Chinese Aeronautical Establishment
Compared with traditional aircraft, electric aircraft employs electric energy as the whole or partial energy for the propulsion system. Therefore, electric aircraft is considered as an important move to implement the "Green Aviation" initiative and address the global environmental challenges, an inevitable choice to cut the global carbon emissions of aviation sector by 50% through 2050 from the emission level in 2005, and an important symbol of "the Third Great Era of Aviation". Electric aircraft has triggered a new wave of innovation and reform in aviation sector, led the aviation technology innovation, and promoted the green aviation development, and it will have a revolutionary impact on the world's aviation industry. As for the electric aircraft sector, domestic and foreign research institutions and enterprises are in their infancy, which provides China's electric aviation industry with an opportunity to rapidly reach or surpass the world's advanced level, and drives China's overall development of multiple related industries.
To further pioneer the development of electric aircraft technology in China and promote the industrial distribution of electric aircraft, Chinese Aeronautical Establishment (CAE) called up top-level China-based organizations to bring forward the White Paper on Development of Electric Aircraft covering such topics as necessity of development, definitions & classification, key products, key technologies, measures & recommendations etc. of electric aircraft. The White Paper suggests that China should give priority to develop four types of electric aircraft, i.e., light sport, urban air transport, commuter transport, as well as mainline and regional aircraft; focus on the development of key technologies such as overall design technology, high-efficiency and high power-to-weight-ratio electric propulsion technology, integrated energy management technology, energy system technology, etc. in major areas; China is recommended to establish its strategic plan for development of electric aircraft, increase investment in R&D, and pay close attention to the airworthiness capability building and talent training, thereby promoting the development of electric aircraft in China.
During drafting the White Paper, the Aviation Industry Development Research Center of China（ADR） played an important role and received substantial support from factories and institutes of AVIC, Liaoning General Aviation Academy, Beihang University, Northwestern Polytechnical University, Xiamen University, Contemporary Amperex Technology Co., Ltd., and other organizations. We hereby express our sincere gratitude to them.
Strategic thrusts of aviation research include global mobility, environmental challenges, and technical spotlight. And the transition to low-carbon aviation propulsion system through alternative fuels and advanced low-carbon propulsion technologies is a key initiative to address environmental challenges. According to NASA studies, electrically propelled aircraft may offer potential benefits for over 60% reduction in energy consumption, over 90% reduction in emissions, and over 65% reduction in noise, respectively; the EU also holds that electrically propelled aircraft is the only way to comply with Europe's carbon emission requirements by 2050.
In recent years, electric aircraft technology development has been booming all over the world. According to incomplete statistics, by June 2019, there were about 170 electrically-propelled aircraft projects under development all over the world, of which most were concentrated in North America and Europe and more than half were launched after 2017. At Paris Air Show in July 2019, the CTOs of 7 aerospace manufacturers, i.e., Airbus, Boeing, Dassault, GE Aviation, Rolls-Royce, Safran, and UTC, released a joint statement that listed electric propulsion technology as an important symbol of "the Third Great Era of Aviation", and they pledged to step up research and development of electric aircraft technology and drive the green development of aviation industry.
CAE attaches great importance to the development of electric aircraft, and actively carries out international cooperation in electric aircraft sector with the support from the Ministry of Industry and Information Technology of the People's Republic of China. In October 2018, CAE and NLR signed a Joint Action Initiative on strengthening cooperation in science and technology of civil aviation under the witness of the leaders of both sides; according to the Initiative, both sides will intensify their exchanges and cooperation in the field of civil aviation science and technology in the principle of "consultation on an equal footing" and "mutual benefit & win-win result". In April 2019, China and the Netherlands convened the 5th Sino-Dutch Civil Aviation Technology Forum & CAE-NLR Aviation Sustainability Seminar, where both sides reached a consensus that a White Paper on Development of Electric Aircraft will be drafted and issued to lead the development of electric aircraft in both countries, promote international exchanges and cooperation between the two sides, and further implement the Joint Action Initiative.
China and other countries are in their infancy in the electric aircraft sector; thanks to the opportunity offered by technological revolution induced by electric aircraft technology, China's aviation industry is expected to rapidly reach or surpass the world's advanced level and drive the overall development of many related industries in China.
