Heuristics to solve the integrated airline crew assignment problem

Article Info Abstract Keywords: air transportation airline crew assignment combinatorial optimization heuristics A typical problem related to airline crew management consists of optimally assigning the required crew members to planned flights for a given period of time, while complying with a variety of labor regulations, safety rules and policies of the airline. This problem, called crew assignment problem (CAP), is of the NP-Hard class. So, it is usually divided into two independent subproblems, crew pairing problem (CPP) and crew rostering problem (CRP), modeled and solved sequentially. This division does not provide a global treatment to the CAP in terms of total cost and quality of the final solution. The state of the art involves the integrated solution of CAP, with both subproblems (CPP and CRP) solved simultaneously. It still requires high computational effort. Its combinatorial nature makes it difficult (or even impossible) to be solved by exact methods. The methodology proposed in this research provides an integrated solution of the CAP with heuristic procedures. The methodology was tested to solve instances related to small and medium-sized Brazilian airlines. The results were also compared with those obtained through an exact model adapted from the literature. Introduction This paper presents the main results of a research addressed to solve the crew assignment problem (CAP) with a proposed heuristic procedure. The importance of this type of approach is given by the combinatorial nature of the problem, which turns it impossible to be solved through exact models for large instances. The proposed heuristics presented results equal to or better than those obtained by exact models for the tested instances related to small and medium-sized Brazilian airlines (up to 894 flights and 36 crew members), with reduced CPU times (less than 5 seconds). Exact models led to feasible solutions in instances with up to 656 flights and 20 crew members. The CAP treated in this paper is defined as the problem of assigning the required crew members of the same category (only technical crew, in this case) to a set of flights of a given aircraft type, such that it minimizes the total cost of the aircrew, taking into consideration the proper legislation and the satisfaction of the crew members. CAP has been decomposed in the literature into two subproblems, both of which are solved sequentially: crew pairing problem (CPP) and crew rostering problem (CRP). The CPP seeks to provide an optimal set of pairings …