Aydan Cavcar’s research while affiliated with Anadolu University and other places

Air Traffic Management (ATM) research generally focuses on achieving a safer, more effective and economical air traffic system. The current airspace system has become increasingly strained as the demand for air travel has steadily grown. Innovative, proactive and multi-disciplinary approaches to research are needed to solve flight congestion and delays as a consequence of this rapid growth. As a result of this growth, air traffic flow becomes more complex, especially in Terminal Airspaces (TMA) where climb and descent manoeuvres of departing and arriving flights take place around airports. As air traffic demand exceeds the capacity in a TMA, the resultant congestion leads to delays that spread all over the system. Therefore, the reduction of delays is critical for airspace designers to increase customer satisfaction and the perception of service quality. Numerous studies have been conducted to reduce delays within TMAs. This research focuses on defining the causes of delays quantitatively through statistical analysis. The first step was to create a fast-time simulation model of sample airspace for collecting delay data. After building up this model using the SIMMOD fast-time ATM simulation tool, simulation experiments were run to produce various traffic scenarios and to generate traffic delay data. The number of airports, entry points, fixes and flight operations in airspace and the probability of wide-body aircraft were considered as independent variables. The correlations between the considered variables were analysed, and the total delay data was modelled using a linear regression model. The findings of regression model present a statistical approach for airspace designers and air traffic flow planners.

This study presents a 0-1 integer programming model for air traffic flow management. The model is used for determining optimum departure times of aircraft so as to avoid aircraft conflicts and to balance capacity and demand on the airports. Standard air traffic control procedural separation minimas were set as conflict criteria, which has never been done before, and this makes it convenient for use in planning of flows in airspace sectors especially without surveillance system. The model was tested on an imaginary scenario, including an airspace sector, airport capacities and flight plans, and solved by a mathematical modeling and optimization software. Considering conflicts before takeoff, as in this study, might prevent riskier and costlier air traffic control measures such as heading, speed and flight level changes. The great need for these measures can be easily inferred from the solution results that presents delay times due to conflict related constraints. Utilizing both standard conflict criteria based on procedural separation minimas used in air traffic control and standard Air Traffic Flow Management strategy based on ground holding of aircraft in planning of flows, makes it easier to adapt the model to current Air Traffic Flow Management system.

Purpose ‐ The aim of this study is to identify the nodes where congestion occurs in the manoeuvring area of a large-scale airport and to provide appropriate suggestions for improvement. Design/methodology/approach ‐ To investigate the air traffic flow in a highly complex system such as an airport manoeuvring area, a two-stage method based on fast- and real-time simulation techniques is applied. The first stage involves the analysis with fast- and real-time simulations of a baseline model created to determine the congestion points. Based on the analysis, improvements to be performed in the layout of the manoeuvring area are proposed. In the second stage, alternative scenarios implementing these improvements are generated and evaluated in a fast-time simulation environment. Based on the results of simulations of different runway configurations, the main areas of congestion in the baseline airport model are determined. Congestion nodes are identified in the departure queue points and in the taxiway system. To mitigate congestion at these points, three alternative models comprising taxiway and fast-exit taxiway reconfigurations are tested using the fast-time simulation technique. The alternative solution found to be the best in these tests is selected for further testing in real-time simulations. Findings ‐ It is shown that the solution would result in an increase in the number of hourly operations and a significant decrease in total ground delays. When conducting the studies needed to identify congestion and design improvements, simulation techniques save both expense and time. Although fast-time simulations are usually adequate for identifying solutions, when critical configurations for the airport are considered, it is shown that it is necessary to also test the results of the fast-time simulations in real-time simulations. Research limitations/implications ‐ The effects of meteorological events, such as rain, fog and snow, etc. are ignored in the simulations. Ground movements in manoeuvring areas are significantly affected by the runways used. Consequently, to enable a comprehensive evaluation in the study, three alternative runway use scenarios are examined. Originality/value ‐ This study utilizes a combination of fast- and real-time simulation techniques to identify the points where congestion occurs in the manoeuvring areas of large-scale airports and to find solutions to minimize the congestion. This approach attempts to combine advantages of both techniques while reducing their shortcomings. No study is found in the literature using both of these techniques together for the capacity analysis of airport manoeuvring areas.

