---
title: "21L.A.23 Demonstration of design capability — Annex Ib, Initial Airworthiness · Avioverse"
description: "An applicant for a type certificate shall demonstrate their design capability by:"
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-a-technical-requirements/21l-a-23"
---

# 21L.A.23 Demonstration of design capability

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

IR Implementing rule

## 21L.A.23 Demonstration of design capability

An applicant for a type certificate shall demonstrate their design capability by:

(a) holding a design organisation approval with terms of approval that cover the respective category of the product, issued by the Agency in accordance with Subpart J of Section A of Annex I ([Part 21](https://avioverse.aero/glossary/easa/part-21)); or

(b) declaring their design capability for the type of design work and the category of the product in accordance with Subpart J of this Annex.

IR · 21L.A.23 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/1358 · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

GM Guidance material

## GM1 21L.A.23(a) Demonstration of design capability

TERMS OF APPROVAL COVERING THE RESPECTIVE PRODUCT CATEGORY

If an applicant holds a design organisation approval (DOA) issued under Subpart J of Annex I ([Part 21](https://avioverse.aero/glossary/easa/part-21)) and it wishes to use this approval to meet the eligibility criteria of point 21L.A.23, that applicant will need to apply for a change to the terms of approval to include the new aircraft type within the list of products.

GM · GM1 21L.A.23(a) — Regulation (EU) No 748/2012 · ED Decision 2023/013/R · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

GM Guidance material

## GM1 21L.A.23(b) Demonstration of design capability

DECLARATION OF DESIGN CAPABILITY

Organisations that have declared their design capability under Subpart J of Annex Ib ([Part 21 Light](https://avioverse.aero/glossary/easa/part-21-light)) should update their declaration of design capability to include the new product type when submitting a new application for a type certificate (see point 21L.A.173 ‘Scope of work’).

GM · GM1 21L.A.23(b) — Regulation (EU) No 748/2012 · ED Decision 2023/013/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-ib/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.