Approaches to solve the fleet-assignment, aircraft-routing, crew-pairing and crew-rostering problems of a regional carrier

This paper presents the results of a research project funded by a regional carrier operating inter-island services within the Canary Islands (Spain) in addition to services to Morocco and Portugal. It operates between 100 and 150 flights a day using three airline operators. The main scope of the project was to solve fleet-assignment, aircraft-routing, crew-pairing and crew-rostering problems on real-world data. The special characteristics of the carrier, flying between 7 am and 11 pm every day, have motivated us to design models and algorithms that are different than the ones addressed in the literature, typically built for large airline companies. This paper shows a solution approach for an integrated fleet-assignment, aircraft-routing and crew-pairing problem covering the flights of a single day. This is a new combinatorial problem that can be considered as a 2-depot vehicle routing problem with driver changes, where the vehicles represent aircrafts and the drivers represent crews. Adapting approaches from the vehicle routing literature, this paper describes a heuristic algorithm based on an integer programming model. In a similar way, this paper also addresses the rostering problem. This problem can be decomposed in smaller problems taking into account operators, bases and crew groups. These problems admit a compact formulation through mixed integer linear programming models which can be tracked by modern general-purpose solvers. This paper illustrates the success of our solution approaches on real-world instances. The airline carrier is currently using these approaches.