A two-stage mixed integer programming approach for optimizing the skill mix and training schedules for aircraft maintenance

This paper presents a two-stage mixed integer programming approach for optimizing the skill mix and training schedule at the aircraft maintenance company Sabena Technics. Of course, when all workers are trained for all skills, cheaper workforce schedules are possible. However, the training that is required to acquire all those skills can become very expensive. In the first stage of our two-staged approach, we therefore make a trade-off between the training costs and the resulting cheaper workforce schedule. As we assume that workers are unavailable to work during their training, the obtained result is only applicable in practice if the required training can be performed without endangering the current maintenance operations. In the second stage, we therefore want to find an optimal and feasible training schedule in order to obtain the desired skill mix with minimal costs. We illustrate our models with a computational experiment based on real-life data of Sabena Technics.