What effect does flying over featureless, dark areas have on the perception of aircraft altitude?

Flying over featureless, dark areas can create a visual illusion where the aircraft appears to be at a higher altitude than it actually is. This phenomenon occurs because the lack of visual reference points—such as landscapes, buildings, or other features—hinders the pilot's ability to accurately gauge altitude. In the absence of these reference points, the uniform, dark expanse of ground can lead to a misperception of height, resulting in the pilot believing they are flying higher than their true altitude.

This effect is particularly accentuated in conditions such as twilight or nighttime, as the lack of contrast and identifiable terrain makes it challenging for pilots to stabilize their perception of altitude. Therefore, pilots might find themselves miscalculating their approach, which can have serious consequences during critical phases of flight, such as landing. Thus, it is crucial for pilots to remain aware of these visual illusions and to rely on instruments for accurate altitude readings when flying over such terrain.