Spatial Disorientation Flashcards
(48 cards)
What is spatial disorientation?
Pilot’s erroneous perception of position,
attitude, or motion in relation to the
gravitational vertical and the Earth’s surface.
What are the three types of SD?
(URI)
Unrecogonized, Recognized and incapacitating
What is unrecognized SD?
Most Dangerous
Pilot does not perceive any indication of
SD. Fails to recognize and correct disorient
leading to crash. (Height/Depth Perception)
What is recognized SD?
Pilot perceives a
problem but may fail to recognize it as SD.
(believes instrument fail / control failure)
What is incapacitating SD?
Pilot experiences
overwhelming sensation of movement.
Transfer controls or focus.
What is incapacitating SD?
Pilot experiences
overwhelming sensation of movement.
Transfer controls or focus.
What are the three systems of SD?
(VVP)
Visual, vestibular, Proprioceptive
Explain the visual system in SD
the most important in maintaining
the ability to orient and move in three-
dimensional space.
Explain the vestibular system in SD
Inner ear contains
Semicircular Canals (angular acceleration using
endolymph fluid sense rotation of head) and
Otolith Organs (linear acceleration and gravity,
hairs and crystals located in vestibule proper
sense head position changes).
Explain the somatosensory system in SD
pressure on joints,
muscles, skin, and internal organ movement
What are the visual illusions?
Vection (Induced Motion Illusion)
• False Horizon
• Confusion with ground lights
• Height/Depth Perception Illusion
• Crater Illusion
• Structural Illusion
• Fascination (Fixation)
• Autokinesis
• Size – Distance Illusion
• Aerial Perspective
• Size Constancy
• Shape Constancy
What is a vection illusion?
(Induced Motion). Falsely perceived motion of oneself when no physical motion is actually occurring.
When stationary and things move around you.
What is confusion regarding visual illusions?
A common occurrence is to confuse ground lights with stars. A good cross check will prevent this illusion.
What is a crater illusion?
Occurs when aircrew members land at night, under NVG conditions, and the IR searchlight is directed too far under the nose of the aircraft. This will cause the illusion of landing with up-sloping terrain in any directions. Depressing lulls the pilot into continuing to lower the collective. Could result in the aircraft prematurely impacting the ground, causing damage.
What is Height/depth perception illusion?
When flying over terrain lacking good contrast (water, desert, snow), crew members may think the aircraft is higher or lower than it actually is. This is due to a lack of visual references. It can be overcome by dropping an object of known size or intensity from the aircraft or by using shadows cast by surrounding objects or the aircraft. At night drop a chem.-stick or flare before landing. Flight in DVE conditions can produce the same illusion.
What is autokinesis?
When a static light is stared at in the dark for 6 to 12 seconds, the light appears to move up to 20 degrees in any direction. Reduce or eliminate by visual scanning, increasing the number of lights, or by varying light intensity.
What is Fascination/fixation?
This occurs when aviators ignore orientation cues & fix their attention on a single goal or object without seeing the whole environment. May occur during times of task saturation or target fixation.
What is false horizon in SD?
Confusing cloud formations, mountain ridges or “cultural” lighting (coastline or highway) w/ the horizon. This is usually occurs when the aviator looks up after a prolonged period in the cockpit or from poor scanning technique.
What is structural illusion?
The distortion of objects caused by heat waves, rain, snow or other factors that obscure vision. Curvature of the wiindscreen can also cause this. This illusion can be linked to mirages.
What is a size distance illusion?
(SSA: Size Constancy, Shape Constancy, Aerial Perspective)
What is size constancy?
occurs when shooting an approach to a large runway vs. a small stage field lane. On larger runways an aviator may perceive he is too low when landing.
What is shape constancy?
can occur on approach to a down-sloping runway giving the illusion that the aircraft is lower than it is; or to a up-sloping runway giving the illusion that the aircraft is higher than it is causing the pilot to fly lower in an attempt to achieve that normal sight picture.
What is aerial perspective?
occurs when visual cues such as a runway or trees are different size than expected. Washington’s vs. Alabama’s vegetation differences.
What is a SOMATOGRAVIC ILLUSION?
caused by
linear acceleration / gravity – causes the otolith
organ to sense a nose-high (or nose low)
attitude.
• G-Excess Illusion - results from a change in
the direction of the net gravitoinertial force, a
G-excess illusion results from a change in the
direction of the net gravitoinertial force.
• Elevator – occurs during upward
acceleration pilots eyes track down, nose
seems to rise and pilot push fwd on cyclic
