Thèse (M. Eng.) -- Université du Québec à Chicoutimi, 2002. / Bibliogr.: f. 154-192. Document électronique également accessible en format PDF. CaQCU

Congestion and delay problems at airports have received much attention in recent years because of the unbalanced condition between demand and supply. Recent demand forecasts indicate that the problems are expected to increase in the next decade. Relieving congestion of the air transportation networks requires several strategies to enhance the runway capacity. Among these strategies is reducing the runway occupancy time a critical factor in affecting runway capacity. And one approach to reducing the runway occupancy time (ROT) is locating the high speed exits optimally. In addressing the reduction of the runway occupancy time, a full information on the distribution of aircraft landing distance is required. The landing performance at a specific airport may be found by observing the actual landings. However, this is costly and may not be transferable to other airports. An alternative approach is to use a simulation model. A simulation model was built at Center for Transportation Research at Virginia Tech based on point mass kinematics in the flying phase over runway and the ground roll phase on runway to predict the landing roll distance and time to a specified exit speed. Many influencing parameters were incorporated into the model, and then were calibrated using the field data obtained from real operations. The prediction of a nominal landing roll distance and time to decelerate to a specified exit speed is not sufficient for estimating ROT because the additional time to reach a designated exit should be taken into account. To compute the additional time, a braking adjustment scheme is selected from several alternative schemes. The combination of the selected braking adjustment scheme and the simulation model approximates very closely the observed ROT. An optimization model is formulated to determine the exit locations so as to minimize the weighted average ROT of the defined aircraft mix. A polynomial-time solution algorithm is developed for this model using Dynamic Programming technique. The major input parameters for the model are the distribution of the landing roll distance to the specified exit speed and the information on the aircraft mix. The model structured to address the problem of designing a new runway as well as the problem of improving an existing runway. A runway capacity model is used to convert the optimized ROT into capacity gains. Four scenarios are analyzed. Among the scenarios, one is based on the present Air Traffic Control procedures, and three are based on the future developments. The capacity analysis reveals that the ROT does not affect the runway capacity for landing operations. However, the ROT is found as a critical factor for the runway capacity for mixed operations. Hence, the ROT should be optimized for the current system and more crucially for the future developments. The capacity gains by optimizing the ROT under the current Air Traffic Control systems and standards are estimated 2 to 7 more operations per hour. These gains will increase to 20 more operations per hour in the future environment. / Ph. D.

This study outlines the development and use of several techniques providing an automated landing, roll out and turnoff of an aircraft, in an airport environment. A maximum runway occupancy time and a certain level of reliability are achieved by the use of a computer software called the Probabilistic Computer Model of Optimal Runway Turnoffs. A bunching of eight optimal high speed exits, representing four TERPS categories, is performed on a single runway. Feasibility of the system is determined by the use of Inertial Navigation and other aids such as the Microwave Landing System, Filtering Devices, Electronic Cockpit Airfield Display Formats, Real Time Flight Simulation and Field Testing, and a Braking Guidance Policy. It is suggested that future testing and a review of the Model be done. / M.S.

A general numerical simulation of closely coupled lifting surfaces in steady and unsteady ground effects was developed. This model was coupled with the equations of motion to simulate aerodynamic-dynamic interaction. The resulting model was then coupled with a feedback-control law to form a general nonlinear unsteady numerical simulation of control of an aircraft in and out of ground effect. The aerodynamic model is based on the general unsteady vortex-lattice method and the method of images. It is not restricted by planform, angle of attack, sink rate, dihedral angle, twist, camber, etc. as long as stall or vortex bursting does not occur. In addition, it has the versatility to model steady and unsteady aerodynamic interference. The present model can be used to simulate any prescribed flare and to model the effects of cross and/or head winds near the ground. The present results show the influences of various parameters on the aerodynamic coefficients for both steady and unsteady flows. Generally, the ground increases the aerodynamic coefficients; the greater the sink rates, the stronger the effects. Increasing the aspect ratio increases both the steady and unsteady ground effects. An exception is a large aspect-ratio wing with large camber. The present results are generally in close agreement with limited exact solutions and experimental data. In the aerodynamic-dynamic simulation, the equations of motion were solved by Hammlng's predictor-corrector method. The aircraft, air stream, and control surfaces were treated as a single dynamic system. The entire set of governing equations was solved simultaneously and interactively. The aerodynamic-dynamic model was used to study a configuration that resembles a Cessna 182 airplane. The ground lowers the effectiveness of the tail in controlling pitch, increases the lift and drag, and makes the hinge-moment less negative. Proportional and rate control laws were used in a feedback system to control pitch. One set of gains was used in and out of ground effect. For the same control input, the pitch angle responds faster and overshoots more near the ground than it does far from the ground. The present results demonstrate the feasibility of using the current simulation to model more complicated motions and the Importance of including the unsteady ground effects when analyzing the performance of an airplane during a landing maneuver. / Ph. D.

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How fashion is being presented today? A retrospective research into the history of the fashion shows in order to observe and examine the metamorphosis of the runway presentations of the present time. Fashion designers from the Swedish School of Textiles have participated in the thesis' interview as to express their point of view and elaborate on the issue.