Spatial Disorientation and Sensory Illusions of Flight Flashcards Preview

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Flashcards in Spatial Disorientation and Sensory Illusions of Flight Deck (32):

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



What percentage of orientation comes from vision?



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



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