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UK Civil Aviation Regulations

These are published by the CAA on our UK Regulations pages. EU Regulations and EASA Access Guides published by EASA no longer apply in the UK. Our website and publications are being reviewed to update all references. Any references to EU law and EASA Access guides should be disregarded and where applicable the equivalent UK versions referred to instead.

Regulation (EU) 376/2014 requires organisations to report with the ADREP taxonomy and an ECCAIRS compatible format. To achieve this, the reporting software solution option has been specially designed for large organisations reporting a significant volume of occurrences and organisations with extended IT technical capabilities who may be capable of developing a compatible report output.

Some of the terminology used in these instructions is aimed at software developers and/or IT departments, and should be used in conjunction with the requirements of the organisation’s Safety Data Department.

Before continuing please ensure you have reviewed these other documents:

  • EU 376/2014, paragraph 16 and Article 7 paragraph 4
  • Guidance Material, paragraphs 3.9 to 3.12
  • CAP 382, Reporting Requirements

The interface

A standard interface to comply with the requirement embedded within a reporting software solution has been created. This interface, or method of Data File Exchange, is the ECCAIRS 5 Exchange file “E5X” file type.

Reduced Interface Taxonomy

The data in an E5X file is based on the Reduced Interface Taxonomy (RIT), a subset of the ECCAIRS aviation taxonomy.

This contains the necessary attributes and values to enable compliance with the regulatory requirements (for example, use of ADREP taxonomy, reporting of mandatory data fields etc) and to convey additional information which may be relevant for enhancing safety analysis and trend monitoring.

The RIT identifies mandatory and conditional mandatory attributes to be completed by the reporter. Through Industry engagement we have identified two of these attributes which have been proving difficult to map against existing entity taxonomies.

We have decided that 'Event Type' (attribute ID 390) and 'Occurrence Category' (attribute ID 430) will be completed by the Authority.

Contents of the E5X file

The format is an XML / XSD specification containing the mandatory data fields and their associated value lists. This specification of the schema and structure of the E5X file is published on the European Commission Joint Research Centre's website - you will need to request an account to access the schema.

Prior to contacting the JRC for your account, you should contact the CAA Safety Intelligence team who will pre-authorise your request with the JRC. Once access has been granted you should navigate to the Electronic Reporting Section and select the E5X Data Files link.

You will be presented with several options leading to downloads which include E5X test files, supporting documentation, XSD Schema's and additional testing software.

Structure of the E5X file

The E5X file to be submitted is constructed and named in a particular way so that ECCAIRS can process the file automatically.

The XML sits in the outer layer of the E5X file alongside a folder of the same name. This folder contains the full PDF (named after the E5X file and folder), and may also contain any additional attachments which can be named independently. See a visual guide of the file structure.

One of the aims behind the introduction of a compliant format and the RIT is to reduce the manual entry of routinely reported attributes into ECCAIRS by Safety Data teams.

To achieve this aim, in addition to the mandatory and conditional mandatory attributes identified in the RIT (other than the two mentioned above), all other attributes which form part of your regular reports and also appear in the RIT are to be mapped into the XML file.

Depending on the aviation sector you are reporting from, certain attributes can be hard coded into your XML. Some of these do not need to appear on the PDF (for example, a report generated by an aerodrome could have the Location ID and State of Occurrence hard coded). All reporters can have the Narrative Language attribute hard coded.


The PDF enclosed in the E5X should contain both the RIT attributes reported in the XML file and those attributes that make up your usual report which are not included in the RIT. Some of the hard coded attributes can be omitted from the PDF.

In order to realise as much of the benefit of automating data entry as possible, effort should be made to highlight attributes on the PDF which are not contained within the XML file. This will speed up their identification for the subsequent manual entry on the report within ECCAIRS.

If the contents of your report is captured completely by the XML file then there is no need to provide the PDF version.

Each initial report and follow up shall be submitted as individual E5X files. Information on what should be reported as part of a follow up can be found on the 'Use of attributes' section of this website.

Close The interface

Submission of the compliant format to the UK CAA

Your email containing the .E5X compliant format shall be structured with:

  • Subject line: Entity name + Report reference + Status (Initial notification / Closed on Issue / Open / Closed
  • Attachments: Only .E5X files shall be attached
  • Body: Report headline (as a minimum)
Close Submission of the compliant format to the UK CAA

Advice and validation

Advice is available on:

  • The creation of the software solution
  • Use of attributes
  • Mapping existing taxonomies
  • Confirmation of mandatory or conditional mandatory attributes
  • What to include in follow-up and final reports
  • Understanding when a follow-up is expected by the authority

Newly developed E5X submissions are required to be validated by the authority. We will confirm the submission can be automatically loaded into ECCAIRS, that any mapping has been completed accurately and that the XML reflects the PDF.

Only after your submission has been confirmed as valid will you be provided with the details of a safety data mailbox to submit your compliant reports into.

Please contact Safety.Intelligence@caa.co.uk for advice on compliant reporting.

Close Advice and validation