What is Electronic Conspicuity?
Electronic Conspicuity (EC) is an umbrella term for the technology that can help pilots, unmanned aircraft users and air traffic services be more aware of what is operating in surrounding airspace. Identifying an aircraft by electronic means involves the use of electronic devices such as Mode S transponders and Automatic Dependent Surveillance-Broadcast (ADS-B).
The information generated by interoperable EC devices can be presented to pilots and air traffic controllers visually, audibly or both to provide them with information on other traffic nearby. EC strengthens the fundamental safety principle of ‘see and avoid’ by adding the ability to ‘detect and be detected’.
ADS-B systems and other technologies enhance aircraft visibility and situational awareness. EC enables the improvement of visibility of airspace users by electronic means and supports the safe and efficient integration of new entrants with existing users into UK airspace. In addition to these benefits, an EC policy will be one of the core enabling policies that will help achieve the AMS ambition for the safe integration of diverse airspace users such as beyond visual line of sight (BVLOS) unmanned aerial system operations, thus supporting the Future of Flight programme.
More information
- Airspace Modernisation Strategy
- Information on EC devices CAP1391
- Information on the licensing and conditions of use of the 978 MHz frequency onboard unmanned aircraft systems.
Consultation Response Document for the Electronic Conspicuity Technical ConOps
We have published our response to the consultation on the Electronic Conspicuity Initial Technical Concept of Operations. This should be read alongside the current ConOps. A public consultation on the implementation of a UK wide EC mandate will launch later this month.
Electronic Conspicuity Initial Technical Concept of Operations
In July 2025, we published the Electronic Conspicuity Initial Technical Concept of Operations. This document sets out our current technical approach to EC and proposes nine key positions on how EC technology can be safely and effectively deployed to improve safety, support innovation, and enable integration across UK airspace.
In October 2025, we closed the formal consultation on this document. We have now published our consultation response, which summarises the feedback received and explains how it will inform the next phase of work.
Consultation feedback will now be used to inform updates to the ConOps, alongside evidence from technical testing and trials planned during 2025 and 2026. Subject to programme dependencies, we expect to publish an updated version of the ConOps in late 2026 or early 2027. Until then, stakeholders should continue to refer to the current ConOps and read it alongside the consultation response document.
Work on a potential UK wide EC mandate
In parallel with the technical work on the EC ConOps, we are also progressing work on the potential implementation of a UK wide EC mandate. The technical and policy elements need to be developed together. A public consultation on the implementation of a potential UK wide EC mandate will launch later this month.
978 MHz Frequency
In March 2025, we published a joint statement with Ofcom that made the 978 MHz frequency available for airborne transmission onboard Unmanned Aircraft Systems (UAS) applications.
In November 2025 we published version 2 of the CAP 1391 Supplementary Amendment for Electronic Conspicuity Devices. This new version includes updates to the licensing conditions on 24-bit aircraft addresses and the differences in SSR Mode A codes for unmanned aircraft with a 978 MHz UAT device.
Electronic Conspicuity Studies 2024
In 2024 the CAA commissioned five interconnected workstream studies to investigate the real-world carriage, use and performance of EC devices. The purpose of the studies was to help inform the CAA what EC can do today, with a final report that will guide the CAA in defining an EC Concept of Operations document.
In July 2025, we published the consolidated report (CAP3139) that brings all five workstreams together with a central set of recommendations for the CAA to consider in the EC ConOps.
This work has been supported by the Department for Transport and directly contributes to the delivery of key objectives within the Airspace Modernisation Strategy and Future of Flight programme, both of which are central government priorities.
Electronic Conspicuity and Airspace Modernisation
In December 2022, we published a joint statement with the Department for Transport (DfT) on the development of a national specification for EC alongside a report commissioned by the DfT from Egis, an independent aviation consultancy .
We have always advocated for the development of a clear national specification for EC and support the recommendations included in the Egis report for aircraft to be equipped with regulated EC devices that meet the proposed specifications. The potential volume and intensity of future air operations in the UK requires a step change in how airspace users safely operate in relation to each other, this EC work is a step towards understanding how that will work and supports the integration of airspace users as described in the Airspace Modernisation Strategy.
Checking your EC Device has a valid declaration
CAP 1391 sets out the expectation that any device using ADS-B on 1090MHz must have a Declaration of Capability and Conformance from the manufacturer before being used onboard an aircraft. The pilot in command of the aircraft is responsible for ensuring that the EC device has a valid declaration.
