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This dissertation presents a research effort to evaluate wake vortex mitigation procedures and technologies in order to decrease aircraft separations, which could result in a runway capacity increase. Aircraft separation is a major obstacle to increasing the operational efficiency of the final approach segment and the runway. An aircraft in motion creates an invisible movement of air called wake turbulence, which has been shown to be dangerous to aircraft that encounter it. To avoid this danger, aircraft separations were developed in the 1970s, that allows time for wake to be dissipated and displaced from an aircraft's path. Though wake vortex separations have been revised, they remain overly conservative. This research identified 16 concepts and 3 sub-concepts for wake mitigation from the literature. The dissertation describes each concept along with its associated benefits and drawbacks. All concepts are grouped, based on common dependencies required for implementation, into four categories: airport fleet dependent, parallel runway dependent, single runway dependent, and aircraft or environmental condition dependent. Dynamic wake vortex mitigation was the concept chosen for further development because of its potential to provide capacity benefit in the near term and because it is initiated by air traffic control, not the pilot. Dynamic wake vortex mitigation discretizes current wake vortex aircraft groups by analyzing characteristics for each individual pair of leader and follower aircraft as well as the environment where the aircraft travel. This results in reduced aircraft separations from current static separation standards. Monte Carlo simulations that calculate the dynamic wake vortex separation required for a follower aircraft were performed by using the National Aeronautics and Space Administration (NASA) Aircraft Vortex Spacing System (AVOSS) Prediction Algorithm (APA) model, a semi-empirical wake vortex behavior model that predicts wake vortex decay as a function of atmospheric turbulence and stratification. Maximum circulation capacities were calculated based on the Federal Aviation Administration's (FAA) proposed wake recategorization phase II (RECAT II) 123 x 123 matrix of wake vortex separations. This research identified environmental turbulence and aircraft weight as the parameters with the greatest influence on wake vortex circulation strength. Wind has the greatest influence on wake vortex lateral behavior, and aircraft mass, environmental turbulence, and wind have the greatest influence on wake vortex vertical position. The research simulated RECAT II and RECAT III dynamic wake separations for Chicago O'Hare International (ORD), Denver International Airport (DEN) and LaGuardia Airport (LGA). The simulation accounted for real-world conditions of aircraft operations during arrival and departure: static and dynamic wake vortex separations, aircraft fleet mix, runway occupancy times, aircraft approach speeds, aircraft wake vortex circulation capacity, environmental conditions, and operational error buffers. Airport data considered for this analysis were based on Airport Surface Detection Equipment Model X (ASDE-X) data records at ORD during a 10-month period in the year 2016, a 3-month period at DEN, and a 4-month period at LGA. Results indicate that further reducing wake vortex separation distances from the FAA's proposed RECAT II static matrix, of 2 nm and less, shifts the operational bottleneck from the final approach segment to the runway. Consequently, given current values of aircraft runway occupancy time under some conditions, the airport runway becomes the limiting factor for inter-arrival separations. One of the major constraints of dynamic wake vortex separation at airports is its dependence on real-time or near-real-time data collection and broadcasting technologies. These technologies would need to measure and report temperature, environmental turbulence, wind speed, air humidity, air density, and aircraft weight, altitude, and speed. / PHD / An aircraft in motion creates an invisible movement of air called wake turbulence, which has been shown to be dangerous to aircraft that encounter it. To avoid this danger, aircraft separations were developed in the 1970s, that allows time for wake to be dissipated and displaced from an aircraft’s path. Though wake vortex separations have been revised, they remain overly conservative. The separation of aircraft approaching a runway is a major obstacle to increasing the operational efficiency of airports. This dissertation presents a research effort to decrease aircraft separations as they approach and depart the airport, which could result in a runway capacity increase. This research identified 16 concepts and 3 sub-concepts for wake mitigation from the literature. The dissertation describes each concept along with its associated benefits and drawbacks. Dynamic wake vortex mitigation was the concept chosen for further development because of its potential to provide capacity benefit in the near term and because it is controlled the by air traffic control, not the pilot. Dynamic wake vortex mitigation, analyzes the characteristics for each individual pair of leader and follower aircraft as well as the environment where the aircraft travel. This research identified environmental turbulence and aircraft weight as the parameters with the greatest influence on wake vortex circulation strength. The wind has the greatest influence on wake vortex lateral behavior, and aircraft mass, environmental turbulence, and wind have the greatest influence on wake vortex vertical position. The research simulated aircraft operations for Chicago O’Hare International Airport, Denver International Airport and LaGuardia Airport. The simulation accounted for real-world conditions of aircraft operations during arrival and departure: aircraft fleet mix, aircraft runway occupancy time, aircraft approach speeds, aircraft wake vortex circulation capacity, environmental conditions, and pilot-controller human error. Results indicate that further reducing aircraft separation distances from static aircraft separations, shifts the operational bottleneck from the airspace to the runway. Consequently, given current values of aircraft runway occupancy time, the airport runway becomes the limiting factor to increase capacity. One of the major constraints of dynamic wake vortex separation at airports is its dependence on real-time data collection and broadcasting technologies. These technologies would need to measure and report temperature, environmental turbulence, wind speed, air humidity, air density, and aircraft weight, altitude, and speed.