2. Necessity of Development
2.1 Electric Aircraft is An Inevitable Choice for the Aviation Industry to Achieve Green Development
The rapid development of the aviation industry all over the world has created significant impact on the environment. Studies show that civil aviation contributes 2.5%~4% of the global carbon emissions; with the rapid growth in air passenger traffic, civil aviation is becoming the fastest growing industry in terms of carbon emissions. Since 1970s, the world's turnover of air passenger traffic has doubled about every15 years; growth is expected to continue at around 4.6% per year for the next 20 years. Air transport continues to put increasing pressure on the environment; how to mitigate the impact of aircraft on the environment has become an imminent problem to be resolved.
Principal countries in the world mandate improvement on the environmental performance of aircraft, and there is a growing call to build a green aviation ecology. ICAO, the United States and Europe developed a series of standards and guiding documents to lead the development of green aviation in terms of energy conservation, emission reduction and noise reduction. According to NASA studies, electric aircraft can help reduce energy consumption by over 60%, cut the emissions by over 90%, and decrease the noise by over 65%. The EU holds that electrically propelled aircraft is the only way to comply with Europe's carbon emission requirements by 2050. Adhering to the strategy of developing green aviation technologies, China's aviation industry carries out comprehensive studies on advanced aerodynamic technologies, noise reduction technologies, more electric aircraft (MEA) technologies, green power technologies, green material technologies, green manufacturing technologies, etc. to support the energy conservation and emission reduction of aircraft.
Based on the concept of environmental protection, high efficiency and energy conservation, electric aircraft has seen significant improvement on the environmental friendliness and comfort, thus become an inevitable choice for green aviation development.
2.2 Electric Aircraft is An Important Sector for China to Keep Pace with the World's Aviation Powers
In recent years, as representatives of the world's advanced level in aviation industry, a number of aircraft manufacturers and research institutions in the United States and Europe are highly focused on the research of electric aircraft. NASA released its electric aircraft development roadmap in 2015, and carries out researches synchronously in several technical routes: For the distributed all-electric propulsion technology, the X-57 Maxwell Demonstration Aircraft Program was launched, where the study on electric flight test of baseline aircraft propulsion system has been finished and the distributed electric propulsion retrofit efforts are underway; the study on STARC-ABL hybrid electric aircraft is carried out for B737 equivalent electric aircraft, where a 2.6 MW motor is installed in the rear fuselage, in addition, boundary layer ingesting technology is employed, thanks to which the drag is expected to be reduced by 7%~12%; the N3-X research program was launched for the future large mainline aircraft, where the specific fuel consumption would be reduced by 70% when compared with B777-200LR thanks to the superconducting power generation and motor technology. Airbus announced its electric aircraft development roadmap that covers general aircraft, urban air transport vehicle and mailline aircraft; the demonstration of E-FAN all-electric two-seat general aircraft has been finished, and the 2MW hybrid propulsion aircraft demonstration program (E-FAN X) is being implemented based on the BAe-146 aircraft.
China has also launched a number of technical researches and product developments in the electric aircraft sector. As for the basic technologies, the energy density of lithium batteries is approaching 300 watt-hours per kilogram, which is at the world advanced level; when it comes to small manned electric aircraft, Liaoning General Aviation Academy developed the Ruixiang (RX) series of two-seat general electric aircraft RX1E and RX1E-A; Hong Kong YUNEEC Aviation Technology Co., Ltd. developed Yuneec E430 two-seat general electric aircraft, and the relevant products have passed the airworthiness certification and launched into the market; for the future mainline and regional aircraft, CAE works with Beihang University, Northwestern Polytechnical University and other institutions of higher education to study new concept layout and key technologies, having carried out related researches on general layout scheme, electric propulsion system, superconducting power transmission, etc. for future large mainline aircraft.
In general, domestic and foreign research institutions and enterprises are in their infancy when it comes to electric aircraft. Thanks to the technological revolution induced by electric aircraft technology, China's aviation industry is expected to rapidly reach or surpass the world's advanced level and drive the overall development of many related industries in China, thereby underpinning China's ambition to become an aviation power.
2.3 Electric Aircraft is in face of Favorable Environment of Cooperation and Development Opportunity
At the Global Summit of the 9th International Forum of Aeronautical Research (IFAR) held in November 2018, 11 of the world's leading aeronautical research institutions, including NASA, DLR and CAE, participated in a seminar themed on the long-term potential, key technologies, and airworthiness certification etc. of electric aircraft, having reached a consensus that "electric aircraft is an important development direction of green aviation in the future"; moreover, they expect an in-depth discussion on the research trend and technology roadmap of electric aircraft at the 10th Summit.
