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Disorientation

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  1. Spatial Disorientation

  2. OUTLINE • Review of Spatial Disorientation Terms • Discuss the Role of Vision in Maintaining Equilibrium • Components of the Vestibular System • Types of Vestibular Illusions • Mechanisms of Proprioceptive Equilibrium • Identify the Classifications of Vestibular Illusions • Prevention and Treatment of Spatial Disorietation

  3. REFERENCES • FM 1-301, Aeromedical Training for Flight Personnel

  4. Vertigo Sensory Illusion Spatial Disorientation TERMINOLOGY

  5. Visual System Vestibular System Proprioceptive System SENSES OF BALANCE

  6. Also called Central Vision Done consciously Enables one to determine distance Allows for depth perception Presents us with clear view FOCAL VISION USASAM SD NEWS

  7. Also called Peripheral Vision Done unconsciously Detects motion and attitude cues Helps to provide balance AMBIENT VISION

  8. Vision is the most reliable sense used during flight 80% of orientation while flying is dependent on the visual senses VISUAL SYSTEM

  9. During a sudden and unexpected transition from VMC to IMC flight conditions THE CONDITION MOST SUSCEPTIBLE TO SPATIAL DISORIENTATION IS --

  10. VESTIBULAR SYSTEM Semicircular Canals Otolith Organs

  11. Semicircular Canals Otolith Organs Auditory Nerve Cochlea Ossicles Ear Drum Middle Ear External Ear Eustachian Tube Opening to Throat

  12. Triggers reflexes that stabilize the eyes during movement of the head or body Assist automatic reflexes Provides orientation information in the absence of vision FUNCTIONS OF THE VESTIBULAR SYSTEM

  13. VISUAL TRACKING Maintains focus of the retinal image

  14. NYSTAGMUS A rapid flickering motion of both eyes back and forth, seriously degrading visual acuity to 20/200 for a few seconds.

  15. REFLEX INFORMATION

  16. ORIENTATION WITHOUT VISION

  17. Right angles to each other Contains endolymph fluid SEMICIRCULAR CANALS

  18. Indicates Roll, Pitch, and Yaw Change in both speed and direction Responsive to angular acceleration and deceleration FUNCTIONS OF THE SEMICIRCULAR CANALS

  19. The Otolith organs are stimulated by gravity and linear accelerations Change in speed without a change in direction Sensitive to linear acceleration and deceleration (forward and backward/up and down) FUNCTION OF THE OTOLITH ORGANS

  20. UPRIGHT TILT FORWARD TILT BACKWARD TRUE SENSATION TRUE SENSATION TRUE SENSATION FUNCTION OF THE OTOLITH ORGANS FORWARD ACCELERATION CENTRIFUGAL /CENTIPUAL FALSE SENSATION OF BACKWARD FALSE SENSATION OF UPRIGHT

  21. Somatogyral The Leans Graveyard Spin Coriolis Somatogravic Oculoagravic Elevator Oculogravic VESTIBULAR ILLUSIONS

  22. THE LEANS Most common form of Spatial Disorientation

  23. Motion is usually undetected during a subthreshold maneuver (less than 2o)

  24. Pilot corrects attitude and compensates for the false sensation of turning in the opposite direction

  25. This illusion seldom affects both pilots at the same time

  26. Graveyard Spiral

  27. THECORIOLISILLUSION • The most deadly illusion • Most likely to occur during an • instrument approach

  28. Pilot enters a turn stimulating one semicircular canal Pilot makes a head movement in a different geometrical plane Stimulating a 2nd / 3rd semicircular canal Results in overwhelming sensation of Yaw, Pitch, or Roll CORIOLIS ILLUSION

  29. Illusions created by the Otolith organs as a result of linear acceleration SOMATOGRAVIC ILLUSION

  30. Upward movement of the eyes during weightlessness, caused by rapid downward motion of the aircraft OCULOAGRAVIC

  31. Occurs during sudden upward acceleration Pilot perceives a nose up attitude Tendency to “nose over” aircraft ELEVATOR ILLUSION

  32. UPRIGHT AFT TILT UPRIGHT EXTREME AFT TILT OCULOGRAVIC ILLUSION NOSE HIGH SENSATION

  33. PROPRIOCEPTIVE SYSTEM

  34. Very unreliable means of orientation Dependent upon gravity Flying without reference to instruments SEAT OF PANTS FLYING

  35. TYPE I - UNRECOGNIZED TYPE II - RECOGNIZED TYPE III - INCAPACITATING CLASSIFICATION OFDISORIENTATION

  36. Pilot does notconsciously perceive any indication of Spatial Disorientation False inputs from sensory organs or cues Crashes with smile on their face UNRECOGNIZEDType I

  37. Pilot consciously perceives a problem, but may not know it is due to spatial disorientation Pilot can correct the situation RECOGNIZEDType II

  38. Pilot experiences overwhelming sensations Conflict of sensory inputs Unable to properly orient themselves by use of instruments or visual cues INCAPACITATINGType III

  39. SPATIAL DISORIENTATION Prevention techniques

  40. Instruments-trust your instruments Good cockpit design Training Instrument proficiency Health Aircraft design Never try to fly both VMC and IMC at the same time SD PREVENTION

  41. Never fly without visual reference points Trust the instruments Never stare at lights Dark adaptation Avoid self -imposed stresses (DEATH) PREVENTION (cont.)

  42. Refer to instruments Develop and maintain cross-checks Delay intuitive reactions Transfer controls TREATMENT

  43. ENSURE THE INSTRUMENTS READ RIGHT !

  44. QUESTIONS ?

  45. Forward Acceleration