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66.A.1 defines who Part 66 applies to, establishing that any person issuing a certificate of release to service under Part 145 or Part M must hold an aircraft maintenance licence compliant with this regulation.
What it means in practice
Part 66 sets the licensing framework for anyone who certifies that maintenance has been correctly carried out on EASA-regulated aircraft. If you sign off a task as a certifying engineer or support staff member working under an approved maintenance organisation, you need a Part 66 licence. This applies across all EU Member States and those third countries that have adopted EASA regulations.
The regulation does not cover every person who physically performs maintenance. Mechanics and technicians who carry out tasks but do not sign the certificate of release to service are not required to hold a Part 66 licence themselves, although they must work under appropriate supervision.
Key requirements
The core requirement is straightforward: no certificate of release to service may be issued unless the person signing holds a valid Part 66 aircraft maintenance licence with the appropriate ratings for the aircraft type and work performed. The licence must be issued or recognised by the competent authority of an EU Member State.
Organisations approved under Part 145 or Part M Subpart F must ensure their certifying staff meet Part 66 requirements. This creates a dual obligation where both the individual and the organisation share responsibility for compliance.
Common compliance gaps
A frequent oversight is assuming that holding any aircraft maintenance licence is sufficient. The licence must specifically match the category of work and the aircraft type being certified. Organisations sometimes allow certifying staff to sign off work outside the scope of their licence endorsements, which is a significant regulatory finding during audits.
Part 66 Training
Working towards your Part 66 licence?
Sofema's Part 66 Foundation course walks you through the full licensing framework — categories, modules, experience requirements, and the path to certification.
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