One of the most promising ways to reduce emissions at airports is by towing aircraft instead of taxiing with their main engines, also known as dispatch towing. One of the airports most involved with this concept is Amsterdam Airport Schiphol (AMS), as it has an emission-free target for 2030. One of the challenges with this concept is to optimize the assignment of Electric Towing Vehicles (ETVs) to maximize the effectiveness. The developed model can assign ETVs to flights and charging moments for the tactical planning phase, minimizing fuel consumption, charging cost and number of chargers. The results of the model are illustrated for two peak days at AMS. Both a small and large fleet of ETVs are assigned on both days for a northbound and southbound runway operation. The total fuel cost savings for the small fleet are 25% and 45% for the large fleet, which are similar on both days. On both days, outbound flights are the preferred direction to be towed due to the distribution of towing times. The savings per ETV are highest for a small fleet and decrease until all flights are towed. Furthermore, the load on the charging infrastructure at AMS for different fleet sizes shows what average and peak power can be expected. It is shown that ETV utilization and computation time can be improved significantly, by implementing costs on time and introducing utilization and symmetry constraints. However, with the important limitation that these improvements are observed only for small planning horizons. Finally, a sensitivity analysis on charging power showed that increasing the charging rate has a positive impact on both fuel cost savings and the minimum number of chargers required. In conclusion, this study shows the potential impact of dispatch towing at AMS in terms of fuel savings, charging infrastructure and operational challenges.@en

In response to the growing demand for air travel, major airports are approaching critical thresholds in their infrastructure capacity. As the transportation sector continues to expand, it is increasingly important to address environmental concerns that arise from aspects, such as noise annoyance and fuel consumption. This paper aims to enhance the existing Flexible Runway Scheduling Model (FRSM) by integrating a tabu search algorithm with Receding Horizon Control (RHC), introducing non-linear noise restrictions, and implementing more sophisticated fuel burn modeling. The main goal is to evaluate how certain improvements affect the FRSM. To achieve this, a methodology has been developed that uses a multi-objective tabu search algorithm to minimize both fuel consumption and noise annoyance while assigning flights to runways. This study provides a comprehensive analysis of Amsterdam Airport Schiphol (AAS) across different scenarios, ranging from a 1.5-hour flight schedule to a full-day simulation, revealing significant findings. For the 1.5-hour and six-hour scenarios, the tabu search algorithm achieves a 55% and 87.3% reduction in computational time with marginal losses of 0.73% and 0.19% in solution accuracy for fuel burn optimization. Throughout all scenarios, the tabu search algorithm consistently results in a reduction of highly annoyed individuals ranging from 2.14% up to 62.5% compared to the existing FRSM, demonstrating its effectiveness. Moreover, the algorithm minimizes the impact on the flight schedule in terms of delay. Notably, as the flight schedule length increases, the performance of the tabu search algorithm improves compared to the existing FRSM. A sensitivity analysis optimization horizon indicates a positive effect on results, albeit with an associated computational cost. In conclusion, this study showcases the positive impacts of the remodeled FRSM, enabling a faster and more accurate trade-off. The research findings provide valuable insights for optimizing runway scheduling at major airports while balancing efficiency gains with environmental considerations. @en

Aircraft performance has always been a focus of attention in aviation. The work of aircraft designers, certifying agencies, aircraft operators, and air traffic controllers relies on aircraft performance models. Current aircraft performance models are based on performance data of brand-new aircraft, independent of airline configuration and customizations. Nonetheless, over time aircraft suffer structure, engine and aerodynamic deterioration, as well as maintenance actions. These factors, which vary with tail number, make aircraft performance deviate from the theoretical and create the need for aircraft performance monitoring, and ultimately for aircraft performance tailoring. This research work proposes a novel approach to develop up-to-date, tail-specific performance models based on the use of Quick Access Recorder (QAR) data and machine-learning techniques. In particular, a methodology was designed to calibrate Base of Aircraft DAta (BADA), a widely consolidated physics-based performance model. As a result, more accurate performance models are generated, maintaining the same applicability over the entire flight envelope and during all phases of flight as BADA nominal models.@en

One of the potentially most significant ways of decreasing emissions at airport is by towing the aircraft on the ground instead of using its main engines. In this paper we will give a high level overview of what the potential average and marginal fuel savings and impact on emissions is for some of the larger airports in Europe and the US. Especially for large hub airports, the savings are significant and are very likely more than enough to make the benefit of fuel saved outweigh the investment and cost of operating a fleet of towing vehicles.