Declared devices
|
Ref No |
Issue No |
Manufacturer |
Type No |
Category |
|
UK.CAA.DoCC.000001 |
Issue 0 |
uAvionix Inc |
Ping1090-20 |
Basic/transmit only |
|
UK.CAA.DoCC.000002 |
Issue 0 |
uAvionix Inc |
Echo ATT-20B |
Basic/transmit only |
|
UK.CAA.DoCC.000005 |
Issue 0 |
f.u.n.k.e. Avionics GmbH |
ATOM-(000)-(000) |
Basic/transmit only |
|
UK.CAA.DoCC.000006 |
Issue 0 |
f.u.n.k.e. Avionics GmbH |
LPAT-(000)-(000) |
Intermediate |
|
UK.CAA.DoCC.000003 |
Issue 1 |
f.u.n.k.e. Avionics GmbH |
PNLMGE71.stp |
Intermediate |
|
UK.CAA.DoCC.000004 |
Issue 1 |
uAvionix Inc |
SkyEcho |
Intermediate |
|
UK.CAA.DoCC.000007 |
Issue 0 |
uAvionix Inc |
SkyEcho 2 |
Intermediate |
|
UK.CAA.DoCC.000008 |
Issue 0 |
uAvionix Inc |
Ping1090i |
Basic/transmit only |
How to use 24-bit addresses with EC Devices on 1090ES
EC devices use a 24-bit aircraft address (AA), (also known as a hex address) for receiving systems to differentiate them from other EC devices. A unique ICAO 24-bit AA will be allocated as part of an aircraft’s Certificate of Registration. However, as some EC devices are portable and may be used by unregistered aircraft, the 24-bit AA may be programmable by the user. You can find details on how to perform this function in your EC device's operating handbook.
For use on an unregistered aircraft
If you are using a 1090ES EC device with a valid declaration on an unregistered aircraft, you should contact the National IFF/SSR Committee secretary and provide the following:
- Your contact details and UK postal address
- The details for your EC device, including: Make, Model and Serial number
- Brief description of how the device will be used (e.g. on multiple unregistered aircraft)
Where appropriate, the NISC will allocate the EC device a unique ICAO 24-bit AA. Allow 4 weeks for the CAA to allocate a 24-bit AA.
For use on registered aircraft
If you are using your EC device on a registered aircraft with an existing ICAO 24-bit AA, then this address shall be used.
If you need to move the device between registered aircraft, it must be reprogrammed with the new aircraft's ICAO 24-bit AA (as appropriate).
Selling your device
If you sell your EC device, you need to clear any registered aircraft ICAO 24-bit AA before the sale. The new purchaser must contact us with their contact details and we will issue a unique ICAO 24-bit AA if necessary.
How to use 24-bit addresses with UAT EC Devices (978 MHz)
To use a 978 MHz Universal Access Transceiver device on unmanned aircraft in the specific category, operators should ensure the device meets the standards prescribed in RTCA DO-282B/C except that where Mode A codes (squawks) are used for flights in the UK, they should adhere to the UK AIP ENR 1.6
The UAT device must be capable of generating a self-assigned temporary Aircraft Address. These will be pseudo-randomly generated each time the device is switched on as per RTCA DO-282B/C. The device will only generate an AA after a GNSS position has been fixed due to the algorithm requiring time, latitude and longitude to generate the AA. The device must have the address qualifier set to 001 indicating that the 24-bit address is NOT an ICAO address. The CAA will not allocate a permanent ICAO 24-bit aircraft address (ADDRp) to UAT devices.
Whilst duplication of self-assigned temporary AAs is highly unlikely, caution should be advised when switching on multiple devices. Due to the time/latitude/longitude randomiser algorithm, devices should not be switched on within 3 metres of each other within the same second.
Any observed duplication of AAs should be reported to the CAA here.
Ensuring you have the correct WTA License to use an EC Device
To operate any radio equipment, aircraft owners/operators must hold a valid Wireless Telegraphy Act (WTA) Aeronautical Radio Licence. 1090 MHz EC devices are radio-transmitting equipment, so are subject to this regulation.
The WTA usually requires anyone operating a transmitter/receiver, on this frequency, to have or be under the direct supervision of someone who possesses a Flight Radio Telephony Operator's Licence or FRTOL. This was because when this radio licence condition was introduced, it was assumed that all aircraft radio stations would include a voice telephony function.
A General Exemption has been issued so that while a WTA licence is still needed, the pilot need not hold a FRTOL if the transponder is the only radio equipment on the aircraft. However, the WTA licence must be varied formally to remove the need for the FRTOL. Variations are available free of charge. They are available from the on request by completing the form here. You must keep the variation with the WTA licence.
Approved transmitting EC devices will be included under the licensee's WTA licence as standard once notified.
When you buy an EC device, it is the responsibility of the aircraft owner/operator to complete the relevant application form to obtain a WTA Aircraft Radio Licence from Ofcom.
If you are a manufacturer wishing to submit a Declaration of Capability and Conformance go to the Aircraft Equipment page and read CAP 1391.