Note on the Non-CO2 Mitigation Potential of Hybrid-Electric Aircraft Using "Eco-Switch"

Non-CO2 effects, like ozone production and contrail cirrus formation, account for about 50-75% of aviation's climate impact, which can be effectively mitigated by re-routing flights around highly climate-sensitive areas, like ice-supersaturated regions (ISSRs). With electric drives forming no contrails and binding all life-cycle emissions to the ground, also hybrid-electric aircraft (HEA) offer the capability to mitigate non-CO2 effects by switching to full-electric mode while passing those areas. For investigating the eco-switch HEA mitigation potential, a cost-benefit assessment of eco-switch trajectories is performed for two weather situations and benchmarked against the mitigation potential of climate-optimized re-routings. We studied the impact of the HEA fuel flow and the cruising time in a full-electric operation and identified distinct weather-related differences. If the eco-switch concept is applied while passing ISSRs, we found a significant mitigation potential for all combinations of full-electric cruise times and HEA fuel flow levels. This strongly implies that the climate impact of flights dominated by contrail-cirrus is largely driven by the level of climate sensitivities along the trajectory, rather than by emission levels (aircraft design). If no ISSR is crossed, the climate impact is increasing with increasing HEA fuel flow, implying that the emission volume outweighs the local climate sensitivity

Estimating the Economic Viability of Advanced Air Mobility Use Cases: Towards the Slope of Enlightenment

While different vehicle configurations enter the AAM market, airlines declare different ticket fares for their operations. This research investigates the operating cost of an airline and the economic viability with the announced fare per km rates. For this purpose, three use cases in the metropolitan area of Hamburg showcase representative applications of an AAM system, whereby a flight trajectory model calculates a flight time in each case. The direct operating cost are investigated for each use case individually and are sub-classified in five categories: fee, crew, maintenance, fuel and capital costs. Here, each use case has its own cost characteristics, in which different cost elements dominate. Additionally, a sensitivity analysis shows the effect of a variation of the flight cycles and load factor, that influences the costs as well as the airline business itself. Based on the occurring cost, a profit margin per available seat kilometer lead to a necessary fare per km, that an airline has to charge

A Collaborative Systems of Systems Simulation of Urban Air Mobility: Architecture Process and Demonstration of Capabilities

Urban Air Mobility (UAM) presents a complex challenge in aviation due to the high degree of innovation required across multiple domains to realize it. From the use of advanced aircraft powered by new technologies, the management of the urban air space to enable high density operations, to the operation of specialized vertidromes serving as a start and end point of the vehicles, the UAM paradigm necessitates a significant departure from aviation as we know it today. In order to understand and assess the many facets of this new paradigm, a Collaborative Agent-Based Simulation is developed to holistically evaluate the system through the modelling of the stakeholders. In this regard, models of vertidrome air-side operations, urban air space management, passenger demand estimation and mode choice, vehicle operator cost and revenues, vehicle maintenance, vehicle allocation, fleet management based on vehicle design performance and mission planning are brought together into a single Collaborative System of Systems Agent-Based Simulation of Urban Air Mobility. Through collaboration, higher fidelity models of each domain can be brought together into a single environment which can then be exploited by all partners, achieving comprehensiveness and fidelity levels not achievable by a single partner. Furthermore, the integration enables the capture of cross-domain effects with ease and allows the domain-specific studies to be evaluated at a holistic level. Agent-Based Simulations were chosen for this collaborative effort as it presents a suitable platform for the modelling of the stakeholders and interactions in accordance with the envisioned concept of operations. This work presents the capabilities of the developed Collaborative System of Systems Agent-based Simulation, the development process and finally a visual demonstration. The objectives of this presentation are: • Detail the development process of the Collaborative System of Systems Agent-Based Simulation • Demonstrate a holistic simulation of UAM built through collaboration of multiple tools/modules such as vertiport and trajectorie

Urban Air Mobility Research at the DLR German Aerospace Center - Getting the HorizonUAM Project Started

Efficiency, safety, feasibility, sustainability and affordability are among the key characteristics of future urban mobility. The project “HorizonUAM - Urban Air Mobility Research at the German Aerospace Center (DLR)” provides first answers to this vision by pooling existing competencies of individual institutes within DLR. HorizonUAM combines research about urban air mobility (UAM) vehicles, the corresponding infrastructure, the operation of UAM services, as well as public acceptance and market development of future urban air transportation. Competencies and current research topics including propulsion technologies, flight system technologies, communication and navigation go along in conjunction with the findings of modern flight guidance and airport technology techniques. The project analyses possible UAM market scenarios up to the year 2050 and assesses economic aspects such as the degree of vehicle utilization or cost-benefit potential via an overall system model. Furthermore, the system design for future air taxis is carried out on the basis of vehicle family concepts, onboard systems, aspects of safety and security as well as the certification of autonomy functions. The analysis of flight guidance concepts and the sequencing of air taxis at vertidromes is another central part of the project. Selected concepts for flight guidance, communication and navigation technology will also be demonstrated with drones in a scaled urban scenario. This paper gives an overview of the topics covered in the HorizonUAM project, running from mid-2020 to mid-2023, as well as an early progress report

Efficient ride matching for optimized resource allocation in a UAM vertiport network

A significant reduction of door-to-door travel time is a key promise of urban air mobility (UAM), which requires the design of efficient route networks. The vertiport positioning problem is a crucial aspect of UAM network design, targeting to locate sufficient throughput capacity in spatial proximity to areas of high demand. In the scope of this presentation, an overview on various investigations addressed in the literature will be given. Predominantly, these investigations comprise analyses regarding achievable time savings, covering location problems and competitiveness with other transport modes. Other examinations are focused on demand and travel behavior, taking network topology and network density into account. Further relevant research in that context is available on the capacity modeling of single vertiports, for instance depending on the number of landing pads, parking positions and gates. Procedures for optimal traffic sequencing of incoming and outgoing vehicles represent a further research field. Results of this presentation highlight a significant research gap regarding the optimal distribution of resources inside a vertiport network, such as parking positions, landing pads as well as infrastructure for charging or maintenance purposes. We propose a four-step design methodology aiming at conducting this resource distribution. The key component of this methodology is an algorithm describing ride matching and tour planning that enables efficient fleet operations. We exemplarily apply a prototype of our model to derive local demand for parking positions inside a vertiport network, and present initial simulation results. The method presented will be applied on an exemplary set of vertiport positions in Hamburg City and potential use cases for further investigations will be discussed

U-Space modeling and efficiency evaluation in the City of Hamburg

In the scope of prior investigations conducted in the research project UDVeo, an exemplary U-Space system has been developed for the City of Hamburg. As a result, a four-stage concept for UAS airspace allocation in U-Spaces has been presented. In this study, that concept is assessed applying numerical optimization methods. Starting by taking an analysis of the system requirements, represented by demand scenarios, we derive boundary conditions regarding the anticipated traffic density. Then, we analyze performance data of available vehicles in order to derive the required extent of well-clear zone. Finally, we present a model for capacity computation of the most complex airspace allocation method and assess the design regarding three kinds of efficiency, which comprise detour over ground, flight time extension and departure delay, caused by deconfliction measures. The results show that for the derived parameters of a well-clear zone and the resulting operational volume, the high traffic densities anticipated due to future use cases, such as delivery, might result in significant values regarding detour, delay and flight time extension