Is there any obligation on competent authorities to translate the AMC in the national language, if they decide to implement them?
This is an internal issue related to each national administrative order. Moreover it is up to each competent authority to organise its own internal processes to help its regulated persons complying with Community law. This will dictate, on a case by case basis, what to do with the EASA AMCs. The internal documents are therefore in the language the competent authorities chooses. It is recommended however that competent authorities systematically use EASA AMCs to produce guidance to persons under their jurisdiction.