There are EASA members who are not EU members, equally there was JAR members who was not member of EU.
True, and they have to abide by EU rules without having a say in formulating those or they will lose the membership and the market access. For example switzerland is currently in danger of losing their access to the EU market if they follow the outcome of their referendum last year. They have to allow the basic four rights (freedom of goods, capital, services and labour) of the EU in order to take part in the EU market.