As the Chinese representative organization at IFAR, CAE carried out extensive international cooperation on electric aircraft, and participated in the workshop "Technical Challenges and Opportunities Related to the Safety of Electric Aircraft" and the IFAR-X electric aircraft design project, having promoted the integration and common progress with international community in terms of electric aircraft technologies. Guided by the Sino-Dutch Joint Action Initiative on intensifying cooperation associated with sustainable development of science and technology for civil aviation, CAE and NLR will seek further cooperation and jointly promote the development of electric aircraft in both countries.
In recent years, a number of institutions of higher education and enterprises in China have been performing electric aircraft-related technical research and product development, and made certain achievements, having built a certain technical foundation for development of electric aircraft. In addition, with the improvement in the awareness of environmental protection and energy crisis and the gradual opening of low-altitude airspace, electric aircraft has seen a broad market prospect.
3. Definition and Classification
Electric aircraft employs electric energy as the whole or partial energy for the propulsion system, and all or part of its electric energy comes from battery, fuel cell, generator and other power supply devices. Different from conventional aircraft propelled by jet fuel engine, electric aircraft can effectively avoid the noise and pollutant emissions caused by traditional aircraft propulsion systems. The White Paper is principally focused on aircraft capable of carrying more than 75 kg payload for passenger/cargo missions.
By application scenarios, electric aircraft is classified into light sport electric aircraft, electric aircraft for urban air mobility, electric aircraft for commuter transport, and electric aircraft for mainline and regional transport services. Light sport electric aircraft is primarily designed for pilot training, tourism and competitions; electric aircraft for urban air mobility is designed for air transport services on demand in cities; electric aircraft for commuter transport is principally used for short-range commuter routes; electric aircraft for mainline and regional transport services is designed for regional services and long-distance routes.
By propulsion system architecture, electric aircraft is classified into all-electric aircraft, hybrid-electric aircraft, and turbo-electric aircraft. The propulsion system of all-electric aircraft is powered only by batteries; the propulsion system of hybrid-electric aircraft comprises gas turbine engine and batteries; according to the relation between gas turbine engine and battery, hybrid-electric aircraft is further classified into parallel hybrid, series hybrid, and partial series/parallel hybrid aircraft; turbo-electric aircraft is designed with gas turbine that drives generator to generate electric energy, thus being divided into all-turbo-electric and partial-turbo-electric aircraft.
4. Key Products
4.1 Light Sport Electric Aircraft
Priority will be given to the all-electric propelled fixed-wing general aircraft designed for sports, training and transportation. Electric light sport aircraft is of single/two-seat class with a range of approx. 150~300 km, a maximum take-off weight of 500~1,000kg, a maximum payload of 150~300 kg, duration of flight of at least 1 hour, and a cruise speed of at least 120 km/h.
Liaoning General Aviation Academy has developed the Ruixiang series of two-seat electric light sport aircraft; RX1E and RX1E-A have obtained type certificate and production license, and the next priority will be given to hydro-electric light sport aircraft.
4.2 Urban Air Mobility Vehicle
Priority will be given to all-electric propelled VTOL (eVTOL) aircraft designed for urban transport within 100 km. Urban air mobility vehicle is a multi-rotor passenger/cargo transport aircraft with a range of approx. 20~100 km, a maximum payload of 80~300 kg, and a duration of flight of at least 20 minutes.
Typical products in China include EHang 184/216 autonomous passenger transport aircraft vehicle and the light electric helicopter to be developed by Liaoning General Aviation Academy. Since the current products cannot meet the needs of urban air mobility market, it's necessary to further develop urban air vehicles with larger payload and longer range.
4.3 Commuter Transport Aircraft
Priority will be given to all-electric/ hybrid-electric commuter aircraft for short direct commuter flights between small airports with a range of less than 400 km and a payload of less than 20 passengers.
CAE proposed the concept of 4~5-seat all-electric commuter aircraft CAE-X1 for demonstrating the key technologies of distributed electric propulsion. With a design take-off weight of approx. 1,100 kg, this aircraft is powered by wing-mounted leading edge distributed motor to achieve a cruise speed of approx. 240 km/h. The technology readiness level is expected to reach Level 6 by 2025.