Increasing automation in aviation is impacting the role of the air traffic controller (ATCO). New support tools and changing work environments require the monitoring of multiple display systems and the detection of potential system failures. When training these requirements, eye tracking holds great promise for gaining a deeper insight into trainees’ perceptual and cognitive processes. Because there are hardly any studies on the effects of training on gaze behavior in air traffic control (ATC), the aim of the present work was to evaluate the applicability of the method in this domain. Three experimental studies were conducted with novices with no ATC experience. These investigated whether training effects are reflected not only in common performance measures such as accuracy and speed, but also in gaze parameters such as relative fixation count, time to first fixation, and normalized entropy. They further examined to what extent future monitoring tasks can be trained and what kind of additional factors play a role in this. An adapted version of the abstract monitoring test (MonT) was used to investigate the research questions. Each study consisted of three test blocks in which air traffic had to be monitored in up to three automatically controlled airspaces. In the first study (N = 60), the adapted simulation environment was evaluated, and initial results on the effect of practice were collected. Improvements, which occurred primarily at the beginning of the test, were reflected in a more accurate failure detection performance and a more strategic gaze behavior. The traffic load, and therefore the amount of information to be monitored, played a decisive role in the results. The second study (N = 139) investigated the influence of different interventions for directing attention. Highlighting relevant information (bottom-up approach) moderated the effect of practice significantly more than an attention strategy (top-down approach) or no intervention (control). Relevant information was viewed more frequently and failures were anticipated more easily—even when a manual control task was added. Repeating the test after an average of four months showed little to no significant changes in performance and gaze behavior (N = 19). Overall, with an average detection rate of 83%, the results indicate that future monitoring can be trained to a high level. However, the design of the system, the difficulty of the task, and the prior knowledge of the individual must always be considered. Because it was shown that gaze behavior predicted performance, the recording of eye movements in future ATC training is encouraged. In this context, current developments in the use of artificial intelligence promise to facilitate the classification of individual scan patterns and promote adaptive training.

The documentation by Frank W. Fischer deals with the development of the German air traffic control centre for the upper airspace of southern Germany RHEIN UAC with the radio call sign RHEIN CONTROL, which was operated on the Erbeskopf in the Hunsrück from 1957 to 1968 and from 1968 to 1977 at Frankfurt am Main Airport. The Rhine UAC air traffic control centre was known to all airlines and military units flying over Germany's upper airspace in the post-war period. In addition, this air traffic control centre had already been confronted with traffic problems since the 1950s, which other air traffic control centres and air traffic control service providers in Europe only had to contend with many years later. Rhein UAC was the cradle of a variety of methods and operational procedures for air traffic control that were unknown to other air traffic services at the time, and it was the time of the Cold War. Germany was divided and the air forces of the occupying powers overcrowded the airspace with almost 2,000 combat aircraft during the day and at night. Military air operations that the population had never heard about. The Cold War - the confrontation between East and West - also took place far above the clouds in the upper airspace. But many aspects of civil and military air traffic control had not yet been regulated. Some things had not even been invented yet. In particular, the mixture of civil and military operating and control procedures was unique. The uniqueness consisted of the combination of joint operations, personnel and air traffic control procedures. Three personnel contingents, namely the US Air Force, the Federal Air Traffic Control Centre and the German Armed Forces, managed flights of all traffic categories. This also included all military training and special flights as well as the target flights of major NATO air manoeuvres.

