Which condition increases the risk of Coriolis illusion?

• A. Looking at the ground outside
• B. Rapid head movements in a sustained turn with limited external cues
• C. Slow head movement in level flight
• D. Flying straight and level

Answer: (B)

Coriolis illusion happens when the inner ear’s semicircular canals misinterpret motion, especially when you’re already in a turn and you move your head quickly. In a sustained turn, your vestibular system is steadily sensing angular velocity. If you snap your head to look around while the aircraft continues turning and there aren’t strong visual cues to confirm orientation, the fluid in one canal can deflect differently and cross-stimulate another canal. That cross-coupled signal creates a false sensation of rotating or tilting in a direction opposite to what the aircraft is actually doing. Because you lack reliable external references to anchor your perception, this illusion is more likely to mislead you.

Looking at a ground reference or staying relatively still in a well-lit, visually rich environment provides accurate cues that counteract the vestibular misperception, and a slow head movement in level flight doesn’t provoke the same confusing canal interaction. Flying straight and level without the accelerations of a turn also minimizes the risk.