The aim of this study was to determine level of work stress in a group of air traffic controllers from the South African Air Force, and also a group of air traffic controllers from the civil sector. It is commonly known that air traffic control is considered a stressful job, and the researcher decided to examine the situation in South Africa. Stressors which may be applicable to the air traffic controller were discussed, to help the controller to identify his source of stress. The air traffic control job was also studied to identify its stressful elements. The research group consisted of 97 persons, 52 from the SAAF, and 45 from the civil sector. Most of them were in the age group of 19-25 years. Rice's Stress&Health questionnaire was used to determine the respondents' stress levels in three sub-categories. These sub-categories were interpersonal stress, physical stress, and job interest. The results show that civil sector controllers experience a higher level of work stress than their colleagues in the SAAF. This is because of the civil sector's higher workload. Results show that the factors influencing stress are complex and include amount of workload and personality type. Proposals were made with regard to stress management. / Thesis (MCom)--University of Pretoria, 2004. / Human Resource Management / unrestricted

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001. / Includes bibliographical references (p. 199-203). / In order to support the development of improved methods for departure operations, the flow constraints and their causalities --primarily responsible for inefficiencies and delays-- need to be identified. This thesis is an effort to identify such flow constraints and gain a deep understanding of the departure process underlying dynamics based on field observations and analysis conducted at Boston Logan International Airport. It was observed that the departure process forms a complex interactive queuing system and is highly controlled by the air traffic controllers. Therefore, Flow constraints were identified with airport resources (runways, taxiways, ramp and gates) and with air traffic controllers due to their workload and control strategies. While departure delays were observed in all airport components, flow constraints manifested mainly at the runway system, where the longest delays and queues concentrated. Major delays and inefficiencies were also observed due to flow constraints at National Air Space locations downstream of the airport, which propagate back and block the departure flow from the airport. The air traffic controllers' main strategies in managing the traffic and dealing with the flow constraints were also identified. / (cont.) Based on these observations, a core departure process abstraction was posed consisting of a queuing element (representing the delays) and a control element (representing the air traffic controller actions). The control element represents blocking the aircraft flow, to maintain safe airport operation according to Air Traffic Control procedures and to regulate the outbound flow to constrained downstream resources. Based on this physical abstraction, an analytical queuing framework was developed and used to analyze the departure process dynamics under three different scenarios: the overall process between pushback and takeoff, departure sub-processes between controller/pilot communication events and under downstream restrictions. Passing which results mainly from aircraft sequencing and their suspension under special circumstances (such as downstream restrictions) was used as a manifestation of the control behavior. It was observed that Logan Airport exhibits high uncertainty and limited sequencing, hindering the air traffic controllers' ability to efficiently manage the traffic and comply with restrictions. In conclusion, implications for improved methods for departure operations are inferred from the observations and analysis. / by Husni Rifat Idris. / Ph.D.

<p>The international aviation industry has embraced a revolutionary future concept of operations known as "free flight". The free flight concept allows each aircraft to travel between destinations using flexible fuel efficient routes rather than the current fixed jet routes. Flying the present inefficient fixed routes costs the airlines millions of dollars annually in fuel and personnel costs. Additionally, because there are only a limited number of the current "highways in the sky", aircraft in the United States and Europe regularly experience delays waiting for their turn to access the jet-routes. This present system also constrains future air traffic growth, particularly in oceanic airspace.</p> <p> To address these deficiencies, direct pilot-to-controller communications are required in oceanic airspace managed by the United States. This functional requirement for direct pilot-to-controller communications is not being met by the present oceanic air-to-ground communications system.</p> <p>Using a systems engineering approach, this project determines the feasibility of extending domestic air traffic control communication systems into the U.S. managed oceanic airspace over the Gulf of Mexico. Two feasible alternatives are evaluated for achieving this capability.</p> / Master of Science

Through application of modern technology, aviation systems are becoming more automated and are relying less on antiquated air traffic control (ATC) voice systems. Aircraft are now able to wirelessly broadcast and receive identity and location information using transponder technology. This helps reduce controller workload and allows the aircraft to take more responsibility for maintaining safe separation. However, these systems lack source authentication methods or the ability to check the integrity of message content. This opens the door for hackers to potentially create fraudulent messages or manipulate message content. This thesis presents a solution to handling many of the potential security issues in aircraft data communication. This is accomplished through the implementation of a Dual Path PKI (DPP) design which includes a novel approach to handling certificate revocation through session certificates. DPP defines two authentication protocols, one between aircraft and another between aircraft and ATC, to achieve source authentication. Digital signature technology is utilized to achieve message content and source integrity as well as enable bootstrapping DPP into current ATC systems. DPP employs cutting-edge elliptic curve cryptography (ECC) algorithms to increase performance and reduce overhead. T is found that the DPP design successfully mitigates several of the cyber security concerns in aircraft and ATC data communications. An implementation of the design shows that anticipated ATC systems can accommodate the additional processing power and bandwidth required by DPP to successfully achieve system integrity and security. / Master of Science