The operational work of air traffic controllers (ATCOs) is characterized by continuous and demanding cognitive tasks. Duties include ensuring a safe and efficient movement of aircraft, often operating in a 24/7 system necessitating shift-based work schedules. However, the nature of shift work introduces significant challenges related to fatigue and its potential impact on performance and safety. Fatigue is a complex physiological and psychological phenomenon originating from multiple factors such as prolonged wakefulness, inadequate sleep, and disruption to circadian rhythms. Those aspects are mainly influenced by working times, shift work, and the shift system itself. Fatigue can impair cognitive functions, including attention, reaction time, decision-making, and memory recall – critical abilities for ATCOs. Organizations and regulators are mandated to develop approaches aimed at reducing fatigue and the associated risks. Currently, fatigue is often managed through a compliance-based approach, which prescribes strict duty time limitations. However, this method oversimplifies fatigue as a non-issue in the workplace, merely because these limitations are adhered to. Recognizing the inaccuracy of this approach, a risk-based approach has been introduced. The approach acknowledges that varying degrees of fatigue risks may be present throughout a shift. This psychologically more accurate perspective has driven a change towards the fatigue risk management system (FRMS). A given shift system has a major influence on fatigue and is critical for any FRMS introduction. The actual shift design and scheduled roster can vary between industries and among air traffic control (ATC) organizations. Heterogenous shift systems differ in terms of fixed or irregular rotation, rotation direction, shift length, recovery times, minimum time between consecutive shifts, and maximum of worked hours per week or month. The impact of these factors on fatigue is, however, underexplored in ATC. A critical consideration of the shift system is indicated. For this dissertation, an irregular and preference-based shift system was investigated. Irregular shift systems, as opposed to fixed shift schedules, offer more variability in the distribution of work shifts over a roster period. The shift combinations do not follow a fixed order. Preference-based shift systems allow workers to request individualized rosters, encompassing their preferred shift types and duty days for the roster period. Particularly with regard to an irregular and preference-based shift system in ATC, there is a lack of systematically obtained fatigue data. The aim of this dissertation is to enhance the understanding of fatigue in an irregular and preference-based shift system in ATC. The shift system was investigated with a focus on fatigue dynamics and their relation to shift types, rostering factors, and night shift design as well as the consistency of subjective and objective fatigue data. In order to understand fatigue in the given irregular shift system, two field studies were conducted at different points in time, using a widely identical methodological approach. Both studies were conducted at an area control center. Fatigue was measured with a subjective and an objective method over a three-week period in all operational shifts at three key timepoints: beginning, middle, and end of the shift. Study 1 covered all four shift types (including morning, evening, and two night shifts) and investigated the differences within and between shift types. Moreover, the influence of the rotation direction and time between shifts was investigated. The results revealed a positive association between time on shift and objective fatigue. Objective fatigue increased significantly in the first half of all shifts, but then maintained at a certain level. However, this effect was moderated by the time of day, with night shifts resulting in overall increased objective fatigue in the middle and end of shifts compared to day shifts. Subjective fatigue increased over time only for the evening and one night shift type. Comparisons between shift types mostly showed higher subjective fatigue during night shifts compared to day shifts. Time on shift appeared to be the most relevant fatigue factor for day shifts, while the time of day was more relevant for night shifts. Individuals working the night shift had a longer continuous duty time, which likely explains the association with fatigue, even though task demands tend to be lower at night. Considering the rostering factors, shift combinations that had less than 11 hours between shifts (quick returns) and a counterclockwise rotation direction were associated with increased fatigue at the beginning of the subsequent duty. Interestingly, this effect diminished as the shifts proceeded. Analyses of the sleep quantity prior the shifts showed differences between all shift types, with the shortest sleep duration before morning shifts and longest prior to evening shifts. Discrepancies between subjective and objective fatigue were found. Study 2 focused on night shifts. A single split night shift arrangement was given. The arrangement included two mirrored night shift types (NA and NB), with sleep and operational phases alternating mid-shift. Both shifts commenced at 10 p.m., with NA starting operational work while NB begun with a sleep phase and being on-call. Around 3 a.m., NB took over from NA and continued operational work until the end of the shift at 7 a.m., while NA had the opportunity to sleep from 3 a.m. onwards and remaining on-call. In addition to the measurements at the key timepoints, subjective fatigue data was collected at four times during the operational work phase. The investigation of the split night shift arrangement showed that, regardless of the night shift type (NA or NB), there was a main effect of time on shift for both subjective and objective fatigue. Comparisons between both night shift types revealed minimal differences. Subjective higher fatigue was observed at the beginning of the shift for NB, although this effect was not observed for objective fatigue. Analysis of sleep duration prior to operational work revealed different preparation mechanisms among participants depending on the type of night shift worked. Specifically, the analysis showed that the average sleep duration prior to the shift was more than one hour shorter for NB compared to NA. However, the cumulative sleep duration prior to the operational work phase was longer for NB, as they achieved an average of three hours and 46 minutes of on-shift sleep. Again, discrepancies between subjective and objective fatigue were found. The objective of enhancing the understanding of fatigue in an irregular and preference-based shift system in ATC has been achieved. A positive association between time on shift and fatigue was found across both studies, predominantly in the first shift half. The results emphasize the crucial role of rostering in subjective and objective fatigue. The revealed discrepancies between self-evaluated (subjective) and performance-based (objective) fatigue might lead to safety risks, as individuals are not aware of reduced performance capabilities due to fatigue and they may request inadequate shift combinations. The interaction of fatigue with secondary factors is discussed, highlighting considerations when implementing an FRMS.

