## Sensing Our Orientation and Movement
Our body relies on three key systems to track our orientation and movement in space. They are:
1. the inner ear sensors ([[Vestibular System]])
2. body/nerves ([[Somatosensory System]]), and
3. eyes ([[Visual System]])
In [[VMC]], our eyes are the major orientation source, and will win out if other senses provide conflicting information.
In [[IMC]], however, visual references are unavailable and we become susceptible to many types of illusions.
> [!youtube] Published by [@SmithsonianChannel](https://www.youtube.com/@SmithsonianChannel)
> 
## Preventing Spatial Disorientation
If we are unsure of our orientation, we are suffering from [[spatial disorientation]]. This is most likely to occur when we loose visual reference to the horizon.
> [!quote] From [[PHAK Ch17]]
> Prevention is usually the best remedy for spatial disorientation.
> - Unless a pilot has many hours of training in instrument flight, **flight should be avoided in reduced visibility** or at night when the horizon is not visible.
> - A pilot can reduce susceptibility to disorienting illusions through **training and awareness** and **learning to rely totally on flight instruments**.
> [!tip] As Jack's grandpa used to say: *Trust your instruments!*
## Illusions
> [!summary] Consider [[ICEFLAGGS]] as a memory aid
- **Long or Slowly Developing Turns**: These result in incorrect banking by the pilot
- [[The Leans]]
- [[Graveyard Spiral]]
- **Accelerations Feeling the Same as Climbs/Descents**: These result in incorrect pitching by the pilot
- [[Somatogravic Illusion]]
- [[Inversion Illusion]]
- [[Elevator Illusion]]
- **From Head Motion**: Depending on the head motion, this could feel like a number of different maneuvers
- [[Coriolis Illusion]]
- **Visual Illusions**: Visual illusions are especially hazardous because pilots rely on their eyes for correct information
- [[False Horizon]]
- [[Autokinesis|Autokinesis (aka UFO Syndrome)]]
- [[Empty Field Myopia]]
***Definition*** ::
***Source*** :: [[AIM 8]]
***Related To***: [[Illusions Leading to Landing Errors]]
***See Also:*** [[Spatial Disorientation Visual Illusions]]
#glossary #aeromedical