Wendell D. Chase
Published: 1971
Total Pages: 52
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A study has been conducted to determine the effect of several variations of two types of visual display systems on subjective pilot evaluations and objective measures of performance in the landing approach. Two types of flight approaches were made with either a projector or quasicollimated monitor visual display: (I) the instrument approach, and (2) the visual approach without the normal cockpit instrumentation assistance. The variables examined were color; differences between displays due to quasicollimation of the monitor display; and reduced resolution as related to brightness, contrast, and sharpness. The use of color had two main effects on pilot performance in the landing approach. The touchdown distance and standard deviations increased more for the monitor displays, and the touchdown rates of descent were slightly lower. With quasicollimation, the standard deviations of touchdown distance increased, and the rate-of-descent standard deviations decreased in a direction more favorable with the actual flight data; an association between the standard deviations of rate of descent and touchdown distance suggests that a corresponding decrease in the deviation of rate of descent will be offset with an increase in the deviations of touchdown distance. The time outside the glide-slope error limits was less with the monitor display than with the projector display, and the lateral localizer error was smaller for the projector display because the pilots intercepted the runway center line at a greater distance from the threshold. With reduced resolution, there was a slight change in the touchdown distance and the standard deviation; for the flights made without color, the landings were predominantly to the right of the runway center line with twice the standard deviation. The pilots were more critical of the black and white variation for either display, and favored more use of a color system. Advantages cited for a color system included greater pilot relaxation, decreased fatigue, better picture quality, and more realistic depth perception, particularly with the monitor display. With regard to the reduced-resolution monitor display, the pilots also noted a loss in depth perception and height references, increased visual fatigue, and increased efforts for a reasonable approach in comparison with the projector display. The objective performance measures of the study were reasonably consistent with the pilots' subjective evaluations and comments.