A multiobjective model for maximizing fleet availability under the presence of flight and maintenance requirements

Every aircraft, military or civilian, must be grounded for maintenance after it has completed a certain number of flight hours since its last maintenance check. In this paper, the author addresses the problem of deciding which available aircraft should fly and for how long, and which grounded aircraft should perform maintenance operations, in a group of aircraft that comprise a combat unit. The aim is to achieve maximum availability of the unit over the planning horizon. A multiobjective optimization model is developed for this problem and its application and solution are illustrated by a real life example drawn from the Greek Air Force. Two heuristic approaches are proposed for solving large scale instances of the problem. The paper concludes with a discussion that gives insight into the behavior of the model and of the heuristics, based on analysis of obtained results.