Based on Ruixiang (RX) series of two-seat electric aircraft, Liaoning General Aviation Academy is developing a four-seat electric aircraft, of which the maiden flight is expected to launch in October 2019.
4.4 Mainline and Regional Aircraft
Priority will be given to the development of hybrid-electric and turbo-electric mainline and regional aircraft. With a load of approx. 50~100 passengers and a range up to 3,000 km, regional aircraft is mainly designed to meet the demand of regional transport service market; with a range of at least 3,000 km and a load of at least 100 passengers, mainline aircraft is principally designed to address the need for mid-to-long range ultra-green transport in the future.
CAE proposed the concept of 60~90-seat hybrid-electric regional aircraft CAE-X2 with a range of 1,200 km. This concept employs rear fuselage-mounted propeller boundary layer ingesting technology, hybrid-electric aircraft energy management and distribution scheme. The technology readiness level is expected to reach Level 6 by 2030.
To meet the future mainline transport requirements, CAE proposed the concept of an ultra-green hybrid-electric and turbo-electric propelled aircraft with a load of more than 250 passengers and a range of 3,500 km. This concept adopts such technologies as distributed propulsion, superconducting power generation and motor. The technology readiness level is expected to reach Level 6 by 2050.
5. Key Technologies
5.1 Overall Design Technology
Compared with traditional propulsion system design, the electric propulsion system demonstrates a certain degree of scale-independent character of power; the overall design of electric aircraft can break through the limitations of traditional architectures, thus gaining a broader design space. On the other hand, due to the restriction by the power density of batteries and other components, when compared with conventional aircraft using traditional propulsion system, the electric propulsion system affects the performance indicators such as range and payload, which require more challenging demands on integrated design of aerodynamics, structures and propulsion, as well as innovative aerodynamic layout design.
(I) Integrated Design Technology of Aerodynamics, structures and propulsion
Compared with traditional fuel propelled aircraft, the design of aerodynamic layout and propulsion system of electric aircraft features higher degree of freedom and they are highly coupled; traditional independent design restricts the integrated optimization design, while the integrated design of aerodynamic, structural and propulsion systems helps effectively improve aircraft performance. The integrated design of aerodynamics, structures and propulsion technology for electric aircraft requires comprehensive trade study and iterative optimization design of aircraft motors, propellers, wings and nacelles, takes into account the geometric parameters, aerodynamic parameters, weight parameters and propulsion system parameters of aircraft, conducts sensitivity analysis and coordination of key parameters, performs scheme evaluation, thus supporting the selection of the optimal layout scheme.
(II) Innovative Design Technology of Aerodynamic Layout
To meet the requirements for aerodynamic layout design of electric aircraft, priority should be given, on the basis of conventional layout, to the technical studies on the new aerodynamic layout such as BWB layout, truss-braced wing layout and distributed propulsion layout, thus optimizing aerodynamic characteristics and improving the flight performance of aircraft.
The BWB layout integrates traditional fuselage and wing structures, and employs integrated design and manufacturing to improve the lift and reduce the structural weight and drag, thereby improving fuel efficiency and significantly improving the flight performance of aircraft.
Compared with traditional wings, the truss-braced wing layout uses trusses to support part of the load, which helps reduce the wing-root bending moment for weight reduction; under the condition of the same weight, this may increase the wing span and thus reduce the drag and improve the lift-drag ratio.
When it comes to the distributed electric propulsion layout, a few propellers/ducted fans are installed over the wings or fuselage in a distributed manner to improve aerodynamic efficiency and reduce the drag. For the boundary layer ingest technology, embedded fans are mounted at the aircraft tail to improve the aerodynamic performance through accelerated ingestion of fuselage boundary layer to reduce drag.
Figure 1 Overall Design Technology Development Roadmap of Electric Aircraft
5.2 High-efficiency and High Power-to-weight-ratio Electric Propulsion Technology
The electric propulsion technology drives the ducted fan or propeller through a motor with high power density to provide part or all of the flight thrust for aircraft, thereby effectively alleviating noise and pollutant emissions that trouble traditional aircraft propulsion system. As the key technology of electric aircraft, the electric propulsion technology determines the key performance indicators such as power and efficiency of electric aircraft. To ensure high efficiency, high power-to-weight ratio and high reliability, the following studies on key technologies should be conducted.
