4 Airline Crew Scheduling

Crew scheduling can be defined as the problem of assigning a group of workers (a crew) to a set of tasks. The crews are typically interchangeable , although in some cases different crews possess different characteristics that affect which subsets of tasks they can complete. Crew scheduling problems appear in a number of transportation contexts. Examples include bus and rail transit, truck and rail freight transport , and freight and passenger air transportation. There are many common elements to all of these problems, including the need to cover all tasks while seeking to minimize labor costs, and a wide variety of constraints imposed by safety regulations and labor negotiations. Nonetheless , each application also has its own unique characteristics and its own research challenges. In fact, most crew scheduling research focuses on a particular application, rather than the general case. In this chapter, we focus on the airline crew scheduling problem. [For additional details on crew scheduling in the railway industry we refer the reader to Caprara et al., 1998 and for crew scheduling in mass transit systems to Wilson, 1999.] There are a number of reasons for focusing on airlines. First, they provide a context for examining many of the elements common to all crew scheduling problems. Second, the airline problem is truly a planning problem in the sense that airlines typically have a fixed schedule that changes at most monthly. Therefore, substantial time and resources can be (and are) allocated to solving it. Third, airline crews receive substantially higher salaries than equivalent personnel in other modes of transportation; the savings associated with an improved airline crew schedule can be quite significant. Finally, a large number of restrictive rules, mandated both by the FAA (or equivalent governing agencies for non-U.S. carriers) and strong labor unions, greatly restrict the set of feasible solutions, making airline crew scheduling one