The First ATC Support Tools Implementation (FASTI) Programme aims to offer improvements in safety, capacity and efficiency by implementing new automated tools to support controllers in conflict detection, planning, monitoring and co-ordination. EUROCONTROLs role is to coordinate, harmonise and expedite the implementation of these tools. ANSPs, supported by industry, will be responsible for implementation and operation. This document is a Preliminary Safety Case (PSC) for the FASTI tools and their associated human and procedural elements. It comprises a structured Argument and Evidence, showing that the FASTI concepts and high-level design as proposed by EUROCONTROL can be made acceptably safe for use in the proposed operational context.