This research addresses the increasing electrification of aircraft systems, driven by the need to improve energy efficiency and reduce CO₂ emissions in global aviation. The transition to more-electric aircraft (MEA) is advocated as a promising strategy, as it is expected to improve environmental performance and economic viability. However, this shift significantly increases the demand for on-board electrical power. One alternative to traditional engine generators is novel power supply systems such as fuel cell systems. In order to design these systems effectively, it is essential to determine the electrical power requirements that the fuel cells must supply. Estimating the electrical power consumption of individual aircraft systems is critical given the proprietary nature of manufacturer data. Using existing literature methods, this study aims to identify the essential variables for estimating the magnitude of power consumption. The research focuses on different aircraft models, taking into account their system architectures and electrification trends, in particular for Airbus and Boeing models. The study includes a detailed description of the aircraft systems, calculation methods, and presentation and analysis of the estimated electrical power requirements. Despite a lack of available data for comparison, the calculated results appear to be reasonably consistent with existing literature and provide valuable insights into the electrical power requirements of aircraft systems.

The change towards carbon neutrality in air traffic involves a huge reduction of greenhouse gas emissions. This goal is beyond reach by the step wise improvement of conventional technologies. Hence, at present a solution which gains much of attraction are electric motors and electric aircraft systems in combination with fuel cells which can be run by green hydrogen. For a holistic comparison of various concepts the consideration of reliability aspects is required even at an early stage of design. In the scope of this work methods from reliability and safety engineering will be introduced and set in context of aeronautical fuel cell systems. On that basis the consequences arising by the requirement of redundancy are investigated on a system level approach. For this purpose, a model of an aeronautical fuel cell system will be set up in order to simulate a generic flight envelope at stationary points. The fuel cell system is chosen to be central-monolithic and its components are sized for the propulsion of a regional aircraft. With the aid of the system simulation, various failure scenarios are investigated from which mitigation strategies can be derived. Finally, the baseline design will be improved in terms of redundancy in order to last in a generic failure scenario. A comparison between the baseline and improved design shows that the additional redundancy comes with the cost of 4.6% weight increase and a 2.5% drop in cruise efficiency.