• Nerves in the body's skin, muscles, and joints constantly send signals to the brain, which signals the body's relation to gravity
  • These tactile signals tell the pilot his or her current position
  • Acceleration will be felt as the pilot is 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, can cause misleading signals to be sent 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 to the brain that are interpreted in relation to the Earth's gravitational pull
  • These signals determine posture
  • Inputs from each movement update the body's position to the brain on a constant basis
    • Again, "seat of the pants" flying is largely dependent upon these signals
  • Used in conjunction with visual and vestibular clues, these sensations 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
Figure 1: Instrument Flying Handbook, Sensations From Centrifugal Force