• CAA opens fourth call period for EU funding claims to 30 September 2018 – see 'Applying for EU funding' section below.

    8.33 kHz radios and frequency conversions

    From 1 January 2018 if you need to communicate on an 8.33 kHz channel you will need to use an 8.33 kHz capable radio. To find out if a ground station has changed to an 8.33 kHz channel please refer to the AIP supplement index. This is updated monthly.

    More VHF channels are needed to increase aviation radio capacity. This will be achieved by moving to 8.33 kHz channels which will create significantly greater availability for the future across Europe.

  • Throughout 2018 ground services will be converting to 8.33 kHz. The conversion date will be decided by each individual ground station. Frequency conversions will be contained within an AIP supplement for the duration of 2018.  Pilots should ensure they are familiar with the latest content of the AIP, including supplementary information each time they fly. 

    Data in the AIP supplement titled 'Transition of frequency assignments to 8.33kHz voice channel spacing' will be updated on a monthly basis in line with the AIS publishing schedule. The supplement can be directly accessed through the NATS AIS website: AIP supplement index 

    Once any ground station or service on your planned flight converts to an 8.33 kHz channel, you must only communicate using an 8.33 kHz capable radio.

    Note that we can also provide the data in spreadsheet format. Please contact us to request a copy.

    Any questions should be directed to the CAA: 833VCS-radios@caa.co.uk

    The law changed on 1 January 2018 when Implementing Rule (IR) 1079/2012 came into force. The UK CAA has chosen to implement this as detailed below, providing more flexibility to those that are struggling to equip with 8.33 kHz capable radios.

    • From 1 January 2018 if you need to communicate on an 8.33 kHz channel you will need to use an 8.33 kHz capable radio. 
    • From 1 January 2019 if your flight mandates carriage of a radio, then it must be 8.33 kHz capable. This rule overrides all others.

    The UK leaving the EU will not affect the implementation of this new legislation. 

    IR 1079/2012 states that from 1 January 2019, all ground services will be operating on 8.33 kHz channels.

    Ground services across the UK will be converting to 8.33 kHz channel spacing at different dates throughout 2018, mostly driven by their annual licence renewal date.

    If a ground service is still using a 25 kHz frequency then you can still communicate with it using a 25 kHz radio.  Once a ground service has converted, aircraft must utilize an 8.33 kHz capable radio to communicate with it.

    In practice, you can only continue to fly with just a 25 kHz radio if throughout your entire flight you only need to communicate on 25 kHz frequencies.  Note, you must check regularly to confirm that your ground services have not converted.  The CAA expects that most ground stations will have converted well before the end of 2018.

    After 1 January 2019, use of a 25 kHz radio will very restricted, principally to only the emergency frequency of 121.5 MHz.

    Common sporting frequencies will continue to operate on 25 kHz for a limited period until 31st December 2018.

    These frequencies are set out in CAP 1606: Exempted Common Channels in the UK.

    25 kHz frequencies end with: 00, 25, 50 or 75.


    An 8.33 kHz channel will have a 6 digit channel ending: 05, 10, 15, 30, 35, 40, 55, 60, 65, 80, 85 or 90.


    If an aircraft radio can tune to 8.33 kHz channels then it is suitable. Radios are backwards compatible so an upgraded radio can communicate on both 8.33 kHz channels and 25 kHz frequencies.  Ground station requirements are contained within CAP 670 COM02.8.


    Pilots are advised to consider safety implications and ensure they are appropriately equipped for each flight. If a radio is unable to display or tune to any required assignment it should not be used to try and communicate with that ground service. 

    Existing radio equipage rules remain the same, circumstances and airspace that do not mandate the carriage of a radio will continue.  However, to ensure situational awareness, equipage of a radio is highly recommended.

    Pilots are advised that it is best to be equipped before ground stations begin to convert in 2018.

