EASA Part-ML: Practical Guide for Owner-Pilots

This guide is the central reference for owner-pilots operating under EASA Part-ML. It covers owner responsibility, the Aircraft Maintenance Programme (AMP), the Certificate of Release to Service (CRS), pilot-owner maintenance, and audit readiness. For detailed treatment of each topic, use the linked cluster articles.

The legal basis is Commission Implementing Regulation (EU) No 1321/2014 (Part-ML, Annex V — Section A). EASA’s Part-ML regulatory page and continuing airworthiness provide the official framework.

1. What is EASA Part-ML?

Part-ML is the set of EU rules on the continuing airworthiness of aircraft and on the maintenance of aircraft and components. It applies, in particular, to aircraft used in non-commercial operations and to aircraft not used in commercial air transport when the regulatory regime so provides (e.g. Part-NCO with Part-ML maintenance).

In practice for owner-pilots:

Part-ML defines who is responsible for continuing airworthiness (the owner), what an Aircraft Maintenance Programme (AMP) is, how maintenance must be released (CRS), and under what conditions the pilot-owner may perform and certify certain tasks.
It works together with Part-NCO (non-commercial operations) and with Part-66 (qualification of certifying staff). Part-ML does not replace the need for a safe, compliant maintenance programme; it defines how that programme is declared or approved and how work is documented and released.

Risk: Treating Part-ML as “light” regulation leads to under-documentation and audit findings. The owner remains fully responsible for ensuring that the aircraft is maintained in accordance with the AMP and that all mandatory requirements (e.g. Airworthiness Directives) are complied with.

2. Owner Responsibilities under ML.A.201

ML.A.201 assigns to the owner the responsibility for the continuing airworthiness of the aircraft. This cannot be delegated away: the owner must ensure that:

The aircraft is maintained in accordance with an approved or declared Aircraft Maintenance Programme (AMP) (see ML.A.302).
All maintenance is performed by appropriate organisations or persons and released in accordance with the rules (e.g. ML.A.801 for CRS).
All applicable Airworthiness Directives (ADs) are applied within the required compliance time.
Defects and occurrences are managed and, where required, reported.

Practical interpretation: Even if you contract or use Part-66 engineers, you remain responsible. Outsourcing tasks does not outsource legal responsibility. See Can You Manage Airworthiness Without CAMO Under Part-ML? for when CAMO is mandatory and how owner-declared AMP fits in.

Risk commentary: Non-compliance with ML.A.201 can lead to findings by the competent authority, grounding, or enforcement action. The owner is the single point of accountability for continuing airworthiness.

3. Aircraft Maintenance Programme (ML.A.302)

ML.A.302 requires that the aircraft be maintained in accordance with an Aircraft Maintenance Programme (AMP) that is either approved (e.g. by a CAMO/CAO) or declared by the owner in accordance with the law.

Key points:

The AMP must be based on the Minimum Inspection Programme (MIP) and, where applicable, on the Instructions for Continuing Airworthiness (ICA) from the design approval holder. Doing less than the MIP is not permitted; see MIP vs ICA Under Part-ML.
The owner may declare an AMP without contracting a CAMO, provided the conditions for declaration are met (ML.A.302(e)). Declaration does not reduce the owner’s responsibility; it defines the programme you commit to. See How to Properly Declare an Aircraft Maintenance Programme (ML.A.302).
The AMP defines what must be done, when, and who may perform and release it (e.g. pilot-owner tasks under ML.A.803, or work released by certifying staff under ML.A.801).

Risk: An inadequate or undeclared AMP is one of the most common audit findings. The AMP must be complete, current, and actually followed.

4. Certificate of Release to Service (ML.A.801)

ML.A.801 requires that maintenance be released to service by appropriate certifying staff (e.g. Part-66 or equivalent) by issuing a Certificate of Release to Service (CRS). The CRS certifies that the work specified on it has been performed in accordance with the applicable data and that the aircraft or component is fit for release to service in that respect.

Critical distinction:

CRS certifies the maintenance that was performed; it does not by itself certify that the whole aircraft is airworthy. Airworthiness is the outcome of the full AMP (inspections, ADs, defects, component limits, etc.). See What Does a CRS Really Mean? (ML.A.801 Explained for Owners).
Pilot-owner sign-off under ML.A.803 is not a CRS; it is a different type of record for tasks that the AMP allows the pilot-owner to perform and certify. See Pilot-Owner Maintenance Under ML.A.803.

