Este trabalho propõe um modelo de análise quantitativa baseado em simulação de eventos discretos para a determinação do nível de resiliência em sistemas de transporte. O nível de resiliência é avaliado considerando as funções de desempenho relacionadas a capacidade, ao nível de serviço e ao tempo de recuperação do sistema de transporte frente a um evento de ruptura. O modelo é validado através de estudo de caso aplicado ao sistema de tráfego aéreo brasileiro, considerando um espaço aéreo composto por 12 setores de uma região de informação de voo (FIR), suas demandas diárias de aeronaves, sua malha de rotas aéreas e sua rede de aeródromos instalada. O evento de ruptura é oriundo de condições meteorológicas adversas que afetam simultaneamente as operações de pouso e decolagem no aeroporto do Rio de Janeiro - Santos Dumont (SBRJ) e no aeroporto de São Paulo - Congonhas (SBSP). Conclui-se que o modelo de análise permite a plena determinação do nível de resiliência em sistemas de transportes, mesmo em situações de rupturas operacionais simultâneas. / This work proposes a quantitative analysis model based on discrete event simulation (DES) to determine the resilience level of transport systems. The resilience level is evaluated considering the performance functions related to capacity, service level and recovery time of the transport system in a presence of disruptive events. The model is validated through a case study applied to the Brazilian air traffic system, considering an airspace with 12 sectors of a flight information region (FIR), its daily aircraft demands, its air route network and its aerodromes network installed. The disruptive event comes from adverse weather conditions that simultaneously affect the landing and takeoff operations at Rio de Janeiro - Santos Dumont (SBRJ) and São Paulo - Congonhas (SBSP) airports. It is concluded that the analysis model allows the full determination of the resilience level in transport systems, even in situations of simultaneous operational disruptions.

A segurança do espaço aéreo pode aumentar consideravelmente com o uso de operações de espaçamento e separação aerotransportados. Sob este paradigma, a tarefa de manter distância em relação a outras aeronaves é delegada aos pilotos, que contarão com o Sistema de Assistência de Separação Aerotransportado (ASAS). Com este sistema, ainda em fase experimental, os pilotos tornam-se cientes dos riscos do tráfego circundante com até 15 minutos de antecedência, sem necessitar de auxílio dos controladores de tráfego aéreo. Esta antecedência é muito maior que a do atual sistema anti-colisão (TCAS), que é de menos de 1 minuto. O sistema ASAS utiliza uma tecnologia de comunicação mais avançada que a tecnologia do transponder modo C, utilizado atualmente pelo sistema anti-colisão. O novo sistema ASAS está sendo desenvolvido intensivamente no Eurocontrol e em outras iniciativas nos Estados Unidos da América, e funcionará em conjunto com o atual sistema anti-colisão, proporcionando redundância, ou seja: se o antigo sistema falhar, o novo ainda pode emitir um alerta, ou vice-versa. O presente trabalho de pesquisa aborda a aplicação do ASAS para aumentar a precisão do espaçamento entre aeronaves que chegam sequencialmente a um determinado aeroporto, por meio de um formalismo matemático denominado \"Rede de Petri Estocástica e Dinamicamente Colorida\", com a obtenção de dados quantitativos sobre o risco de acidente. Esses dados indicam que o risco de acidente é significativamente menor com o uso do ASAS do que sem o uso do ASAS. / The safety in the airspace can considerably increase with the use of airborne spacing and separation operations. Under this paradigm, the task of maintaining a safe distance between aircraft is delegated to the pilots, which will be supported by the Airborne Separation Assistance System (ASAS). With this system, which is still in experimental phase, pilots become aware of the surrounding air traffic risks with up to 15 minutes in advance, without the help of air traffic controllers on the ground. This antecedence is much greater than the one provided by the current Traffic Collision Avoidance System (TCAS). ASAS uses a more advanced communication technology than Mode-C transponder, broadly used in the current civil aviation for collision avoidance purposes. The development of ASAS is being carried out intensively in Eurocontrol and in other initiatives in the United States of America, and this novel system is intended to work in parallel with the current collision avoidance systems, acting as safety nets. The present study approaches the ASAS application to improve the precision of spacing between aircraft that sequentially arrive at an airport, using the so called mathematical formalism \"Stochastically and Dynamically Coloured Petri Net\", for evaluating quantitative data about accident risk. These data indicate that the accident risk is significantly smaller when aircraft pairs use ASAS Spacing than when aircraft pairs do not use ASAS Spacing.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO. / Includes bibliographical references. / by Shinsuke Endoh. / M.S.

