Spatial Disorientation and Sensory Illusions of Flight Flashcards
A sensory Illusion is
A false perception of reality coming from one or more of the senses of orientation. Leads to spatial disorientation.
What is spatial disorientation
Inability to determine one’s position, attitude, and motion relative to a point of reference, usually the surface of the Earth.
What are the senses of orientation
- Visual
- vestibular
- proprioceptive
Which of the senses of orientation is most reliable
Visual
What percentage of orientation comes from vision?
80%
When is spatial disorientation most likely to occur
When the pilot has lost visual reference to the horizon
Name the visual illusions
“Fire Fire Fire CRASH CSAR”
- Fascination/ Fixation in flying
- False Horizon illusion
- Flicker Vertigo
- Confusion of ground lights (celestial lights)
- Relative motion illusion
- Altered Planes of reference
- Structural illusion
- Height-depth perception illusion
- Crater Illusion
- Size-distance illusion
- Autokinesis
- Reversible perspective
Fascination/ Fixation in flying
Occurs when aircrew members ignore orientation cues and focus their attention on their object or goal
Fixation:commonly referred to as target hypnosis, occurs when an aircrew member ignores orientation cues and focuses their attention outside the aircraft.
Fascination: Crew members may become so engrossed with a task inside the aircraft. that they fail to properly scan outside
False Horizon illusion
Occurs when the aviator confuses cloud formations with the horizon or the ground. This illusion occurs when an aviator subconsciously chooses the only reference point available for orientation
Flicker Vertigo
Technically NOT an illusion; may be created by helicopter rotors blades or airplane propellers interrupting direct sunlight at a rate of 4 to 20 cycles per second however,other sources include such things as anti-collision strobe lights flashing, especially while in the clouds.
Crater Illusion
When landing at night, the position of the landing light may be too far under the nose of the aircraft. This will cause the illusion of landing into a hole (crater)
Relative motion illusion
The falsely perceived self-motion in relation to the motion of another object.
EXAMPLE: You are sitting in a car stopped at a stop light and unconsciously reduce your scan outside the vehicle.You perceive the forward motion of the car beside you as the rearward motion of your own vehicle. Alarmed, you slam on the brakes
Altered Planes of reference
Inaccurate sense of altitude, attitude, or flight path position in relation to an object very great in size so that the object becomes the new plane of reference rather than the correct plane of reference; the horizon
Size-distance illusion
A false perception of distance from an object or the ground, created when a crew member misinterprets an unfamiliar object’s size to be the same as an object he/she is normally accustomed to viewing
Height-depth perception illusion
Due to a lack of sufficient visual cues, the aircrew member will experience the illusion that they are higher above terrain than they actually are
Confusion of ground lights (celestial lights)
Occurs when an aviator, mistakes ground lights for stars. This illusion prompts the aviator to place the aircraft in an unusual attitude to keep the misperceived ground lights above them
Autokinesis
Results when a static light appears to move when it is stared at for several seconds. Uncontrolled eye movement may possibly cause the illusion of movement as the eye attempts to find some other visual reference points
Structural illusion
Caused by heat waves, rain, snow, sleet, or other visual obscurants
Reversible perspective
At night, an aircraft may appear to be going away when it is actually approaching. This illusion is often experienced when an aircrew member observes an aircraft flying a parallel course. To determine the direction of flight, the aircrew member should observe the position of the aircraft lights (red, right, return)
What are the functions of the vestibular system
Reflexes, orientation in the absence of vision, and visual tracking
What are the components of the vestibular system
Semicircular canals and Otolith organs
Semicircular Canals detects changes in
angular acceleration in the yaw, pitch, and roll.
Otolith Organs detects changes in
linear motion of the head (Forward, aft, up, and down)
What are the semicircular canals comprised of
three canals, an ampulla, and a cupula
In regards to the vestibular system, what somatogyral illusion is the most common in aviation
The leans
In regards to the vestibular system, what somatogyral illusion is the most dangerous in aviation
Coriolis illusion
What are the types of spatial disorientation
- Type 1 unrecognized – most dangerous
- Type 2 recognized
- Type 3 incapacitating
Describe the dynamics of spatial disorientation
- Visual dominance
- vestibular supression
- vestibular opportunism
How can you best prevent spatial disorientation
Maintain good visual reference with the horizon; maintain instrument proficeincy; if you suspect SD or loose the horizon transition to instruments; trust your instruments; transfer the controls (two pilots rarely affected at the same time)
How is proprioceptive system or “Seat of the pants flying” often inaccurate and misleading
In the absence of visual cues, a pilot will be unable to maintain a level attitude because the proprioceptive system detects gravito-inertial forces that are often inaccurate. The information provided by the proprioceptive system might be misleading, which is why aviators should not rely solely upon seat of the pants flying
What are the types of spatial disorientation?
Type I - Unrecognised
Type II - Recognised
Type III - Incapacitating
Which type of spatial disorientation is the most dangerous?
Type I: Unrecognised
