To incorporate the knowledge about the effects of visual
perceptions and visual illusions into an aviation unit safety
You will know the difference between perceptions and visual
illusions, the effects of depth perception on flight, the
effects of illusion on flight and how to overcome illusions.
You may use the lesson text and reference to complete the
You must correctly answer 8 of 10 review exercise questions.
FM 1-301 (Mar 83).
Vision is man's strongest and most dependable sense of balance.
Accurate perception of aircraft orientation necessary for adequate aircraft
control is dependent primarily on correct interpretation of visual cues
obtained from flight instruments. Vision is dependent upon varied cues; the
more cues available, usually the more accurate our orientation. With only a
few cues our perception can be false, resulting in what are commonly called
a. Perception. A perception is defined as an awareness acquired
directly from any one of a person's senses (sight, hearing, smell, taste or
b. Illusion. An illusion is defined as an erroneous perception of
reality or a-misinterpretation of what is occurring.
Perceptions are based on the nature of the stimulus regardless of the
sense used for interpreting the stimulus. Due to the predominant use of
vision, sight will be the source of perceptions examined in depth.
a. Characteristics. There are several characteristics of the visual
perceptions that must be considered for the safe operation of an aircraft.
(1) Threshold differences: The ability to visually perceive things
is primarily based upon changes; therefore, the rate and the duration of