A segurança do espaço aéreo pode aumentar consideravelmente com o uso de operações de espaçamento e separação aerotransportados. Sob este paradigma, a tarefa de manter distância em relação a outras aeronaves é delegada aos pilotos, que contarão com o Sistema de Assistência de Separação Aerotransportado (ASAS). Com este sistema, ainda em fase experimental, os pilotos tornam-se cientes dos riscos do tráfego circundante com até 15 minutos de antecedência, sem necessitar de auxílio dos controladores de tráfego aéreo. Esta antecedência é muito maior que a do atual sistema anti-colisão (TCAS), que é de menos de 1 minuto. O sistema ASAS utiliza uma tecnologia de comunicação mais avançada que a tecnologia do transponder modo C, utilizado atualmente pelo sistema anti-colisão. O novo sistema ASAS está sendo desenvolvido intensivamente no Eurocontrol e em outras iniciativas nos Estados Unidos da América, e funcionará em conjunto com o atual sistema anti-colisão, proporcionando redundância, ou seja: se o antigo sistema falhar, o novo ainda pode emitir um alerta, ou vice-versa. O presente trabalho de pesquisa aborda a aplicação do ASAS para aumentar a precisão do espaçamento entre aeronaves que chegam sequencialmente a um determinado aeroporto, por meio de um formalismo matemático denominado \"Rede de Petri Estocástica e Dinamicamente Colorida\", com a obtenção de dados quantitativos sobre o risco de acidente. Esses dados indicam que o risco de acidente é significativamente menor com o uso do ASAS do que sem o uso do ASAS. / The safety in the airspace can considerably increase with the use of airborne spacing and separation operations. Under this paradigm, the task of maintaining a safe distance between aircraft is delegated to the pilots, which will be supported by the Airborne Separation Assistance System (ASAS). With this system, which is still in experimental phase, pilots become aware of the surrounding air traffic risks with up to 15 minutes in advance, without the help of air traffic controllers on the ground. This antecedence is much greater than the one provided by the current Traffic Collision Avoidance System (TCAS). ASAS uses a more advanced communication technology than Mode-C transponder, broadly used in the current civil aviation for collision avoidance purposes. The development of ASAS is being carried out intensively in Eurocontrol and in other initiatives in the United States of America, and this novel system is intended to work in parallel with the current collision avoidance systems, acting as safety nets. The present study approaches the ASAS application to improve the precision of spacing between aircraft that sequentially arrive at an airport, using the so called mathematical formalism \"Stochastically and Dynamically Coloured Petri Net\", for evaluating quantitative data about accident risk. These data indicate that the accident risk is significantly smaller when aircraft pairs use ASAS Spacing than when aircraft pairs do not use ASAS Spacing.

