Hybrid-electric propulsion systems offer the potential to make aircraft more efficient by using electric energy to cover a share of the total energy demand. However, resolving questions related to aircraft hybridization, such as the potential emission benefits and the energy management throughout the mission, is vital. This highlights the importance of holistic evaluation methods. Hence, this paper introduces a method for the design and evaluation of hybrid-electric propulsion systems. The method enhances current sizing methods by modeling a hybrid-electric turbofan and estimating electrical losses for the electric power train to explore energy management strategies. The method is demonstrated using the short-medium range concept aircraft D239. Initial simulations indicate a total increase in block fuel mass of approximately 1.8 % with constant hybridization throughout the 800 nm reference mission. However, optimizing the energy management strategy reveals a slightly improved result of a 1.25 % increase in mission block fuel. Key factors contributing to this improvement include using hybrid-electric power exclusively during the climb phase, shorter mission ranges, and omitting battery charging during flight. The paper concludes that further technological developments help to reduce the block fuel demand. However, an overall increase in block fuel mass persists under realistic assumptions. This highlights the need for further studies hybrid architectures and methodical refinement.

The trend for optimized electric secondary power generation and distribution systems in commercial aircraft requires electric actuation technology. Electro-hydraulic systems with electric motor-driven pumps (EMP) will likely serve as bridge technology for several actuation functions in the medium- (or long-) term. They enable to apply dissimilar actuation technologies in critical applications or where intrinsic advantages of hydraulic actuation shall be kept. Following the general design requirements for more electric aircraft (MEA) systems, like higher efficiency, lower cost, easier maintenance, and quicker installation, this study investigates the application of electro-hydraulic high efficient power packages (eHEPP) as electro-hydraulic supply modules. The eHEPP integrates the hydraulic system components and the EMP in a compact line replaceable unit. A variable speed EMP concept is applied to achieve a high efficiency of the eHEPP. Under the assumption that landing gear and empennage flight control actuation is hydraulic, different system configurations, ranging from a centralized system with one main eHEPP to a distributed system with local eHEPPs, are designed. In order to find the best concept the key performance of these configurations is evaluated according to the criteria system mass, reliability, availability and efficiency. The evaluation is based on a steady state system sizing and preliminary safety studies. A typical short range aircraft, similar to the Airbus A320 or the Boeing 737, serves as reference for geometry and flight control concept. The study was performed in cooperation with Liebherr-Aerospace Lindenberg GmbH as part of its contribution to the Clean Sky 2 Systems ITD.

Recent statements by the FAA regarding commercial aircraft certification guidelines indicate that structural elements have to be considered in safety analysis of flight control systems in a wider scope. The monitoring of failure modes within the drivetrain is expanding to include the kinematics and control surface itself. Among other aspects, this leads to implications for the high-lift system, since it is unclear if structural defects can be reliably detected by conventional fault detection systems, such as angle sensors on the drivetrain or torque sensors at the drive unit. Consequently, this has to be investigated and alternative monitoring concepts have to be considered to meet the new requirements. This paper presents a study of a new monitoring concept for future leading edge slat systems using a virtual test environment. Utilizing a co-simulation consisting of MSC Adams for the flexible multibody simulation and Matlab Simulink/Simscape for the modelling of the drive train, the functionality and performance of a use-case monitoring concept for future leading edge slats based on position sensors is investigated based on various test cases.