CAMO or CAO? Choosing the Right Continuing Airworthiness Organisation for Your Light Aircraft

A CAMO holds an approval to manage the continuing airworthiness of aircraft; it does not maintain them under that approval. A CAO (combined airworthiness organisation) can hold maintenance, continuing airworthiness management, airworthiness review and permit-to-fly privileges together, but only for aircraft that are not complex motor-powered aircraft and are not on a licensed air carrier's air operator certificate. The CAO's scope therefore stops at light, non-complex aircraft; the CAMO's extends to complex and air carrier aircraft.

This article looks at the choice from two sides: an owner picking a provider for a light aircraft on an EU register, and a small maintenance business deciding which approval to seek. It draws only on Regulation (EU) No 1321/2014 (Annexes Vb, Vc and Vd), consolidated to 22 February 2026, and EASA's continuing airworthiness FAQ. The UK has had its own CAA regime since Brexit; it is outside these sources, so nothing here describes UK approvals.

The legal basis in one paragraph

Article 4 of the regulation requires organisations involved in continuing airworthiness, including maintenance, to be approved under Part-145, Part-CAMO or Part-CAO, as applicable. EASA's FAQ dates both new annexes: Part-CAMO and Part-CAO apply from 24 March 2020, introduced by Regulation (EU) 2019/1383. Article 4(4) lets holders of Part-M Subpart F or G approvals, or of Part-145 approvals, obtain a Form 3-CAO on request, with the same privileges, capped at what Part-CAO allows.

For owners: when you must, and when you may

Part-ML leaves most private owners free to choose. ML.A.201(f) says the owner may contract continuing airworthiness management to a CAMO or CAO, using the written contract in Appendix I; otherwise the owner carries out those tasks and answers for them. The obligation appears in ML.A.201(e): aircraft used by commercial ATOs and DTOs, or not operated under Part-NCO, or operated under Part-BOP Subpart-ADD or Part-SAO Subpart-DEC, must be managed by a CAMO or CAO and maintained only by approved organisations.

EASA's FAQ draws a related line for training organisations. A commercial DTO's non-complex aircraft need a CAO (with management privilege) or a CAMO, and maintenance by a CAO, Part-145 or Part-M Subpart F organisation. A non-commercial DTO needs neither a CAMO nor a CAO for such aircraft.

For businesses: what each approval demands

Part-CAMO

• An accountable manager with corporate authority to fund the activity, who nominates people responsible for compliance, compliance monitoring and safety management (CAMO.A.305).
• A management system with defined accountabilities, a safety policy, hazard identification and risk management, training, documented key processes and compliance monitoring (CAMO.A.200).
• An information security management system under Implementing Regulation (EU) 2023/203 (CAMO.A.200A) and an internal safety reporting scheme (CAMO.A.202).
• A CAME approved by the authority, listing among other things approved AMPs and maintenance contracts (CAMO.A.300).
• Occurrence reports within 72 hours of identifying the condition (CAMO.A.160).
• Records: continuing airworthiness records kept until 3 years after responsibility for the aircraft is permanently transferred; management system records and contracts for at least 5 years (CAMO.A.220).

Part-CAO

• An accountable manager and a person or group responsible for compliance (CAO.A.035), and a combined airworthiness exposition (CAE) approved by the authority (CAO.A.025).
• A quality system with a quality manager (CAO.A.100). A small CAO may replace it with regular organisational reviews, with the authority's approval, provided it does not contract out management tasks.
• If maintenance is in scope: adequate hangars and workshops, secure segregated storage, calibrated tools, current maintenance data and written work orders (CAO.A.030 to CAO.A.055).
• Certifying staff meeting Article 5 and the 6-months-in-2-years recency rule in 66.A.20(b) (CAO.A.040).
• Records: maintenance records for 3 years from release to service; management and ARC records for 2 years after the aircraft is permanently withdrawn from service (CAO.A.090).

Privileges compared

Airworthiness review staff requirements also differ. A CAMO's reviewers need at least 5 years' continuing airworthiness experience plus a Part-66 licence, aeronautical degree or national equivalent, or 5 more years' experience instead (CAMO.A.310). A CAO's need 1 year for sailplanes and balloons or 3 years for other aircraft, plus a licence or degree, or 2 or 4 more years' experience (CAO.A.045).

Neither annex requires formal deputies for nominated persons. EASA's FAQ nonetheless recommends naming one or more deputies in the CAME or CAE to stay compliant during short absences, and appointing a new nominated person for long ones.

What the owner signs up to

For Part-ML aircraft, the contract with either type of organisation follows Appendix I to Part-ML. It identifies the aircraft (registration, type, serial number), the owner or registered lessee, the organisation and the type of operation, and includes a fixed statement: the owner entrusts the organisation with continuing airworthiness management, development and approval of the maintenance programme and organisation of maintenance, and undertakes not to alter the aircraft without the organisation's prior approval. If either side fails to honour it, the contract becomes null, the owner retains full responsibility and must tell the authority of the Member State of registry within 2 weeks.

Day to day, the owner presents the aircraft for maintenance when asked, reports defects through the logbook, passes on flight hours as agreed, tells the organisation about any maintenance done without its knowledge, and informs it within 30 days of any pilot-owner maintenance. The organisation, in turn, organises the bridging inspection, maintenance and AD compliance, archives the records and sends a copy of any ARC it issues or extends to the authority within 10 days.

A note for organisations based outside the EU

For an organisation whose principal place of business is in a third country, the competent authority is the Agency (CAO.1(1)(b); CAMO.A.105(b)). The airworthiness review privilege is reserved for organisations with their principal place of business in a Member State, under both CAMO.A.125(e) and CAO.A.095(c). A UK-based firm therefore needs to read these points carefully, and check its position under UK rules separately, since those are not in this base.

Choosing, in practice

1. Owner of a privately flown Part-ML aircraft, happy to manage it: no organisation needed, but a declared AMP and good records are.
2. Owner wanting one counterpart for maintenance, planning and the ARC: a CAO holding maintenance, management and review privileges.
3. Owner or operator with a preferred maintenance shop, or with complex or air carrier aircraft: a CAMO.
4. Small maintenance firm working on light aircraft only: a CAO, possibly qualifying as a small CAO.
5. Firm serving licensed air carriers: Part-CAO is not available for those aircraft.

The Part-ML, Part-CAMO and Part-CAO knowledge base can take the next question for you, such as “Is there a real difference between a CAO and a CAMO, or are they basically the same thing?”, and answers with the relevant point of the annex.

This article explains EU rules and is not advice on an approval application. Sources: EUR-Lex and EASA's FAQ. EASA's AMC/GM and UK CAA rules are outside the knowledge base.