Pilot-Owner Maintenance Under Part-ML: What You Can and Can't Sign Off Yourself

Under EASA's Part-ML, a pilot-owner may issue a certificate of release to service (CRS) for limited pilot-owner maintenance: simple visual inspections or operations that check the airframe, engines, systems and components for general condition, obvious damage and normal operation. Anything that is a critical maintenance task, needs special or calibrated tools, involves an AD (unless the AD allows it) or is part of the 100-hour/annual check is off-limits. The CRS must be entered in the logbooks, and the regulation requires CRS entries in the records no later than 30 days after the work is completed.

This guide is written for American pilots who own, or co-own, a light aircraft registered in an EU Member State, and for U.S. mechanics who work alongside European owners. It covers only the EU rule: Annex Vb (Part-ML) to Regulation (EU) No 1321/2014, in the consolidated version dated 22 February 2026, and EASA's official continuing airworthiness FAQ. FAA rules on owner maintenance are not part of this material, so nothing here should be read as a comparison with them.

Who qualifies as a pilot-owner under ML.A.803

Part-ML applies to aircraft registered in a Member State (Article 1 of the regulation), so the starting point is the register, not where you live. Point ML.A.803(a) then sets two cumulative conditions to qualify as a pilot-owner:

1. Hold a valid pilot license or equivalent license issued or validated by a Member State for the aircraft type or class rating.
2. Own the aircraft, as sole or joint owner, either as one of the natural persons on the registration form, or as a member of a non-profit recreational legal entity named on the registration document as owner or operator. That member must be directly involved in the entity's decision-making and designated by it to carry out pilot-owner maintenance.

The license wording matters for U.S. pilots: the text speaks of a license “issued or validated by a Member State”. The base does not say how a non-EU license gets validated, so check that point with the competent authority of the Member State of registry, which Part-ML defines as the authority responsible for the aircraft (point ML.1(b)).

There is also an operating condition. ML.A.803(b) allows the pilot-owner CRS for aircraft operated under Annex VII (Part-NCO) to Regulation (EU) No 965/2012, for balloons not operated under Subpart-ADD of Part-BOP and for sailplanes not following Subpart DEC of Part-SAO. EASA's FAQ sums it up: the pilot-owner route is only applicable to aircraft not operated commercially.

What a pilot-owner may sign off

Appendix II to Part-ML is the operative text. Its positive scope is short: the pilot-owner “may carry out simple visual inspections or operations to check the airframe, engines, systems and components for general condition, obvious damage and normal operation.” Two basic principles come first:

• Responsibility: the pilot-owner is always responsible for any maintenance he or she performs.
• Competence: the pilot-owner must hold a satisfactory level of competence for the task and is responsible for becoming familiar with the standard maintenance practices for the aircraft and with its aircraft maintenance program (AMP).
• Data: the maintenance data defined in ML.A.401 (ADs, the manufacturer's instructions for continuing airworthiness, and similar) must be available during the work and must be complied with.

Tasks described in the aircraft flight manual, such as rigging sailplane wings, the pre-flight inspection or assembling a balloon's basket, burner, cylinders and envelope, are not maintenance and need no CRS. The person assembling them is still responsible for making sure the parts are eligible for installation and serviceable. Article 2 of the regulation backs this up: its definition of maintenance excludes the pre-flight inspection.

The nine exclusions you can't override

Appendix II lists the conditions under which a task shall not be released by the pilot-owner. If any one applies, the job goes to an approved maintenance organization or to independent certifying staff.

The appendix closes the loophole explicitly: these nine criteria “cannot be overridden by less restrictive instructions” in the AMP. Even an AMP you declared yourself cannot widen the list.

What “critical maintenance task” means

Article 2(n) defines it as a task involving the assembly or any disturbance of a system or part on an aircraft, engine or propeller that, if an error occurred during its performance, could directly endanger flight safety. For anyone doing other work, ML.A.402(b)(8) also requires an error-capturing method after any critical task, which is one reason it is kept away from pilot-owners.

Complex tasks in Appendix III

Appendix III lists the complex tasks that must be released by an approved organization or independent certifying staff. Among them: riveting, bonding, laminating or welding repairs to spars, wing ribs, engine mounts, longerons, landing-gear struts, axles or wheels; repairs to load-bearing control-system parts; dismantling and reassembling a piston engine other than to reach the piston/cylinder assemblies or to inspect or replace oil pump assemblies without touching internal gears; propeller balancing, except static balancing where the manual requires it and dynamic balancing with electronic equipment where permitted; and work on high-pressure power-plant reservoirs and lines.

Airworthiness directives: the narrow exception

EASA's FAQ answers the question many owners ask: can I do the AD inspection myself? For Part-ML aircraft the answer has three layers. The aircraft must not be operated commercially; the AD itself must specifically allow pilot-owner accomplishment; and the work must still fit within ML.A.803(a) and (b) and Appendix II. According to the FAQ, an EASA AD that grants this will say so expressly, with wording stating that the action may be accomplished by the pilot-owner under M.A.803 or ML.A.803.

If the AD is silent, the exclusion in point (b)(3) of Appendix II applies and the pilot-owner may not release it.

Paperwork: the CRS and the 30-day deadline

Point ML.A.803(c) says what a pilot-owner CRS must contain. It is entered in the logbooks and includes:

• basic details of the maintenance carried out;
• the maintenance data used (Appendix II, point (c), repeats that the data references must be in the CRS);
• the date the maintenance was completed;
• the identity, signature and pilot license (or equivalent) number of the pilot-owner.

Timing comes from ML.A.305(a): every CRS goes into the aircraft continuing airworthiness record system “as soon as possible but not later than 30 days after the day of the completion of the maintenance task.” If a CAMO or CAO manages the aircraft, Appendix II and the contract template in Appendix I add a second obligation: tell the contracted organization about any pilot-owner maintenance no later than 30 days after completion.

Common mistakes and a pre-task checklist

Most of these mistakes come from reading Appendix II too loosely. Before you pick up a tool, run through this list:

1. Is the aircraft within Part-ML, and operated non-commercially (Part-NCO)?
2. Do you meet both ML.A.803(a) conditions: license issued or validated by a Member State, and owner on the registration form (or designated member of a non-profit recreational entity)?
3. Does the AMP authorise pilot-owner maintenance?
4. Is the task a simple visual check or operation, and does it avoid all nine exclusions?
5. If it is an AD, does the AD itself expressly allow pilot-owner accomplishment?
6. Do you have the applicable maintenance data in hand?
7. Will you enter the CRS, with data references and your license number, well within 30 days, and notify your CAMO/CAO if you have one?

Two related points are worth knowing. Defects found during your checks follow ML.A.403: a defect that seriously endangers flight safety is fixed before further flight, and any defect not fixed before flight is recorded and the record made available to the pilot. And if you are stuck at a remote field with no approved organization or certifying staff available, ML.A.801(c) lets the owner authorise a person with at least 3 years of maintenance experience and proper qualifications. The work must then be rechecked and released within 7 days, or 30 days for Part-NCO aircraft, and the CAMO/CAO or authority notified within 7 days.

You can test your own edge cases against the official texts in the Part-ML and Part-66 knowledge base, with questions such as “Can I personally sign off on maintenance I carried out myself on my own aircraft?” Each answer cites the point of the regulation it relies on.

This article explains the EU rule; it is not maintenance or legal advice for a specific aircraft. Sources: the consolidated text on EUR-Lex and EASA's continuing airworthiness FAQ. EASA's AMC and GM to Part-ML are not included in the knowledge base and are not reflected here.