Source: EUROCONTROL
Airways designators:
- A, B, G, R — for routes which form part of the regional networks of ATS routes and are not area navigation routes;
- L, M, N, P — for area navigation routes which form part of the regional networks of ATS routes;
- H, J, V, W — for routes which do not form part of the regional networks of ATS routes and are not area navigation routes;
- Q, T, Y, Z — for area navigation routes which do not form part of the regional networks of ATS routes;
- K — low level routes established for use by helicopters;
- U — the upper airspace route;
- S — a route established for use by supersonic aircraft;
- F — Advisory service available only;
- G — Flight Information Services available only;
- Y — for RNP1 routes at or above FL200;
- Z — for RNP1 routes at or below FL190.
The above mentioned description relates to the classic airways network structure which are part of the European Airways Network ( maps 2, 3, 4 ). Map no. 1 shows the airspace where Free Route Airspace has been implemented. The idea of this kind of network is to let the airlines plan their routes between particular entry and exit points. Depends on availability, it’s also possible to plan the route via intermediate points without need to follow the particular airways. Some of the countires had already implemented mentioned structure, in some others it’s possible to use FRA in some periods of the day only.