La recherche d’aide est une stratégie qui peut améliorer l’apprentissage et la réussite scolaire. Malgré ce constat, la littérature montre que les étudiants ou élèves décident fréquemment de ne pas rechercher de l’aide. Par ailleurs, dans le domaine de l’aéronautique, peu d’études ont été consacrées à la formation des contrôleurs aériens, qui jouent un rôle central dans le système de régulation du trafic aérien. Étant donné que la performance humaine est classiquement considérée comme un facteur qui contribue à la majorité des incidents et accidents aériens, l’enjeu de ces formations est majeur. L’objectif de cette thèse est double: au plan général, comprendre pourquoi les étudiants décident de ne pas rechercher de l’aide alors que la tâche à réaliser n’est pas à leur portée. Cela relève-t-il d’une décision rationnelle? Quels sont les coûts impliqués? Au plan particulier, vérifier si ce problème existe aussi dans l’environnement d’apprentissage des contrôleurs aériens et si les mêmes conclusions concernant la décision de rechercher ou non de l’aide peuvent être tirées. En ayant pour base un modèle rationnel de prise de décision, dans lequel la décision est une fonction des coûts, de la probabilité et des bénéfices, quatre expériences ont été menées: trois dont les participants étaient des étudiants universitaires et une avec les élèves contrôleurs aériens. Les résultats montrent que les étudiants hésitent à demander de l’aide quand elle est objectivement coûteuse; que le temps consommé en l’utilisant n’est pas considéré comme un coût; et que les étudiants sont prêts à demander de l’aide même quand elle n’est pas assurément utile. En outre, il y a un coût social impliqué dans la décision de rechercher de l’aide: la présence d’un expert baisse les taux de recherche d’aide, notamment quand la tâche est considérée comme facile. Les données de la quatrième expérience suggèrent que le coût social n’impacte pas la décision des élèves contrôleurs d’utiliser les aides. / Learners who encounter difficulties can improve learning and achievement by seeking help. However, literature shows that students frequently decide to not seek help. In aeronautics domain, few studies were dedicated to the training of air traffic controllers, who play an important role in the air traffic regulation system. Given that the human performance is traditionally considered a factor that contributes to the majority of incidents and accidents in aviation, the challenge of their training is greater. This thesis has two goals: generally, understand why students decide not to seek help while the task they have to realize is beyond their reach. Is this a rational decision? What are the costs involved? Specifically, to verify if this issue also exists in the context of air traffic controller training and if we find the same conclusions about help-seeking decision. Based on a rational decision model, where the decision is a function of costs, expectancies and benefits, four experiences were conducted: three of them in a general context, having university students as participants, and an experience with air traffic controllers’ students. Results show that students hesitate to seek help when it is objectively costly; the time consumed to seek help is not considered as a cost; and that students are ready to seek help even when its utility is not assured. Besides, there is a social cost implicated in the decision to seek help: the presence of an expert reduces the levels of help-seeking, particularly when the task is considered easy. The results of the fourth study suggest that the social cost adversely do not have an effect in the decision of air traffic controller students of using all help tools, but the difficulty of the exercise may affect the decision of seeking some kinds of help.

It is becoming widely recognised that shiftwork has significant implications for the health, safety and quality of life of shiftworkers. To date, little research has been carried out on how individuals cope with the problems caused by shiftwork and how effective coping strategies maintain their health and well-being. It has been proposed, by Monk (1994), that there are a number of aspects of a shiftworker's life which are important in determining the ability of an individual to cope with shiftwork. These factors are an individual's circadian rhythms, sleep patterns, and social and domestic situation. Further literature also suggests that workplace factors and coping style are an important part of tolerating shiftwork. The primary aim of the present study was to determine which factors are important in predicting the physical and mental well-being of Air Traffic Services staff working on shifts. It was hypothesised that individuals who are evening types, have few social, domestic, sleep, and work place difficulties will be physically and mentally healthy. In addition, it was hypothesised that the use of engagement strategies in dealing with shiftwork related problems will relate to better physical and mental health. To test the hypotheses, 183 Air Traffic Services staff from Melbourne centre, Australia were surveyed by questionnaire. The results of the regressions showed that physical health was predicted by variables from each of the five areas considered; circadian typology, the social and domestic situation, work place factors, sleep patterns and coping style. Mental well-being was best predicted by a single domestic variable, which is the extent to which shiftwork caused domestic problems and the two coping variables of engagement and disengagement. The results support the suggestion that in order for an individual to be able to tolerate shiftwork they must have strategies in place to help them deal with the effect of shiftwork variables on a range of factors in their lives. An additional aim of the present study was to determine the reliability of a questionnaire for use with Air Traffic Services staff. This was due to a lack of suitable questionnaires for use in this occupational context. Overall the items in the questionnaire were found to have acceptable reliability, although the collection of sleep data by subjective reporting is not recommended.

