false horizon

false horizon

[¦fȯls hə′riz·ən]

(navigation)

A line resembling the visible horizon but above or below it.

false horizon

A case of perception of false horizon when flying between two cloud layers.

A visual illusion that occurs when flying between two cloud layers that are not horizontal when there is no natural horizon. In this case, there is a tendency to use a cloud base or the cloud top as the horizon and fly with a corresponding bank. Other conditions conducive to causing this illusion are sloping cloud formations, an obscured horizon, a dark spread with ground lights and stars, and certain geometric patterns of ground lights.