There are several objectives in demonstrating these various  maneuvers.  A pilot should not attempt any of these maneuvers at  low altitudes or in the absence of an instructor pilot or an  appropriate safety pilot.  With the pilot’s eyes closed, the instructor pilot maintains  approach airspeed in a straight-and-level attitude for several  seconds, then accelerates while maintaining straight-and­ level attitude. The usual illusion during this maneuver,  without visual references, is that the aircraft is climbing.  With the pilot’s eyes still closed and the aircraft in a straight­ and-level attitude, the instructor pilot now executes, with a  relatively slow entry, a well coordinated turn of about 1.5  positive G (approximately 50° bank) for 90°. While in the  turn, without outside visual references and under the effect of  the slight positive G, the usual illusion produced is that of a  climb. Upon sensing the climb, the pilot should immediately  open the eyes to see that a slowly established, coordinated  turn produces the same sensation as a climb.  Repeating the previous procedure, but with the pilot’s  eyes should be kept closed until recovery from the turn is  approximately one-half completed, can create the illusion of  diving while turning.  While in a straight-and-level attitude, with the pilot’s eyes  closed, the instructor pilot executes a moderate or slight skid  to the left with wings level. This creates the illusion of the  body being tilted to the right.  This illusion can be demonstrated in any of the three planes  of motion. While straight and level, with the pilot’s eyes  closed, the instructor pilot smoothly and positively rolls the  aircraft to approximately 45° bank attitude while maintaining  heading and pitch attitude. This creates the illusion of a strong  sense of rotation in the opposite direction. After this illusion  is noted, the pilot should open his or her eyes and observe  that the aircraft is in a banked attitude.  This maneuver may produce extreme disorientation. While  in straight-and-level flight, the pilot should sit normally,  either with eyes closed or gaze lowered to the floor. The  instructor pilot starts a positive, coordinated roll toward a  30° or 40° angle of bank. As this is in progress, the pilot  tilts his or her head forward, looks to the right or left, then  immediately returns his or her head to an upright position.  The instructor pilot should time the maneuver so the roll is  stopped as the pilot returns his or her head upright. An intense  disorientation is usually produced by this maneuver, and the  pilot experiences the sensation of falling downward into the  direction of the roll.  In the descriptions of these maneuvers, the instructor pilot is  doing the flying, but having the pilot do the flying can also  be a very effective demonstration. The pilot should close his  or her eyes and tilt the head to one side. The instructor pilot  tells the pilot what control inputs to perform. The pilot then  attempts to establish the correct attitude or control input with  eyes closed and head tilted. While it is clear the pilot has no  idea of the actual attitude, he or she will react to what the  senses are saying. After a short time, the pilot will become  disoriented and the instructor pilot will tell the pilot to look  up and recover. This exercise allows the pilot to experience  the disorientation while flying the aircraft.  To prevent illusions and their potentially disastrous  consequences, pilots can:  1. Understand the causes of these illusions and remain  constantly alert for them. Take the opportunity to  experience spatial disorientation illusions in a device,  such as a Barany chair, a Vertigon, or a Virtual Reality  Spatial Disorientation Demonstrator.  2. Always obtain and understand preflight weather  briefings.  3. Before flying in marginal visibility (less than 3 miles)  or where a visible horizon is not evident, such as flight  over open water during the night, obtain training and  maintain proficiency in aircraft control by reference  to instruments.  4. Do not fly into adverse weather conditions or into  dusk or darkness unless proficient in the use of flight  instruments. If intending to fly at night, maintain  Coping with Spatial Disorientation  Reversal of Motion  Tilting to Right or Left  Diving While Turning  Climbing While Turning  Climbing While Accelerating  Diving or Rolling Beyond the Vertical Plane  1. They teach pilots to understand the susceptibility of  the human system to spatial disorientation.  2. They demonstrate that judgments of aircraft attitude  based on bodily sensations are frequently false.  3. They help decrease the occurrence and degree  of disorientation through a better understanding  of the relationship between aircraft motion, head  movements, and resulting disorientation.  4. They help instill a greater confidence in relying on  flight instruments for assessing true aircraft attitude.  17-9 