FAA Private Pilot Airplane (PAR)Aeromedical Factors and ADMHard
While flying in a coordinated turn in instrument conditions, a pilot abruptly tilts their head down to pick up a dropped chart. Immediately afterward, the pilot experiences a strong, disorienting sensation of tumbling or rotating on a completely different axis than the actual turn. This dangerous illusion is best identified as which spatial disorientation phenomenon?
- AElevator illusion
- BAutokinesis
- CCoriolis illusion
- DFalse horizon illusion
Show answer & explanationAnswer & explanation
Correct answer: C. Coriolis illusion
The Coriolis illusion occurs when a pilot moves their head out of the plane of an existing turn, causing the semicircular canals of the inner ear to signal a false and often severe sensation of rotation on a completely different axis, which can lead to spatial disorientation and loss of control.
Why the other options are wrong
- A. Elevator illusion (an entry into an updraft or downdraft) causes a false climbing or descending sensation, not related to head movement in a turn.
- B. Autokinesis is the illusion of a stationary light appearing to move when stared at in the dark, unrelated to turning or head movement.
- D. False horizon illusion is caused by misinterpreting sloping cloud formations or terrain as the horizon, not head movement.
Coriolis Illusion
A vestibular illusion caused by moving the head out of the plane of a prolonged turn, producing a false and often overwhelming sensation of rotation or tumbling on a different axis.
- Triggered by head movement during a sustained turn
- Considered one of the most dangerous spatial disorientation illusions
- Prevention: avoid abrupt head movements during turns, especially in IMC
Memory trick: Tilt your head in a turn, feel the world spin off-axis