In 2014, the Federal Aviation Administration (FAA) highlighted to the U.S. Senate the need to focus on air traffic control (ATC) training to meet job qualification and attrition rates within the career field. One U.S. Department of Defense military service assists the FAA in providing worldwide ATC services. This service is referred to as the agency throughout this paper to ensure confidentiality. The agency's ATC career field manager echoed the FAA's call for action in his 2014 Strategic/Action Plan. In August 2013, the agency's ATC trainer program was published. As of December 2015, the program had not been evaluated. The purpose of this study was to ascertain if the program facilitated the learning of critical ATC on-the-job training skills. An ad hoc expertise-oriented evaluation was conducted using the lenses of andragogy, experiential learning, and instructional system design (ISD). Purposeful sampling procedures were used to select 20 participants across the subgroups of supervisors, trainers, managers, and training developers from 7 focus sites. The semi-structured interviews queried 4 topical areas derived from Kirkpatrick's 4 levels of evaluation model. Data collected via documents and interviews were analyzed using descriptive, emotion, eclectic, and pattern coding. Key findings indicated that the program was not developed compliant with ISD principles and did not promote adult learning as endorsed by andragogy and experiential learning theory. The implications for positive social change include providing stakeholders with data needed to make evidence-based decisions regarding the current and future state of the program. The evaluation report project can be shared with the FAA, an agency partner, and has the potential to create a platform for improved training practices focusing on optimum and successful adult learning transactions.

The aim of self-directed team learning initiatives is to provide a further level of defence against an eventuality by ensuring that air traffic controllers are aware of the sources of human fallibility, and by developing in the individual controllers and air traffic control teams the knowledge, skills and attitudes that will result in the successful management and containment of inadvertent error. To gain a deeper understanding of self-directed team learning, I investigated the role and contribution of self-directed team learning principles and strategies that were present in the South African Air Force air traffic control team-based work environment. This research study was directed by the following primary research questions: Does self-directed team learning impact on the air traffic control work environment, and what is the nature of self-directed team learning’s impact on the air traffic control work environment? Insights gained as a result of this study contributed to the body of research concerned with learning design, development, implementation and evaluation by self-directed teams as well as the air traffic control discipline. In this mixed-method study quantitative data collection was performed by means of a self-directed team learning questionnaire and a learning approach questionnaire, whereas qualitative data collection relied on individual interviews and focus group interviews. This study involved 25 South African Air Force air traffic controllers (from three operational air traffic control centres). The nature of self-directed team learning’s impact on the air traffic control work environment was illustrated by individual and collective (team) views and dynamics. The impact of air traffic control team performances was traced in terms of identified teamwork characteristics, activities, dynamics, performance measures and focus areas and reflective practices. Results of this study indicated that self-directed team learning offered opportunities to individuals and teams to influence air traffic control performances in an air traffic control work environment. A perceived positive relationship between self-directed team learning and air traffic control operational outputs could be traced. Lastly I concluded that self-directed learning by air traffic control teams had an impact on air traffic control operational outcomes, thus contributing towards a critical air traffic control goal – aviation safety. / Thesis (PhD (Currriculum Studies))--University of Pretoria, 2009. / Curriculum Studies / unrestricted

Background: Low morale is classified as a latent condition for performance variability in safety-critical environments. Morale management may assist in the control of performance variability as part of a systems approach to safety. A context-specific model for measuring and managing morale with reference to followership in a safety-critical air traffic control (ATC) environment could not be found. Purpose/Aim: The purpose of this study was to develop a model that enables the measurement and management of air traffic controller (ATCO) team morale. Research Design: An exploratory sequential mixed method design was adopted. A census approach to sampling was used to conduct 21 focus group sessions as the qualitative phase, providing the definition and drivers of morale. The Measure of Morale and its Drivers (MoMaD) survey instrument was created from qualitative data, then administered to 256 ATCOs in the quantitative phase. Statistical methods included exploratory factor analysis, correlation and regression analysis to construct the final MoMaD model. Results: A context-specific definition of morale is provided and communication management, team cohesion, leadership interaction, staff incentive, staffing level, workplace health and safety and mutual trust were found to be the drivers of morale in a safety-critical ATC environment. A single-item measure of perceived morale reflected the state of context-specific ATCO team morale more accurately than an existing generalisable multi-item measure. Conclusion: This study contributes to the body of knowledge by integrating applicable aspects of morale, followership, performance variability and organisational culture and climate in safety-critical ATC environments into a new theoretical framework. The MoMaD instrument is presented as a context-specific model for measuring and managing ATCO team morale in an ATC environment. Recommendations: Future research opportunities include the possible influence of morale as a predictor of morale in safety-critical environments and the development of a context-specific multi-item measure of morale for integration into the MoMaD model. / Business Management / D. B. L.

