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66.A.40 establishes that a Part 66 licence remains valid only as long as the holder does not have a period exceeding five consecutive years without exercising certification privileges, and addresses what happens when validity lapses.
What it means in practice
Unlike some professional licences that require periodic renewal, a Part 66 licence does not have a fixed expiry date. However, it does have a continuation of validity condition: if you go more than five years without exercising your certification privileges, the licence is no longer valid for the purpose of issuing certificates of release to service. You would need to demonstrate compliance with the experience and recency requirements before the licence can be used again.
This provision ensures that certifying staff remain competent. The aviation industry evolves constantly with new technologies, regulatory changes, and updated maintenance procedures. A person who has been away from aircraft maintenance for an extended period cannot simply return and start certifying work without first re-establishing their competence.
Key requirements
To maintain your licence validity, you must either exercise certification privileges or undertake sufficient maintenance experience within any five-year rolling period. The regulation does not mandate a specific number of hours per year but requires that the holder can demonstrate recent practical involvement in aircraft maintenance.
If the five-year period has lapsed, the licence holder must satisfy the experience requirements of 66.A.30 again to the satisfaction of the competent authority before the licence can be used for certification. This may include additional training or a period of supervised experience. The licence itself is not revoked, but its privileges cannot be exercised until compliance is re-established.
Common compliance gaps
Organisations sometimes fail to monitor the recency of their certifying staff, particularly for engineers who may have been in management or non-certifying roles for several years. When these individuals wish to return to a certifying role, both the organisation and the individual may be surprised to find that the five-year window has closed. Proactive tracking of recency through the organisation's competence management system is essential to avoid this situation.
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