Refer to figure.

Note: So far, it seems that EASA does not differentiate between vertigo and Coriolis illusion. Although the symptoms are similar, vertigo is different from Coriolis illusion. Vertigo develops when a person experiences a mismatch between spatial information from the eyes, vestibular system, and proprioceptors. This question really asks for the Coriolis illusion.

CORIOLIS ILLUSION

Coriolis illusion happens when you're in a constant turn long enough for the fluid in your ears to stop moving. When the fluid in your ears stops moving, your brain thinks it is 'straight-and-level'. At this point, if you move your head too quickly, such as tilting your head down to change a fuel tank or pick up a pen, you can start the fluid in your ears moving in an entirely different axis. This makes you feel like the airplane is maneuvering in a way that it isn't, an overwhelming sensation of rotating, turning, or accelerating along an entirely different plane. An attempt to stop the sensation by maneuvering the plane may put it into a dangerous attitude.

• To avoid this illusion, do not move your head too fast in limited visibility or darkness.