Optimizing integrated aircraft assignment and turnaround handling

Abstract

Airlines face many different planning processes until the day of operation. The assignment of aircraft to flights is of central importance and is determined by the optimization of the two planning problems Fleet Assignment and Tail Assignment. The competitiveness of the derived flight sequences strongly depends on the Turnaround Handling, which coordinates the processes on the ground between two flights. All of these planning problems have in common that they often need to be reoptimized on the day of execution due to unplanned events. In many cases, this is still done manually with the expertise of airline operators in the airline operations center. In order to automate this process and to find the best possible reoptimization solution, the medium-term aircraft assignments and the short-term plannable turnaround processes should be optimized in a combined manner. For this purpose we provide a new mixed integer program, which considers Fleet Assignment, Tail Assignment and Turnaround Handling. Due to the size of the model, it cannot be solved efficiently as a complete model using available solvers. Hence, we develop a new decomposition algorithm that alternately solves the combined assignment problems and the turnaround model, and projects the turnaround costs into the aircraft assignment’s objective function. In a computational study with realistic airline data, it is shown that for many problem instances this method yields feasible and optimal solutions much faster than comparable benchmark algorithms.