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21L.A.173 Declaration of design capability

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

IRImplementing rule

21L.A.173Declaration of design capability

(a)Prior to or at the same time as applying for a design approval under this Section, or prior to submitting the application for the approval of flight conditions in accordance with point 21.A.710 of Annex I (Part 21) of a product designed by it, whatever comes first, the organisation shall submit a declaration of design capability to the Agency.

(b)The declaration, and any subsequent changes thereto, shall be made in a form and manner established by the Agency.

(c)The declaration shall include the information necessary for the Agency to become familiar with the organisation and the intended scope of work, and shall include at least the following:

1.the registered name of the organisation;

2.the contact details of the organisation’s registered address of the principal place of business and, where applicable, of the operating sites of the organisation;

3.the names and contact details of the head of the design organisation;

4.the intended scope of work;

5.a statement confirming that the organisation:

(i)has a management system for design in accordance with point (a) of point 21L.A.174; and

(ii)will maintain the management system for design in compliance with this Subpart;

6.a statement confirming that the organisation will adhere to the processes and procedures established in accordance with point (d) of point 21L.A.174;

7.a statement that the organisation agrees to undertake the obligations of a declared design organisation in accordance with point 21L.A.177.

(d)The declaration of design capability shall be submitted to the Agency.

IR · 21L.A.173 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/1358 · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

GMGuidance material

GM1 21L.A.173(b)Declaration of design capability

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SUBMISSION OF THE DECLARATION The EASA form to request the registration of the declaration of design capability is available on the EASA website. The documents to be sent with the request are indicated in the form and include the Declaration of Design Capability — see AMC1 21L.A.173(c) / EASA Form 204.

GM · GM1 21L.A.173(b) — Regulation (EU) No 748/2012 · ED Decision 2023/013/R · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

AMCAcceptable means of compliance

AMC1 21L.A.173(c)Declaration of design capability

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DECLARATION FORM The natural or legal person that declares its design capability should provide the information required by point 21L.A173(c) in the declaration form that is available on the EASA Website. EASA Form 204 PART 1 – REQUEST FOR REGISTRATION AND DECLARATION OF DESIGN CAPABILITY

