To achieve lower Specific Fuel Consumption (SFC) and CO2/NOx emissions, modern turbomachineries operate at high velocities and high temperature conditions. The lack of confidence in the prediction of combustor-turbine interactions leads to apply extra safety margins on components design. Therefore, the understanding of combustor-turbine flow field interactions is mandatory to preserve High Pressure Turbine (HPT) life and performance when optimising the design of new HPT. The FACTOR objective is to optimise the combustor turbine interactions design to develop low-cost turbines and reduce SFC by 2%, HPT weight by 1.5% and accordingly engine cost by 3% compared to the results from the TATEF2 and AITEB2 projects.To achieve this objective, FACTOR will develop and exploit an innovative test infrastructure coupling a combustor simulator with a HPT for aerodynamic and aerothermal measurements. The infrastructure will improve the knowledge of aerothermal external flows since the inlet profile of the turbine and the secondary flows will be modelled and optimised together in the same facility, under engine representative conditions. Collected data will be fed into the design techniques and simulation software used to optimise HPT components. In parallel, the use of advanced CFD (e.g. LES or DES) will provide new knowledge on wall temperature and heat transfer predictions. This will be particularly important to design future combustor-turbine systems in an integrated manner, especially for the next generation of lean burn combustion systems having complex and severe flow constraints.By optimising the combustor-HPT interaction, FACTOR project will contribute to achieving the 50% CO2 and 80% NOx reductions ACARE 2020 environmental objectives. FACTOR will also strengthen the competitiveness of the European aeroengine industry by making available a new test infrastructure with experimental abilities beyond those of the US.