Effect of different runway sizes on pilot performance during simulated night landing approaches.

Both anecdotal reports from pilots and theories of visual cues would predict lower approaches to narrow or long runways than to wide and short runways. Similar, practice approaches made by pilots to a particular width of runway should lead to an increase in subsequent approach angles flown to wider runways and a decrease in approach angles flown to narrower runways. Two experiments with instrument-rated pilots made quantitative tests and these predictions. In Experiment I, three pilots flew simulated approaches and landings in a fixed-base simulator with a computer-generated image visual display. Practice approaches were flown with an 8,000-ft long runway that was either 75, 150, or 300 ft wide; test approaches were to runways with widths or 75, 100, 150, 200, and 300 ft. In Experiment II, 40 pilots controlled the slant of a moving model runway during simulated night visual approaches. Five different models simulated runways from 100 to 300 ft wide and 3,000 to 9,000 ft long. As predicted, training on a wide runway in Experiment I lowered approach angle in approaches to narrower runways; a narrow practice runway also raised approach angles to wider runways. The magnitude of these practice effects increased as distance from runway threshold decreased. There was also a general tendency for approach angles to decrease as runway width decreased. The latter effect was corroborated in Experiment II; in addition, generated approach angles decreased with increasing runway length. Giving half the pilots information about runway size prior to each approach had no effect on responses. These findings add to the quantitative evidence of danger in night visual approaches due to visual illusions and large variability in the visual perception of approach angle.