spatial disorientation & illusions

Question 1

3 systems the body uses for spatial orientation

Answer 1

vestibular
somatosensory
visual

Question 2

vestibular system

Answer 2

• organs in the INNER EAR
• 3 semicircular canals sense movement in 3 axes: PITCH, ROLL & YAW
  
  • the canals r filled with fluid which moves against tiny sensory hairs as
    the head is moved
  • the brain gets these signals & interprets a sense of movement
• 2 otolith organs sense ACCELERATION in the horizontal and vertical
  planes

Question 3

somatosensory system

Answer 3

consists of nerves in the skin, muscles & joints

Question 4

visual system

Answer 4

visual cues from out eyes

Question 5

what are the vestibular illusions

Answer 5

• the leans
• coriolis illusion
• graveyard spiral
• somatogravic illusion
• inversion illusion
• elevator illusion

Question 6

the leans

Answer 6

• vestibular illusion
• after leveling the wings following a prolonged turn, pilot may feel that the aircraft is banked in the opposite direction of the turn

Question 7

coriolis illusion

Answer 7

• vestibular illusion
• after a prolonged turn, the fluid in the ear canal moves at the same speed
  as the canal
• a head movement on a different plane will cause the fluid to start moving
  & resulting in a false sensation of acceleration or turning on a different
  axis

Question 8

graveyard spiral

Answer 8

• vestibular illusion
• in a prolonged, coordinated constant rate turn after a while pilot may feel
  like they’re aren’t turning
• after leaving the wings, pilot may feel the leans, causing the pilot to turn in
  the original direction
• since a higher angle of attack is required during a turn to stay level, pilot
  may notice a loss in altitude & apply back pressure on the elevator
• this may tighten the spin & increase the loss of altitude

Question 9

somatogravic illusion

Answer 9

• vestibular illusion
• rapid acceleration simulates the inner ear otolith organs in the same way
  as tilting the head up
  
  • may create the illusion of a nose up attitude
• deceleration simulates the inner ear otolith organs in the same way
  as tilting the head down
  
  • may create the illusion of a nose down attitude

Question 10

inversion illusion

Answer 10

• vestibular illusion
• an abrupt change from a climb to straight & level may create the illusion
  of tumbling backwards due to the fluid movement in the otolith organs

Question 11

elevator illusion

Answer 11

• vestibular illusion
• an abrupt upward vertical acceleration may create the illusion of climbing
  due to fluid movement in the otolith organs

Question 12

what are the visual illusions

Answer 12

false horizon & autokinesis

Question 13

false horizon

Answer 13

• visual illusion
• an illusion where the pilot misidentifies the horizon line
• caused by sloping cloud formation, obscured horizon, aurora borealis,
  dark night with scattered lights & stars or the geometry of the ground

Question 14

autokinesis

Answer 14

• visual illusion
• staring at a stationary point of light in a dark or featureless scene for a
  prolonged period of time may cause the light to be moving
• pilot may attempt to align the aircraft with the “moving light” = loss in
  aircraft control

Question 15

optical illusions

Answer 15

• runway width illusion
• runway & terrain slope illusion
• featureless terrain illusion ( aka black hole approach)
• water refraction
• haze
• fog
• ground lighting illusion

Question 16

runway width illusion

Answer 16

• optical illusion
• NARROW RUNWAY = pilots thinks they’re too HIGH
• WIDE RUNWAY = pilots thinks they’re too LOW

Question 17

runway & terrain slope illusion

Answer 17

• optical illusion
• UP-SLOPING terrain or runway = illusion plane is HIGHER then it actually is

Question 18

featureless terrain illusion (aka black hole approach)

Answer 18

• optical illusion
• flying over dark or featureless terrain = illusion aircraft is higher, causing
  the pilot to fly lower than desired

Question 19

water refraction

Answer 19

• optical illusion
• light refraction due to rain on the windshield = illusion that horizon is
  lower & therefore the aircraft is higher
• causes the pilot to fly lower than desired

Question 20

haze illusion

Answer 20

• optical illusion
• during an approach, haze causes the illusion the runway is FURTHER or
  that the aircraft is higher than it rly is

Question 21

fog illusion

Answer 21

• optical illusion
• flying into fog may create an illusion of a nose- up motion

Question 22

ground lighting illusion

Answer 22

• optical illusion
• lights along straight paths (like roads) can be mistaken for runway or
  approach lights
• bright runway & approach lights can make the runway appear closer than
  it is, especially when the surround terrain in dark
  • may lead pilot to fly higher approach then desired