What can occur when approaching a narrower-than-usual runway?

When approaching a narrower-than-usual runway, pilots often experience the illusion of being higher than they actually are. This common visual illusion occurs because our visual perception is influenced by the width of the runway. A narrower runway creates a perception of increased altitude, leading pilots to believe they are above their desired glide path.

This phenomenon is related to the concept of "size constancy" in visual perception, where the perceived size of an object can influence our judgment of distance and altitude. A wider runway gives the illusion of being closer to the ground due to the broader visual cues, while a narrower runway can make the pilot feel as if they are at a greater height than they truly are.

Understanding this illusion is crucial for pilots as it can result in a misjudgment of their position relative to the runway, potentially leading to a higher-than-appropriate landing approach. This emphasizes the importance of relying on instruments and visual aids, rather than solely on visual perception, especially in situations with unusual runway dimensions.