Spatial orientation is the body’s natural ability to maintain orientation and/or posture in relation to the surrounding physical environment, both at rest and in motion. It’s a highly evolved ability, which uses visual and vestibular (inner ear) sensory inputs, as well as our sometimes unconscious ability to understand positioning of our body and its various parts. Together, these senses tell our brain what our body is doing and what is happening to it.
Unfortunately, evolution has let down pilots, at least so far, because most of the time humans have spent orienting ourselves in space has been in a two-dimensional environment. Flying is a three-dimensional activity, and we simply haven’t been doing it long enough as a species for evolution to provide the tools we need to determine our orientation when we’re not on terra firma. To compensate, humans developed gyros, which retain their position in space, and are used to determine just how far displaced we are from straight and level. When we don’t have some reference by which to determine our body position and relative motion, spatial disorientation results, and it can be lethal.
