Pilot Training: Disorientation 1973 Federal Aviation Administration (FAA) Pilot Training Film FA-09-73

more at http://quickfound.net/

'This program alerts pilots to inflight situations that are potentially disorientating by describing how this physiological phenomenon influences and often distorts flying judgments. It suggests that when physical senses are at variance with cockpit instruments, you should not randomly hit buttons.'

Originally a public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://en.wikipedia.org/wiki/Spatial_disorientation

Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/

Spatial disorientation, spatial unawareness, or "Spatial-D" is the inability to determine one's position, location, and motion relative to their environment. This phenomenon most commonly affects aircraft pilots and underwater divers, but also can be induced in normal conditions—or reproduced in the lab with instruments such as the Barany Chair. In aviation, the term means the inability to correctly interpret aircraft attitude, altitude or airspeed, in relation to the ground or point of reference. This most commonly occurs after a reference point (e.g., the horizon) has been lost. Spatial disorientation, often referred to as 'Spatial-D' by aviators occurs when aircrew's sensory interpretation of their position or motion conflicts with reality. Spatial disorientation is often separated into 3 main categories by mishap investigators:

Type 1: Unrecognized

Type 2: Recognized

Type 3: Incapacitating

A pilot who enters such conditions will quickly lose spatial orientation if there has been no training in flying with reference to instruments. Approximately 80% of the private pilots in the United States do not have an instrument rating, and therefore are prohibited from flying in conditions where instrument skills are required. Not all pilots abide by this rule and approximately 40% of the National Transportation Safety Board's accident reports on fatal general aviation accidents list "continuation of flight into conditions for which the pilot was not qualified" or the like as a cause...

Senses during flight

There are 4 physiologic systems that interact to allow humans to orient themselves in space. Vision is the dominant sense for orientation, but the vestibular system, proprioceptive system and auditory system also play a role. During the abnormal acceleratory environment of flight, the vestibular and proprioceptive systems do not respond truthfully. Because of inertial forces created by acceleration of the aircraft along with centrifugal force caused by turning, the net gravitoinertial force sensed primarily by the otolith organs is not aligned with gravity, leading to perceptual misjudgment of the vertical. In addition, the inner ear contains rotational "accelerometers", known as the semicircular canals, which provide information to the lower brain on rotational accelerations in the pitch, roll and yaw axes. However, prolonged rotation (beyond 15–20 s) results in a cessation of semicircular output, and cessation of rotation thereafter can even result in the perception of motion in the opposite direction. Under ideal visual conditions the above illusions are unlikely to be perceived, but at night or in poor weather the visual inputs are no longer capable of overriding these illusory nonvisual sensations. In many cases, illusory visual inputs such as a sloping cloud deck can also lead to misjudgments of the vertical and of speed and distance or even combine with the nonvisual ones to produce an even more powerful illusion. The result of these various visual and nonvisual illusions is spatial disorientation. Various models have been developed to yield quantitative predictions of disorientation associated with known aircraft accelerations...