffic off-track (light grey aircraft) to their as- signed sector exit points (indicated on their electronic label), and 2) ascertain traffic separation (5 nmi horizontally). Participants interacted with the SSD, by means of mouse and keyboard, to control and communicate with aircraft. The SSD represen- tations used a nominal propagation method for which future state values (position and trajectory) were calculated by a simple projection of an aircraft’s current state into the future, without factoring in uncertainty and without intent information (no flight plans, just state-based vectoring). In addition, a decision aid provided partic- ipants with conflict resolution advisories. Advisories were plotted within the SSD representation. Because flight level changes were not possible, conflicts had to be solved by using heading, speed, or combinations thereof. There was no wind or other weather phenomenons affecting traffic.