The project scope is therefore to design and integrate a hybrid-electric aircraft Flight Test Demonstrator, and perform the ground and flight test demonstrations at full scale, including:

• The definition and selection of overall FTD architecture and configuration, capable to achieve the full-scale demonstration of the hybrid electric powertrain and more electric on-board systems, and their aircraft integration, compatible with the performance targets detailed in next section, for a regional aircraft concept with 2 wing-mounted engines based on a parallel hybrid architecture. A regional aircraft platform with high wing configuration and 2 engines, including 1 side retrofitted as hybrid-electric is foreseen, to be confirmed by the ultra-efficient regional aircraft concept owner.
• The definition and cascade of FTD requirements at aircraft, system, and sub-system levels, and the associated Validation & Verification plan and compliance matrix as needed to support the FTR and permit to fly.
• The design, analysis, manufacture, assembly, testing and qualification of the modifications of the selected FTD platform, as required to accommodate the hybrid-electric powertrain and enable the permit to fly and flight tests execution:
  • Wing modifications and redesign of components, such as:
    • Structural and systems adaptations and interfaces with the new propulsion system including structural reinforcements, installation of the High Voltage network to supply the electric motor in close proximity to the fuel system, and adaptation of the fuel systems.
    • Aerodynamic impact analysis and integration of the nacelle and propeller with the wing, including interaction studies supported by adequate modelling and Wind-Tunnel Testing (WTT) as required to achieve permit to fly.
  • Fuselage modifications and redesign of components, such as:
    • Installation and structural integration of additional equipment and functionality related to hybrid-electric propulsion, covering electrical, thermal management, energy management, and battery systems, including the associated structural analysis and reinforcements, routing installation, equipment supports.
    • The identification of the best suitable design solution especially for batteries integration according to safety requirements, represent a specific challenge to be addressed by the project.
  • Empennage modifications: evaluation of potential impact on empennage and if necessary, adequate modification of components.
  • FTD platform systems and global layout modifications and adaptations as needed for the flight-tests, such as cockpit engine control and display, and any adaptation related to the presence of two different powertrains on each wing (being assumed that the hybrid electric powertrain will be installed on one-side of the FTD platfoirm).
  • Specific attention should be given, and adequate safety precautions taken, related to the integration of novel technologies, such as High Voltage network (e.g. high altitude phenomena), battery packs (e.g. venting systems and fire protection to address thermal runaway), and additional thermal dissipations in proximity with the FTD platform structure and systems.
• The assembly and integration of all technological bricks on FTD platform for the hybridelectric propulsion:
  • The hybrid-electric propulsive system and associated nacelle and pylon (including systems related to thermal/electric power management located within the nacelle) o The on-board systems (Electrical Power Generation and Distribution System, Thermal Management System, Energy Management solutions) and the battery system delivering the electrical power for hybrid-electric propulsion.
  • The Flight Test Instrumentation (FTI) and relevant aircraft modifications required for the permit to fly and the flight test execution, data acquisition and performance monitoring.
• The preparation of the dossier for the safety of flight, including all needed analysis, testing and qualification evidences and documentation (e.g. weight and balance, flight manual,…) to achieve the permit to fly from relevant aviation national authorities and EASA.
• The preparation and execution of ground and flight-testing demonstrations making use of the FTD platform.
• The post-processing, analysis and assessment of testing campaigns results.

Performance Targets: A number of top-level goals for the Ultra-Efficient Regional Aircraft concept will be the basis for performance targets, in particular:

• Contribute to 30% CO2 emission reduction for the ultra-efficient Regional aircraft concept, without the inclusion of 100% SAF fuels, and to 86% CO2 reductions when 100% SAF is considered (assuming an 80% carbon footprint of SAF on average). This KPI is based on 2020 state-of-the-art technologies, paving the ground towards CO2-neutral aviation by 2050.
• To achieve this:
  • a 20% or greater CO2 emission reduction (without SAF) is expected for the hybridelectric powertrain, when integrated at aircraft level. This number accounts for weight and aerodynamic effects of the propulsive system and ancillary systems integration, hence the weight and size of the overall powertrain is to be minimised to achieve the highest aircraft performance.
  • 100% drop-in SAF compatibility shall be ensured.
• The evaluation, monitoring and reporting of key parameters needed to assess non-CO2 effects (including NOx, water and non-volatile Particulate Matter emissions), to ensure compliance with foreseen regulations and standards for a 2035 EIS.
• Noise emissions levels fully compliant with ICAO noise standard (chapter 14 noise limits), with adequate certification cumulative noise level margin, while considering future updates to the noise standard in view of a 2035 EIS.
• Targets must be compatible with safety as an overarching requirement, consistent with the certification path, including the CRL objectives (refer to topic conditions and expected outcomes), and the safety of flight of the FTD shall be ensured through Permit to Fly obtention. The top-level goals shall be broken down in a consistent manner at the different levels: from top-level aircraft requirements to propulsive system, sub-systems and components level requirements. Pertinent performance targets including Key Performance Indicators (KPIs) shall be derived et each level, including relevant weight, aerodynamics and Specific Fuel Consumption targets.