Traffic synchronization with controlled time of arrival for cost-efficient trajectories in high-density terminal airspace

The growth in air traffic has led to a continuously growing environmental sensitivity in aviation, encouraging the research into methods for achieving a greener air transportation. In this context, continuous descent operations (CDOs) allow aircraft to follow an optimum flight path that delivers major environmental and economic benefits, giving as a result engine-idle descents from the cruise altitude to right before landing that reduce fuel consumption, pollutant emissions and noise nuisance. However, this type of operations suffers from a well-known drawback: the loss of predictability from the air traffic control (ATC) point of view in terms of overfly times at the different waypoints of the route. In consequence, ATC requires large separation buffers, thus reducing the capacity of the airport. Previous works investigating this issue showed that the ability to meet a controlled time of arrival (CTA) at a metering fix could enable CDOs while simultaneously maintaining airport throughput. In this context, more research is needed focusing on how modern arrival managers (AMANs)—and extended arrival managers (E-AMANs)—could provide support to select the appropriate CTA. ATC would be in charge to provide the CTA to the pilot, who would then use four-dimensional (4D) flight management system (FMS) trajectory management capabilities to satisfy it. A key transformation to achieve a more efficient aircraft scheduling is the use of new air traffic management (ATM) paradigms, such as the trajectory based operations (TBO) concept. This concept aims at completely removing open-loop vectoring and strategic constraints on the trajectories by efficiently implementing a 4D trajectory negotiation process to synchronize airborne and ground equipment with the aim of maximizing both flight efficiency and throughput. The main objective of this PhD thesis is to develop methods to efficiently schedule arrival aircraft in terminal airspace, together with concepts of operations compliant with the TBO concept. The simulated arrival trajectories generated for all the experiments conducted in this PhD thesis, to the maximum possible extent, are considered to be energy-neutral CDOs, seeking to reduce the overall environmental impact of aircraft operations in the ATM system. Ultimately, the objective of this PhD is to achieve a more efficient arrival management of traffic, in which higher levels of predictability and similar levels of capacity are achieved, while the safety of the operations is kept. The designed experiments consider a TBO environment, involving a high synchronization between all the involved actors of the ATM system. Higher levels of automation and information sharing are expected, together with a modernization of both current ATC ground-support tools and aircraft FMSs to comply with the new TBO paradigm.L’increment de tràfic aeri ha portat a una major sensibilitat mediambiental en l’aviació, motivant la recerca en mètodes per aconseguir un transport aeri més ecològic. En aquest context, les operacions de descens continu (CDOs) permeten a les aeronaus seguir una trajectòria que aporta grans beneficis econòmics i ambientals, donant com a resultat descensos amb els motors al ralentí des de l’altitud de creuer fins just abans d’aterrar. Aquestes trajectòries redueixen el consum de combustible, les emissions contaminants i el soroll generat per les aeronaus. No obstant això, aquest tipus d’operacions té un gran desavantatge: la pèrdua de predictibilitat des del punt de vista del controlador aeri (ATC) en termes de temps de pas als diferents punts de la ruta. Com a conseqüència, l’ATC necessita assignar una major separació entre les aeronaus, la qual cosa comporta una reducció en la capacitat de l’aeroport. Estudis previs investigant aquest problema han demostrat que la capacitat de complir amb un temps controlat d’arribada (CTA) a un punt de la ruta (utilitzat per seqüenciar les aeronaus) podria habilitar les CDOs tot mantenint la