ED-205 provides a process to assess the extent to which the ATM/ANS ground systems are appropriately secure for use. The process is able to be used to identify, evaluate and manage impacts on safety, operational delivery and other commercial concerns. In ED-205A, the document has been updated to incorporate answers to the ‘non-concur’ comments received at the end of the open consultation phase in the form of further integration of the outcomes of the regulatory work being done by EASA’s ESCP and STORM work streams. Furthermore, previous version is here refined and detailed where necessary in order to be in line with the new basic regulation and the Part AIS. In doing so it is believed that the document could serve as an AMC for the aforementioned regulation.