Rationalisation of Class F Airspace in the UK FIRs

Within the UK Flight Information Regions (FIRs), Class F is specified for UK Advisory Routes (ADRs). International Civil Aviation Organization (ICAO) Annex 11 states that where an air traffic advisory service is implemented, this is normally considered as a temporary measure. Five existing ADRs will be disestablished into two; five will be partially disestablished and partially redesignated as Class E+ Transponder Mandatory Zone (TMZ) airways; and four will be redesignated as Class E+ TMZ airways.