capacitat de l’aeroport. En aquest context, es necessita investigar més en com els gestors d’arribades (AMANs) i els gestors d’arribades ampliats (E-AMANs) podrien donar suport en la selecció de la CTA més adequada. L’ATC seria l’encarregat d’enviar la CTA al pilot, el qual, per tal de complir amb la CTA, faria servir la capacitat de gestió de trajectòries d’un sistema de gestió de vol (FMS) de quatre dimensions (4D). Una transformació clau per aconseguir una gestió més eficient del tràfic d’arribada és l’ús de nous paradigmes de gestió del tràfic aeri (ATM), com per exemple el concepte d’operacions basades en trajectòries (TBO). Aquest concepte té com a objectiu eliminar completament de les trajectòries la vectorització en “bucle obert” i les restriccions estratègiques. Per aconseguir-ho, es proposa implementar de manera eficient una negociació de la trajectòria 4D, amb l’objectiu de sincronitzar l’equipament de terra amb el de l’aeronau, maximitzant d’aquesta manera l’eficiència dels vols i la capacitat del sistema. El principal objectiu d’aquest doctorat és desenvolupar mètodes per gestionar aeronaus de manera eficient en espai aeri terminal, juntament amb conceptes d’operacions que compleixin amb el concepte de TBO. Les trajectòries d’arribada simulades per tots els experiments definits en aquesta tesi doctoral, en la mesura que s’ha pogut, són CDOs d’energia neutral. D’aquesta manera, la idea és reduir el màxim possible l’impacte mediambiental de les operacions aèries al sistema ATM. En definitiva, l’objectiu d’aquest doctorat és aconseguir una gestió del tràfic d’arribada més eficient, obtenint una major predictibilitat i capacitat, i assegurant que la seguretat de les operacions es manté. Els experiments dissenyats consideren una situació on el concepte de TBO és present, el que comporta una sincronització elevada entre tots els actors implicats en el sistema ATM. Així mateix, s’esperen nivells majors d’automatització i de compartició d’informació, juntament amb una modernització de les eines de suport en terra a l’ATC i dels FMSs de les aeronaus, tot amb l’objectiu de complir amb el nou paradigma de TBO.El incremento de tráfico aéreo ha llevado a una mayor sensibilidad medioambiental en la aviación, motivando la investigación de métodos para conseguir un transporte aéreo más ecológico. En este contexto, las operaciones de descenso continuo (CDOs) permiten a las aeronaves seguir una trayectoria que aporta grandes beneficios económicos y ambientales, dando como resultado descensos con los motores al ralentí desde la altitud de crucero hasta justo antes de aterrizar. Estas trayectorias reducen el consumo de combustible, las emisiones contaminantes y el ruido generado por las aeronaves. No obstante, este tipo de operaciones tiene una gran desventaja: la pérdida de predictibilidad desde el punto de vista del controlador aéreo (ATC) en términos de tiempos de paso en los diferentes puntos de la ruta. Como consecuencia, el ATC necesita asignar una mayor separación entre las aeronaves, lo cual comporta una reducción en la capacidad del aeropuerto. Estudios previos investigando este problema han demostrado que la capacidad de cumplir con un tiempo controlado de llegada (CTA) en un punto de la ruta (utilizado para secuenciar las aeronaves) podría habilitar las CDOs manteniendo al mismo tiempo la capacidad del aeropuerto. En este contexto, es necesario investigar más en cómo los gestores de llegadas (AMANs)—y los gestores de llegadas extendidos (E-AMANs)—podrían dar soporte en la selección de la CTA más adecuada. El ATC sería el encargado de enviar la CTA al piloto, el cual, para cumplir con la CTA, usaría la capacidad de gestión de trayectorias de un sistema de gestión de vuelo (FMS) de cuatro dimensiones (4D). Una transformación clave para conseguir una gestión más eficiente del tráfico de llegada es el uso de nuevos paradigmas de gestión del tráfico aéreo (ATM), como por ejemplo el concepto de operaciones basadas en trayectorias (TBO). Este concepto tiene como objetivo eliminar completamente de las trayectorias la vectorización en “bucle abierto” y