The Route per State Overflown (RSO) distance tool is an application allowing airspace users to calculate the chargeable distance of a flight plan and obtain an estimate of the route charges they will incur when operating flights within the EUROCONTROL charging area.
For a standard installation under Windows and in order to ensure that the tool uses the latest area boundaries download the below file “Charge Area Boundary Model.txt”, copy and replace it in C:\Program Files\Eurocontrol\RSO Distance Tool\4.0 folder.