Preferential Bidding System

Preferential bidding system, or PBS, is a computer program for crew scheduling, a method of solving airlines workforce schedules consisting of specific flights and certain qualified crew members while allowing those crew members to request periodic work schedules using weighted preferences. The solution must be as efficient as possible while respecting crew member preferences, honoring seniority, conforming regulations, and operation coverage requirements.

Work schedules in the airlines industry must cover not just a shift or a day, as workers in other industries might. Airlines work schedules consist of assignments called "crew pairings" or simply "pairings", which is a sequence of flights or legs that starts and then ends at the same domicile. Pairings are usually created by another computer program called pairing optimizer.

The process of requesting a certain schedule is called "bidding". Generally this is done on a monthly basis. The monthly schedule called "line" which a crew member gets will consist of a series of "pairings". Each month the airlines crew planning sets the new pairings due to new locations being added or removed, new times, or changes in aircraft. These new pairings are then made available for assignment or bidding. In the United States, crew members are often working under a union's collective bargaining agreement, and sometimes including non-union workplaces, seniority is used to give senior crew member the right to override junior crew member requests. A line itself must also satisfy legal and contractual constraints. Ideally it should also satisfy the crew members choices and preferences.

Each month, airlines crew planning must generate legal crewing solutions. These crewing solutions strive to achieve a minimum-cost of operation by matching specific aircraft, the routes they fly and crew pairings in a manner that each leg is covered by one crew that is capable of flying that aircraft at that time and in that place. The factors that must be respected when assigning a crew member line are called "constraints" which include:

These include:

There are three general approaches to solving this complex crewing challenge: Assigned Lines, Bid lines and PBS.

In the Assigned Lines approach, the properties of the line, and days off are simply managed via the use of constraints to build "legal" lines. The optimizer finds the most efficient use of the pairings and reserve assignments. A crew member will have no bidding or preferences.

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