Regulation (EU) No 376/2014 requires occurrence reporting systems to be established at organisation, Member State and Union levels, in view for all relevant civil aviation safety information to be reported, collected, stored, protected, exchanged, disseminated, analysed and followed-up. In addition, it provides for rules limiting the use of information collected to the enhancement of aviation safety and appropriately protecting the reporter and other persons mentioned in occurrence reports in view of ensuring a continued availability of safety information. Regulation (EU) No 376/2014 applies to all aircraft defined and covered by that Regulation, including manned aircraft and Remotely Piloted Aircraft Systems.

According to the first subparagraph of Article 4(5) of Regulation (EU) No 376/2014, the Commission is required to adopt a list classifying occurrences to be referred to when reporting occurrences, under mandatory reporting systems set out in that Regulation, and which fall within the categories of Article 4(1) of that Regulation. A second list should contain, in accordance with the second subparagraph of Article 4(5) of Regulation (EU) No 376/2014, a classification of occurrences applicable to aircraft other than complex motor-powered aircraft. This second list should where appropriate, be adapted to the specificities of that aviation sector.

The division in categories of occurrences to be reported provided for in Regulation (EU) No 376/2014 was established in order to allow the identification, by the persons designated by that Regulation, of the occurrences to be reported by each of them. In line with that objective, the lists of occurrences should be divided following the categories to which reporters should refer, according to their respective situation, in accordance with Regulation (EU) No 376/2014.