Modeling decision-making for vertical navigation of long-haul aircraft

In aviation almost all decisions relate to safety, and most have therefore been proceduralized in order to reduce risk. There are very few decisions that are made on the basis of a value metric such as utility or economic cost. One decision that can be shown to be value-based is the selection of a flight profile. Fuel consumption and flight time have significant effects on aircraft operating cost, but they cannot be minimized simultaneously. In addition, winds, turbulence, and performance vary widely with altitude and time. These factors make it important and difficult for pilots to decide among alternative trajectories. A three-space, three-operation paradigm for decision-making was developed and used as a framework for the analysis of in-flight decision-making. Pilots and dispatchers from several US airlines were surveyed to determine which attributes of the outcome of a flight they considered most important. Avoiding turbulence-for passenger comfort-topped the list of items that were not directly related to safety. Pilots´ decision-making about the selection of a flight profile on the basis of flight time, fuel burn, and exposure to turbulence was then observed. Each pilot´s decisions were compared to those produced by a separately elicited utility model, the airline´s minimum-cost objective function, and a lexicographic behavioral model. Of these decision models, utility maximization is shown to reproduce the pilots´ decisions with the greatest accuracy. Furthermore, the airline´s cost-minimization approach is shown to be inadequate for predicting in-flight decisions. Finally, we propose a decision aid that would present the pilot with attribute-space information (rather than feature-space information) about several pareto-optimal trajectories including minimum cost and maximum utility.