(I) Permanent Magnet Synchronous Motor
Permanent magnet synchronous motor (brushless DC motors) features high efficiency, high power-to-weight ratio and high reliability etc. when compared with other motors, thus being preferred for electric aircraft. With the new electric aircraft evolving towards large size, long range and high reliability etc., lightweight, efficient and reliable permanent magnet synchronous motor represents an important development trend of motors for electric aircraft in the future. Its key research topics include high-temperature and high-speed motor, the electromagnetic field-temperature field-flow field-stress field coupled design method of motor, and redundancy/fault tolerant control, etc.
(II) Superconducting Motor
Superconducting motor is a device where superconductor replaces routine conductor materials to realize the energy conversion between electromagnetic energy and mechanical energy. Featuring compactness, high efficiency, light weight and small synchronous reactance etc., this motor is much superior to ordinary motors in terms of torque with the same weight and the same energy input; with an extremely high potential for application in electric aircraft, this motor will be the key component of the novel aircraft propulsion system that will take the place of fuel jet engine.
Most of currently studied superconducting motors are semi-superconducting motors; all-superconducting motor represents an important development trend of superconducting motors in the future. The studies on superconducting motor focus on motor topology, the current carrying capacity of superconductor, superconducting permanent magnet technology, superconducting AC winding fabrication technology, and the tests on strength/reliability/service life of motors, etc.
(III) Motor Drive Controller
Motor drive controller is a key device that guarantees the efficient and reliable operation of permanent magnet synchronous motor and superconducting motor; it principally consists of control module and drive module to control the speed, angle and direction of motor. Electric propulsion system of electric aircraft requires motor drive controllers with high power, high efficiency, high reliability, and high power-to-weight ratio.
Motor drive controllers with new-generation power devices made from silicon carbide and gallium nitride represent the future development direction; its key research topics include the change mechanism of dynamic characteristics of WBG power device in extreme temperature environments, the variation law of motor loss and its inner mechanism at high temperature and high frequency, the multi-level modular topology and redundancy/fault tolerant drive control, and the phase change material-based heat dissipation of drive, etc.
(IV) Low-noise High-efficiency Propeller Technology
As an important power component for aircraft with distributed electric propulsion system, low-noise high-efficiency propeller improves the aerodynamic performance and reduces the noise of aircraft at the same output power. Its key research topics include the study on dedicated airfoil for advanced propeller, design technology of aerodynamic layout of high-efficiency propeller blade, aerodynamic/noise mechanism of propeller and numerical simulation method, 3D parametric modeling of blade and integrated design and optimization technology of aerodynamic/noise, etc.
Figure 2 Development Roadmap of High-efficiency and High Power-to-weight-ratio Electric Propulsion Technology
5.3 Integrated Energy Management Technology
As the primary energy of electric aircraft, electric energy will lead to rapid increase of grid capacity and increasingly complex load characteristics, which will require higher performance of the power distribution system; in addition, thermal management problem will become more prominent for power electronics and electric equipment of electric aircraft. Therefore, the following studies should be performed in terms of integrated energy management.
(I) Grid Architecture
The grid architecture of aircraft comprises power supply regime, power distribution system and topology, and power distribution fault tolerance and protection, which serves as a key factor affecting the safety, reliability, system quality and efficiency of aircraft. Moreover, the constraints (e.g., weight, volume, and change of operating conditions of aircraft propulsion system, etc.) over electric system of electric aircraft are important factors affecting the design of power distribution system. Therefore, a multi-objective optimization approach should be adopted to address the system requirements of electric aircraft. Its key research topics include the design and model simulation study of grid architecture; study on HV power supply regime; research on load characteristics of power grid; optimization evaluation study of grid architecture; study on operation, control protection, insulation and corona protection of power grid.
(II) Power Electronics Technology
Power electronics technology serves as the basis for transmission, conversion and control of aircraft electric energy; the electric system of each electric aircraft consists of large number of rectifiers, inverters, control components, etc. The power density and efficiency etc. of power electronic devices determine the performance of electric power system, and may significantly affect the safety and reliability of aircraft. The following studies should be conducted in terms of high-voltage, high-power, and high-efficiency power electronic devices: Topological design technology of power electronics; power conversion technology; silicon carbide, gallium nitride and other new materials-based high-power and high temperature-resistant power devices (e.g. solid-state power controller, and superconducting fault current limiter); module encapsulation design, etc.
