FAA Instrument Rating Airplane (IRA)Aeromedical and ADMEasy
A pilot enters a bank to the left that gradually increases without the pilot's awareness because the fluid in the semicircular canals has stabilized. When the pilot glances at the attitude indicator and abruptly rolls the wings level, the pilot experiences a strong sensation of banking in the opposite direction even though the wings are now level. Which illusion is being described?
- AThe leans
- BElevator illusion
- CCoriolis illusion
- DSomatogravic illusion
Show answer & explanationAnswer & explanation
Correct answer: A. The leans
The leans occurs when a slow roll into a bank goes undetected by the vestibular system because the fluid in the semicircular canals reaches equilibrium; a sudden correction to level flight then creates a false sensation of banking in the opposite direction, causing the pilot to lean to counteract it.
Why the other options are wrong
- B. Not a recognized spatial disorientation illusion in FAA material.
- C. Coriolis illusion involves a head movement during a prolonged turn, not a gradual bank correction.
- D. Somatogravic illusion is caused by acceleration/deceleration mimicking pitch changes.
The Leans
A spatial disorientation illusion caused by a sudden return to level flight after a gradual, undetected bank, producing a false sensation of banking in the opposite direction.
- Most common vestibular illusion in flight
- Caused by fluid equilibrium in semicircular canals during slow bank changes
- Pilot may physically lean to compensate for the false sensation
Memory trick: Slow bank sneaks in, fast fix leans you out.