---
title: "ML.A.401 Maintenance data — Part-ML · Avioverse"
description: "The person or organisation maintaining an aircraft shall only use applicable maintenance data during the performance of maintenance."
url: "https://avioverse.aero/regulations/easa/continuing-airworthiness/part-ml/section-a-technical-requirements/ml-a-401"
---

# ML.A.401 Maintenance data

Annex Vb (Part-ML) · Regulation (EU) No 1321/2014 · EAR revision 2 Sep 2025

IR Implementing rule

## ML.A.401 Maintenance data

(a) The person or [organisation](https://avioverse.aero/glossary/easa/organisation) maintaining an [aircraft](https://avioverse.aero/glossary/easa/aircraft) shall only use applicable [maintenance](https://avioverse.aero/glossary/easa/maintenance) data during the performance of maintenance.

(b) For the purposes of this Annex, “applicable maintenance data” means any of the following:

1\. any applicable requirement, procedure, standard or information issued by the competent authority or the Agency;

2\. any applicable AD;

3\. the applicable ICA and other maintenance instructions, issued by the type-certificate holder, supplemental type-certificate holder, declarant of a declaration of design compliance and any other organisation that publishes such data in accordance with Annex I (Part 21) or, as applicable, Annex Ib (Part 21 Light) to Regulation (EU) No 748/2012;

4\. for components approved for installation by the design approval holder or the declarant of a declaration of design compliance, the applicable maintenance instructions published by the [component](https://avioverse.aero/glossary/easa/component) manufacturers and acceptable to the design approval holder or the declarant of a declaration of design compliance;

5\. any applicable data issued in accordance with point 145.A.45(d).

IR · ML.A.401 — Regulation (EU) No 1321/2014 · Regulation (EU) 2022/1360 · Continuing Airworthiness Easy Access Rules · EAR revision 2 Sep 2025

GM Guidance material

## GM1 ML.A.401(b) Maintenance data

Similar provisions to those in GM1 M.A.401(b)(3) and (b)(4) and GM1 M.A.401(b)(4) apply.

GM · GM1 ML.A.401(b) — Regulation (EU) No 1321/2014 · ED Decision 2021/009/R · Continuing Airworthiness Easy Access Rules · EAR revision 2 Sep 2025

[All rules in SECTION A — TECHNICAL REQUIREMENTS](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-ml/section-a-technical-requirements)

Consolidated from the EASA Easy Access Rules (revision 2 Sep 2025, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.