When dangerous substances are carried on board a vessel, an expert with special knowledge of ADN must be on board, in accordance with paragraphs 7.3.1.15 and 7.2.3.15 of the Regulations annexed to ADN. Chapter 8.2 of ADN sets out the requirements for the training of such experts. Proof of this knowledge must be provided by means of a certificate issued by the competent authority or a body authorized by it. This certificate is issued to people who at the end of their training have passed a qualifying examination on ADN. Experts must take part in at least one basic training course. Experts on the transport of gas or chemicals must take part in ‘gas’ or ‘chemicals’ advanced training courses, and must pass the examination. For the examinations referred to in paragraph 8.2.2.7.0 of the Regulations annexed to ADN, multiple-choice questions are chosen from a catalogue of questions drawn up by the Administrative Committee of ADN. These questions and the directive on the use of the catalogue of questions appear below, updated in accordance with the provisions of ADN 2013.