Spatial disorientation occurs when pilots interpret sensory impressions that do not correspond to real position and motion in space as real.
That is, spatial disorientation is the misperception and misinterpretation of one’s position and motion relative to the earth. Any situation that deprives the pilot of natural and visual references can quickly lead to spatial disturbances for untrained as well as inexperienced pilots. These include clouds, fog, haze, darkness terrain or sky backgrounds with inseparable contrast.
Spatial disorientation can be compensated for by, for example, instrument flight training, since here flying is specially trained using the instruments.
Spatial disorientation is a contributing factor in many aviation accidents, and in some it is the primary cause. Every pilot, regardless of whether he is flying under visual or instrument flight rules, is susceptible to disorientation and may have experienced one form or another himself.
Humans have three sensory organs for positional orientation with respect to the earth’s surface.
- Sense of sight (eyes)
- Vestibular sense (vestibular organ of the inner ear)
- Muscle, pressure, sense of touch (surface and depth sensitivity of the human body, proprioceptive system)
For orientation in three-dimensional motion sequences of flying, the eye is by far the most important and reliable organ. As long as reliable visual reverence is available, spatial disorientation is unlikely to occur. Incorrect assessments of the other two sensory organs are compensated and corrected. In flight, the vestibular organ and the proprioceptive senses are unreliable sources of information. In particular, when outward vision is absent, the eye cannot correct the misinformation of the vestibular organ and the muscular, pressure, and tactile senses. This is the beginning of delusions (illusions) and spatial disorientation.