Think led both Validation and Safety activities on behalf of NATS, for a recent validation exercise, VP-501, as part of the SESAR project P04.07.02, Separation Management. VP-501 involved validating the Conflict Detection and Resolution Tools for Planner Controllers in En-route airspace. This was a complex validation exercise involving integration of these planner tools onto an iTEC based IBP with CATSi (a version of iFACTS that works with iTEC). Six days’ real time simulation were undertaken at NATS Corporate and Technical Centre in Fareham, UK. Think staff are now currently analysing the results and working on the SESAR SAR and Validation Report which are due in June and July respectively.