FAQ n.70136

The opt-in in Article 2(4) does not cover air operations and air crew, but only design, production and maintenance of the aircraft concerned. So for aircraft to which this opt-in applies, the Basic Regulation will apply to airworthiness (design, production, maintenance), but for the air operations and licensing areas the aircraft will remain excluded from the scope of the Regulation, meaning that national rules will apply.   So the situation would be as under the initial Basic Regulation (Regulation (EC) 1592/2002), where the rules were harmonised in the airworthiness field but air operations and air crew licencing remained under the national competence (without mutual recognition).