(III) Thermal Management Technology
Thermal management technology is intended to dissipate heat and cool various aircraft components and systems, and it is essential to ensure normal and efficient operation of components and systems of electric aircraft (especially motors and power electronics). Furthermore, superconducting motors need low temperatures to maintain the superconducting state, and thermal management technology can guarantee the heat insulating capacity of superconducting system, thus preventing external heat affecting the superconducting low temperature environment. Its key research topics include closed-loop vapor cycle refrigeration technology, heat sink (fuel) cooling technology, and deeply cryogenic superconducting refrigeration technology.
(IV) Intelligent Energy Management
Since aircraft systems are increasingly complex and highly coupled, it is impossible to achieve efficient use of aircraft energy with traditional standalone energy management for each system. Intelligent energy management addresses integrated optimization design and control management of energy by taking each aircraft as a whole to effectively improve energy efficiency. Its key research topics include aircraft integrated energy management model, top level analysis & design of energy management, system quantitative evaluation method, and studies on intelligent adaptive energy management for each flight phase.
Figure 3 Development Roadmap of Integrated Energy Management Technology
5.4 Energy System Technology
Energy system is an energy supply component of electric aircraft, and its performance fundamentally determines the flight duration, range and operating cost of aircraft. With the technical advancement in lithium battery, fuel cell, supercapacitor and other new energy sources, as well as superconducting power generation and superconducting motor, the electric propulsion technology will be gradually applied in general aircraft, commuter aircraft, and mainline and regional aircraft. Energy system with long service life and high reliability features more stable power supply capacity and lower maintenance and replacement frequency, which can effectively improve the availability of electric aircraft.
(I) Pure Electric Energy System
In a pure electric energy system, only batteries supply energy to aircraft propulsion and airborne systems. Battery performance is a vital factor restricting the development of electric aircraft, and battery with long service life, high energy density and high power density is a key technology that needs to be addressed in the future, and has an immediate effect on aircraft range and flight duration, the efficiency of take-off, landing and climb, and the fast charging capacity. Its key research topics include lithium batteries with high energy density, fuel cells with high power density, high-capacity supercapacitors, structure-function integrated energy storage materials, flywheel energy storage, small-scale controllable nuclear energy, etc.
Figure 4 Energy System Technology Development Roadmap
(II) Hybrid-electric Energy System
In a hybrid-electric system, fuel and batteries work together to supply energy to the aircraft propulsion and airborne systems. According to the relationship between fuel and battery, the hybrid-electric system is classified into series hybrid-electric system, parallel hybrid-electric system, and turbo-electric hybrid system. Its key research topics include series hybrid-electric system configuration, electric power matching and switching technology, parallel hybrid-electric system configuration, power generation and grid connection technology, turbo-electric system configuration, and power generation and power conversion technology.
6. Measures & Recommendations
First, it's necessary to formulate electric aircraft development strategies and design the development route at the state level. The design ideas and concepts of electric aircraft are different from that of traditional aircraft, and its technical R&D involves huge investment and high risk. It is recommended that an Electric Aviation Council should be established to pool China's advantageous resources, initiate studies on China's electric aircraft development strategies and plans, call up China's relevant organizations to study and formulate an electric aircraft development roadmap, and guide the electric aircraft to develop in a healthy, rapid and orderly fashion.
Second, attach great importance to the development of electric aircraft and increase investment at the state level. Since electric aircraft exhibits a broad market prospect, both the United States and Europe is actively developing electric aircraft technologies and grabbing more market shares. Since electric aircraft represents an important area for China to keep pace with the world's aviation powers, it's advisable to attach great importance and make early arrangement by formulating special research plans for electric aircraft, increasing investment in R&D, thus stimulating rapid development of electric aircraft industry in China.
Third, enhance building the standards, specifications and airworthiness capacity of electric aircraft. It's necessary to establish a market-oriented and enterprise-focused open standard and specification system for electric aircraft, and lead efforts to resolve problems in key standards and basic standards for electric aircraft; make breakthroughs in airworthiness certification and verify key technologies, and improve the airworthiness certification and verification capacity of electric aircraft.
Fourth, further develop composite talents and professionals. The cross-disciplinary collaborative style innovation of electric aircraft will overturn the traditional aircraft R&D and operation patterns, so it's essential to train and introduce more high-quality, cross-disciplinary and cross-domain talents and build specialized electric aircraft R&D teams to guarantee the sound development of electric aircraft.
The White Paper is to be published in Issue 11 (2019) of Aeronautical Science and Technology.
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