In this work, a user-friendly MATLAB tool is introduced to solve nonlinear optimal control problems by applying collocation techniques using Coupled Radial Basis Functions (CRBFs). CRBFs are a new class of Radial Basis Functions combined with a conical spline r^5, which provides the advantage of insensitivity to the shape parameter while maintaining accuracy and robustness. To solve optimal control problems, software tools are often employed to implement numerical methods and apply advanced techniques to solving differential equations. Although several commercial software tools exist for solving optimal control problems, such as ICLOCS2, GPOPS, and DIDO, there are no options available that utilize adaptive collocation with CRBFs. A unified MATLAB tool named Radial Optimal Control Software (ROCS) is introduced and not only implements the CRBF method, but also enables any user, from professionals to students, to solve nonlinear optimal control problems through a user-friendly interface. The tool accepts user input for boundary conditions, necessary conditions, and the governing equations of motion. The two-point boundary value problem (TPBVP) is approximated through collocation using CRBFs, and the resulting nonlinear algebraic equations (NAEs) are solved with a MATLAB solver. The tool's usefulness and application are demonstrated by solving classical nonlinear optimal control problems and comparing the results with the solutions found in the literature. Compared to classical numerical method techniques, the present tool is shown to solve optimal control problems more efficiently for the same level of accuracy. By introducing this unified MATLAB tool to solving nonlinear optimal control problems, the intent is to enable professionals and students to solve nonlinear optimal control problems, e.g., in astrodynamics and space-flight mechanics, without the need for extensive manipulation of code in existing software tools and without extensive knowledge of applying numerical solvers.

This thesis deals with the development of an Airspace Sector Occupancy Model (ASOM). The model determines the occupancy of Air Traffic Control Center (ARTCC) sectors for a given geometry of sectors and flight schedules, and can be used to study the impact of alternative flight schedules on the workload imposed on the sectors. Along with complimentary airspace analysis models, this can serve as an advisory tool to approve flight plans in the Free Flight Scenario, or to reschedule flights around a Special Use Airspace (SUA). ASOM is developed using Matlab 5.2, and can be run on an IBM compatible PC, Macintosh, or Unix Workstation. The computerized model incorporates the powerful features of graphics and hierarchical modeling inherent in Matlab, to design an effective tool for analyzing air traffic scenarios and their respective sector occupancies. / Master of Science

In order to increase the safety of all air travel, technologies that continueto augment the pilot's ability to avoid collisions and stay clear of danger areneeded. But, before these can be certified and deployed, their performance andpotential failure cases have to be understood. This requires evaluating a modelof the system on simulated encounters, consisting of different trajectoriesthat should replicate the real world. This is commonly done using a statistical encounter model, which produces largeamounts of data but relies on the accuracy of the statistical model, thuslimited in its ability to produce realistic data. The goal with this project isto create an encounter dataset of real trajectories that would provide analternative to encounter models. This is done using an ADS-B dataset from The OpenSky Network (provided byDaedalean AI), consisting of 226 billion air traffic data points from 2019.First, a solution to efficiently query and reconstruct trajectories from thedataset is designed and implemented. Using it, a NMAC (Near Mid-Air Collision)dataset is created to demonstrate the viability of ADS-B as a source forcreating an encounter dataset, and to prove the capabilities of the designedsolution.

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The National Aeronautics and Space Administration (NASA) is leading a research effort to develop a Small Aircraft Transportation System (SATS) that will expand air transportation capabilities to hundreds of underutilized airports in the United States. Most of the research effort addresses the technological development of the small aircraft as well as the systems to manage airspace usage and surface activities at airports. The Federal Aviation Administration (FAA) will also play a major role in the successful implementation of SATS, however, the administration is reluctant to embrace the unproven concept. The purpose of the research presented in this dissertation is to determine if the FAA can pursue a resource management strategy that will support the current radar-based Air Traffic Control (ATC) system as well as a Global Positioning Satellite (GPS)-based ATC system required by the SATS. The research centered around the use of the System Dynamics modeling methodology to determine the future behavior of the principle components of the ATC system over time. The research included a model of the ATC system consisting of people, facilities, equipment, airports, aircraft, the FAA budget, and the Airport and Airways Trust Fund. The model generated system performance behavior used to evaluate three scenarios. The first scenario depicted the base case behavior of the system if the FAA continued its current resource management practices. The second scenario depicted the behavior of the system if the FAA emphasized development of GPS-based ATC systems. The third scenario depicted a combined resource management strategy that supplemented radar systems with GPS systems. The findings of the research were that the FAA must pursue a resource management strategy that primarily funds a radar-based ATC system and directs lesser funding toward a GPS-based supplemental ATC system. The most significant contribution of this research was the insight and understanding gained of how several resource management strategies and the presence of SATS aircraft may impact the future US Air Traffic Control system. / Ph. D.