Risk: Assuming “CRS = aircraft airworthy” leads to a false sense of compliance. The owner must still ensure that all AMP tasks, ADs, and defect control are satisfied.

5. Pilot-Owner Maintenance (ML.A.803)

ML.A.803 allows the owner who is also the pilot to perform and certify certain limited maintenance tasks, but only those explicitly listed in the approved or declared AMP (e.g. in an appendix “Pilot-Owner Maintenance Tasks”). Such certification is not a CRS; it is a record that the task was completed in accordance with the AMP.

Scope: Only tasks in the AMP. No discretion beyond that list.
Limit: Pilot-owner cannot issue a CRS; tasks requiring a CRS must be released by certifying staff.
Documentation: Each pilot-owner task must be recorded (e.g. in the tech log) with date, task, and signature.

Full detail: Pilot-Owner Maintenance Under ML.A.803 – What You Can (and Cannot) Sign.

Risk: Signing tasks not in the AMP or treating pilot-owner sign-off as a CRS creates non-compliance and audit findings.

6. Airworthiness vs Maintenance – Key Distinction

Airworthiness is the state of the aircraft in relation to the approved/declared AMP, ADs, and applicable requirements. The owner is responsible for continuing airworthiness (ML.A.201).

Maintenance is the set of tasks (inspection, repair, replacement, etc.) performed to maintain or restore airworthiness. Maintenance is released by certifying staff (CRS) or, where permitted, by the pilot-owner (ML.A.803).

Implications:

Releasing a task (CRS or pilot-owner) does not by itself make the aircraft airworthy; the full programme (AMP, ADs, defects, component limits) must be satisfied.
The owner must ensure that all conditions for airworthiness are met, not only that the last maintenance event was released. A practical checklist: How to Know If Your Aircraft Is Airworthy Today (Part-ML Checklist).

Risk: Confusing “maintenance done” with “airworthy” leads to flying when ADs are overdue, inspections are missed, or component limits are exceeded.

7. Audit Readiness under Part-ML

Competent authorities and, where applicable, contracted CAMOs audit owner-managed aircraft against Part-ML. Typical areas of review:

AMP: Declared/approved, complete, up to date, and followed.
ADs: Applicability established, compliance status and times recorded.
CRS and records: All maintenance properly released and documented; pilot-owner tasks within AMP scope and recorded.
Component limits: Life-limited parts and overhaul times tracked and not exceeded.

Common findings and how to prepare: 12 Most Common Part-ML Audit Findings for Owner-Managed Aircraft. Flying with overdue ADs: Can You Legally Fly with an Overdue AD Under Part-ML?. Working clearly with engineers: How to Work with a Part-66 Engineer as an Owner Under Part-ML.

Risk: Poor documentation and unclear division of roles between owner and certifying staff are a major source of findings.

8. Frequently Asked Questions

Can I manage my aircraft without CAMO under Part-ML?

In many cases, yes. Part-ML allows the owner to declare an AMP (ML.A.302(e)) and to manage continuing airworthiness without contracting a CAMO, subject to national rules. CAMO is mandatory in certain operations (e.g. some commercial or complex setups). The owner remains responsible in all cases. See Can You Manage Airworthiness Without CAMO Under Part-ML?.

Does CRS mean the aircraft is fully airworthy?

No. A CRS (ML.A.801) certifies that the specified maintenance was performed correctly and that the aircraft or component is fit for release in that respect. Full airworthiness also requires a compliant AMP (all tasks current), all ADs complied with, no open defects that affect airworthiness, and component limits within limits. See What Does a CRS Really Mean? and How to Know If Your Aircraft Is Airworthy Today.

Who is responsible when something goes wrong?

The owner is responsible for continuing airworthiness (ML.A.201). If maintenance was performed or released incorrectly, the certifying staff may have professional liability, but the owner cannot transfer regulatory responsibility. Ensuring that the AMP is adequate, that ADs are complied with, and that records are complete remains the owner’s duty.

Summary: Part-ML assigns continuing airworthiness to the owner; the AMP (declared or approved) defines what must be done and when; CRS releases specified work only. Use the linked articles for detail on each topic and keep AMP, AD status, and records complete for audit readiness.