Commission Regulation (EU) No 748/2012, Article 3, paragraph 1 (a) (iii) specifies that “the applicable airworthiness directives were those of the State of design”.
This means that all ADs issued by the State of Design before 28 September 2003 (start date of EASA), either applicable to European or non-European products (i.e. aircraft, engines, propellers), parts or appliances (or STC modifications), have been adopted by EASA under that Regulation.
As a result, all ADs issued by the State of Design authority for the affected product(s), part(s) or appliance(s) are valid in Europe, unless EASA has issued a different decision.
Commission Regulation (EU) No 1321/2014, M.A.301, paragraph 5 (i) requires that the “aircraft continuing airworthiness […] shall be ensured by […] the accomplishment of any applicable airworthiness directive”, as identified by Regulation (EU) 748/2012.
All Foreign State of Design ADs issued after 28 September 2003 have been (and still are) ‘automatically’ adopted by EASA under the provisions of EASA Executive Director’s ED Decision 02/2003. This decision implies that any AD issued by the State of Design authority for the products, parts or appliances (or STC modification) to which that AD applies, becomes valid in Europe upon the day that AD becomes effective, unless the Agency issues a different decision (e.g. deviating AD, or statement of non-adoption) before that AD becomes effective. This decision applies to all State of Design ADs, not only those issued by the FAA.