Tunnel display for four-dimensional fixed-wing aircraft approaches

A computer-gener ated perspective tunnel display for the four-dimensional fixed-wing aircraft approach to landing is evaluated. Attention is focused on the development and experimental evaluation of superimposed predictor symbology. It is investigated whether more complex predictive information, such as a perspective vehicle symbol predicting the future position as well as future attitude angles of.tthe vehicle contributes to a better system response, as compared to a flat predictor cross, indicating the predicted vehicle position only. Methods for utilizing the predictor symbol motions in controlling the forward velocity of the aircraft in four-dimensional approaches are investigated. Simulator tests show that the complex perspective vehicle symbol yields a decrease in bank-angle activity as compared to a flat predictor cross, but yields, in most cases, generally larger lateral and vertical deviations. It is also shown that the perspective vehicle symbol motions can be utilized successfully in controlling the forward velocity of the aircraft, yielding a sufficiently accurate velocity control response, without affecting path following performance. Since the flat predictor cross already yields a satisfactory response, the advantage of the perspective vehicle symbol over the flat predictor cross is marginal, so that for graphic systems with limited computation power the flat predictor cross is recommended/Although the tunnel display is shown to yield a very satisfactory response and pilot acceptance in the lateral axis of control, the vertical axis of control is found to lack sensitivity to variations in the vertical path angle, and the development of superimposed symbology, enabling a more accurate vertical path-angle control, is recommended.