    Throughout 2018 ground services will be converting to 8.33 kHz. The conversion date will be decided by each individual ground station. Airspace users are strongly advised to ensure they use up to date and accurate information before flying and follow any instructions given by units. Once any ground station or service on your planned flight converts to an 8.33 kHz channel, you must only communicate using an 8.33 kHz capable radio.

    There are a number of options for purchasing and installing equipment in time for the 8.33 kHz changeover deadline, including a number of ways the installation design approval can be simplified. Implementing Rule (IR) 1079/2012 says that radio equipment put into service after November 2013 should be 8.33 kHz voice communications system (VCS) capable and manufacturers must ensure radios placed on the market from this date meet this requirement.

    Backwards compatibility

    Users are reminded that new 8.33 compatible radios will retain the capability to communicate with existing 25 kHz ground stations before conversion takes place.

    Dual radios and existing 25kHz systems

    Aircraft will need to be equipped with the number of 8.33 kHz capable radios required by operational rules. So where the carriage of two radios is required, both radios must be 8.33kHz VCS capable.

    Non-commercial operations fall under Part NCO which does not include a requirement for aircraft to carry dual radios. But owners are advised to check the relevant regulation to their own operations in order to establish what is required.

    Existing 25kHz radios can be left installed provided that they are only used for exempted frequencies, such as the emergency frequency.

    Technical Standards Order (TSO)/European TSO (ETSO)

    Following an agreement between EASA and the FAA, each organisation now mutually recognises TSO/ETSO approvals for certain aircraft products, which includes VHF radio communications equipment. In Europe there is no longer a requirement for a manufacturer to separately approve a piece of equipment that holds a TSO; the equipment can be installed and used as if it has the corresponding EASA approval. Further details on the scheme are at EASA website.

    The CAA holds a list of common equipment, and the EASA and FAA lists can also be accessed online.

    LA3 approved equipment

    In certain circumstances the use of a LA3 approved 8.33 kHz radios may be appropriate. The CAA has issued an approval for handheld devices that meet certain stipulations.

    Pilot owners should obtain confirmation from the manufacturer that their radio meets the conditions of the Approval. Once confirmed, the pilot may then use the Equipment Approval LA301075 as the reference when applying to the CAA for their Aircraft Radio Licence, which is required by the Wireless and Telegraphy Act. We are aware of the following 8.33 kHz handheld radios that meet the specified requirements:

    • ICOM IC-A6E
    • ICOM IC-A24E
    • Yaesu FTA-550
    • Yaesu FTA-750
    • Yaesu FTA-450

    This is not an exhaustive list: there may be other models that meet the requirement. Above are those currently identified to the CAA by manufacturers.

    EASA aircraft

    Minor change: EASA aircraft can achieve a minor change approval to enable the replacement of a VHF radio. Minor changes can be approved by EASA and a radio manufacturer will often seek approval for a modification through EASA. The approval can then be re-distributed by the manufacturer to enable the minor change approval to be used by another individual. As the approval would be aircraft type specific, avionics manufacturers may hold minor change libraries for distribution to aircraft owners, licensed engineers and maintenance organisations.

    CS-STAN: Certification specification for standard changes and standard repairs (CS-STAN) is a new EASAspecification that enables owners of non-complex aircraft to benefit from a quicker approval process for the installation of certified avionics that includes VHF radios. CS-SC001a 'Installation of VHF voice communication equipment' enables, under certain conditions, the replacement of a radio through this route that can be used:

    • To exchange radio equipment on VFR/IFR aircraft.
    • For initial-installation of radio equipment for VFR aircraft only.
    • CS-SC001a does not include antennas. More detail is available from EASA.

    Broadly, CS-STAN approvals are applicable to aircraft operating under VFR that meet the following conditions:

    • Certified EASA aircraft below 5700kg.
    • Certified EASA helicopters below 3175kg.
    • Motor sailplanes, sailplanes and lighter than air types.

    Non-EASA/CAA-regulated aircraft

    Minor modification: Non-EASA aircraft can receive an equivalent to the above EASA Minor Change through a CAA minor modification approval.

