Which action may trigger Coriolis Illusion?

• A. Moving the head in a plane different from the flight path.
• B. Maintaining a constant gaze straight ahead.
• C. Leveling off after a climb without visual cues.
• D. Reducing power while turning.

Answer: (B)

Coriolis illusion happens when the head is moved in a way that stimulates the inner-ear semicircular canals along an axis different from the aircraft’s actual path of motion. In a turn, the aircraft is rotating around one axis; if you move your head in a perpendicular or different plane (for example tilting your head up or sideways while the aircraft is turning), the canals respond to a cross-axis rotation. The brain then receives conflicting signals and may perceive a bank, roll, or turning in a direction different from the true motion, which can be dangerous.

Therefore, the action that may trigger Coriolis illusion is moving the head in a plane different from the flight path. Keeping a constant gaze straight ahead doesn't add new canal stimulation and is less likely to provoke the illusion. Leveling off or changing power in a turn affect other aspects of flight but do not by themselves create the cross-axis vestibular stimulation that leads to this illusion.