The authors have recent experience of the specification, procurement, customisation and operation of advanced air traffic control simulator systems. This paper summarises the specification of the software and hardware components of air traffic control simulators within a framework of user needs and advances in simulation technology. Both the required conventional characteristics and the desired innovative features which can accommodate future requirements are defined using taxonomy within this framework. Considering the high investments and challenges involved in the acquisition and operation of modern simulators, the proposed classifications and approaches will provide important benefits to users when selecting or renovating their systems.

Numerous academic and industrial studies have been conducted and different approaches have been developed for the current air transportation system with its rapidly increasing traffic volume. Congestion due to capacity limitations is among the most basic problems in this system. Air traffic control services require communication between pilots and air traffic controllers at every stage of flight. Therefore, the inclusion of pilots and airlines in the decision-making process when addressing air traffic control system problems can increase customer satisfaction. This study aims to determine the perceived service quality of pilots in the process of receiving air traffic control services. A survey model is used in this study. First, using a semistructured interview technique with air traffic controllers and pilots, problems are detected and classified and then survey forms are prepared accordingly. A total of 116 questionnaires were studied and data from these questionnaires were tested through Microsoft Office Excel software. Answers to the questions are compared using a one-way analysis of variance test and checked to identify whether any differences exist among them. In general, training-based problems are detected among air traffic controllers, and the problems related to airspace technical equipment are found to be slightly above average. Although shortcomings regarding technical equipment can be solved in the short term, problems regarding controller training have to be solved in the long term.

More accurate analytical solutions of the maximum rate of climb and maximum climb angle are proposed for the climbing flight of the piston-propeller airplane. For the solutions, it is assumed that the propeller efficiency is a function of the airspeed and the airplane has cambered wing drag polar. The solutions are compared with the performance calculated through traditional assumptions of a constant propeller efficiency and a symmetrical wing drag polar. Moreover, the quartic equation to find the best climb angle speed is solved exactly. The comparison proved that the solutions with traditional assumptions result in a higher service ceiling, a shorter climb time, and a shorter climb distance. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Each system is specifically designed to achieve certain goals, and an important component of systems is regular evaluation processes to determine to what extent these goals are achieved. Air traffic systems are not an exception for the application of such evaluation processes. In fact, there is a great demand in this field for effective and efficient processes of evaluation. This study presents an evaluation method developed by considering the needs or demands of the international civil aviation sector and air traffic systems. This development process includes the initial determination of the areas for evaluation and the designing of various figures of merit for both fields accordingly. This model was applied to the air traffic systems of 16 EUROCONTROL member countries and important results were obtained.

Purpose The purpose of this paper is to develop a knowledge‐based decision support tool used for assisting en‐route air traffic controllers by generating resolutions for dual aircraft conflicts after being integrated into a model‐based conflict detection and conflict resolution system. Design/methodology/approach Air traffic controller knowledge, which was obtained from the literature research, about solving aircraft conflicts is represented in a decision tree. Then it is written in Visual Basic programming language. With reference to several rules form the expert air traffic controller knowledge and some factors which affect controller conflict resolution process, the tool generates advisories consisting of eight kinds of separation strategies. Findings The paper finds that it is expected to increase the safety of air traffic system by supporting air traffic controller in conflict resolution process. Controller workload can be reduced by fast, reliable and acceptable resolution advisories of the tool. Research limitations/implications The accuracy of decision tree is limited with the adequacy and quality of knowledge obtained from references, several assumptions and interpretation. Because of the unavailability of a model‐based conflict detection and resolution tool, the tool could not be evaluated in simulations. Originality/value After being integrated into a model‐based decision support tool, it can reduce the deficiencies of the model‐based tool such as low degree of resolution acceptance by controllers and low‐resolution speed by providing expert air traffic controller knowledge to the tool.

An approximate solution of the constant altitude-constant Mach number cruise range for high subsonic speed flight of the turbojet/fan aircraft is proposed. The solution considers cambered wing drag polar of modern transport aircraft, dependence of the specific fuel consumption on Mach number, and compressibility effects on aerodynamic characteristics of the aircraft. The method aims for a quick assessment of the cruise range during conceptual or preliminary design phase. An application of the method to a known type of aircraft is also presented.

An exact solution of the maximum range, and a highly accurate approximate solution of the maximum endurance, are proposed for cruising flight of the piston-powered aircraft installed with a constant-speed propeller and cambered wing. It is proven that the constant-altitude/constant-speed cruise range can be independently optimized, even for the aircraft with cambered wing, without substitution of the optimum speed of other flight regimes.