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The Federal Aviation Administration (FAA) is continuously assessing the operational performance of the National Airspace System (NAS), where they analyze trends in the aviation industry to help develop strategies for a more efficient air transportation system. To measure the performance of various elements of the aviation system, the FAA and the International Civil Aviation Organization (ICAO) developed nineteen key performance indicators (KPIs). This dissertation contains three research studies, each written in journal format, addressing select KPIs. These studies aim at answering questions that help understand and improve different aspects of airport operational efficiency. In the first study, we model the flight times within the terminal airspace and compare our results with the baseline methodology that the FAA uses for benchmarking. In the second study, we analyze the efficiency of deicing operations at Chicago O'Hare (ORD) by developing an algorithm that analyzes radar data. We also use a simulation model to calculate potential improvements in the deicing operations. Lastly, we present our results of a clustering analysis surrounding the response of airports to demand and capacity changes during the COVID-19 pandemic. The findings of these studies add to literature by providing a methodology that predicts travel times within the last 100 nautical miles with greater accuracy, by providing deicing times per aircraft type, and by providing insight into factors related to airport response to shock events. These findings will be useful for air traffic management decision makers in addition to other researchers in related future studies and airport simulations. / Doctor of Philosophy / The Federal Aviation Administration (FAA) is the transportation agency that regulates all aspects of civil aviation in the United States. The FAA is continuously analyzing trends in the aviation industry to help develop a more efficient air transportation system. They measure the performance of various elements of the aviation system. For example, there are indicators focused on the departure phase of flights measuring departure punctuality and additional time in taxi-out. On the arrivals side, there are indicators that measure the additional time spent in the last 100 nautical miles of flight. Additionally, there are indicators that measure the performance of the airport as a whole such as the peak capacity and the peak throughput. This dissertation contains three research studies, each one aims at answering questions that help understand and improve a different aspect of airport operational efficiency. The first study is focused on arrivals where we model the flight times within the last 100 nautical miles of flight. Our model incorporated factors such as wind and weather conditions to predict flight times within the last 100 nautical miles with greater accuracy than the baseline methodology that the FAA currently uses. The resulting more accurate benchmarks are important in helping decision makers, such as airport managers, understand the factors causing arrival delays. In the second study, we analyze the efficiency of deicing operations which can be a major source of departure delays during winter weather. We use radar data at Chicago O'Hare airport to analyze real life operations. We developed a simulation model that allowed us to recreate actual scenarios and run what-if scenarios to estimate potential improvements in the process. Our results showed potential savings of 25% in time spent in the deicing system if the airport changed their queueing style towards a first come first served rather than leaving it for the airlines to have their separate areas. Lastly, we present an analysis of the response of airports to demand and capacity changes during the COVID-19 pandemic. In this last study, we group airports by the changes in their throughput and capacity during two time periods. The first part of the study compares airports operations during 2019 to the pandemic during the "shock event" in 2020. The second part compares the changes in airports operations during 2020 with the "recovery" time period using data from 2021. This analysis showed which airports reacted similarly during the shock and recovery. It also showed the relationship between airport response and factors such as what kind of airlines use the airport, airport hub size, being located in a multi-airport city, percentage of cargo operations. The results of this study can help in understanding airport resilience based on known airport characteristics, this is particularly useful for predicting airport response to future disruptive events.

