Structural Illusion is caused by which conditions?

• A. Structural Illusion caused by rain, snow, sleet
• B. Occurs during autopilot engagement
• C. Resulting from rapid yaw change
• D. Related to glare on windshield

Answer: (A)

Structural Illusion happens when the outside visual reference is distorted or hidden by weather on the windshield. Rain, snow, or sleet coats the glass, scattering light and reducing horizon cues, so the pilot can’t clearly judge attitude. With the horizon obscured, the brain may rely on fixed features of the cockpit or vague visual patterns, leading to a mistaken sense of bank or pitch even when the aircraft is actually level. Glare can worsen visibility but isn’t the defining cause here, and rapid yaw changes or autopilot use produce other disorientation effects rather than this weather-related visual illusion.