Carl Westin

196 Solution Space Diagram approaching. The color coding indicates time to separation loss, with the red color indicating less time than the orange color. B-3 Using the SSD For a given aircraft, the SSD provides the conflict areas, and conflict-free areas, imposed by surrounding traffic. Provided all intruder aircraft maintain their speed and heading, any velocity vector (of the controlled aircraft) placed outside the no-go areas implies safe passage. For example, in Figure B-3, all three velocity vectors point to go areas that ascertain conflict-free flight paths. In real life, however, con- trollers’ are often very selective of the velocity vectors given. Several parameters are known to affect this decision, such as the deviation required from the intended flight path, rules of the air, and environmental factors (e.g., wind direction and strength). 29 Moreover, internal (subjective) parameters are known to influence conflict solutions, such as controllers’ training, experience, strategies and preferences, and physical and psychological states. 25, 29, 80 B-4 Towards higher degrees of automation A number of broadly accepted taxonomies of human-automation system control have categorized levels of automation (LOA), from fully manual to fully automatic. Sheridan and Verplank’s automation model proposed in 1978 is generally consid- ered the first LOA taxonomy. 44 Parasuraman et al. proposed a LOA continuum, independently crossed with four stages of human information processing they cat- egorized as: information acquisition: information analysis, decision selection, and ! go area go area no-go area no-go area Current velocity vector magenta blue red F IGURE B-3: The current position of the velocity vector indicate a conflict with another aircraft. Any velocity vector (magenta, blue, or red arrow) would ascertain safe separation, all pointing to conflict-free ares (white space).