Persistent condensation trails are clouds, induced by the exhaust of an aircraft engine in a cold and ice-supersaturated environment. These artificial ice clouds can both cool and heat the atmosphere by scattering solar radiation and absorbing terrestrial radiation, respectively. The influence of condensation trails on the Earth-atmosphere energy balance and therewith the answer to the question of the dominating process had been mostly approximated on a global scale by treating the condensation trail as plane parallel layer with constant optical properties. Individual condensation trails and the influence of the solar angle had been analyzed, always using a course spatial grid and never under consideration of the aircraft performance, generating the condensation trail. For a trajectory optimization, highly precise results of the impact of condensation trails on the radiation budget and the influence of the aircraft performance on this impact is needed, so that future air traffic may consider the main factors of flight performance on the environmental impact of condensation trails. That’s why, a model is developed in this thesis to continuously estimate the scattering and absorption properties and their dependence on the aircraft performance. / Langlebige Kondensstreifen sind Eiswolken, welche durch Kondensation von Wasserdampf an Rußpartikeln in einer eisübersättigten Atmosphäre entstehen. Der Wasserdampf entstammt einerseits aus dem Triebwerkabgas und andererseits aus der Atmosphäre. Kondensstreifen können die Atmosphäre durch Rückstreuung solarer Strahlung kühlen und durch Rückstreuung und Absorption terrestrischer Strahlung erwärmen. Der Einfluss von Kondensstreifen auf den Wärmehaushalt der Atmosphäre und damit die Antwort auf die Frage nach dem dominierenden Effekt wurde bisher zumeist auf globaler Ebene ermittelt, wobei der Kondensstreifen als planparallele Schicht mit konstanten optischen Eigenschaften angenähert wurde. Individuelle Kondensstreifen und der Einfluss des Sonnenstandes wurden bisher nur mithilfe eines groben Rasters betrachtet und niemals unter Berücksichtigung der Flugleistung des Luftfahrzeuges, welches den Kondensstreifen generiert hat. Für eine Trajektorienoptimierung sind jedoch präzise Berechnungen des Strahlungseinflusses und eine gewissenhafte Berücksichtigung der Flugleistung notwendig. Nur so kann der zukünftige Luftverkehr die Haupteinflussfaktoren der Flugeigenschaften auf den Strahlungseinfluss der Kondensstreifen berücksichtigen. Aus diesem Grund wurde in dieser Arbeit ein Modell entwickelt, welches die Eigenschaften des Strahlungstransfers durch den Kondensstreifen kontinuierlich bestimmt und die aus der Flugleistung resultierenden Parameter berücksichtigt.

Le trafic aérien en Europe représente environ 30 000 vols quotidiens actuellement. Selon les prévisions de l’organisme Eurocontrol, ce trafic devrait croître de 70% d’ici l’année 2020 pour atteindre 50 000 vols quotidiens. L’espace aérien, découpé en zones géographiques appelées secteurs de contrôle, atteindra bientôt son niveau de saturation vis-à-vis des méthodes actuelles de planification et de contrôle. Afin d’augmenter la quantité de trafic que peut absorber le système, il est nécessaire de diminuer la charge de travail des contrôleurs aériens en les aidant dans leur tâche de séparation des avions. En se fondant sur les demandes de plans de vol des compagnies aériennes, nous proposons une méthode de planification des trajectoires en 4D permettant de présenter au contrôleur un trafic dont la plupart des conflits auront été évités en avance. Cette planification s’établit en deux étapes successives, ayant chacune un unique degré de liberté : une allocation de niveaux de vol permettant la résolution des conflits en croisière puis une allocation d’heures de décollage permettant de résoudre les conflits restants. Nous présentons des modèles pour ces deux problèmes d’optimisation fortement combinatoires, que nous résolvons en utilisant la programmation par contraintes ou les algorithmes évolutionnaires, ainsi que des techniques permettant de prendre en compte des incertitudes sur les heures de décollage ou le suivi de trajectoire. Les simulations conduites sur l’espace aérien français mènent à des situations où tous les conflits sont évités, avec des retards alloués de l’ordre d’une minute en moyenne (80 à90 minutes pour le vol le plus retardé) et un écart par rapport à l’altitude optimale limité à un niveau de vol pour la quasi totalité des vols. La prise en compte d’incertitudes de manière statique dégrade fortement ces solutions peu robustes, mais nous proposons un modèle dynamique utilisant une fenêtre glissante susceptible de prendre en compte des incertitudes de quelques minutes avec un impact réduit sur le coût de l’allocation. / Air traffic in Europe represents about 30,000 flights each day and forecasts from Eurocontrol predict a growth of 70% by 2020 (50,000 flights per day). The airspace, made up of numerous control sectors, will soon be saturated given the current planification and control methods. In order to make the system able to cope with the predicted traffic growth, the air traffic controllers workload has to be reduced by automated systems that help them handle the aircraft separation task. Based on the traffic demand by airlines, this study proposes a new planning method for 4D trajectories that provides conflict-free traffic to the controller. This planning method consists of two successive steps, each handling a unique flight parameter : a flight level allocation phase followed by a ground holding scheme. We present constraint programming models and an evolutionary algorithm to solve these large scale combinatorial optimization problems, as well as techniques for improving the robustness of the model by handling uncertainties of takeoff times and trajectory prediction. Simulations carried out over the French airspace successfully solved all conflicts, with a mean of one minute allocated delay (80 to 90 minutes for the most delayed flight) and a discrepancy from optimal altitude of one flight level for most of the flights. Handling uncertainties with a static method leads to a dramatic increase in the cost of the previous non-robust solutions. However, we propose a dynamic model to deal with this matter, based on a sliding time horizon, which is likely to be able to cope with a few minutes of uncertainty with reasonable impact on the cost of the solutions.