    CS-STAN equivalent: CAA has provided a process to enable use of CS-STAN on non-EASA/CAA-regulated aircraft through publication CAP1419.

    Your aircraft maintenance organisation should be contacted for further guidance about installation and design certification.

    We have been encouraging GA aircraft owners to purchase 8.33 kHz radios as early as possible and secured EU funding to cover a 20% rebate on radio and associated equipment purchases. The scheme includes support for the purchase of handheld units which may offer an equipage option for some airspace users.

    The Innovation and Networks Executive Agency (INEA) awarded €4.3 million of EU funding for the CAA to use to assist the transition of aircraft to use 8.33 kHz voice communications. The funding will be distributed to aircraft owners or pilots to contribute toward the cost of new radio equipment.

    The CAA has negotiated an extension to the EU Funding scheme and a fourth and final call period is now open. This will close on 30 September 2018 and supports the impending change of law on 01 January 2019 where, if your flight mandates carriage of a radio, then it must be 8.33 kHz capable.

    View the detailed eligibility criteria and funding application form

    For more information on funding see our 8.33 kHz funding application page.


  • Updates

    We have negotiated an extension to the EU Funding scheme and a fourth call period is now open. This will close on 30 September 2018 and supports the impending change of law on 01 January 2019 where, if your flight mandates carriage of a radio, then it must be 8.33 kHz capable.

    Updates on the 8.33 kHz implementation project for GA will be published on this webpage.

    To keep up to date with developments you can sign up for alerts through our Skywise system, which offers targeted alerts on news and information from across the CAA. You can access this system through a free app, email or website. For more information on Skywise, to download the app or sign-up for alerts via email go to http://skywise.caa.co.uk/

  • A number of ground stations have converted to 8.33 kHz and this will continue to grow throughout the year. Visiting aircraft must be equipped with 8.33 kHz radios in order to communicate with these assignments. Failure to operate the correct equipment could place aircraft operators and other airspace users in danger, and could result in enforcement action from the CAA.

    Facilities including North Weald, Oxford, Popham Southampton and Southend have already converted or are soon to convert: a full list of converted ground stations is available in the current version of the AIP Supplement. NATS AIS has indicated that they will not be able to ensure that all requested changes will be made to the AIP in good time. Airspace users should therefore consult the supplement in conjunction with the AIP and be aware that other sources of information may be out of date.

    Emergency and Fire frequencies

    The Fire frequency (121.600) will remain 25 kHz for the time being, and ground stations are not required to take any action. Users will be notified in due course regarding this assignment.

    The Emergency frequency 121.500 will not change.

    IFR flying

    IFR flyers are required to ensure that the relevant sections of their flight plans are updated and strongly advised to ensure that they are appropriately equipped. 8.33 kHz equipped flights must confirm equipage in their flight plans in accordance to the guidance set out by Eurocontrol. If using software such as Sky Demon, ensure that the 'profile' of the aeroplane is up to date as this data is used when submitting a flight plan through such platforms.
    IFR flight plans may be rejected due to incorrect equipage in converted sectors, or a state's FIR if flying abroad.

    Ground station conversion process

    Ground station licence holders are encouraged to contact the CAA frequency manager 8-10 weeks before their radio licence renewal is due, to ensure that relevant coordination can take place and the appropriate paperwork can be raised.

    CAP 1573 - Technical information for ground stations has been updated to highlight the importance of ensuring that appropriate safety assurance is completed and to clarify the required changes for aeronautical information. This publication also notifies that ground station licence holders need not submit AIP changes or NOTAMs as all changes will be included as they are processed by the CAA in the AIP supplement mentioned above.

    Radio licence fees for ground stations are set by Ofcom but managed on their behalf by the CAA. The design of the scheme results in reduced bandwidth assignments attracting lower licensing costs. Conversion to 8.33 kHz channel spacing therefore leads to reduced licence costs, but it should be noted that Administered Incentive Pricing is a separate activity to 8.33 kHz conversion.

  • More detail and technical information

  • ECfunding