Regulation (EU) 2017/373 that requires DAT provider’s certification from 1 January 2019.
This regulation is accessible here: Regulation (EU) 2017/373
To support the implementation of said Regulation, please note the associated AMC/GM issued with EASA ED Decision 2017/001/R.
The listed regulatory materials are consolidated in Easy Access Rules for Air Traffic Management/Air Navigation Services: Easy Access Rules for ATM/ANS. These consolidated, up-to-date rules are displayed in an easy-to-read format with advanced navigation features through links and bookmarks and are for free download from the EASA website. The document contains the applicable rules for the providers of Air Traffic Management/Air Navigation Services and other Air Traffic Management network functions, incl. DAT providers. It covers Regulation (EU) 2017/373 and all its annexes (together with the related AMC and GM).
Furthermore, in order to assist stakeholders to prepare for the implementation, EASA organised a workshop focusing on the new requirements and aiming to familiarise with the use of Acceptable Means of Compliance and Guidance Material, being established by the Agency. The presentations provided during this Workshop can be found on the page for the event: '1st EASA Workshop for DAT providers'.