This thesis analyses the programme Single European Sky, which aims to reorganise the air space and to supply navigation and air traffic services in Europe. It describes the current state of implementation in the individual functional blocks of the air space as well as presents Maastricht Upper Area Control.

La gestion des flux de trafic aérien (ATFM) cherche à structurer le trafic de manière à réduire la congestion dans l'espace aérien. La congestion étant causée par les avions volant dans les mêmes portions de l'espace aérien en même temps, l'ATFM organise le trafic dans les dimensions spatiales (ex. le réseau de routes) et dans la dimension temporelle (ex. séquencement et fusion de flux d'avions atterrissant ou décollant aux aéroports). L'objectif de cette thèse est de développer une méthodologie qui permet au trafic aérien de s'auto-structurer dans les dimensions spatiales et temporelle quand la demande est élevée. Cette structuration disparait quand la demande diminue. Pour remplir cet objectif, un système multi-agents a été développé, dans lequel les avions coopèrent pour structurer le trafic. Les systèmes multi-agents possèdent plusieurs avantages, incluant une bonne résilience aux perturbations, la résilience étant la capacité du système à modifier ses décisions de manière à retrouver un état stable après l'occurrence d'une perturbation dans son environnement. Dans ce système, trois algorithmes sont implémentés, visant à réduire la com- plexité du trafic de trois manières différentes. Le premier algorithme permet aux agents avions volant sur un réseau de route de réguler leur vitesse de manière à ré- duire le nombre de conflits, un conflit se produisant quand deux avions ne respectent pas les normes de séparation. Le deuxième algorithme permet aux avions de résoudre les conflits quand le trafic n'est pas structuré par un réseau de routes. Le troisième algorithme crée des réseaux de routes locaux temporaires pour structurer le trafic. Les trois algorithmes implémentés dans ce système multi-agents permet de réduire la complexité globale du trafic, qui devient plus simple à gérer pour les contrôleurs aériens. Ces algorithmes sont appliqués à des exemples réalistes et sont capables de structurer le trafic de manière résiliente. / Air Traffic Flow Management (ATFM) aims at structuring traffic in order to reduce congestion in airspace. Congestion being linked to aircraft located at the same position at the same time, ATFM organizes traffic in the spatial dimension (e.g. route network) and in the time dimension (e.g. sequencing and merging of aircraft flows taking off or landing at airports). The objective of this thesis is to develop a methodology that allows the traffic to self-organize in the time and space dimensions when demand is high. This structure disappears when the demand diminishes. In order to reach this goal, a multi-agent system has been developed, in which aircraft cooperate to structure traffic. Multi-agent systems have several advantages, including a good resilience when confronted with disruptive events, resilience being the ability of the system to adapt its decisions in order to get back to a stable state when confronted to a disruption in its environment. In this system, three algorithms have been implemented, aiming at reducing traffic complexity in three different ways. The first algorithm allows aircraft agents flying on a route network to regulate speed in order to reduce the number of conflicts, a conflict occurring when two aircraft do not respect separation norms. The second algorithm allows aircraft to solve conflicts when the traffic is not structured by a route network. The third algorithm creates temporary local route networks allowing to structure traffic. The three algorithms implemented in this multi-agent system allow to decrease overall traffic complexity, which becomes easier to manage by air traffic controllers. This algorithm was applied on realistic examples and was able to structure traffic in a resilient way.

