Alternative Procedures to Design Organisation Approval (ADOA)

An ADOA approval is the recognition that a Design Organisation complies with certain criteria of Part 21. This is done by implementing procedures setting out the specific design practices, resources and sequence of activities necessary to comply with the various Subparts of Part 21 dealing with design approval processes.

This ensures that the Design Organisation has understood the applicable requirements and will perform relevant activities as expected by EASA.

Due to its simplified nature, an ADOA does not include privileges.
The establishment of these alternative procedures may be seen as a starting phase for a Subpart J DOA, allowing at a later stage, at the discretion of the Design Organisation, to move towards a full Subpart J DOA by the addition of the missing elements.

Relevant legislation

The following legislation is applicable to ADOA:
Essential Requirements:

Implementing Rule:

  • Commission Regulation (EU) 748/2012 - Initial Airworthiness Regulation, including Part 21
    • Relevant section of Regulation: Articles 1(h) & 8
    • Annex I to Regulation (EC) No 748/2012 - Part 21 - Certification of aircraft and related products, parts and appliances, and of design and production organisations
    • Relevant section of Part 21: Articles 21.A.14(b), 21.A.112B(b), 21.A.432B(b), 21.A.602B(b)(2)
  • Acceptable Means of Compliance (AMC) and Guidance material (GM) page.
  • ED Decision 2012/020/R - Acceptable Means of Compliance and Guidance Material
    • Relevant section of AMC & GM document:
    • Subpart B - 'GM 21A.14(b) Eligibility for alternative procedures' and 'AMC 21A.14(b) Alternative Procedures'
    • Subpart E - 'GM 21A.112B Demonstration of capability for supplemental type-certificate cases'
    • Subpart O - 'AMC 21A.602B(b)(2) Procedures for ETSO authorisations'

Templates for manual of procedures (see under “Downloads” on the right):

  • TC/STC/Repair case: see "Model STC" and "Change Repair Dossier"
  • ETSOA case: see "Model ETSOA"

This legislation is updated regularly by issuing amendments. A full overview can be found on the Regulations page.


An ADOA can be applied for by submitting an application Form (FO.DOA.00081) to EASA. The application form can be found in the “Downloads” box on the right of this page.

In addition, the following information needs to be provided to EASA for the investigation:

  • Manual of procedures

After acceptance of an application, EASA will assign a Project Manager to conduct the investigation.

Fees & Charges

In accordance with Commission Implementing Regulation (EU) 2019/2153 of December 16, 2019, DOA table 9A and ADOA 9B and explanatory notes 11 and 12 of Part V – Explanatory Note. Relevant sections for ADOA can be found in the Annex:

  • for new applications: in Part I, Table 7B;
  • for updates of ADOA, charged per hour: in Part II.

For more information, please refer to the above-mentioned Fees & Charges Regulation or consult the Fees & Charges FAQ page

Contacts for Design Organisations Approvals

Queries related to Design Organisations can be sent to: doa [at] (doa[at]easa[dot]europa[dot]eu)
Letters and paper documents/records can be sent to:

European Union Aviation Safety Agency
Design Organisation Approvals
P.O. Box 10 12 53
D-50452 Cologne, Germany


See also:

Answers to Frequently Asked Questions can be found here.