Article 34 — Review of compliance with the performance and charging schemes

1. The Commission shall regularly review compliance of Member States with Articles 21 to 27 and 29 to 32 and the implementing acts referred to in Articles 28 and 33. When carrying out that review, the Commission shall assess whether Member States ensure, in line with their duty of sincere cooperation, compliance by the air navigation service providers with their obligations under those Articles. The Commission shall act in consultation with the PRB and with national supervisory authorities. 2. Where the Commission has indications of non-compliance with the provisions referred to in paragraph 1, it may initiate an investigation. It shall conclude the investigation within four months, after having heard the Member State, and the national supervisory authority concerned. 3. Without prejudice to Article 52(1), the Commission shall share the results of the investigation with the Member State and, where appropriate, the air navigation service providers designated under Articles 8 and 10 concerned and the Commission may issue an opinion on whether Articles 21 to 27 and 29 to 32 and the implementing acts referred to in Articles 28 and 33 have been complied with by that Member State. It shall notify this opinion to the Member State concerned.