The book series Die Entwicklung der Flugsicherung in Deutschland has been published in German. This is the first of two translated books. This documentation on the development of air traffic control in West Germany after 1945 explains the continuation of the further development of the establishment of military tactical air traffic control units, which began under the military governments of the victorious powers and the subsequent Allied occupation forces in Germany. This transport service of the first decade after the end of the war forms the cradle of modern European air traffic control as the main component of the entire air traffic control system. It ended with the partial restoration of air sovereignty in West Germany (BRD) in 1955 and the end of supervision of the restored Federal Air Traffic Control Administration by HICOM's Allied Civil Aviation Board - CAB in mid-1956.

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.

Wake vortices pose a threat to a following aircraft, because they can induce a roll and compromise the safety of everyone on board. Caused by a difference in pressure between the upper and the lower part of the wings, these invisible flows of air are a major hazard and have to be avoided by separating the aircraft at considerable distances. One of the known constraints in airport capacity for both departure and arrival operations is the large headway resulting from the wake spacing separation criteria. Reducing wake vortex separations to a safe level between successive aircraft can increase capacity in the National Airspace System (NAS) with corresponding savings in delay times. One of the main goals of the Wake Encounter Model (WEM) described in this thesis is to assess the outcome from future reduced separation criteria in the NAS. The model has been used to test probable encounters in today's operations, and can also be used to test NextGen scenarios, such as Close Parallel Approaches and reduced in-trail separation flights. This thesis presents model enhancements to account for aircraft turning maneuvers, giving the wake a more realistic shape. Three major airspaces, New York, Southern California and Atlanta, were analyzed using the original and the enhanced WEM to determine if the enhanced model better represents the conditions in today's operations. Additionally, some analysis on the wake lateral travel for closely spaced runways is presented in this thesis. Finally, some extension tools for post -analysis, such as animation tool and various graphs depicting the interactions between wake pairs were developed. / Master of Science

This document provides a comprehensive historical account of the International Advisory Group - Air Navigation Services (ANSA) and shows the achievements, organizational changes, and contributions to the aviation industry. Established in 1967 by German air traffic controllers from the Rhein Control upper airspace ATC center, ANSA is a non-profit organization dedicated to improving air traffic control systems and procedures. Initially formed to support German air navigation authorities and EUROCONTROL, the group expanded its membership to include experts from over 20 countries. In 1985, ANSA moved its legal seat to Switzerland, continuing its mission to enhance flight safety and modernize ATC systems.

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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 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