Which of the following is NOT one of the Vestibular Illusions?

Motion sickness is the correct response because it is not classified as a vestibular illusion. The vestibular system is primarily responsible for balance and spatial orientation and can produce various illusions related to the sensation of movement or position in space. Vestibular illusions occur when there is a mismatch between the sensory information from the inner ears and what is visually perceived.

In contrast, motion sickness is characterized by a physical response to conflicting sensory signals, often resulting from perceived motion when the body is stationary. It involves symptoms like nausea, dizziness, or disorientation, but it's a condition rather than an illusion. The other options are examples of vestibular illusions where the body misinterprets motion or orientation:

• The Leans occur when a pilot incorrectly perceives their bank angle during a turn.

• The Graveyard Spiral is a situation where a pilot may not recognize a gradual descent despite the perception of level flight.

• The Elevator Illusion happens when a rapid ascent or descent is misperceived, contributing to altered sensory inputs.

Understanding these distinctions is crucial in aviation to help pilots recognize and counteract the effects of vestibular illusions and ensure safe operation of the aircraft.