---
title: "21.A.609 Obligations of holders of ETSO authorisations — Annex I, Initial Airworthiness · Avioverse"
description: "The holder of an ETSO authorisation under this Subpart shall:"
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-i/section-a-technical-requirements/21-a-609"
---

# 21.A.609 Obligations of holders of ETSO authorisations

Annex I · Regulation (EU) No 748/2012 · EAR revision 27 Nov 2025

IR Implementing rule

## 21.A.609 Obligations of holders of ETSO authorisations

The holder of an [ETSO](https://avioverse.aero/glossary/easa/etso) authorisation under this Subpart shall:

(a) manufacture each [article](https://avioverse.aero/glossary/easa/article) in accordance with Subpart G or Subpart F that ensures that each completed article conforms to its design data and is safe for installation;

(b) prepare and maintain, for each model of each article for which an ETSO authorisation has been issued, an updated set of complete technical data and records in accordance with point 21.A.5;

(c) prepare, maintain and update master copies of all manuals required by the applicable airworthiness specifications for the article;

(d) make available to users of the article and to the Agency on request those maintenance, overhaul and repair manuals necessary for the usage and maintenance of the article, and changes to those manuals;

(e) mark each article in accordance with point 21.A.807;

(f) comply with points 21.A.3A, 21.A.3B, 21.A.4 and 21.A.9;

(g) continue to meet the qualification requirements of point 21.A.602B.

IR · 21.A.609 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/201 · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

AMC Acceptable means of compliance

## AMC1 21.A.609(c) and (d) Obligations of holders of ETSO authorisations

In CS-[ETSO](https://avioverse.aero/glossary/easa/etso), there is no specification related to ICA, neither in Subpart A, nor in each specific ETSO.

Although an ETSO [article](https://avioverse.aero/glossary/easa/article) itself typically does not require ICA, the applicable airworthiness standards may require the design approval holder (DAH) or the design approval applicant (DAA) who install an ETSO article into their product to develop ICA that describe an ETSO article’s installation requirements, within the context of the product, to the extent necessary to ensure the product’s continued airworthiness.

In addition, if the DAH or the DAA who install an ETSO article into their product explicitly uses ETSO provisions to demonstrate compliance with an installation requirement, they should review all the maintenance and inspection instructions for the particular ETSO article when defining the ICA of the product.

It may be necessary for the DAH or the DAA to incorporate these instructions into the ICA of the product to ensure that the ETSO article continues to satisfy the terms of its ETSO authorisation after installation.

Any DAH or DAA who wishes to install an ETSO article should comply with point 21.A.303.

For this, the applicant for an ETSO authorisation may provide by the time of the application and before the authorisation is issued (in accordance with point 21.A.605) the following:

instructions that cover periodic maintenance, calibration, and repair for the continued airworthiness of the article, including specific guidance on the limits of wear and damage that would warrant replacement;

the recommended inspection intervals, which may be affected by storage and operating conditions (i.e. temperature, humidity, etc.).

AMC · AMC1 21.A.609(c) — Regulation (EU) No 748/2012 · ED Decision 2021/007/R · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

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

Consolidated from the EASA Easy Access Rules (revision 27 Nov 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.