The role of design organizations in the aeronautical world

DOAs (Design Organizations Approvals) play a really important role in aeronautical certification but, probably, if you have never tried to certify an equipment or an aircraft, you will not know to what extent they are. In this article, we explain it to you.

Approval by the Certification Authority of a Design Organization is recognition that this organization meets the requirements of Part 21, subpart J. The approval includes the terms of approval that define:

  • Approval scope: the type of design activities, including fields of specialization.
  • Product Categories: Applicable products such as Large Airplanes, Engines, Small Helicopters, Gliders, etc.
  • The Product List: The list of products for which the DOA holder is an applicant or Type Certificate holder (if applicable).

The most important thing about obtaining a DOA is that the Certification Authority grants a series of privileges.

A DOA holder can:

  • Perform design activities within the scope of approval.
  • Have the Certification Authority accept compliance documents without further verification.
  • Carry out activities independently of the Certification Authority.
  • Limitations: The Certification Authority may impose any limitations on the foregoing.

As we can see, the privileges are the objective to be achieved by the company, thus being able to be self-sufficient in the Certification process.

The Certification Authority, which is present throughout the process, reserves the right to study and approve certain documents and to attend certain verification tests.

To obtain a DOA, we must be able to design an aeronautical product and, most importantly, have set out procedures on how to do it, how to control it, and how to prepare the justification documents that meet the requirements set by the standards applicable to the product we design.

We must take into account that these procedures must be managed by a Configuration Control that guarantees the evolution and applicability to a certain product that we design, that the Certification Authority can audit and its non-compliance would lead to losing the DOA.

It is important, therefore, to have a good tree of procedures, which guarantees that the correct development of the product is followed, that it is auditable and therefore consistent. Of course, we do not forget that the procedures are documents that have to be prepared and they will also tell us how to prepare the justification documents, here it is clear that having a tool that helps us to prepare this set of documents and above all the evolution of them consistently is a huge advantage.

This process must be carried out together with the Certification Authority, which in the civil world is EASA, at European level, and AESA in Spain. These are distributed:

The Design Organization Approval, in the sense described in Part 21 Subpart J of Annex I of Regulation (EU) 748/2012. This is applicable for those design activities that fall within the scope of work of EASA, as stated in article 2 of Regulation (EU) 2018/1139. In these cases, it is EASA itself that is in charge of managing both the approval process and the subsequent supervision of the approved design organisations.

In the case of design organizations that carry out activities that do not fall within the scope of work of EASA, the reference regulations are the JAR-21 Subparts JA and JB standards of the Annex to Royal Decree 660/2001. In these cases, it is the State Aviation Safety Agency (AESA) that is in charge of the approval process and subsequent supervision of the approved design organizations.


Therefore, AESA can approve Design Organizations for those aircraft certification projects and their modifications, provided that these are excluded from the application of European regulations according to the aforementioned article 2 of Regulation (EU) 2018/1139. For this reason, and due to the limited scope of approval that can be given by EASA, it is normal for all Design Organizations to apply for EASA approval.

Organizations that carry out design, modifications, repairs or maintenance, find in the regulations of the European Union Nº2018/1139 and 748/2012, the legislative reference framework within which the privileges and limitations that a company approved as an Approved Design Organization (DOA) will have to comply in carrying out the activities of design, modify or manufacture, aircraft components and equipment.

This scheme reflects the steps that we should follow in case we want to request the DOA certificate:

Font: European Union Aviation Safety Agency  

CENTUM DIGITAL and its digitization tools

At Centum Digital we know how expensive it is to deal with aeronautical regulations and generate large volumes of documentation that undergoes many changes in the approval process.

For this reason, we develop tools that automate your processes and guide you through the regulations, allowing you to reduce costs and time. 



Artículo propiedad de CENTUM Solutions, S.L

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