Operational Control (OPC), Fire Service 121.6 MHz and Data Link

This page provides information on OPC, Fire Service 121.6 MHz and Data Link communications which are not classified as ATS and whose frequency assignments fall within a similar category.

Operational control (OPC) and operational control communications are defined by ICAO and are intended to be used for the exercise of authority over the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of the flight.  Such communications are normally required for the exchange of messages between aircraft and aircraft operating agencies.

Aeronautical Radio Stations

Operational Control (OPC) aeronautical radio stations are typically established and operated by airlines operating scheduled and charter flights for passengers and cargo transportation; airport and aerodrome operators; companies, organisations and individuals who either operate their own aircraft or provide maintenance facilities for other aircraft; airport ground handling agencies and flight training organisations.

Frequency assignments for OPC aeronautical radio stations are generally assigned on a non-protected basis and are shared between users so as to provide an efficient use of the aeronautical radio spectrum.

OPC frequency assignments may also be used to provide frequencies for use by aeronautical radio stations which do not fall within any other category of aeronautical radio station operation and do not require a protected frequency assignment and are not used for any Air Traffic Service purpose.  These may include such purposes as aircraft flight test, radio or radar equipment trials, search and rescue or other non-Air Traffic Service communications.


Fire Vehicle 121.6 MHz

Aeronautical radio stations, comprising mobile and portable radio equipment, are typically established and operated by an aerodrome fire service providing direct radio communications with aircraft on the ground for use during a declared emergency.

The requirements for the provision of radio equipment operating on 121.6 MHz are contained in CAP 168 Licensing of Aerodromes Chapter 8 Rescue and Fire Fighting Service (RFFS), paragraph 23 Communications and Alerting Systems.

The frequency assignment 121.6 MHz is assigned on a non-protected basis and is shared between users so as to provide an efficient use of the aeronautical radio spectrum.

Please note that applications for the ANO approval of fire service communications an 121.6 MHz are dealt with by the relevant Air Traffic Standards Regional Office.


Data Link

Aeronautical Radio Stations

Aeronautical radio stations for data link communications are generally established and operated as a network of stations providing a variety of data link services to aircraft over a wide geographical area.  In the UK networks are operated by either ARINC Incorporated or Société Internationale de Télécommunications Aéronautiques (SITA).

Data link frequency assignments are granted in accordance with an ICAO plan and are not shared with any other aeronautical radio stations providing analogue voice communications.

Air Traffic Standards Regional Offices manage the approval processes for the Air Traffic Service Providers associated with the ARINC Incorporated / SITA Data Link services.  More information can be found in CAP 670 ATS Safety Requirements in Part C, Section 1, COM 04 ATC Datalinks.