las restricciones estratégicas. Para conseguirlo, se propone implementar de manera eficiente una negociación de la trayectoria 4D, con el objetivo de sincronizar el equipamiento de tierra con el de la aeronave, maximizando de esta manera la eficiencia de los vuelos y la capacidad del sistema. El principal objetivo de este doctorado es desarrollar métodos para gestionar aeronaves de manera eficiente en espacio aéreo terminal, junto con conceptos de operaciones que cumplan con el concepto de TBO. Las trayectorias de llegada simuladas para todos los experimentos definidos en esta tesis doctoral, en la medida de lo posible, son CDOs de energía neutra. De esta manera, la idea es reducir lo máximo posible el impacto medioambiental de las operaciones aéreas en el sistema ATM. En definitiva, el objetivo de este doctorado es conseguir una gestión del tráfico de llegada más eficiente, obteniendo una mayor predictibilidad y capacidad, y asegurando que la seguridad de las operaciones se mantiene. Los experimentos diseñados consideran una situación xxi donde el concepto de TBO está presente, lo que comporta una sincronización elevada entre todos los actores implicados en el sistema ATM. Asimismo, se esperan mayores niveles de automatización y de compartición de información, junto con una modernización de las herramientas de soporte en tierra al ATC y de los FMSs de las aeronaves, todo con el objetivo de cumplir con el nuevo paradigma de TBO. Primero de todo, se define un marco para la optimización de trayectorias utilizado para generar las trayectorias simuladas para los experimentos definidos en esta tesis doctoral. A continuación, se evalúan los beneficios de volar CDOs de energía neutra comparándolas con trayectorias reales obtenidas de datos de vuelo históricos. Se comparan dos fuentes de datos, concluyendo cuál es la más adecuada para estudios de eficiencia en espacio aéreo terminal. Las CDOs de energía neutra son el tipo preferido de trayectorias desde un punto de vista medioambiental pero, dependiendo de la cantidad de tráfico, podría ser imposible para el ATC asignar una CTA que pueda ser cumplida por las aeronaves mientras vuelan la ruta de llegada publicada. En esta tesis doctoral, se comparan dos estrategias con el objetivo de cumplir con la CTA asignada: volar CDOs de energía neutra por rutas más largas/cortas o volar descensos con el motor accionado por la ruta publicada. Para ambas estrategias, se analiza la sensibilidad del consumo de combustible a diferentes parámetros, como la altitud inicial de crucero o la velocidad del viento. Finalmente, en esta tesis doctoral se analizan dos estrategias para gestionar de manera eficiente el tráfico de llegada en espacio aéreo terminal. Primero, se utiliza una estrategia provisional a medio camino entre la negociación completa de trayectorias 4D y la vectorización en “bucle abierto”: se propone una metodología para gestionar de manera eficaz tráfico de llegada donde las aeronaves vuelan CDOs de energía neutra en un procedimiento de navegación de área (RNAV) conocido como trombón. A continuación, se propone una nueva metodología para generar rutas de llegada dinámicas que se adaptan automáticamente a la demanda actual de tráfico. De igual manera, se aplican CDOs de energía neutra a todo el tráfico de llegada. Hay diferentes factores a considerar que podrían limitar los beneficios de las soluciones propuestas. La cantidad y distribución del tráfico de llegada tiene un gran efecto sobre los resultados obtenidos, limitando en algunos casos una gestión eficiente de las aeronaves de llegada. Además, algunas de las soluciones propuestas comportan elevadas cargas computacionales que podrían limitar su aplicación operacional, motivando mayor investigación en el futuro con el fin de optimizar los modelos y metodologías utilizados. Finalmente, permitir a algunos aviones volar descensos con el motor accionado podría facilitar la gestión de las aeronaves de llegada en los experimentos que se centran en el procedimiento de trombón y en la generación de rutas de llegada dinámicas.Postprint (published version

