EASA states that Certification Specifications (e.g. CS-25) is non-binding on their website. See the regulations structure PDF.

Each Part to each implementing regulation has its own Acceptable Means of Compliance and Guidance Material (AMC/GM). These AMC and GM are amended along with the amendments of the regulations. These AMC/GM are so-called ‘soft law’ (non-binding rules), and put down in form of EASA Decisions. A comprehensive explanation on AMC in form of questions and answers can be found on the FAQ section of the EASA website.

Furthermore, Certification Specifications are also related to the implementing regulations, respectively their parts. Like AMC/GM they are put down as Decisions and are non-binding.

The FAA's 14 CFR 25 is certainly what I would interpret as binding or required. As a manufacturer you are required to show compliance to applicable parts of 14 CFR 25.

What does EASA mean then? Or what are they trying to communicate about Certification Specifications such as CS25? Or what is different about their organization that makes CS-25 “non-binding”?

  • 5
    $\begingroup$ why did you remove the quoted text? In my opinion, it was much better before. Now people have to follow the link, open the PDF, and find the text you refer to. It's much simpler to include the relevant quote here (in addition to the link), especially for users on mobile devices. $\endgroup$
    – DeltaLima
    Commented Oct 9, 2018 at 14:31
  • 2
    $\begingroup$ @Greg the SE model is based on co-operation. This includes editing posts from other users to improve them and bring them up to the standards of the community. You are free to ignore the suggestions, of course, but be aware that the other users are trying to help you. $\endgroup$
    – Federico
    Commented Oct 10, 2018 at 6:24

1 Answer 1


The reason is that EASA cannot provide legally binding interpretations of EU Regulations, and the Certification Specifications are an interpretation of the EU Regulations.

Within the European Union (EU), legally binding interpretations of the EU regulations are exclusively provided by the national and EU courts and the European Commission.  The EU Member States are responsible for interpreting and implementing EU law in their national legal system.

The European Commission (EC) has created the European Aviation Safety Agency by decision EC 218/2008, recently repealed and succeeded by EU 2018/1139. The EC tasked EASA with creating certification specification and other material:

EU 2018/1139, Article 76


  1. The Agency shall, in accordance with Article 115 and with the applicable delegated and implementing acts adopted on the basis of this Regulation, issue certification specifications and other detailed specifications, acceptable means of compliance and guidance material for the application of this Regulation and of the delegated and implementing acts adopted on the basis thereof.

And thus EASA is tasked with creating certification specifications that allow application of the high level EU aviation safety regulations, which requires of course the interpretation of those regulations.

At the same time, they don't have the power to give a legally binding interpretation, because that is reserved for the national and EU courts and the EC.

Consequently the Certification Specifications published by EASA that give the required detail to comply with the regulations, are not binding. They are referred to by EASA as "soft law", whereas the Regulations and Implementing Regulations on which they are based and which are published by the EC are referred to as "hard law"

As an aircraft manufacturer, you may argue that there are alternative ways of complying with the EU aviation safety regulations (hard law), whilst deviating from the Certification Specifications (soft law). If you make your case well, you will still get a type certificate.

This is not any different in the US, where aircraft can be certified with deviations from FAR 25. You don't necessary need to show compliance with all of FAR 25, if you can convince the FAA that the deviation from FAR 25 is reasonable and safe, a type certificate will be granted.

For example, see this table of granted exemptions from FAR 25 for the Boeing 737-8 and 737-9:

table of granted exemptions

source: 737 type certificate(PDF)

Relevant EASA FAQ's:

  • $\begingroup$ I understand most of your impressive response. Where I struggle to connect, is with the phrase “they” (the agency aka EASA) “don't have the power to give a legally binding interpretation”. While this make sense and I have no doubt it is true, if a manufacturer requests an Exemption, ELOS, etc. in regards to a CS, would not EASA then have to give a legally binding interpretation of 2018/1139? EASA would need to assess and interpret the basic regulation 2018/1139, to ensure the request (e.g. ELOS) met the intent of 2018/1139? $\endgroup$
    – Greg
    Commented Oct 10, 2018 at 21:47
  • $\begingroup$ Per 2018/1139 Article 76 (1.) & (3) does this mean EASA produces the proposals (e.g. Certification Specification, AMC) and then must have them approved by the EU Commission? The language of “opinions” gave me that impression. $\endgroup$
    – Greg
    Commented Oct 10, 2018 at 21:47
  • $\begingroup$ Hi Greg, good follow-up questions, I am afraid I don't have an answer for you off-hand. I was trained as an aerospace engineer, not as a lawyer, so I am out of depth on this level op detail. I find the subject interesting, and I'll try and research a bit more, but don't hold your breath. Maybe somebody else will chime in with a legally binding answer :-) $\endgroup$
    – DeltaLima
    Commented Oct 10, 2018 at 22:21

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .