---
title: "21.A.451 Obligations and EPA marking — Annex I, Initial Airworthiness · Avioverse"
description: "Each holder of a major repair design approval shall: undertake the obligations:"
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-i/section-a-technical-requirements/21-a-451"
---

# 21.A.451 Obligations and EPA marking

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

IR Implementing rule

## 21.A.451 Obligations and EPA marking

(a) Each holder of a major repair design approval shall:

1\. undertake the obligations:

(i) laid down in points 21.A.3A, 21.A.3B, 21.A.4, 21.A.5, 21.A.6, 21.A.7, 21.A.9, 21.A.439, 21.A.441 and 21.A.443;

(ii) implicit in the collaboration with the type-certificate, supplemental type-certificate and with the APU [ETSO](https://avioverse.aero/glossary/easa/etso) authorisation holder under point 21.A.433(b), as appropriate.

2\. specify the marking, including [EPA](https://avioverse.aero/glossary/easa/epa) letters, in accordance with point 21.A.804(a).

(b) Except for type-certificate holders or APU authorisation holders for which point 21.A.44 applies, the holder of a minor repair design approval shall:

1\. undertake the obligations laid down in points 21.A.4, 21.A.5 and 21.A.7;

2\. specify the marking, including EPA letters, in accordance with point 21.A.804(a).

IR · 21.A.451 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/201 · 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.