We use necessary cookies to make our website work. We'd also like to use optional analytics cookies to help us improve it.
For more information, please read our cookie policy.

UK – EU Transition, and UK Civil Aviation Regulations

To access current UK civil aviation regulations, including AMC and GM, CAA regulatory documents, please use this link to UK Regulation. Please note, if you use information and guidance under the Headings below, the references to EU regulations or EU websites in our guidance will not be an accurate information or description of your obligations under UK law. These pages are undergoing reviews and updates.

Applicants who require approval for equipment to be installed in EASA aircraft should make an application for a European Technical Standard Order Authorisation (ETSOA), which must comply with Part 21, Subpart O and the relevant ETSO Standard(s) (CS-ETSO).

Applicants that require approval of equipment to be installed in non-EASA aircraft should apply for a UK CAA national approval (British Civil Airworthiness Requirements (BCAR) Approval). Equipment that meets an ETSO may also be installed in non-EASA aircraft and does not need additional national approval.

European Technical Standard Order (ETSO) authorisations (European approval)

All ETSO Authorisations are prefixed with one of the following:

EASA.21O. (ETSO Authorisation)

  • This is an Authorisation (approval) issued for an EU manufactured piece of equipment.

EASA.IM.21O. (ETSO Authorisation for Import)

  • This is an Authorisation (approval) issued to a manufacturer from a non-EU Member State. In addition, before EASA can issue an ETSO Authorisation for Import (under Part 21, Subpart O), EASA must have an 'Arrangement' with the exporting Authority.

General information and a complete listing of ETSO Authorisations (issued) can be found on the EASA website.

Joint Technical Standard Order (JTSO) Authorisations (European approval)

JTSO Authorisations that were issues by the UK CAA are prefixed with one of the following:

CAA.O. (JTSO Authorisation)

  • This is an Authorisation (approval) issued for a UK manufactured piece of equipment, which complies with JAR-21, Subpart O and the relevant JTSO Standard (JAR-TSO).

CAA.N-O. (JTSO Authorisation for Import)

  • This is an Authorisation (approval) issued to a manufacturer from a non-JAA Member State, which complies with JAR-21, Sub-subpart N-O and the relevant JTSO Standard.

In addition, before a JAA Authority could issue a JTSO Authorisation for Import (under JAR-21 Sub-subpart N-O), the JAA must have had an 'Arrangement' with the exporting Authority (as required by JAR 21N5). The UK CAA had such an Arrangement with the following non-JAA exporting Authority:

  • Federal Aviation Administration (FAA) in the United States of America.

General information and a complete listing of JTSO Authorisations (issued) can be found on the JAA Website.

There are currently five other National Aviation Authorities (NAAs) within the JAA which are able to issue JTSO Authorisations. Country and approval number prefixes are as follows:

  • Austria - 'ACG'
  • France - ‘F.‘
  • Germany - ‘LBA.‘
  • Italy - ‘ENAC.‘
  • Sweden - 'LFV'

Aircraft equipment approved in the United Kingdom or originally approved in the United Kingdom now supported by EASA under Grandfather Rights, falls into the following categories indicated by the approval numbers prefixed by the following letters;

British Civil Airworthiness Requirements (UK national approval)

Radio Equipment

WR (Wireless Receiver)

Equipment manufactured in the United Kingdom approved for use in any UK registered civil aircraft. Applicants must demonstrate compliance with BCAR A4-10. This category may also be used for equipment manufactured outside the United Kingdom, where the manufacturer is a CAA approved organisation.

Close WR (Wireless Receiver)

VC (Validation Certification)

Equipment manufactured in countries other than the United Kingdom or ex-military equipment approved for use in any UK registered civil aircraft. Applicants must demonstrate compliance with BCAR B4-10.

Close VC (Validation Certification)

LA (Light Aircraft)

The prefix LA is followed by the Class in which the equipment is approved. 'LA1' for Class 1 and 'LA3' for Class 3.

Class 1

equipment is without operational restrictions and may be used for VFR and IFR flight in any airspace, provided that it has adequate frequency coverage and number of channels for the particular area in which the aircraft is to operate. It may also be used for any of the purposes specified for Class 3.

Class 3

communication equipment may be used outside controlled airspace under VFR and IFR, to communicate with airfield ATCs where it is not a condition of use of the airfield that R/T equipment be carried, or for communication with the Flight Information Region Controller. It may also be used within controlled airspace under special VFR or under Special entry/exit lane procedures. Class 3 navigation equipment may only be used outside controlled airspace under VFR or IFR, or 'Special VFR' within controlled airspace.

NB: For equipment installed in aircraft not exceeding 5700kg

Close LA (Light Aircraft)

G (Glider)

Equipment for use in any motorless aircraft, self launching or self-sustaining gliders.

This may generally be interpreted to include balloons, hang gliders, microlights and other sporting and recreational aeronautical communications.

NB: For equipment installed in aircraft not exceeding 5700kg

Close G (Glider)

MIS (Miscellaneous)

Non-flight operational radio equipment. Such approvals may be subject to limitations on operational usage and may apply to individual applicants and specific aircraft only.

Close MIS (Miscellaneous)

Airframe Parts and Equipment

E (Equipment)

An 'E' approval is granted for equipment (other than radio apparatus) to UK Manufacturers. Applicants must demonstrate compliance with BCAR A4-8.

Close E (Equipment)

AR (Appliance Registration)

An 'AR' approval is granted for equipment (other than radio apparatus) to non-UK Manufacturers. Applicants must demonstrate compliance with BCAR B4-8.

Close AR (Appliance Registration)

SA (Safety Acceptance)

An 'SA' approval is issued when it has been shown that the equipment presents no hazard to an aircraft.

It should be noted that Safety Acceptance of cabin service equipment by the CAA does not imply acceptance of the item's performance, efficiency or its serviceability.

Close SA (Safety Acceptance)

Provide page feedback

Please enter your comments below, or use our usual service contacts if a specific matter requires an answer.

Fields marked with an asterisk (*) are required.

Latest from UK Civil Aviation Authority

  1. UK Civil Aviation Authority update on ATOL Reform consultation
  2. 2022 quarter one flight data
  3. Continued focus on change for GA Team

View all latest news