1. Design Organisation Details
1.1 Head of Design OrganisationTitleMr Ms
Name
First name
Phone
Email
1.2 Operating Sites where design and testing activities are taking place - may be left blank if same as in 2.1 Declarant DataAddress(es), Phone, Email
2. Intended Scope of Work
2.1 Product CategoryAeroplane with a MTOM of 2 000 kg or less and a max. seating configuration of 4 persons Sailplane with a MTOM of 2 000 kg or less Powered Sailplane with a MTOM of 2 000 kg or less Rotorcraft with a MTOM of 1 200 kg or less and a max. seating configuration of 4 persons Gyroplanes Balloons Hot Air Airships Passenger gas airships designed for no more than 4 persons Piston engines Fixed pitch propellers
2.2 Certification ActivitiesType Certification under Part 21 Light Subpart B Supplemental Type Certification (STC) under Part 21 Light Subpart E Major Repair approval under Part 21 Light Subpart M
2.3 Detailed Scope of Work DescriptionFor Type Certification activities:
Aircraft type(s): - [product 1] - [product 2] Note: In the case of type-certification activities, all relevant technical areas are included.
For STC activities:
[N/A or see below] A. Technical areas: <table> <tr> <td></td> <td>Aeroplanes</td> <td>(Powered) Sailplanes</td> <td>Balloons</td> <td>Hot-air airships</td> <td>Gas airships</td> <td>Rotorcraft</td> <td>Gyroplanes</td> <td>Engines</td> <td>Propellers</td> </tr> <tr> <td>Flight</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Structures</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Cabin</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Hydromechanical systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Environmental control systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Electrical systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Avionics</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Powerplant and fuel systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Rotor drive systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Propulsion</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> </table> B. Limitations
2.3 Detailed Scope of Work Description continuedFor Major Repair activities:
[N/A or see below] A. Technical areas: <table> <tr> <td></td> <td>Aeroplanes</td> <td>(Powered) Sailplanes</td> <td>Balloons</td> <td>Hot-air airships</td> <td>Gas airships</td> <td>Rotorcraft</td> <td>Gyroplanes</td> <td>Engines</td> <td>Propellers</td> </tr> <tr> <td>Flight</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Structures</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Cabin</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Hydromechanical systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Environmental control systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Electrical systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Avionics</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Powerplant and fuel systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Rotor drive systems</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> <tr> <td>Propulsion</td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> <td></td> </tr> </table> B. Limitations
3. Declarant’s Statements
3.1. Declaration of Compliance
The Declared Design Organisation (DDO) has established and implemented a management system for design in accordance with point 21L.A.174. This management system will be maintained in compliance with Subpart J of Annex Ib (Part 21 Light) to Regulation (EU) No 748/2012. The references of the elements of the management system for design are included in the Annex to this Declaration. All the personnel of the DDO must adhere to the processes and procedures referred to in the Annex to this Declaration. I hereby commit to undertake the obligations of a Declared Design Organisation in accordance with point 21L.A.177. I confirm that all information contained in this Declaration, including its Annex, is complete and correct.
Date/LocationName (Head of Design Organisation)Signature
Important Note: EASA cannot accept Declarations without signature. Please make sure that you sign the Declaration.
This Declaration should be sent by email to: applicant.services@easa.europa.eu
ANNEX TO THE DECLARATION OF DESIGN CAPABILITY
This Annex includes references to the Declared Design Organisation’s (DDO) documentation showing compliance with the requirements of Annex Ib (Part 21 Light) to Regulation (EU) No 748/2012.
NoPart 21 LightSubjectDDO reference DDOE* reference, as relevant
1. General
1.121L.A.174(d)Process and procedure documentation issuance, approval or change
2. Organisation, key personnel and compliance verification staff
2.121L.A.175(e)Organisational structure documented and kept updated
2.221L.A.175(b)Identification of key personnel nominated by the head of design organisation to ensure that the organisation is in compliance with the requirements of Part 21 Light Subpart J: — head of airworthiness function, — head of independent monitoring function, — others
2.321L.A.175(c)Nomination process for key personnel ensuring they have the appropriate knowledge, background and experience to discharge their responsibilities
2.421L.A.174(b)(2)List of authorised staff to perform compliance verification and the criteria and process for their initial nomination and maintenance of their authorisation
2.521L.A.175(d)The numbers of staff in all technical departments and their level of experience are sufficient, and staff have been given the appropriate authority to be able to discharge their allocated responsibilities and that there is full and effective coordination within the declared design organisation in respect of airworthiness and environmental compatibility matters
3. System monitoring
3.121L.A.174(c)System monitoring procedure
4. Subcontracting
4.121.A.174(b)(3) 21L.A.174(e)Subcontracting procedure and a list of subcontractors
5. Changes to the DDO
5.121L.A.178Procedure for the notification of organisational changes to EASA according to point 21L.A.178
NoPart 21 LightSubjectDDO reference DDOE* reference, as relevant
6. Design and certification processes
6.121L.A.26Identification and issuance of type design documentation and configuration control
6.221L.A.24Type-certificate application (including: type-certification basis, environmental-protection requirements and certification plan)
6.321L.A.25Compliance demonstration (preparation, verification and issuance of compliance documentation)
6.421L.A.25(c)Testing procedure and conformity of test specimen/prototype
6.521L.A.25(d)Flight-testing procedure and flight test operations manual (FTOM)
6.621L.A.241Procedure for requesting the issuance of permits to fly and the approval of associated flight conditions
6.721L.A.25(e) 21L.A.241(c) 21L.B.46 21L.B.242Preparing and supporting EASA in conducting its investigations (critical design review, pre-flight inspection, first-article inspection)
6.821L.A.241(b) 21L.B.241Preparing and supporting the competent authority in conducting its inspections
6.921L.A.25(f)Issuance of compliance declaration
6.1021L.A.63Classification of changes to a type certificate
6.1121L.A.67Approval of minor changes to a type certificate (TC)
6.1221L.A.68Approval of major changes to a type certificate (TC)
6.1321L.A.86Approval of a supplemental type certificate (STC)
6.1421L.A.203Classification of repair designs
6.1521L.A.207Approval of minor repair designs
6.1621L.A.208Approval of major repair designs
7. Obligations
7.121L.A.3Reporting system
7.221L.A.4Airworthiness directives
7.321L.A.5Collaboration between design and production
7.421L.A.6Marking
7.521L.A.7Record-keeping
7.621L.A.8Manuals
7.721L.A.9Instructions for continued airworthiness
*Instructions: If the DDO, for the purpose of compliance with point 21L.A.174(d), has produced a Declared Design Organisation Exposition (DDOE), then the DDOE sections should be referenced in the right-hand column of the form.

AMC · AMC1 21L.A.173(c) — 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

Consolidated from the EASA Easy Access Rules (revision 27 Nov 2025, extracted 17 Aug 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.

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