February 2011 - Indian Airforce

Sqn Ldr Juhi BorgohainIn aviation’s early days, pilots flew by the “seatof their pants.” They trusted their eyes and gutfeelings, even though doing so sometimes killedthem, especially when vertigo set in at night orduring bad weather. Such loss of equilibrium wasconsidered part of the business, a rite of passagethat fliers just had to handle. Till date, SpatialDisorientation (SD) remains the numero unostressor in aviation. It has costed many a lives andaircraft. It is for this reason that the maximal use ofground- based SD training devices is encouragedfor the physiological training of pilots.The story of invention of DisorientationSimulators is something that is quite interesting. Doyou know who invented the SD Simulator? Well, itwas none other than a pilot himself!Colonel William Charles Ocker, also known asthe “Father of Blind Flying” was a veteran pilot inthe US Army in 1920s. In World War I, he had knownmany competent fliers who became disorientedand died needlessly; he himself had narrowlyescaped death when lost in the clouds with novisibility, he discovered that the flight indicatorshowed his plane in a turn while his senses toldhim he was straight and level. The confusion senthim into a spiral dive: emerging from the clouds,he had just enough time to regain control. Ocker,rather than blaming the instruments understoodthat, despite his training and experience, his pilotinstincts had failed him.The story of disorientation is as old as theorigin of the word ‘pilot’ itself. Well, the wordpilot is derived from the name ‘Pilatre deRozier’ - the first person to fly. Pilatre flew in a hotair balloon launched by the Montgolfier brothersof France in 1783. He is said to have had a feelingof disorientation during his first free floatingballoon flight across Paris.Throughout his career, Ocker remained hauntedby his close call and the reasons why it happened.Years later, a routine physical exam by a flightsurgeon, Capt. David Myers, provided him withsome answer. Dr. Myers sat Ocker in a Barany chair,a swiveling, spinning seat designed to measure aperson’s sense of balance and equilibrium, andchallenged him to take the exam with his eyes closed.Ocker discovered that when robbed of visual cueshe couldn’t tell whether the chair was spinning orstationary, or even what direction he turned. Myershad re-created the same disorientation that Ockerhad once experienced in the clouds.22 Aerospace Safety F e b r u a r y 2 0 11INDIAN AIR FORCE