I know that in the U.S. low altitude airways are called Victor (below 18.000ft, e.g. V123) and high altitude routes are called Jet (above 18.000ft,e.g. J123). Can somebody explain the European airspace routes naming? Thanks!
ATS routes in Europe are designated just like the rest of the world. ICAO publishes guidelines for the designation of ATS routes in Annex 11, which are adopted by almost all countries.
A route will consist of a possible prefix (see below) a letter (see below) and a basic designator (a number between 1-999).
The three types of prefix are:
K (Kopter) to indicate a low-level helicopter route
U to indicate an upper route, available only in upper airspace
or S to indicate a route only used by supersonic aircraft (not very common).
The letters can be:
A, B, G, R for regional routes which are not RNAV routes
L, M, N, P for regional RNAV routes
H, J, V, W for non-regional non-RNAV routes
Q, T, Y, Z for non-regional RNAV routes
In addition, states may add the letters F or G to the end of a route to indicate that the route is in class F or G airspace respectively. To my knowledge, this is not very common (and most ATS routes are in controlled airspace anyway).
KY80 ("Kopter Yankee 8-0)
UN872 ("Upper November 8-7-2)
T54 ("Tango 54")
Your map shows the Czech Republic. By checking the Czech AIP GEN 1.7, we see that they don't list any differences from the standards of the ATS route designators listed in ICAO SARPs Annex 11 Appendix 1.
By contrast, in the UK AIP, it says (emphasis mine):
The majority of ATS route designators have been changed to comply with Appendix 1 requirements.
In plain language: When it comes to airway (ATS route) designators (1 letter and 1–3 digits; additional supplementary letters are not part of the basic designator), ICAO has set standards (as opposed to recommendations) for the world to use. And the Czech Republic uses those standards.
The current groups are:
- A, B, G, R (regional non-RNAV)
- L, M, N, P (regional RNAV)
- H, J, V, W (non-regional non-RNAV)
- Q, T, Y, Z (non-regional RNAV)
A regional ATS route is usually one that passes through more than 1 FIR (usually 1 FIR covers a whole country – out of 151 countries on that list, 116 have 1 FIR, and 28 have 2). And an RNAV route is one that doesn't require external navaids.
You may also find a preceding U (Upper) acting as a supplementary letter to indicate upper-airspace routes (analogous to the US J-airways). Example close to LKKV in your screenshot: