Page 28 - Volume 17 Number 11

26 • TWIN & TURBINE NOVEMBER 2013From The Flight Deck by Kevin R. DingmanSeat-Of-The-Pants“There is no such thing as a natural born pilot.”— Chuck Yeagerthen why do we get confused and what’s all the hoopla about spatial disorientation? Instructors and safety experts harp on “trusting your instruments” instead of reliance on seat-of-the-pants instincts, and they are right, mostly. Ignoring the artificial horizon, altimeter or airspeed indicator has often resulted in a less-than-rewarding experience, and excuses for our errors are numerous. Many times, we’ve read about a pilot doing circles over the home of an acquaintance, getting slow and stall/spinning into their barbeque grill. And how often do we read about a VFR pilot continuing flight into IMC and losing all orientation with the world, only to be found several winters later by a hunter in the woods? When our senses provide conflicting data, it’s time to trust and rely on our instruments. Notice that “instruments” is plural....more on this in a bit. Our senses create illusions and it’s our job to know when that is the case; when we are unsure, the instruments should always win.IllusionsEven in VMC, when we would normally have the use of all three of these senses, there are circumstances in which they disagree with each other. When they do, the result is called an illusion, and the illusion creates a mental condition called spatial disorientation. Our eyes provide about 75% of our orientation. A short list of visual illusions includes sloping cloud decks or mountain ranges, very narrow or very wide runways, and a plethora of night lighting phenomenon. A simple example of a visual illusion in our everyday lives is when we are stopped at a traffic light and the car next to us backs up slowly—typically, we push on the brake because it “feels” like we are the one moving forward. In-flight illusions can be just as convincing.The inner ear reacts to acceleration forces. Maintaining a turn, climb or descent for a long period of time will stimulate the inner ear fluid,If you look up the definition of seat-of-the-pants, most explanations will include a reference about flying as the original venue of its use, with g-force as the phenomenon responsible for the moniker.Modern interpretations explain seat-of-the-pants as doing something by guessing, trial and error, or figuring things out as you go along--- rather than by careful planning, thought or technique. This is not a definition aviators would prefer to have used to explain the way in which we fling our eager craft through footless halls of air.A compilation of several other definitions, however, describe it in a more positive light, as not using technological aids or formal theory. One goes on to say “without the aid of instruments,” and uses the words experience, judgment, effort and instinct. I like this one better; it sounds more like the flying on laughter-silvered wings of which we dream.In a well-seasoned aviator, the sensation of flying is interpreted by experienced gluteus maximus muscles. A visual system capable of spotting birds, aircraft, airports, and even insects, from great distances, provides our primary reference. Add to this an auditory system, able to discern minute variations in engine and airframe noises--especially at night. And an equally-skilled set of semi-circular canals in the vestibular system of the ears that provides balance and orientation equivalent to that of a tight-rope walker. These senses are then filtered through a comparator system which bolsters or discredits the data.Symphonic and SymbioticThe compilation of information is then analyzed for pattern and sensation recognition. After evaluating the data and instituting corrections from the comparator system, a “learning” algorithm then helps to avoid repetition of previous errors. Requests are then transmitted to sensitive control- moving hands, fingers and feet. The maneuvering aircraft and the new sensations are evaluated and minor corrections are entered. The result of this bio-mechanical interface is a change in the path of our flying machine. When executed properly, this symphonic and symbiotic relationship generates one of the most rewarding experiences known to man, one dreamed of since the beginning of time: flight.True seat-of-the-pants flying, without reference to instruments, uses three of our senses: visual, auditory and kinesthetic. The visual sense means our sight-- including peripheral vision--and is our primary sense. Auditory means both the sounds of flying and the balance provided by the inner ear. Kinesthetic is the true seat-of-the- pants element--- meaning the feeling of gravity and the relative position of our torso and limbs to each other. These often-chastised senses have a bad reputation because we get confused when they disagree with each other. Once confused, we often initiate extreme maneuvers as we attempt to fly using conflicting data; hence, the trust-your- instruments lecture.If our bodies and minds are so skilled at interpreting g-forces and the sights and sounds of aviating,