somatogravic illusion

somatogravic illusion

somatogravic illusionclick for a larger image
An optical illusion that can result in spatial disorientation. A rapid acceleration during takeoff can create an illusion of being in a nose-up attitude. The disoriented pilot will push the aircraft into a nose-low, or dive, attitude. A rapid deceleration by quick reduction of the throttles can have the opposite effect, with the pilot pulling the aircraft into a nose-up, or stall, attitude. See also oculogravic illusion.
When head is level or when aircraft is flying at constant speed, sensing hairs are erect. However, if the head is raised or if the aircraft accelerates the sensing hairs bend backward. If visual clues are absent or the pilot is not concentrating on instruments, any acceleration will induce a sensation of nose-up attitude forcing a nose-down attitude.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
A probable cause found by the NTSB pointed to the "pilot's failure to maintain a positive climb rate after takeoff due to spatial disorientation (somatogravic illusion).
Analysis by the UK's Air Accidents Investigation Branch, aimed at assessing the effect of somatogravic illusion, concluded that the crew could have perceived that the aircraft had inverted as it transitioned rapidly from climb to descent.
The investigators concluded: "Evidence suggests that the flight crew may have been subject to somatogravic illusion caused by the helicopter's flight path and the lack of external visual cues.
Investigators added: "Evidence suggests the crew may have been subject to somatogravic illusion caused by the helicopter's flight path and the lack of external visual cues."
This is the somatogravic illusion in which the otolith organs in your ear behave as if you were tilting your head backwards.
Air accident investigators said yesterday they believe Capt Furniss, one of the Air Corps' most experienced teachers, was misled by an airborne phenomenon known as somatogravic illusion.
The somatogravic illusion is powerful--the inner ear tells the pilot that the airplane is climbing when it is accelerating in level flight.
When adding power and accelerating during a go-around, especially in more powerful aircraft, the otolith organs in the inner ear send signals to the brain that create the somatogravic illusion of pitching up abruptly.
For relatively low-time IFR geezers like me, the first experience of the somatogravic illusion at 200 feet on a missed in hard IMC was quite an awakening.
More scientifically labeled "Somatogravic Illusion," it describes the result of fluid moving in a pilot's inner ear when an aircraft accelerates.
In its curriculum for teaching student pilots, the FAA primarily focuses on the aeromedical causes of spatial disorientation--the vestibular-ocular system, somatogyral and somatogravic illusions, visual illusions and otolith organs.