Validation projects

Air traffic flow management slot swapping

Release: 2014

Reference: -

Location: Brussels


Slot swapping is a means to reduce the impact of delays on airspace user operations. It is estimated that between 100 and 200 slot swaps take place each day in Europe. With this solution, aircraft operators’ tactical priorities are introduced in a cooperative process with the NM through air traffic flow management (ATFM) slot exchanges made between flights within a single airline company. Both the NM and the airspace user can propose a slot swap.

However it is not always easy to identify which flights would benefit from a swap. This solution offers system support for the slot-swapping process, and makes it possible to carry out multiple swaps for a single flight, thereby splitting the delay assigned to one flight between a maximum of three flights.

Validation results

Exercises simulating European city pairs validated a swapping tool for identifying viable swaps and for allowing multi-swap whereby airspace users could swap the same flight up to three times, and for substituting slots in case of cancellation. Over a 7-week time period, 199 swaps requests were made using the tool with only a 5 % rejection.

The results were as follows:

• At the network level, the additional features offered by the solution were acceptable for the Network Management Operating Centre (NMOC) in terms of workload with no perceived change in the response time to requests;

• Airspace users indicated that the average cost saved per swap was between EUR 4 600 and EUR 4 900, while costs saved per flight varied from less than EUR 1000 euros and more than EUR 10 000.


The validation results for this solution are conclusive and sufficient to support a decision for industrialisation.