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Aviation significantly contributes to anthropogenic radiative forcing with both CO (Formula presented.) and non-CO (Formula presented.) emissions. In contrast to technical advancements to mitigate the climate impact, operational measures can benefit from short implementation times and thus are expected to be of high relevance in the near future. This study evaluates the climate mitigation potential of nine operational improvements, covering both in-flight and ground operations. For this purpose, an innovative approach is presented to compare the results of measure-specific case studies, despite the wide differences in the underlying modeling assumptions and boundary conditions. To this end, a selection of KPIs is identified to estimate the impact of the studied operational improvements on both climate and the stakeholders of the air transport system. This article presents a comparative method to scale the results of the individual studies to a comparable reference, considering differences in traffic sample size as well as CO (Formula presented.) and non-CO (Formula presented.) climate effects. A quantitative comparison is performed for operational improvements belonging to the same category, i.e., trajectory-related, network-related, and ground-related measures, and a qualitative comparison is carried out among all considered operational improvements. Results show that the in-flight operational improvements are more effective in mitigating the impact on climate with respect to ground operations. However, the latter generally have a weaker impact on the aviation industry and a higher maturity level. Further research could expand this study by assessing the effects of implementation enablers, such as actions at the regulatory level, to facilitate the acceptance of the studied measures in the aviation industry.

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One of the proposed methods of decreasing fuel consumption and emissions at airport is by equipping aircraft with electric motors for movement on the ground. In this paper a high level determination is given on what the potential average and marginal fuel savings and impact on emissions is for some of the larger airports and airlines in Europe and North America. The system could potentially be deployed on a selected sub fleet of aircraft, but fleet wide integration is not likely to result in cost covering benefits. The system is shown to be most beneficial on shorter flights between large airports, provided aircraft are not towed there.@en

The 2020 coronavirus pandemic lead to a virtual standstill of air passenger traffic in the spring of that same year. While some travel restrictions have since been lifted, passenger air travel is not expected to return to pre-coronavirus levels for several years. Then the question arises of how to park the large amounts of grounded aircraft efficiently, minimizing valuable airport space used. While aircraft parking for this purpose is a largely unexplored area in academic literature, the problem shows similarities with cutting and packing problems which have been researched for many years. Hence, the proposed model in the paper is modelled similar to that of the irregular strip packing model, where a fixed width is used and the length of the parking layout is to be minimized. Aircraft are represented as non-convex polygons and are allowed to rotate in discrete intervals. The concept of the no-fit polygon (NFP) is used in order to prevent overlap between aircraft. A tabu search algorithm with an adaptive tabu list is proposed in order to optimize the sequence and orientations in which the aircraft are placed onto the placement area using a bottom-left (BL) placement strategy. In order to evaluate the effectiveness of the proposed algorithm, several instances are created and tested using computational experiments.@en

Runway usage at complex airports is currently prescribed by a preference list focusing on minimizing noise and providing a manageable flow for ATC. However, fuel burn and the demand of flight is not considered. This study proposes a flexible runway scheduling model and is an improvement of the current flexible runway allocation model. The model is able to assign continuous delay to the scheduled flights and by changing the decision variables a new separation constraint is proposed to accurately model complex runway dependencies. A multiobjective optimization is performed for fuel burn and noise disturbance using Mixed-Integer Linear Programming (MILP). The model is tested on Amsterdam Airport Schiphol (AAS) for different scenarios. A fuel reduction of up to 7% is possible depending on the operational peak and O/D data. At the same time, noise violations are limited in the vicinity of the airport. This provides the opportunity to expand operations while complying with local noise regulations. Furthermore, the model can be used to explore operating strategies for different objectives for every runway configuration. @en

