Introduction:

  • Nerves in the body's skin, muscles, and joints send signals to the brain, which, along with other sensory organs, signals the body's position
  • These tactile signals tell the pilot his or her current position
  • The pilot feels acceleration when pushed back into the seat
    • Often termed "flying by the seat of your pants"
  • Forces created in turns can lead to false sensations of the true direction of gravity and may give the pilot a false sense of which way is up
  • Uncoordinated turns, especially climbing turns, send misleading signals to the brain
  • Skids and slips give the sensation of banking or tilting
  • Turbulence can create motions that confuse the brain as well
  • Pilots need to be aware that fatigue or illness can exacerbate these sensations and ultimately lead to subtle incapacitation

Postural Considerations:

  • The postural system sends signals from the skin, joints, and muscles for the brain to interpret relative to the Earth's gravitational pull [Figure 1]
  • These signals determine posture
  • Inputs from each movement update the body's position to the brain constantly
    • Again, "seat of the pants" flying is largely dependent upon these signals
  • These sensations, used in conjunction with visual and vestibular clues, can be fairly reliable
  • However, because of the forces acting upon the body in certain flight situations, many false sensations can occur due to acceleration forces overpowering gravity
  • These situations include uncoordinated turns, climbing turns, and turbulence
  • Instrument Flying Handbook, Figure 1-8. Sensations From Centrifugal Force
    Instrument Flying Handbook, Sensations From Centrifugal Force

References: