Which Vestibular Illusion is associated with a pilot experiencing a sense of falling during straight and level flight?

The Leans is a vestibular illusion that occurs when a pilot experiences a sensation of rolling or falling during straight and level flight, usually after a prolonged period of uncoordinated turns or changes in orientation that have not been correctly perceived by the inner ear.

In a scenario where a pilot is flying straight and level but has previously experienced a turn, the inner ear may misinterpret the absence of the expected sensation associated with turning. The pilot might feel as if they are still in a banked position, leading to an erroneous perception that the aircraft is falling or is not level, which can result in inappropriate control inputs. This can happen especially after recovering from a maneuver, causing the pilot to inadvertently make corrections that might lead to a dangerous situation, such as an unintentional loss of altitude or orientation.

Understanding this illusion is crucial for pilots to maintain proper situational awareness and control of the aircraft, particularly in visual flight conditions where physical cues are less pronounced. Being aware of the Leans helps pilots recognize when they might be experiencing discrepancies between their physical sensations and reality, allowing them to rely on instruments rather than their vestibular senses alone.