On-board electric motors can be used to drastically reduce the fuel usage during the taxiing phase of aircraft, leading to cost reductions for airlines and lower amounts of harmful emissions. This study analyses the current state of this innovation and its potential impact on aviation. On a global level, full adoption of electric aircraft taxiing is expected to cause a reduction in jet fuel usage of 846 million kg per year, equivalent to 186 million euros of reduced costs and 2.67 million tonnes of carbon dioxide emissions. This results in a reduction of 0.3% of the total global carbon dioxide emissions of the aviation sector. Locally, airports and their surroundings will benefit significantly from the reduced emissions, because a substantial fraction of airport emissions are due to the taxiing phase. Analysis of the effect of electric aircraft taxiing to key stakeholders such as airlines shows that American airlines would reap substantially larger benefits than European competitors because of consistently higher taxi times in the United States. Low-cost carriers are expected to see smaller impact than traditional hub-and-spoke airlines, due to short taxi times in the secondary airports they predominantly fly to. KLM could save 17.3 million kg of jet fuel annually, representing a cost of 3.8 million euros, which would potentially increase profits by 3%, and a carbon dioxide emission of 55 million kg. Since the road to full adoption is still long, a strategic analysis of the fleet shows the marginal yearly cost reduction per installed electric taxiing system starts at 82 thousand euros for the first product, which reduces to 10 thousand after 100 systems have been installed. Especially the flights between Amsterdam and London, Paris and Manchester should be assigned to aircraft with electric taxiing systems, because these flights would have the most impact given their relatively low flight distance and high taxi times. @en

Even though aircraft have become less pollutant over the years, the increase in air traffic results in a growing production of emissions in the aviation industry. In other words, the annual decrease in pollution due to more fuel efficient aircraft, cannot compete with the increase of pollution caused by air traffic growth. Unlike the aviation sector, most sectors can replace fossil fuels with alternate energy sources, but the airline industry is currently confined to kerosene for flight operations. On the ground, electric taxiing is an alternative to conventional taxiing, which would have less impact on the environment and could solve aircraft congestion problems at airports. This research focuses on the feasibility of an airport based electric towing system, which eliminates the need for using fossil fuels while on the ground as much as possible. @en

One of the infrastructural components that limits airport capacity is the available gate capacity. In order to use existing airport infrastructure, especially gates, more efficiently, one can look at new techniques to relieve congestion. One such technique is introducing socalled gate pit-stops. By introducing gate pit-stops, aircraft will be towed to a remote parking position between arrival and departure from the gate, in order to make space for other flights in the meantime [1]. The main risk of introducing gate pit-stops in airport operations is that the additional towing movements will inevitably increase the number of apron movements, potentially interfering with other traffic on or near the apron. As such, the main challenge in introducing gate pit-stops is modelling and integrating gate and apron movements, where a tradeoff can be made between gate utilization, towing movements, turnaround times and gate flexibility. Additionally, technological innovations such as an Electric Taxi System (ETS) need to be assessed as they can have a big impact on apron operations. Therefore, the effectiveness of gate pit-stops needs to be assessed, as well as the impact of factors such as gate utilization, towing movements and turnaround times on the effectiveness of such gate pit-stops. @en

The static apron capacity for aircraft with a wingspan higher than 65m is limited at Amsterdam Airport Schiphol (AMS). With the introduction of new large aircraft with increasing wingspan, such as the B777-9X, Schiphol is faced with the challenge of realizing larger gates. Currently, the taxi wingtip clearance is used for pushback and towing and the goal of this research is to see if it is possible to decrease the wingtip clearance there. Using aircraft transponder data and reproducing the pushback tracks for five gates, it is shown that some room is available to limit clearance and thus increase capacity at some gates, but more capacity could be gained by providing tug drivers with extra guidance through Differential GPS or a ‘Follow the Greens’ system.@en

If we would take fuel consumption and noise annoyance into account in the runway allocation process,runway allocation can take place more efficiently, both in terms of fuel cost as well as noise annoyance. In this research, the focus is on the further development of a model in order to make the calculationsmore refined. Moreover, the improvements conducted in this research relate to the methodologies to compute the cost of the decision variables and the level of complexity of specific linear programming constraints in the optimization model. Consequently, the aim of this research is to answer the following research question: Can the performance of Standard Flex be further optimized by applying pairwise flight dependencies, while ensuring and contributing to a valid trade-off between runway capacity, noise emission, fuel burn and safety. By means of this research, the flexible runway allocation model has been improved on many aspects. The computation strategy of both objectives has moved from a reference aircraft based computation strategy to an analysis based on each unique aircraft on its own. This refined computational approach has resulted in a better understanding and modeling strategy of the operations that take place at an airport. Finally, the implementation of RECAT-EU separation minima has resulted in a reduction of 5-10% in overall separation times with respect to the regular ICAO WTC strategy, based on multiple air traffic demand mixture scenarios, based on a specific demand of flights?.@en

http://www.ascos-project.eu/downloads/ascos_wp1_tud_d1.4_version-1.1.pdf@en