The Taxiway Repair Schedule Problem

After an attack on an airbase, the system of taxiways that connect aircraft shelters or parking areas to the airbase runway may be so damaged that some of the aircraft are not able to reach the runway. In this Note, the Taxiway Repair Schedule Problem is defined to be the problem of finding the optimal sequence for repairing the damaged taxiway sections, assuming that each section has a known repair time and that the sections are repaired one at a time. An optimal taxiway repair sequence minimizes the average time that aircraft have been denied access to the runway. Two procedures are presented for selecting repair schedules: one, a branch-and-bound algorithm, actually determines an optimal schedule, but at a high computational cost (which becomes infeasibly high for a large number of damaged taxiway sections); the second, a heuristic rule, is computationally simple but does not select optimal schedules for all problems. The two procedures are compared for 100 example problems.