Evaluation of flight efficiency for Stockholm Arlanda Airport using OpenSky Network data

Identification of causes of the delays within transition airspace is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Services: without knowing the current performance levels, it is difficult to identify which areas could be improved. Inefficient vertical profiles within TMA and deviations from the optimal flight paths due to bad weather conditions are the main sources of performance decline. In this work, we analyse punctuality and vertical efficiency of Stockholm Arlanda airport arrivals, and seek to quantify the fuel consumption impact associated with the inefficient vertical flight profiles within the Terminal Maneuvering Area (TMA). We use Opensky Network data for evaluation of the Stockholm Arlanda airport performance, comparing it to the DDR2 data provided by Eurocontol, outlining the advantages and disadvantages of both.Peer ReviewedPostprint (author's final draft

Comparison of fuel consumption of Continuous Descent Operations with required times of arrival

Continuous descent operations (CDOs) with required times of arrival (RTAs) have proven to deliver major environmental benefits in terminal maneuvering areas (TMAs) without degrading capacity. When traffic density is high, air traffic controllers (ATC) have to delay flights and assign an RTA different from the aircraft's estimated time of arrival (ETA). In such case, aircraft may have to follow a non-optimum speed profile and possibly be forced to fly powered descents instead of neutral CDOs. Furthermore, ATC may also stretch the planned route to keep the safety of the operation. In that case, aircraft might be able to fly neutral CDOs, but at the expense of flying a longer route. In this paper, the differences in fuel consumption between powered descents and path stretching are quantified. A simplified scenario has been defined in which an Airbus A320 is approaching a generic airport with a finite number of arrival routes (i.e. distances to go), and several fictitious RTAs. Then, an optimal control problem has been formulated and solved in order to generate several trajectories meeting the assigned RTAs. In terms of fuel consumption results show that, for RTAs later than the ETA, although in the beginning path stretching represents a higher fuel consumption, in the end flying powered descents is the strategy that consumes more fuel. For RTAs earlier than the ETA, path stretching shows lower consumption values. The methodology presented in this paper could help to define a ground supporting tool to help ATC to decide which would be the best decision under the trajectory based operations paradigm.Peer ReviewedPostprint (published version

Optimal assignment of 4D close-loop instructions to enable CDOs in dense TMAs

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Continuous descent operations (CDOs) with required times of arrival (RTAs) represent a potential solution to reduce the environmental impact in terminal maneuvering areas without degrading capacity. However, flight management systems require to know the remaining distance to the metering fix in order to compute the CDO complying with the CTA. This paper assesses the feasibility of replacing the current air traffic control sequencing and merging techniques, which are mainly based on open-loop vectoring, by a control based on RTAs over known and pre-defined arrival routes (i.e., with known distances to go). An optimal control problem has been formulated and solved in order to generate CDO trajectories, while a mixed-integer-linear programming model was build in order to solve the aircraft landing problem in the metering fix. The assessment has been performed for Berlin-Schonefeld airport (Germany), by using arrival traffic gathered from historical data and by taking advantage of its tromboning procedure. Furthermore, a second scenario was studied by adding more simulated traffic to the existing one. Results show that, after assigning an RTA and a route to every arriving aircraft, a time separation of 120 is ensured in the metering fix, while at least 90 seconds of separation are maintained in the the rest of waypoints of the procedure.Peer ReviewedPostprint (author's final draft

Generation of RNP approach flight procedures with an RRT* path-planning algorithm

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.We present a framework capable of generating required navigation performance authorization required approach (RNP AR APCH) procedures by using a combination of the optimal version of the path-planning rapidly-exploring random tree (RRT*) algorithm and Dubins paths. Procedures are generated by taking into account design constraints defined by the international civil aviation organization (ICAO) procedures for air navigation services - aircraft operations (PANS-OPS). The framework is used to compute several approach procedures for two airports in Japan, Kumamoto and Kitakyushu airports. Several feasible procedures are successfully obtained in a low amount of computational time, many of them resembling the actual procedures published in the selected airports. The output of our framework represents a valuable input for procedure designers, who could later refine the obtained results with specific flight-procedure-design software.Peer ReviewedPostprint (author's final draft

Analysis of weather impact on flight efficiency for Stockholm Arlanda Airport arrivals

Analysis of punctuality of airport arrivals, as well as identification of causes of the delays within transition airspace, is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Ser- vices. In this work we analyse how different weather events influence arrival punctuality and vertical flight efficiency on example of Stockholm Arlanda airport. We quantify the impact of the deviations from the flight plans influenced by different weather events, by demonstrating that they result in significant arrival delays, vertical inefficiencies and calculating how much extra fuel is wasted due to vertical flight inefficiency within Stockholm TMA.Peer ReviewedPostprint (published version