A evolução de sistemas de gerenciamento de tráfego aéreo é pesquisada para suportar o crescimento na demanda por transporte aéreo. Uma alternativa para essa evolução é o aumento no grau de automação. Os sistemas automatizados precisam ser tão seguros quanto os sistemas em operação atualmente. Com o uso de técnicas de especificação e verificação formal é possível avaliar os requisitos de sistemas. Neste trabalho, é proposto um ciclo de especificação formal, que consiste em um conjunto de diretrizes para aplicação de técnicas de métodos formais em requisitos escritos em linguagem natural. O resultado esperado da aplicação deste ciclo é um conjunto de requisitos escritos em linguagem natural verificados formalmente. O ciclo é composto pelas etapas: levantamento de requisitos do sistema e classificação em padrões de especificação; mapeamento dos requisitos para as linguagens de especificação formal LTL (Linear Temporal Logic) e CTL (Computation Tree Logic); verificação formal da especificação com o verificador NuSMV; ajustes na especificação baseada nos resultados da verificação; ajustes nos requisitos baseados nos ajustes na especificação. As diretrizes propostas são definidas com a análise da verificação formal do Automated Airspace Concept (AAC), padrões de especificação e diretrizes para uso do verificador NuSMV. Os resultados esperados são obtidos na aplicação do ciclo de especificação em dois estudos de caso. A principal contribuição do trabalho é o conjunto de diretrizes para elaboração de expressões escritas em linguagem de especificação formal baseadas em requisitos escritos em linguagem natural e que podem ser verificadas formalmente. / Air traffic management systems evolution is being researched to support air transportation demand growth. An evolution alternative is system automation degree increase. Automated systems need to be as safe as current operating systems. It is possible to analyze system requirements with the application of formal specification and formal verification techniques. In this work, a specification cycle is proposed. The specification cycle is a set of guidelines to use formal method techniques on requirements written in natural language. The specification cycle application expected result is a set of formally verified requirements written in natural language. This cycle is comprised of the following stages: system requirements elicitation and specification pattern classification; requirements mapping to LTL (Linear Temporal Logic) and CTL (Computation Tree Logic) formal specification languages; specification formal verification using the NuSMV verifier; formal specification adjustment based on verification results; requirements adjustment based on formal specification adjustment. The proposed guidelines are defined with the Automated Airspace Concept (AAC) formal verification analysis, specification patterns and guidelines for the NuSMV formal verifier use. The expected results are accomplished in the specification cycle application on two study cases. The main contribution of this work is the set of guidelines applied to formulate formally verifiable expressions specified in formal specification languages based on system requirements written in natural language.

La congestion dans les Terminal Manoeuvring Area (TMA) des aéroports en hub est le principal problème dans le transport aérien chinois. Face au trafic extrêmement dense dans les TMAs, nous pouvons envisager d'automatiser une grande partie des opérations de routine, comprenant la planification, le séquencement et la séparation. Nous proposons dans cette thèse un nouveau système automatisé de séquencement des avions et de fusion des flux vers des pistes parallèles, qui sont utilisées dans la plupart des aéroports chinois. Notre méthodologie intègre un réseau de route 3D nommé Multi-Level and Multi-Point Merge System (MLMPMS) basé sur le concept de l'Area Navigation (RNAV) et un algorithme d'optimisation heuristique hybride pour trouver une solution correcte, opérationnellement acceptable. Un algorithme de Simulated Annealing (SA) spécifique et un module de génération de trajectoire collaborent pour rechercher la solution quasi optimale. Notre objectif est de générer en temps réel des trajectoires sans conflit, minimisant la consommation de carburant et permettant des méthodes de contrôle faciles et flexibles. Dans ce but, nous explorons en permanence les solutions possibles avec le moins de retard et assuront l'atterrissage le plus rapide. Nous déterminons quatre variables de décision pour contrôler chaque vol : l'heure et la vitesse d'entrée dans la TMA, le temps de vol sur l'arc de séquencement et le choix de la piste utilisée. La simulation de trajectoire dans les différentes phases de vol est basée sur le modèle de performances BADA. Dans le cas de l'aéroport de Beijing Capital International Airport (BCIA), les résultats numériques montrent que notre système d'optimisation de bonnes performances sur le séquencement et la fusion des trajectoires. Tout d'abord, il permet d'assurer des performances de résolution conflit très stables pour gérer les flux de trafic continuellement denses. Par rapport à l'algorithme Hill Climbing (HC), le SA peut toujours trouver une solution sans conflit, non seulement pour l'approche parallèle mixte ou séparée~(pour les arrivées), mais aussi pour les configurations parallèles indépendantes~ (départs et arrivées intégrés). Ensuite, avec un réseau d'itinéraires Multi-Level Point Merge (ML-PM) unique, il peut fournir une bonne solution de contrôle de la trajectoire pour traiter efficacement et économiquement différents types de flux d'arrivée. Il peut réaliser un temps de vol plus court et une descente vers le bas en Continuous Descent Approach (CDA) pour l'avion d'arrivée. Il peut réaliser un re-séquencement plus facile des avions avec un déplacement de position plus relâché. Théoriquement, les Maximum Position Shifting (MPS) peuvent atteindre 6 positions, surpassant la contrainte difficile