ATS Route Designators and Usage in voice communication

As per ICAO Annex 11 basic designators for ATS routes shall consist of a maximum of 6 alpha numeric characters as per the rules defined below. Route designation includes type of route: high/low altitude, specific airborne navigation equipment requirements (RNAV), aircraft type using the route primarily or exclusively.

Basic designator of ATS route contains one of the letter from alphabet followed by number from 1 to 999. These letters may be:

A, B, G, R these letters are for routes which form the part of regional networks of ATS routes and are non-RNAV routes
L, M, N, P these letters are for routes which form the part of regional networks of ATS routes
H, J, V, W these letters are for routes which do not form part of regional networks are are non-RNAV routes
Q, T, Y, Z these letters are for routes which do not form part of regional networks

If applicable one supplementary letter shall be added as a prefix to the basic designator as follows:

K to indicate a low level route established for use primarily by helicopters
U to indicate that the route or portion therof is established in upper airspace
S to indicate a route established exclusively for use by supersonic aircraft during acceleration/deceleration and while in supersonic flight

These prefixes are pronounced as:

  • K : Kopter
  • U : Upper
  • S : Supersonic

Where applicable, a supplementary letter may be added after the basic designator of ATS route as suffix as follows:

F to indicate that on the route or portion thereof advisory service only is provided
G to indicate that on the route or portion therof flight information service only is provided
Y for RNP1 routes at and above FL200 to indicate that all turns on the route between 30 and 90 degrees shall be made with the tolerance of tangential arc between the straight leg segments defined with radius of 22.5 NM
Z for RNP1 routes at and below FL190 to indicate that all turns on the route between 30 and 90 degrees shall be made with the tolerance of a tangential arc between the straight leg segments defined with radius of 15 NM

These letters F, G, Y, Z are not required to be used in voice communication.

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