SPATIAL DISORIENTATION TERMINOLOGY Vertigo Sensory Illusion Spatial Disorientation

SPATIAL DISORIENTATION ? ? ? ?

TERMINOLOGY (Vertigo (Sensory Illusion (Spatial Disorientation

SENSES OF BALANCE (Visual System (Vestibular System (Proprioceptive System

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

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

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

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

VISUAL ILLUSIONS (Relative Motion (False Horizons (Depth perception (Structural Illusion (Fascination/Fixation (Size - Distance (Altered planes of reference (Autokinesis (Reversible perspective (Crater illusion (Confusion with ground lights (Flicker Vertigo

RELATIVE MOTION Falsely perceived self-motion in relation to the real motion of another object

FALSE HORIZONS Occurs when the pilot unconsciously chooses the wrong reference point for orientation

DEPTH PERCEPTION (Due to lack of of sufficient visual cues pilots may experience the illusion of being higher than they actually are: (Whiteout / Brownout (Flying over desert / water (Hovering over tall grass

STRUCTURAL ILLUSION (The phenomenon in which objects become distorted when visual obscurants are present (Rain, snow, sleet (Curvature of wind screen

FIXATION/ FASCINATION (Pilot (Flies intent on hitting target forgets to fly aircraft into target or ground through shrapnel

SIZE DISTANCE (False perception of distance from an object on the ground or in the air (Misinterprets an unfamiliar object’s size to be the same as an object they are normally accustomed to viewing

ALTERED PLANES OF REFERENCE (Inaccurate sense of altitude, attitude, or flight path (Mountains / Valleys

AUTOKINETIC ILLUSION Occurs when a static light appears to move when it is stared at for several seconds.

REVERSIBLE PERSPECTIVE At night, an aircraft may appear to be going away when it is actually approaching.

CRATER ILLUSION An illusion that the aircraft is landing into a hole or crater, created when the search light is positioned too far under the nose of the aircraft.

CONFUSION WITH GROUND LIGHTS When flying at night, along seashores or rural areas, a pilot may falsely perceive the ground lights as part of the sky and put the aircraft in an unusual attitude.

FLICKER VERTIGO Caused by sunlight flickering through rotor blades or rotating beacons reflecting against an overcast sky or on the windscreen.

VESTIBULAR SYSTEM (Semicircular Canals (Otolith Organs

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

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

VISUAL TRACKING Maintains focus of the retinal image

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

ORIENTATION WITHOUT VISION

SEMICIRCULAR CANALS (Right angles to each other (Contains endolymph fluid

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

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

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

THE LEANS Most common form of Spatial Disorientation

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

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

This illusion seldom affects both pilots at the same time

THE CORIOLIS ILLUSION The most deadly illusion

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

THE CORIOLIS ILLUSION Most likely to occur during an instrument approach

THE CORIOLIS ILLUSION Most often unrecoverable

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

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

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

LET’S TAKE A BREAK

PROPRIOCEPTIVE SYSTEM

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

CLASSIFICATION OF DISORIENTATION TYPE I - UNRECOGNIZED TYPE II - RECOGNIZED TYPE III - INCAPACITATING

UNRECOGNIZED Type I (Pilot does not consciously perceive any indication of Spatial Disorientation (False inputs from sensory organs or cues (Crashes with smile on their face

RECOGNIZED Type II (Pilot consciously perceives a problem, but may not know it is due to spatial disorientation (Pilot can correct the situation

INCAPACITATING Type III (Pilot experiences overwhelming sensations (Conflict of sensory inputs (Unable to properly orient themselves by use of instruments or visual cues

SPATIAL DISORIENTATION Prevention techniques

SD PREVENTION (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

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

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

QUESTIONS