Visual Search in Complex Displays: Factors Affecting Conflict Detection by Air Traffic Controllers

Abstract

Recent free flight proposals to relax airspace constraints and give greater autonomy to aircraft have raised concerns about their impact on controller performance. Relaxing route and altitude restrictions would reduce the regularity of traffic through individual sectors, possibly impairing controller situation awareness. We examined the impact of this reduced regularity in four visual search experiments that tested controllers' detection of traffic conflicts in the four conditions created by factorial manipulation of fixed routes (present vs. absent) and altitude restrictions (present vs. absent). These four conditions were tested under varying levels of traffic load and conflict geometry (conflict time and conflict angle). Traffic load and conflict geometry showed strong and consistent effects in all experiments. Color coding altitude also substantially improved detection times. In contrast, removing altitude restrictions had only a small negative impact, and removing route restrictions had virtually no negative impact. In some cases conflict detection was actually better without fixed routes. The implications and limitations of these results for the feasibility of free flight are discussed. Actual or potential applications include providing guidance in the selection of free flight operational concepts.

Measuring Sector Complexity: Solution Space-Based Method

“…Previous research on sector complexity showed that the aircraft intercept angle [27,28,29], speed [27] and horizontal proximity [3,16] are some of the variables that are responsible for the sector complexity. The goal of the present study is to systematically analyze the properties of the SSD due to changes in the sector design.…”

“…Based on previous researches, the ability of the controller to ascertain whether or not an aircraft pair will lose separation (more commonly known as conflict detection) is affected by a variety of variables that include, but are not limited to, the convergence angle [27,28,29]. However, previous research also found that conflict angle as a factor affecting conflict detection ability, is often confounded with speed [27].…”

Effects of aircraft trajectories geometrical features upon air traffic controllers' conflict judgments

“…In consequence, conflict judgments reflect the performance (and biases) of the visual system. If the latter is proved to be quick, holistic and resistant to disruption, it also has its own limits concerning extrapolation of current situations [9,10]. Moreover, in ATC judgments integrate additional margins, in order to cope with data uncertainty and contingencies [11].…”

ATC-lab: An air traffic control simulator for the laboratory

“…Examples include investigations of prospective memory (Stone, Dismukes, & Remington, 2001) and of the effects of time demands and attentional demands on operator information processing load (Hendy, Liao, & Milgram, 1997). Other researchers have used mediumlevel ATC simulators to isolate key variables needed in the study of applied problems-such as controller performance in free flight (Metzger & Parasuraman, 2001;Remington, Johnston, Ruthruff, Gold, & Romera, 2000). Most of these ATC simulators are generally flexible in the number and type of aircraft presented, what is displayed on aircraft data blocks, the temporal (e.g., onset time) and spatial (e.g., angle and speed) properties of aircraft events, and the types of responses that participants are required to make (e.g., detect conflicts, control traffic/avoid separation loss, hand-off aircraft).…”