The aeronautical fixed service (AFS) is a telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air services. [1] ("Air service" means any scheduled air service performed by aircraft for the public transport of passengers, mail or cargo. [2]) The AFS is provided by voice and data networks, including AFTN, AMHS and CIDIN. [3]
However, any aeronautical radiocommunication between specified fixed points belongs – in accordance with article 1.20 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – to the Fixed service. [4]