Which visual illusion occurs when the runway appears high and leads to a low approach?

The visual illusion described in the question occurs due to the perception of the runway's width, which misleads the pilot's judgment regarding altitude and approach. When a runway appears narrow, it creates an optical illusion that makes the aircraft seem higher than it actually is. As a result, the pilot may instinctively lower the approach angle to correct for this perceived height, leading to a low approach.

This phenomenon can be particularly dangerous during landing, as pilots may misjudge their altitude and end up too low on final approach, posing risks of undershooting the runway or experiencing a hard landing. Understanding this illusion is crucial for pilots, as it emphasizes the need to rely on their instruments and training rather than visual cues, especially under stressful or low-visibility conditions.

The other visual illusions relate to different perceptions of runway slope or width, which do not correspond to the situation described.