Which visual illusion makes a pilot perceive that the horizon is a certain way when it isn’t?

The false horizon illusion occurs when a pilot misinterprets non-horizontal reference points as the true horizon. This can happen in conditions where visibility is poor or the natural horizon is obscured, such as during twilight or when flying over water. In these situations, cultural landmarks or the visual appearance of terrain can create a misleading cue that pilots mistakenly rely on for level flight. This can lead to dangerous maneuvers, as pilots may attempt to adjust their aircraft to what they perceive as the correct horizon, potentially resulting in a loss of control.

Understanding this illusion is crucial for pilots, as it highlights the importance of using instruments in flight, particularly in conditions where visual references might be deceiving. Recognizing the limitations of visual perception can help pilots maintain situational awareness and avoid making erratic control inputs based on misleading visual cues.