Through stabilization of the fluid in the semicircular canals, a pilot may perceive straight and level flight while actually in a banked turn.
This is caused by a quick return to level flight after a gradual, prolonged turn that the pilot failed to notice.
If a pilot does not notice the disorientation and continues to lean, the plane may over bank in the wrong direction and cause rolling.
In all cases of spatial orientation, pilots must be able to rely on their flight instruments when making control inputs to override false sensations.
[3][5] The Federal Aviation Administration warns pilots qualified solely under visual flight rules to avoid situations "when there is a possibility of getting trapped in deteriorating weather.