The first purpose of this study was to map the field of psychodiagnostic methods in the selection process for the position of Air traffic controller in selected countries in Central Europe. The second one was to see how differs the results of FEAST and psychological testing among different groups of candidates in relation to their success in training. This is a quantitative research. The method used in collecting data was the analysis of results of selected tests for individual candidates. The research was realized at 93 candidates who successfully completed the selection procedure for the position of the Air traffic controller at ŘLP Čr from 2005 - 2009. The data were analyzed using SPSS statistical program. In the vast majority of performance or personality tests did any statistically significant difference was not found between the group of successful and unsuccessful candidates in training. A statistically significant difference was detected in the scale "Noticed matches" in the FEAST test battery, where unsuccessful candidates scored above. Another one was discovered in the test CAQ in factor Q1: Radicalism, where successful candidates achieved lower scores than the unsuccessful. We believe that candidates who manage the selection procedure are so good that it is not possible their further...

Historicamente, os sistemas de tráfego aéreo incorporaram níveis de automação nas atividades de controle do espaço aéreo com o intuito de atender à crescente demanda por serviços aéreos e de melhorar os níveis de segurança nos procedimentos de voo. Com o crescimento expressivo previsto para os próximos anos, devido ao aumento nos números de voos e de usuários, as opções tradicionais de expansão da malha aérea e / ou construção de novos aeroportos se tornaram onerosas economicamente, tornando necessária a adoção de alternativas, tais como as técnicas / procedimentos para pousos em pistas paralelas, como forma de aproveitar parte da atual infraestrutura aeroportuária existente, sem a necessidade de enormes aportes financeiros. Para avaliar a viabilidade de projetos de pousos simultâneos em pistas paralelas, um dos fatores importantes a serem analisados é o da avaliação do risco de colisão entre aeronaves associado durante esses procedimentos. Nesse cenário, este trabalho de pesquisa propõe uma extensão no modelo de avaliação de segurança de Ogata para procedimentos de pouso em pistas paralelas, considerando que o modelo original tem o objetivo de medir o nível de risco associado somente para operações de pouso convencionais em pistas paralelas. A extensão deste modelo ocorre no sentido de também permitir a simulação em outros cenários distintos de pouso, o que torna possível tanto a realização de comparativos entre técnicas / procedimentos utilizadas em operações de pouso em pistas paralelas, quanto a avaliação do nível de risco associado. Este modelo estendido de segurança utiliza o método de Monte Carlo, da mesma forma que o original, em que um número elevado de simulações de cenários possíveis de pousos em pistas paralelas é avaliado. Com os resultados obtidos, é analisado o impacto da variação da distância entre as pistas na segurança de pousos em pistas paralelas. / Historically, air traffic control systems have incorporated some levels of automation to manage procedures of airspace control in order to meet the growing demand for air transportation services and to improve levels of safety in flight procedures. With significant growth expected in the coming years due to an increase in numbers of flights and passengers, the traditional options of expanding the air traffic network and / or construction of new airports have become economically burdensome, requiring the adoption of alternatives such as techniques / procedures for landings on parallel runways as a way of taking advantage of part of the current airport infrastructure, without requiring enormous financial contributions. To assess the feasibility of projects of landing in parallel runways, one of the important factors to be analyzed is the evaluation of the risk of collision between aircraft, associated to these procedures. In this scenario, this research proposes to extend the Ogata safety assessment model in procedures for landing on parallel runways, whereas the original model aims to measure the level of risk associated only with conventional landing operations in parallel runways. The extension of this model occurs in order to allow the simulation of different landing scenarios, which makes possible both the conduct of comparative techniques / procedures used in landing operations on parallel runways, such as the risk level assessment. This model uses the Monte Carlo simulation, the same as the original model, in which a large number of simulations of possible scenarios for landings on parallel runways are evaluated. With these results, it studies the impact of the change of distance between lanes on the safety of aircraft landing on parallel runways.