For UK aviation maintenance, repair and overhaul (MRO) organisations, two frameworks often come up side by side: AS9110 certification and UK Part-145 approval. They’re related, but they are not the same thing, and understanding the difference matters when deciding what your organisation needs, and why.
Who Should Consider AS9110 and UK Part-145?
This guide is particularly relevant to:
- UK Part-145 approved maintenance organisations
- Organisations preparing for UK Part-145 approval
- Aircraft Maintenance organisations
- Aerospace OEM maintenance operations
- Component and engine maintenance organisations
- MRO organisations supplying aerospace and defence organisations
- Organisations evaluating whether AS9110 certification would support customer or contractual requirements
AS9110 vs UK Part-145: The Key Distinction
AS9110 is a third-party quality management certification. UK Part-145 is a regulatory approval issued by the UK Civil Aviation Authority (CAA). One demonstrates the strength of your quality management system; the other authorises you to perform regulated maintenance work.
| AS9110 | UK Part-145 |
| Aerospace quality management standard | Regulatory maintenance organisation approval |
| Third-party certification | UK CAA regulatory approval |
| Focuses on the organisation’s quality management system | Establishes regulatory requirements for approved maintenance organisations |
| Part of the IAQG 9100-series | Part of the UK continuing airworthiness regulatory framework |
| Certification through an accredited scheme | Approval and oversight by the UK CAA |
| International aerospace supply-chain recognition | Authorisation to perform regulated maintenance activities |
| Does not replace regulatory approval | Required where UK aviation regulations mandate Part-145 approval |
An organisation may need both, depending on its activities, customers, and contractual requirements.
The UK Regulatory Framework
Following the UK’s departure from the EU, aviation law applicable in the UK is UK law, including retained/assimilated EU legislation as amended by UK legislation. For aircraft maintenance organisations, the key regulatory basis is UK Regulation (EU) No. 1321/2014, as retained and amended in UK domestic law. The CAA publishes the applicable UK versions of this regulation along with Acceptable Means of Compliance (AMC) and Guidance Material (GM).
UK Part-145 approval is based on an organisation’s management, resources, facilities and scope of work as described in its Maintenance Organisation Exposition (MOE). Significant changes to any of these can affect the approval and may require CAA notification or approval.
Where AS9110 Fits Alongside Part-145
AS9110 doesn’t replace Part-145, it complements it. A Part-145 approval holder can use an AS9110-certified quality management system to strengthen:
- Maintenance process control: consistent controls over work instructions, technical data, and operational processes
- Personnel competence: training, authorisation, human factors, and ongoing competence monitoring, alongside UK Part-145’s certifying staff requirements
- Parts and component traceability: identification, status, storage, and control of nonconforming outputs
- Safety management: AS9110’s risk-based approach can
- Compliment the organisation’s Part-145 Safety Management System (SMS), but AS9110 certification does not replace the SMS requirements applicable under UK Part-145
- Document control: supporting the MOE without duplicating or replacing it
Organisations should treat their AS9110 management system and their regulatory (Part-145) arrangements as integrated, not interchangeable. AS9110 certification is not a substitute for CAA approval.
Frequently Asked Questions
Is AS9110 required by the UK CAA?
No. AS9110 and CAA approval are separate. Whether an organisation pursues AS9110 depends on customer, contractual, and supply-chain requirements.
Does AS9110 replace UK Part-145 approval?
No. Where an organisation’s maintenance activities require UK Part-145 approval, that approval must be obtained and maintained separately from AS9110 certification
Can a UK Part-145 organisation benefit from AS9110 certification?
Yes. AS9110 is built for aviation maintenance organisations and is designed to complement existing regulatory and quality arrangements rather than duplicate them.
Does AS9110 apply outside the UK?
Yes. AS9110 is used internationally across the aviation, space, and defence supply chain; the applicable regulatory framework depends on the country and aviation authority involved.
Does AS9110 certification grant aviation regulatory approval?
No. It demonstrates conformity of the quality management system to the standard, it does not grant CAA, EASA, FAA, or any other aviation authority’s regulatory approval.
AS9110 and UK Part-145: Can one replace the other?
No, they serve different purposes:
- UK Part-145 address regulatory approval to conduct specified maintenance activities
- AS9110 address the organisation’s aerospace quality management system
Where both are applicable, they can operate within the same organisational management framework, but AS9110 certification does not confer UK CAA approval.
Next Steps
If your organisation holds or is pursuing UK Part-145 approval, an AS9110-certified quality management system can provide additional structure around risk, traceability, and personnel competence. For more information on AS9110 certification services, contact PJR UK at +44 (0) 2033 071986.