IBM Haifa Research Lab has developed an aircraft assignment system for El-Al Israeli Airlines using IF/Prolog with Constraint Technology Package.

This project was aimed to save operational costs and reduce the use of hired airport authority parking slots which are heavily priced.

The system is connected on-line to EL-Al's scheduling system and is updated in real time as to flight schedule changes. El-Al owns a dozen parking slots with different characteristics. Some of them are suitable only for certain types of aircraft maintenance activities, there are constraints on whether passengers up/download can be performed on specific parking slots.

The solvers run is limited to a couple of minutes, and different strategies where used in order to quickly converge on a good solution.

The system was develped on NT and is operational for more than 6 months.