Where en route air navigation services are provided to airspace users, States divide the airspace falling under their responsibility into charging zones.
But what precisely is a charging zone?
An "en-route charging zone" is a volume of airspace for which States establish a single cost base and a single unit rate. This “en-route charging” zone extends from the ground up to, and including, upper airspace. A Contracting State is permitted to establish a specific zone for a complex terminal area, after consultation with airspace user representatives.
Charging zones may evolve to be consistent with air traffic control operations and services, after consultation with airspace user representatives. They may extend across the airspace of several States .
In each charging zone, there is full transparency on how charges to be paid by airspace users are established and collected.