When the UK left the European Union, aviation was one of the most complicated areas to untangle. The UK had been operating under EASA rules for decades. Overnight, that changed.
The good news is that the UK did not start from scratch. The Civil Aviation Authority (CAA) took the existing EASA regulations and made them part of UK law. So on day one after Brexit, the rules looked almost identical.
But that was 2021. It is now 2026, and the two systems have started to drift apart.
What stayed the same
The core structure of aviation regulation in the UK is still recognisable to anyone who worked under EASA. The UK adopted EASA’s Part 145 for maintenance organisations, Part M for continuing airworthiness, Part 66 for certifying staff licences, and Part 147 for training organisations directly into UK law at the point of Brexit.
The terminology, the forms, and the general approach are all similar to the EASA versions you already know. If you have spent your career working under EASA rules, the UK CAA framework will feel familiar, because it started from exactly the same place. The key word is “started.” The two systems have been diverging since 2021, and that gap is the focus of the rest of this article.
What has changed
The UK CAA is now making its own amendments independently of EASA. This means the two rulebooks are no longer identical and the gap is growing over time.
Some of the key differences that have emerged include changes to acceptable means of compliance, updates to guidance material, and differences in how certain approvals are processed. The UK CAA has also introduced its own versions of documents that previously came from EASA.
For organisations that operate across both the UK and EU, this creates a real compliance challenge. You are now effectively managing two separate regulatory frameworks that look similar but are not the same.
What this means for MROs
If your organisation holds both a UK CAA Part 145 approval and an EASA Part 145 approval, you are already dealing with dual oversight. Two sets of audits, two sets of requirements, two approving authorities.
The practical impact shows up in documentation, in training requirements for certifying staff, and in the way you manage your exposition and procedures. What satisfies one authority does not automatically satisfy the other.
Organisations that are managing this with spreadsheets and paper systems are finding it increasingly difficult. The administrative burden of dual compliance is significant.
What this means for CAMOs
A UK CAMO approval is issued by the UK CAA. An EASA CAMO approval is issued by an EASA member state authority. If you manage aircraft that operate in both jurisdictions, you may need both.
For operators who previously held a single EASA approval that covered everything, the post Brexit world means more applications, more oversight, and more paperwork.
The Form 1 change: small document, big implications
One of the most practical changes Brexit created for MROs is the airworthiness release certificate, what the industry knows as Form 1.
A Form 1 is the document that says a part has been maintained or manufactured to approved standards and is fit to be installed on an aircraft. Every component that comes off a workshop bench needs one to be legally installable.
Before Brexit, UK Part 145 organisations issued an EASA Form 1, which was accepted everywhere in the EASA system. After Brexit, UK CAA approved organisations issue a CAA Form 1 instead. The layout is near identical and only the authority block at the top is different. But the regulatory wrapper around it is where the real complexity sits.
Here is what that means in practice depending on where your organisation sits:
UK based MROs need UK CAA Part 145 approval to issue a CAA Form 1. If you also want to release parts onto EU registered aircraft, you need a separate EASA Part 145 approval as a third country organisation. That means two audits, two sets of fees, two manuals, and two sets of ongoing surveillance. The same engineer doing the same job on the same component may need to decide which approval they are working under before issuing the form.
EU based MROs releasing parts to UK customers face the mirror image. You need a UK CAA third country Part 145 approval on top of your EASA approval to issue CAA Form 1s for UK registered aircraft.
US and other third country MROs faced the most visible disruption. Before Brexit, the EU and US bilateral agreement let FAA approved repair stations issue an EASA Form 1, and the UK accepted it. That arrangement ended on 1 January 2025. From that date, US repair stations releasing parts onto UK registered aircraft need a UK CAA Part 145 approval and must issue a CAA Form 1. Over 700 US shops applied for approval. Those that did not can no longer legally release parts into the UK system.
Stock, traceability, and component pools
Parts released on an EASA Form 1 before January 2021 remain valid permanently. They do not need to be re certified. So you will still see legacy EASA Form 1s in service for years. The cutover only applies to new releases.
In practice this means MRO stores need to track which form a part came in on, because it determines which aircraft register it can be installed on. A part with a CAA Form 1 can go on a UK registered aircraft. A part with an EASA Form 1 can go on an EU registered aircraft. Getting this wrong is a traceability and airworthiness issue.
For airlines and lessors running shared component pools across the UK and EU, this has become a standing operational headache. A wheel that comes back from overhaul has either a CAA Form 1 or an EASA Form 1, not both. Pool managers either need workshops with dual approval so they can choose which form to issue at the point of release, or they need to segregate stock by destination registry.
Lease returns have also become more complex. UK registered aircraft accumulate CAA Form 1 paperwork during their UK life. Getting them re certificated for an EU register at end of lease involves additional inspection and documentation work that did not exist before Brexit.
How SAM helps MROs manage this
SAM supports the creation of multiple release certificates from within the same system. An MRO engineer can generate a UK CAA Form 1, an EASA Form 1, or an FAA 8130 release document depending on the aircraft register and customer requirement, without switching systems or maintaining separate paper trails for each authority.
This matters practically because the choice of which form to issue is not always made in advance. It depends on the aircraft, the customer, and sometimes the specific work order. Having all three available in one place, with the correct authority details and traceability information automatically populated, removes a significant source of error and rework.
SAM also supports importing external CAMO work orders directly into the system, either manually or using AI assisted import. For MROs receiving work packages from multiple CAMOs operating under different authorities, this means incoming work orders can be brought into SAM quickly and accurately without manual re entry, regardless of whether the originating CAMO is working under UK CAA, EASA, or another framework.
Learn more about how SAM can help you and your Organisation with your GA operations
The practical takeaway
The UK CAA and EASA are not the same anymore. They are heading in the same general direction but via different paths. Organisations that treat them as identical are taking a compliance risk.
The Form 1 change is a good illustration of why. The document looks almost the same. The process of issuing it looks almost the same. But the approval you need, the aircraft it can be installed on, and the authority that will accept it are all different depending on which version you issued.
For MROs operating across both frameworks, the answer is not more paperwork. It is a system that handles the distinction automatically so your engineers can focus on the maintenance work rather than the administrative wrapper around it.
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