Pilot Actions during Traffic Situations in a Free-Flight Airspace Structure

One facet of the proposed restructuring of the National Airspace System currently generating much interest is called ‘Free Flight’. At the heart of the Free Flight system is an increased flexibility in pilot decision making and responsibility for the definition and maintenance of separation, of preferred routes and speeds, and the conduct of maneuvers in response to potential conflicts and other emergencies in the airspace. Here, we describe a simulation experiment where fifteen commercial pilots were presented with traffic conflict situations in the en route environment. Within the scenarios we manipulated density, type of conflict, and relative bearing of conflict aircraft. Pilots were required to navigate a simulated 757 aircraft to destination airport, avoiding all possible traffic conflicts. Their ability to maintain separation was the principle dependent measure. Results indicated that density and bearing did not appear to have any substantive effect on pilot response. However, overtaking conflicts produced a higher frequency of operational errors than crossing or converging conflicts. Further analysis of individual pilot responses revealed different strategies. Analysis of individual overtaking scenarios revealed patterns of pilot action associated with efficient and often creative conflict resolutions. An example of an inefficient conflict resolution was also identified.