Document Type


Publication Date





In the past, aviation spatial disorientation (SD) has been considered predominantly an isolated vestibular problem, associated with lack of outside visual cues. Recent research has challenged the prevailing position by suggesting pilot SD is more commonly caused by problems with cognitive processing of visual spatial strategies. Among the confounding visual stimuli known to occur in-flight, several visual perspective illusions have been identified as reoccurring mishap causal factors. These illusions occur in part because humans exhibit a strong instinctive tendency toward considering themselves level with distant horizontal references, regardless of their true altitude. Also contributing to perspective illusion occurrence is the fact that objects viewed slightly above the perceived horizon will appear magnified in size and exaggerated in elevation above actual aircraft altitudes. Although perspective illusions have been recognized and studied for centuries, the impact of these sensory misperceptions on aviation safety has only recently been subjected to close scientific scrutiny.