Evaluation of flight efficiency for Stockholm Arlanda Airport arrivals

Analysis of punctuality of airport arrivals, as well as identification of causes of the delays within transition airspace, is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Services: without knowing the current performance levels, it is difficult to identify which areas could be improved. Deviations from the flight plans is one of the major reasons for arrival delays. In this work, we quantified the impact of the deviations from the flight plans on the fuel burn. One of the main reasons of fuel waste is non- optimal vertical profiles during the descent phase. We calculated how much extra fuel is wasted due to vertical flight inefficiency within Stockholm TMA.Peer ReviewedPostprint (published version

Interacting multiple model filtering for aircraft guidance modes identification from surveillance data

Accurate and reliable trajectory prediction (TP) is required in several air traffic management systems. Estimating the aircraft trajectory in a vertical plane typically requires the knowledge of a pair of operational instructions. A sequence of operational instructions specifies the aircraft intent, information that is seldom available, besides for the ownship trajectory planning system. In the execution of the trajectory, the aircraft is directed by the (auto)pilot through a series of sequential guidance modes that might override some of the planning instructions of the aircraft intent. Therefore, having reliable guidance mode information is fundamental for the next generation of air- or ground-based TP. The main goal of this contribution is to develop a methodology able to identify in real-time the active guidance modes for both vertical climb and descent profiles, using only Automatic Dependent Surveillance-Broadcast and Enhanced Mode-S Surveillance data. The proposed solution is based on an interacting multiple model (IMM) filtering approach, which uses a bank of filters, each one matched to a possible guidance mode. The guidance mode identification performance of the IMM-based solution is validated with i) a set of simulated representative trajectories and ii) real flight data obtained from flight data recorders.This work has been partially supported by a EU ENGAGE KTN PhD Fellowship, and the DGA/AID project 2022.65.0082.Postprint (updated version

On the impact of guidance commands mismatch in IMM-Based guidance modes identification for aircraft trajectory prediction

This study presents a sensitivity analysis to model mismatch of an interacting multiple model (IMM) filter when used for aircraft guidance modes identification. The mismatch appears in the guidance command parameters (related to the elevator flight surface and engine throttle), which are assumed to be known filter inputs. First, we analyse the filtering sensitivity when the model mismatch is induced by additive Gaussian noise. Three model mismatch scenarios are considered: i) mismatch on the elevator parameter; ii) mismatch on the throttle parameter; and iii) mismatch on both guidance commands. Such sensitivity analysis is conducted for several realistic trajectories. Second, we consider the case where the guidance parameters are estimated. It is found that a guidance command parameters misspecification clearly affects the IMM performance, therefore such possible mismatch must be taken into account for real-life applicability.Peer ReviewedPostprint (author's final draft

Non-Ionic Surfactant Recovery in Surfactant Enhancement Aquifer Remediation Effluent with Chlorobenzenes by Semivolatile Chlorinated Organic Compounds Volatilization

Surfactant enhanced aquifer remediation is a common treatment to remediate polluted sites with the inconvenience that the effluent generated must be treated. In this work, a complex mixture of chlorobenzene and dichlorobenzenes in a non-ionic surfactant emulsion has been carried out by volatilization. Since this techhnique is strongly affected by the presence of the surfactant, modifying the vapour pressure, P0v,��0, and activity coefficient, γ�, a correlation between P0vjγj���0�� and surfactant concentration and temperature was proposed for each compound, employing the Surface Response Methodology (RSM). Volatilization experiments were carried out at different temperatures and gas flow rates. A good agreement between experimental and predicted remaining SVCOCs during the air stripping process was obtained, validating the thermodynamic parameters obtained with RSM. Regarding the results of volatilization, at 60 °C 80% of SVCOCs were removed after 6 h, and the surfactant capacity was almost completely recovered so the solution can be recycled in soil flushing.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEComunidad de MadridMinisterio de Economía, Industria y CompetitividadEU Life ProgramMinisterio de Economía, Industria y Competitividadpu