Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 111-113). Also available via the Internet.

No description available.

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.

Thesis (Ph. D.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 229-234).

Thesis--Naval War College, 2006. / Includes bibliographical references (p. 23-24). Also available online via the Defense Technical Information Center website (http://www.dtic.mil/).

The scope of this study was to evaluate the impact of the air traffic controller-to-pilot communication standard known as CPDLC or Data-Communication on the future air traffic operations. The impact was evaluated from the double viewpoint of airport delays and air traffic controllers' workload. RAMS simulation software is used to perform all the runs and from its output data the values of terminal area delays and controllers workload are obtained. The New York Metroplex terminal area was used as a case study. Because of its complexity, where three major airports (i.e. JFK, Newark, and La Guardia) interact and constraint each other, this area was particularly interesting to be studied and the data analyzed gave a valuable insight on the possible future impact of Data-Communication in congested terminal areas. The results of the study, based on some previous man-in-the-loop simulations performed by the FAA in the nineties, showed that significant potential benefits could be obtained with the complete implementation of such technologies in the workload experienced by air traffic controllers. Moreover some small but not negligible benefits were obtained in the total delays accrued by each airport studied. On the other hand, the simulations of the future demand predicted by the FAA demonstrated that without a significant increment in capacity or limitation on the traffic growth intolerable delays would be recorded across the NAS in the future. For the complexity of the simulation model calibration and for the very time-consuming run time not all the scenarios described in the methodology were tested, demonstrating the weakness of RAMS as a ground simulation model. / Master of Science

One of the major problems plaguing the airline industry in recent years has been the steady increase in the number and duration of flight delays. Airports have not been able to keep pace with the increase in air traffic. Consequently, Congress has directed the Federal Aviation Administration (FAA) to initiate programs to reduce delays and improve airport capacity. One program the FAA has initiated evaluates the simultaneous use of three and four closely spaced parallel runways. These operations would allow cost efficient capacity increases through concurrent use of already constructed runways and through the construction of additional runways at existing airports. Recent simulation studies have indicated that improvements in controller displays are required to safely conduct multiple parallel ILS approaches to runways spaced 4300 ft apart or less. This study was designed to quantify the ability of the Precision Runway Monitor (PRM) display to enhance controller performance over the current display, the Automated Radar Terminal System (ARTS) ILIA. Additionally, the effects of blunder degree and the number of simultaneous parallel approach operations (dual or triple approaches) on the controller's ability to detect aircraft blunders were also examined. A blunder is an unusually sharp turn by an aircraft off its ILS localizer course toward an adjacent ILS course. The PRM display, a high resolution raster scan color monitor, enhanced the controller's ability to quickly detect aircraft blunders over the ARTS ILIA display (the current display system), a Plan position Indicator (PPI). The average controller response times were smaller (4 seconds) and the average closest points of approach (CPAs) between the blundering and the evading aircraft were larger (776 ft) when the controllers used the PRM display. As in earlier studies, the thirty degree blunders resulted in conflicts that were more severe than the conflicts associated with twenty degree blunders. Conversely, contrary to earlier studies, the controllers were able to detect the twenty degree blunders as quickly as they detected thirty degree blunders. The controllers performed as well in the dual parallel approach operation as they did in the triple approach operation for all measures. The results of this study generally agreed with those found in earlier studies on controller performance. Controller performance can be improved with the use of high resolution displays with alert systems. However, unlike earlier studies, this study provided a quantification of the benefit of a proposed system relative to the current system. / Master of Science

No description available.

Two studies are reported which investigated the effect of individual demographics on training performance in air traffic controllers. The first study investigated the relationship between the demographics of age, sex and education level, and pass/fail rates at an air traffic control training centre. The data for this study was an historic data set provided by Airways Corporation, which oversees air traffic management in New Zealand. This includes training all controllers and providing all air traffic control in the country. The primary result of the first study was that trainees with post-secondary education achieved better during training than trainees with a high school education. Additionally, the level of education attained by the trainee appeared to be the best predictor (of the three demographic characteristics) for a trainee’s success. The data was limited, due to a significant amount of incomplete trainee records. This impaired the ability to conclusively resolve the role of these demographic characteristics for trainee success. The second study, investigated the impact these same demographics may have on trainee success in a much smaller (N=16), but complete (i.e., no missing records) and current cohort. In addition, the feedback given and received in a training centre to the 16 trainees was examined. The trainees under consideration in this study were attending the Airways training centre. The trainees’ debriefs after their air traffic control training sessions in Airways’ immersive tower simulator were recorded. The trends in the data validate the need for further research. The primary result of the second study however, was that there was a significant difference in the pass rates of those trainees with only a high school education (66.7% failed) and those with post-secondary education (0% failed). The other two demographic characteristics of interest, age and sex, did not significantly differ for those trainees who passed and failed. The combined results of these studies indicate that the air-traffic control community in New Zealand may benefit from further investigating these differences and potentially raising education requirements for air traffic control trainees.

In ongoing efforts to balance air traffic demand and airspace capacity, airspace complexity stands as a fundamental research problem. Taking a more analytic approach, this thesis proposes that airspace complexity can be described in terms of how the airspace (together with the traffic inside it and the traffic control algorithm) responds to disturbances. The response of the airspace to a disturbance is captured by the degree of control activity required to accommodate such disturbance. Furthermore, since the response of the airspace depends on the disturbance, this thesis introduces a complexity map which shows how an airspace responses to a set of different disturbances. Among the many possible types of disturbances, this thesis considers an aircraft entering into the airspace, and the proposed method of describing airspace complexity is illustrated with examples. The time evolution of a complexity map is investigated using a statistical approach. In addition, the proposed method is illustrated in relation to current and future traffic flow management concepts. It is also shown that the proposed method can be applied to airspace design problems.