de 3 positions. Troisièmement, l'algorithme montre son efficacité dans un modèle d'approche parallèle séparé avec une capacité de séquencement plus relâché. Par rapport au décalage de position forcé dur, qui est souvent utilisé dans le système actuel Arrival Manager (AMAN) et la méthode First Come First Served (FCFS) utilisé par les contrôleurs, il peut réduire le délai et le temps de transit moyens dans une situation d'arrivée très dense. Le palier par vol est inférieur à 12\% du temps de transit total dans la TMA. Quatrièmement, en configuration parallèle indépendant, il peut fournir des informations différentes concernant la valeur objectif associée, le temps de vol moyen, les trajectoires de croisement en point chaud entre les arrivées et les départs, l'efficacité avec différents arcs de séquencement conçus dans le réseau de route ML-PM etc.. / Congestion in Terminal Manoeuvring Area (TMA) at hub airports is the main problem in Chinese air transportation system. Facing extremely dense operations in complex TMA, we can consider reducing traffic complexity by solving all potential conflicts in advance with a feasible trajectory control for controllers, or automating a large proportion of routine operations, such as sequencing, merging and spacing. As parallel runways are a common structure of Chinese hub airports, in this thesis, we propose a novel system to integrated sequencing and merging aircraft to parallel runways. Our methodology integrates a Area Navigation (RNAV)-based 3D Multi-Level and Multi-Point Merge System (MLMPMS), a hybrid heuristic optimization algorithm and a simulation module to find good, systematic, operationally-acceptable solutions. First, a Receding Horizon Control (RHC) technique is applied to divide 24-hour traffic optimization problem into several sub- problems. Then, in each sub-problem, a tailored Simulated Annealing (SA) algorithm and a trajectory generation module worn together to find a near-optimal solution. Our primary objective is to rapidly generate conflict-free and economical trajectories with easy, flexible and feasible control methods. Based on an initial solution, we continuously explore possible good solutions with less delay and shorter landing interval on runway. Taking Beijing Capital International Airport (BCIA) as a case to study, numerical results show that our optimization system performs well. First, it has very stable de-conflict performance to handle continuously dense traffic flows. Compared with Hill Climbing (HC), the tailored SA algorithm can always guarantee a conflict-free solution not only for the mixed or segregated parallel approach (arrivals only) pattern, but also for the independent parallel operation (integrated departures and arrivals) pattern. Second, with its unique Multi-Level Point Merge (ML-PM) route network, it can provide a good trajectory control solution to efficiently and economically handle different kinds of arrival flows. It can realize a shorter flying time and a near-Continuous Descent Approach (CDA) descent for arrival aircraft, compared with baseline. It also realizes an easier re-sequencing of aircraft with more relaxed position shifting as well, compared with conventional sequencing method. Theoretically, the Maximum Position Shifting (MPS) can be up to 6 positions, overcoming the hard constraint of 3 position shifts (MPS <= 3). Third, it is efficient for the segregated parallel approach patterns. Compared with hard constrained position shifting, which is often used in current Arrival Manager (AMAN) system and controller's manual-control First Come First Served (FCFS) method, it can reduce the average delay, average additional transit time in super dense arrival situations. The average time flown level per flight is less than 12% of total transit time in TMA. Fourth, in independent parallel patterns, it can provide a range of useful information concerning the associated objective value, the average flying time, crossing trajectories in hot spots between arrivals and departures, the efficiency of using different designed sequencing legs in ML-PM route network.

The purpose of our thesis is to investigate the incentive mechanisms that may be used for a timely and successful implementation of Public-Private Partnership (PPP) projects. This purpose is achieved by investigating challenges and success factors within one of the largest Public-Private Partnership projects in Europe, the SESAR programme which stands for Single European Sky ATM Research and that aims at modernising the European air traffic management (ATM) system. The categories of SESAR actors that we investigated include: stakeholders (airspace users such as Air France, KLM, SAS; ANSPs from Sweden,Finland, Netherlands and the CANSO organisation; airport representatives including Swedavia, Zürich Airport and Guernsey Airport); as well as manufacturers (e.g. Airbus, Frequentis, Thales); international organisations as principals (e.g. European Commission – SESAR Joint Undertaking-, EUROCONTROL) and advisers (e.g. Helios UK). Referring to our contribution to the theory, we identify four categories of incentive mechanisms for timely implementation of large PPP projects: i. Financial incentives such as loans, proportionate with the level of risks the implementer bears; the deduction of loan fees or reduction of service charges can motivate stakeholders to implement earlier, once they identify a positive business case. ii. Operational incentives can refer to certain preferential treatment to those who comply and detrimental treatment to those who do not comply. iii. Legal incentives such as mandates can force commitment and have an impact on the timely implementation of PPP projects within a certain time-frame. iv. Intangible incentives, such as transparent communication, collaboration and less political behaviour, are seen as major factors contributing to the commitment and trust level among the actors involved, thus, enabling the success of the PPP project implementation.