FedEx generates bid lines using simulated annealing

We built a bid-line generator to help Federal Express perform what-if analyses of work rules during contract negotiations with ALPA, the bargaining unit for the company's pilots. The objectives were to minimize both the number of bid lines produced (a measure of required manning) and the amount of flying not assigned to bid lines (flying requirements that must be accommodated during subsequent phases of scheduling). The tool was useful in negotiations since it was automated and easily modified in-house to provide quick responses to bid line what-ifs. Using a two-step process, the tool produces a complete set of legal, flyable lines for an airplane fleet and identifies the remaining open (unscheduled) flying. First it uses simulated annealing to find as many good bid lines as possible; then it uses a greedy heuristic to complete as many more lines as possible.