Visual illusions Flashcards
Description
Visual Illusions give false impressions or misconceptions of actual conditions.
Therefore, crew members must understand the types of illusions that can occur and resultant potential for
disorientation
Visual Illusions (FF-CASH-CVS)
- False Horizon Illusion
- Fascination (Fixation) in Flying
- Confusion with Ground Lights
- Autokinesis
- Size-Distance Illusion
- Size Constancy
- Shape Constancy
- Aerial Perspective
- Height-Depth Perception Illusion
- Crater Illusion
- Vection (Induced Motion Illusion)
- Structural Illusion
False Horizon Illusion:
When a pilot confuses a wide sloping plane of reference such as cloud tops, mountain ridges, cultural lighting at night (coastline or highway), etc. with the true horizontal
Fascination (Fixation) in Flying:
Not a visual illusion, per se. Task saturation (engrossed
with a problem or task within the cockpit) or target fixation (ignore orientation cures and focus attention on an object or goal)
Confusion with Ground Lights:
When a pilot mistakes ground lights for stars
Autokinesis:
At night when ambient visual cues are minimal and a small, dim light is seen against a dark background. After about 6-12 seconds of visual fixation on the light, an
individual may perceive up to 20 degrees of movement in any direction.
Size-Distance Illusion:
(SSA)
Misperceiving an object of unfamiliar size and shape by comparing
it with what is familiar based on experience
- Size Constancy: ex. Landing at an unfamiliar runway that is a different size than one is used to
- Shape Constancy: ex. Sloping runways cause a change in sight picture
- Aerial Perspective: if visual cues are of a different size or perspicuity (clarity and discrimination) than expected
Height-Depth Perception Illusion:
Due to absent or insufficient visual cues and causes
crewmembers to misjudge depth perception (flying over areas devoid of visual references)
Crater Illusion:
Under NVG conditions and the IR searchlight is directed too far under the aircraft’s nose, creating the illusion of landing in a crater
Vection (Induced Motion Illusion):
Falsely perceived motion of oneself when no physical
motion is actually occurring (formerly known as Relative Motion Illusion)
Structural Illusion:
Caused by the effects of rain, snow, sleet, heat waves, or other visual obscurants. Can cause a straight line to appear curved or a single light to appear as a double light. Curvature of the windscreen can cause structural illusions.
Reference:
Reference: TC 3-04.93 Ch. 9
