Spatial Disorientation Flashcards
Describe the Coriolis illusion.
An illusion of angular motion (usually pitch or roll) that occurs when the head is removed from the plane of rotation; this illusion is also known as cross-coupling and is frequently associated with nausea, vomiting, and other symptoms.
Describe False Horizon illusion
Misperception of the actual horizon caused by the presence of sloping terrain on or near the horizon, or strings of lights near the horizon, as on a well lit highway at night.
Describe Flicker Vertigo
Primary occurs in helicopters as the sunlight comes through the rotors and appears like a strobe light or flashing lights at 5 to 20 Hz. Can cause vertigo.
Describe the G-excess illusion
An illusion that occurs when a pilot moves his or her head in a greater than 1 G environment, which leads to excessive shearing of the otolith organs and to an exaggerated senation of head, body or aircraft tilt
Describe the leans
A feeling of being banked when the aircraft is upright and level. this illusion is caused by both gravitoinertial forces (leveling out after a prolonged turn) or by visual factors (a sloping cloud deck).
Describe the runway width illusion
A wider or narrower runway than expected by the pilot will give the illusion of being too low on a wide runway, and too high on a narrow runway.
Describe the somatogyral illusion
A false sensation of rotation (or absence of rotation) that results from misperceiving the magnitude or direction of an actual rotation. This results from the inability of the semicircular canals to register acurrately a prolonged rotation.
After a long crew duty day, a pilot is performing a difficult approach in marginal weather conditions. While in a right standard rate turn, he turns his head to check his wingman’s position. He subsequently feels the control stick thrust to the right. He is unable to center the stick after repeated effort. When he releases his grip on the stick, it returns to a centered position. The most likely cause of this pilot’s difficulty is:
a) a control malfunction
b) the somatogravic illusion
c) the Giant Hand phenomenon
d) severe turbulence
c) The Giant Hand Phenomenon
A pilot, who has just departed base and is performing a steep climbing turn to the left, turns his head to the console on his right to change radio frequencies to departure control. He may experience:
a) oculogravic illusion
b) coriolis illusion
c) oculogyral illusion
d) autokinesis
b) Coriolis illusion- He turned his head across the plane of rotation on an already rotating system which could result in a coriolis illusion.
Spatial disorientation has been a causal or contributing factor in what percentage of USAF aircraft accidents?
4 to 7% of major accidents, 10-15% of fatal accidents
Somatogravic illusions (thrust off a carrier for example) can give the pilot a sense he is tipping upward due to the acceleration and G force into his seat. He then lowers the stick thinking he is leveling the aircraft and instead noses in. This is due to stimulation of what organ?
Otoliths
How long after the end of a typical aircraft carrier catapult launch would you expect the peaks of the resulting somatogravic and oculogravic illusions to occur?
5-20 secs
The most common form of spatial disorientation is the:
a) coriolis illusion
b) graveyard spin
c) leans
d) somatogravic illusion
c) leans
Controlled flight into terrain without evidence the pilot was aware or attempting to correct is considered what type of spatial disorientation?
Type 1 spatial disorientation- No pilot awareness
Type 2 - Pilot is aware and attempting to correct or overcorrect
Type 3- Pilot is incapacitated such as ocular nystagmus
In a study by the Air Force between 1980 and 1988, what percentage of operator-related fatalities were due to either spatial disorientation or loss of situational awareness?
85%
