Course planning at Lufthansa Technical Training: Constructing more profitable schedules

Lufthansa Technical Training GmbH (LTT) runs training courses for Lufthansa Technik AG and for several other international airlines. If offers about 670 types of courses of which several hundred take place each year. The course-scheduling problem LTT faces is to develop a schedule for the year that maximizes its profit while meeting complex precedence, temporal, and resource-related constraints. A good operational schedule should also meet a number of subordinate objectives. In the past, LTT did all its scheduling manually. We developed a prototype course-scheduling module, using the operational planning situation of 1996 as our major test instance. It turned out that most of the schedules generated were substantially better than the solution LTT constructed manually, both in terms of profit and computation time. We subsequently developed a fully fledged decision-support system.