Orientation and disorientation in aviation

A sense of orientation is a fundamental requirement for all free-living creatures. The fact that it is a largely unconscious activity, like breathing, is some evidence of its physiological importance to everyday activities and even survival. The term orientation implies an awareness of self in relation to objects in one’s surroundings, either in the immediate environment or more remotely as a sense of geographic location. There is also an important sense of orientation within the body, namely proprioception. In flight, orientation refers more specifically to an awareness of the attitude and spatial position of the aircraft relative to the external frame of reference provided by the flat surface of the earth and the gravitational vertical. A pilot's sense of orientation cannot afford to be the unconscious activity that it is on the ground; he/she needs at all times to maintain an awareness of what the aircraft is doing.The flight environment generates a number of hazards that relate to human physiology. For example, hypoxia at altitude and loss of consciousness during high G manoeuvres may have fatal consequences. The disorientating environment of flight may be less physiologically stressful, but the psychological stress of task saturation and the distraction of an in-flight emergency are important causes of accidents attributable to disorientation, a disproportionate number of which are fatal.Why do pilots become disorientated? Many authors, in attempting to give a concise answer to this question, have fallen back on the statement that humans did not evolve to fly and that their sensory systems, in particular the vestibular system, are not adapted to the flight environment. The implication is that if only this system were a more perfect inertial navigation system, then flight without external visual reference would be less prone to orientation error. The problem with this explanation is that creatures that did evolve to fly share the same sensory systems, and in all