Spatial Disorientation in Flight 1958 US Air Force Pilot Training Film TF1-5251 (Patreon)

more at http://quickfound.net/

Produced for the USAF by Graphic Films.

Originally a public domain film from the United States Air Force, 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 other conditions—or reproduced with equipment 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 a point of reference. This most commonly occurs after a reference point (e.g., the horizon) is no longer visible. In aviation, spatial disorientation occurs when aircrew's sensory interpretation of their position or motion conflicts with reality.

A pilot who enters such conditions will quickly lose spatial orientation, especially if they have not been trained to rely on their instruments (IFR). Approximately 79% of the private pilots in the United States do not have an instrument rating,[citation needed] 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.

Spatial disorientation is often separated into 3 main categories by mishap investigators:

Type 1: Unrecognized

Type 2: Recognized

Type 3: Incapacitating

Senses during flight

There are four 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.

Effects of disorientation

Once an aircraft enters conditions under which the pilot cannot see a distinct visual horizon, the drift in the inner ear continues uncorrected. Errors in the perceived rate of turn about any axis can build up at a rate of 0.2 to 0.3 degrees per second. If the pilot is not proficient in the use of gyroscopic flight instruments, these errors will build up to a point that control of the aircraft is lost, usually in a steep, diving turn known as a graveyard spiral. During the entire time, leading up to and well into the maneuver, the pilot remains unaware of the turning, believing that the aircraft is maintaining straight flight. One of the most famous mishaps in aviation history involving the graveyard spiral is the crash involving John F. Kennedy Jr. in 1999...