Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Introduction to Illusions What ever the illusion, it will take a few moments for you to get reoriented. If the illusion occurs in trimmed flight the problem is not as severe as it might be if it occurs during maneuvers as it usually does. Spatial disorientation caused by loss of horizon, change in power, banking, or other acceleration forces can lead the pilot to believe that the aircraft is doing something that it is not. These forces cause the pilot's vestibular and proprioceptive system to give the somatogravic illusion. A pilots first reaction will be to over-control in a direction exactly the opposite to what should be done. The only safe procedure during the onset of any illusion is to increase your instrument scan rate. The brain is capable of separating out the conflict of information between the eye and the inner ear when the eyes are looking outside the cockpit. A conflict between the sensory inputs of the body can be overwhelmed when the natural horizon disappears. When the conflict of information comes with the eyes viewing relatively unfamiliar instruments inside the cockpit, the brain can become confused and then give improper information. This is the origin of an illusion. You must trust your instruments in IFR conditions. (See IFR material) Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM