Definition
Sets of published Air Traffic Service (ATS) routes that are organized and designated for use within a specific geographic region of the world, as opposed to routes that cross between regions. Within ICAO's route designator system, regional networks are identified by a basic letter (A, B, G, R) for conventional routes or (L, M, N, P) for area navigation (RNAV) routes.
Plain English
Groups of official airway routes that stay inside one part of the world, like Europe or North America, rather than crossing between regions. They get their own set of identifying letters when named on charts.
Context Anchor
Seen in instrument procedure and airway-designator discussions, especially when explaining why certain route names begin with certain letters.
Derivation
‘Regional’ comes from Latin regio, meaning ‘a defined area or district.’ ‘ATS’ stands for Air Traffic Service. So the phrase literally means ‘networks of air traffic service routes that belong to a defined area of the world.’
Why Pilots Care
The first letter of an airway designator tells you whether the route is regional or crosses between regions. Recognizing this helps a pilot quickly understand the scope and category of the route they are flying.
Intuition Check
Do not read “regional network” as an informal group of nearby routes. Here it means an officially organized set of Air Traffic Services routes within a defined region.
Example Sentence 1
Airways beginning with A, B, G, or R are part of the regional networks of ATS routes used for conventional navigation.
Example Sentence 2
Designators in the handbook identify individual segments inside these regional networks of ATS routes.