This document presents Safety Case Guidance Material for the EUROCONTROL Airport Collaborative Decision Making (A-CDM) Project. The relevant A-CDM milestones, flight phases and data flows have been systematically analysed. The safety impacts of A-CDM have been identified and documented. Where concerns or new hazards have been found, appropriate risk mitigation has been proposed with the aim of ensuring that the A-CDM project is acceptably safe in principle. Guidance has been provided by EUROCONTROL to assist stakeholders in implementing the A-CDM elements safely and in preparing their own local safety assessments/ cases.