Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Vertigo Unrecognized spatial disorientation is caused by some combination of channeled attention, distraction and target fixation. These most often occur in conjunction with loss of situational awareness due to excessive workload. A 10-degree bank with only the approach lights visible can cause an illusion that the lights are sloping from above. The future microwave landing system flown mostly with curved approaches is going to require special illusion training. Recognized spatial disorientation is when the pilot is aware of his disorientation and should be able to work through a recovery sequence by establishing recommended power and attitude changes. Pilots have, over the radio, acknowledged their vertigo and inability to overcome it prior to crashing. Incapacitating spatial disorientation occurs when the motion of aircraft is so severe that pilot may be incapable of rationally perceiving and processing information and making decisions. May cause nystagmus (trembling of the eyes) which makes reading of instruments impossible. Rare but can occur in extremes of weather or flight conditions. Other types of spatial disorientation are illusions such as caused by runway/cloud sizes, shapes, or slope. Vertigo is the #1 cause of Air Force fatal accidents. Vision is the pre-installed vertigo preventative. A moments glance out-the-window is all it takes. This will overcome any sensations from other sources. However, without vision, the organs of balance in the inner ear take over. The semicircular canals approximate the three axes. They contain a fluid that stimulates our senses of angular acceleration in these axes. The otolith organs establish our sense of uprightness. Tiny stones affect hair sensors in reaction to "gravity". Otoliths sense linear accelerations, not angular accelerations, and regardless of the direction interpret such accelerations as gravity. In our muscles and joints we have sensors which give additional information about push or pull. Unless one or all of these sensors are confirmed by vision we are on our way to vertigo. Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM