The EFACA project consists of 6 main objectives at 3 levels. Level 1 consists of three TRL3 demonstrations of technologies relevant to the greening of aviation: (WP1) bench testing of a gearbox combining input from gas turbine and electric motor for an hybrid turbo-electric propulsion system for a propeller-driven regional aircraft; (WP2) comparative testing of fuel cells with conventional liquid and novel phase cooling, to show the benefits up to 20% of the latter in higher net power, reduced heat losses, and smaller volume and weight also reengineering of fuel cell and structural components to increase power-to-weight ratio up to 80%; (WP3) static ground testing of a complete liquid hydrogen fuel system from cryogenic tank to vaporization and combustion in a wide range of operating regimes and simulation of application to the speed and altitude flight envelope of jet airliners. Level 2 consists of two preliminary designs: (WP7) an 80-seat 1000-km range regional propeller driven aircraft including design and integration of hybrid turbo-electric propulsion; (WP89) a 150-seat 2000-km range jet liner with liquid hydrogen fuel including design and integration of cryogenic tanks and fuel system. At level 3 a road map (WP10) for the achievement of the EU environmental targets for aviation synthetizing conclusions in four steps:

1. current status on (WP4) emissions and (WP5) noise versus future targets and gap to be covered;
2. assessment of relevant technologies to cover the gaps, including (WP6) battery electric and (WP9) sustainable aviation fuels, besides hydrogen (WP7) fuel cells and (WP8) turbines;
3. most suitable technology for each class of aircraft (light, small and medium regional, single and twin aisle jetliners), and maturation time of the technology;
4. contribution of each aircraft class to CO2 and non- CO2 global and local emissions and noise, leading to (WP10) a comprehensive road map of actions for carbon-free or emissions-free flight.