Non-controlled airports are literally that - uncontrolled. Safe separation is achieved by pilot vigilance. The consensus of reports on incidences at noncontrolled airports generally conclude that pilots cannot rely entirely on vision to avoid collision and attempts should be made to obtain all available traffic information to enable a directed traffic search. Ideally, a system is required which has the ability to provide advice to all parties to ensure separation minima is maintained. Provision of a such a system would remove a measure of pressure from the pilot to allow that person to devote their attention to their prime responsibility of flying the aircraft. To this end, research on use of intelligent remote advisory systems for non-controlled airports was undertaken with emphasis on those systems which could minimize human resources and associated recurring costs, to provide a measure of repeatability and to provide an acceptable level of safety. A rule based system was developed and evaluated. The evaluation showed that use of a rule based system as the basis of an intelligent remote air traffic control system for non-controlled airports is a viable proposition. In test scenarios, collision hazards were identified and evasion tactics generated. For a full operational system, the application of the rules and definition of the aircraft circuit area may need refining; however, the results are certainly encouraging.

The aim of the present research was to examine the impact of mental workload on conflict resolution decision making in air traffic control (ATC). While previous studies have examined the effect of workload on performance (Averty, 2004; Kopardekar & Magyrits, 2002) and conflict detection (Mogford, 1997; Seamster, Redding, Cannon, Ryder & Purcell, 1993), limited research examines the effect of workload on conflict resolution decisions. The aim of the first study was to gain an initial understanding of how controllers manage their airspace. Results demonstrated that controllers scan repetitively, in a clockwise and top-bottom pattern; group aircraft with similar characteristics and use at least five lateral and eight vertical conflict resolution heuristics. Study two examined the effect of conflict type on conflict resolution under different levels of workload. Under moderate workload controllers used a mix of solutions, while under high workload, solutions became more conservative. Study three examined the effect of other contextual factors on conflict resolution. Results again suggested conflict type affects conflict resolution decisions and also that other contextual parameters, such as aircraft performance may play a role in solution preferences. Study four examined the effect of workload on conflict resolution using a realistic ATC task. Workload not only impacted on controllers’ performance scores, but interacted with conflict type to determine whether an efficient solution was preferred over a less efficient solution. This research identifies some of the heuristics experts use when competing priorities are present and provides an understanding of how conflict type, contextual factors and workload affect decisions. Findings contribute to the naturalistic decision making (NDM) literature by demonstrating how the situation can influence decision making.

<p>The purpose of this Master’s Thesis is to produce a specification for the aircraft conflict alert system STCA, and implement a prototype as a module in the air traffic surveillance system NOVA9000. </p><p>The specification is constructed based on functional requirements from EUROCONTROL and describes a system using a nominal trajectory method, where the future paths of aircraft are estimated. The trajectory is created using a probabilistic approach, where future positions are described with probability fields. </p><p>The prototype is implemented using the specification with some simplifications. The prototype is evaluated using recorded traffic from a heavy air traffic region surrounding an airport with parallel runways. 15 alerts were induced in 1,5 hour of morning traffic; this is far too much to be acceptable. Improvements are proposed and explanations to the high rate of alerts are made.</p>

<p>As air traffic is forecasted to increase, air traffic control software subsequently needs to be more sophisticated. To efficiently push development forward, testing is important in order to determine usability. The tests need to be adapted to fit a particular purpose and carried out with methods that preserve the validity of the results. </p><p>This thesis describes an implementation project carried out at the EUROCONTROL Experimental Centre, Bretigny-sur-Orge, France. The purpose of the project is to create an application that enables a user to create datasets of air traffic to be used for these tests. The application allows for manual work or bulk imports from external data sources. Furthermore it compiles scenarios as output datasets intended for prototype air traffic control software developed at Linköping University. </p><p>The application design rationale and development process is described. Some time is spent on demonstrating the flexibility of the application and how its usage fits in a bigger picture.</p>