Periodic Reporting for period 3 - NGCTR DIGIFuel (Distribution and Gauging Interconnected Fuel System for the Next Generation Civil Tilt Rotor) Reporting period: 2019-12-01 to 2021-05-31 Summary of the context and overall objectives of the project The objectives of this project are both scientific/technological and industrial regarding competitiveness.With reference to the technical aspects, DIGIFuel aims at achieving the following objectives:- studying, designing, developing, manufacturing, testing and qualifying a flight-cleared fuel distribution and gauging system for the demonstrator vehicle;- identifying and experimenting an innovative fuel system architecture;- maximizing the reliability of the engine feed function;- pioneering the use of intelligent transfer pumps and innovative level sensors;- removing the risk of explosion by introducing a gauging system which will feature only optical cables with electrical power inserted inside the tanks only via power-on-fiber;- validating the functionality of the fuel system;and, through the achievement of the previous goals, reaching a mature definition of the Fuel System and its components, which might stand out as a benchmark for future aircrafts.Thanks to its expected outstanding technical outcomes, fostered within such relatively long industrial collaboration on research topics between the partners and the airframer, DIGIFuel can also target the following:- a set of new, game-changing equipment, featuring innovative technologies and validated by operational data in the field of aeronautical Fuel Systems, will be mature for the implementation on the Tilt-Rotor platform, as well as on other conventional types of aircrafts;- the partnership between Secondo Mona and Politecnico di Milano will be strengthened with mutual benefits on further collaborations in the development of innovative solutions for aerospace applications even beyond the scope of NGCTR;- Secondo Mona will make a step forward and gain solid expertise on the integration of novel fuel system components and technologies onto peculiar airframes such as the NGCTR, which will make Europe competitive towards the rest of aerospace industry;- at the same time a European airframer (Leonardo Helicopters) will get first-hand touch of the promising potentialities of such novelties and be the first to enjoy their benefits;- the joint cooperation in the operational context of Clean Sky 2 will establish an example of durable, open and fruitful collaboration within Europe, thus shaping and reinforcing a worldwide industrial excellence in the integration of systems and aircrafts. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far As regards Work Package 1 (program and risk management), periodic reviews have been performed between DIGIFuel and Leonardo Helicopters as well as Joint Meetings the partners working on the project (T-WING, DEFENDER) in order to enhance the co-operation between parties and help the proceeding of the activities.The Trade-Off studies (Work Package 2) resulting from joining work between the technical team of SM and LHD have led to the release of the technical documentation included in the Deliverable D2.1.The detailed Trade-Off studies carried out by DIGIFuel are as follows:- definition of the fuel system final layout;- definition of the corresponding parts list;- fuel pump smart controls studies;- fuel gauging and sensing technology studies involving optical fiber sensors and power-over-fiber solutions;- a preliminary system safety analysis.A preliminary design of Technology Demonstrator gauging and distribution sub-system with optical fiber (partially Work Package 3, and Work Package 4 for Partner PoliMi) also started during the first reporting period.A recap of the NGCTR-TD Gauging and Distribution SubSystems Preliminary Design (Work Package 3 in the NGCTR-TD Fuel System Master Program Plan) developed by Secondo Mona (SM) and Leonardo Helicopter Division (LHD) in order to achieve the Preliminary Design Review OPENING MILESTONE (PDR) for Next Civil Generation Tilt-Rotor Program is reported in the 2nd technical periodic report. The preliminary design studies resulting from the joining work between the technical team of SM and LHD have led to the release of the Deliverable D3.1. The list of the activities performed is reported here below:- preliminary equipment interface and performance definition;- study and definition of equipment validation campaign;- study and definition of lab testing on demonstrators;- preliminary innovative equipment performance calculation and reporting;- reliability analyses;- preliminary safety and hazard analysis;- preliminary simulation data and SW plans.Dissemination has been performed either by Secondo Mona (by displaying information leaflets with JU/CS2 logo and project titles and main information during Air Shows in the period covered by present document and illustrating the project to attendees) as well as by Politecnico of Milan through preparation of scientific document such as dissertation thesis. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) NGCTR DIGIFuel will be carried out following the standard path of typical aeronautical system development programmes.It is worth to recall, in this regards, that the main target of the whole project actually consists in the supply of qualified, flyable hardware: a complete working fuel system and not just isolate development units.The engineering design life cycle of the fuel system to be developed will undergo documented, comprehensive, systematic examinations of the design to evaluate the adequacy of the design requirements, to evaluate the capability of the design to meet these requirements, and to identify problems.It should be made clear that the technical effort of this project focuses on the development of an innovative system configuration itself, and on reaching the demonstration of the advantages that the innovative features introduced in the dedicated components yield to it. Which is why the purpose of this project is limited to the equipment/technologies that enable the demonstration of the innovative concept, and it is assumed that only those equipment which have no remarkable innovation content, yet are needed to complete the regular functionalities of the fuel system, will be selected among suitable equipment already available at Leonardo Helicopters, supplied by Secondo Mona for other programmes. Communication leaflet