What visual illusion can make a runway appear narrower than it is?

The correct answer, which identifies the visual illusion that can make a runway appear narrower than it is, is the upslope runway illusion. This phenomenon occurs when pilots approach a runway that is actually sloping upwards. The pilot's visual perception is affected, leading to the impression that the runway is narrower than its actual width. This is primarily because the ascending terrain can create a visual distortion that compresses the appearance of the runway.

Understanding this illusion is crucial for pilots, especially during landing approaches, as it can lead to misjudgment in the landing phase, potentially causing unsafe maneuvers or approaches. Recognizing the effects of sloping runways on visual perception aids pilots in maintaining situational awareness and making accurate decisions.