Foundation for the Development and Certification of Aviation Products

1. When is a DOA Required?

Any organisation intending to develop aviation products such as aircraft, engines, or propellers, or to implement changes to existing type designs, generally requires – depending on scope, responsibilities, and requested privileges – an approval as a Design Organisation in accordance with (EU) 748/2012, Part 21, Subpart J, known as the Design Organisation Approval (DOA).

This also applies to the development of parts and appliances – such as structural components, landing gear, avionics, or ETSO articles – in accordance with the applicable Certification Specifications (CS).

For organisations with a clearly defined and limited scope of development, alternative procedures in accordance with 21.A.14 (Alternative Procedures to DOA – ADOA) may apply.

2. Demonstration of Certification Compliance

2.1 Requirements and Formal Demonstration of Compliance

The applicant – whether a legal entity or a natural person – must demonstrate compliance with all applicable certification specifications. These include in particular:

• Design standards of the respective aircraft category
• Environmental requirements
• Operational suitability data
• Special Conditions, where applicable

Compliance must be demonstrated in accordance with EASA Part 21, Subpart J, as well as other relevant subparts (including A, B, D, E, K, P, and Q), and based on the organisation’s approved procedures.

Upon successful completion, and depending on the scope of approval, the following declarations may be issued:

• Declaration of Compliance (DoC)
• Declaration of Design and Performance (DDP) – exclusively for ETSO articles

Compliance with certification specifications must be demonstrated in accordance with the approved procedures within the Design Management System (DMS).

2.2 Systemic Prerequisites for Approval Eligibility

To demonstrate an organisation’s suitability for the approval of a specific design, clear organisational and procedural prerequisites must be established and documented.

The greater the complexity or level of innovation of a product – whether aircraft, engine, or propeller – or of a change to an already approved type design, the higher the requirements placed on the Design Management System (DMS).

The following prerequisites may be fulfilled to demonstrate an organisation’s suitability for the requested approval of a specific design:

* For definitions see (EU) 748/2012 Article 1
  **For definitions see GM 21.A.112B
*** Upon Agency agreement
 Quelle: EASA

3. The Design Management System (DMS)

The Design Management System (DMS) – referred to in regulatory terms as the “Design Assurance System” in accordance with 21.A.239 and 21.A.243 – is the central control and oversight system for designs and design changes to products and parts falling under the respective approval conditions.

It forms the organisational and procedural foundation for:

• Managing development projects
• Ensuring certification compliance
• Monitoring external design subcontractors
• Maintaining continued airworthiness within the organisation’s area of responsibility

3.1 Integration of the Safety Management System (SMS)

An integral component of the DMS is the Safety Management System (SMS).

The SMS is organisation-based and serves to:

• Identify hazards related to the product, product changes, or the design organisation at an early stage
• Systematically assess safety-related risks
• Define appropriate mitigation measures and continuously monitor their effectiveness

It is an integral part of the Design Assurance System and ensures that safety-relevant aspects are proactively and systematically managed.

3.2 Core Elements of System Integrity

An effective DMS is based on two independent control mechanisms defined within the approved organisational procedures and monitored by the competent authority as part of its oversight:

a. Design Control (Product-related)

Independent design verification by a Compliance Verification Engineer (CVE) in accordance with the four-eyes principle.
This function ensures the technical integrity of individual designs.

b. System Monitoring (Organisation-related)

Implementation of an Independent System Monitoring Function (ISM) to continuously assess the effectiveness of the overall system.
This ensures organisational integrity and long-term approval capability.

4. Organisational Requirements for DOA

To establish a design organisation in accordance with EASA Part 21, Subpart J, the following fundamental requirements must be fulfilled:

• Establishment of appropriate technical, organisational, and personnel structures in accordance with Part 21 Subpart
• Preparation of a Design Organisation Handbook (DOH) describing the Design Management System (DMS), taking into account the relevant Part 21 sections (J, A, B, D, E, K, P, Q)
• Preparation of a Flight Test Operations Manual (FTOM), where flight testing is conducted within development or modification projects

Only once these elements have been structured, implemented, and documented is successful approval as a Design Organisation (DOA) possible.

5. Our DOA Consulting under Part 21

We support you in establishing or optimising your design organisation in accordance with EASA Part 21, Subpart J – through to successful approval as a Design Organisation.

Our service portfolio includes:

• Development and tailored adaptation of your Design Organisation Handbook (DOH) – aligned with your organisation and specific development activities
• Preparation or optimisation of a Flight Test Operations Manual (FTOM)
• Training and coaching of your personnel on relevant processes, regulatory requirements, and standards
• Gap analysis of your existing system against Part 21 requirements (in particular J, A, B, D, E, K, P, Q)
• Conducting internal audits and pre-approval audits prior to the official EASA audit (Phase 3)
• Interim management for the Independent System Monitoring (ISM) function
• Preparation, support, and follow-up of EASA audits and technical meetings
• Our objective is to deliver a structured, audit-ready, and practical DOA solution – regulatory robust and efficiently implemented.