Aviation Psychology
Psy 410/510
Fall 2005
Spatial Orientation
Robert Mauro
University of Oregon
I.
Key Ideas
A. Most human factors problems occur when people are placed outside their normal
environment.
B. If you want to understand most human factors problems, ask:
1. What are the key characteristics of the normal environment?
2. On these dimensions, how is the problematic environment different?
II.
Basic Brain Development
A. The brain is organized hierarchically.
B. Older structures still function.
C. Older connections are often faster and more direct.
III.
Historic Human Environment
A. People are adapted for:
1. Relatively slow, occasional motion; not adept at continuous steady motion
2. Diurnal
3. Land-based
4. Social creatures.
B. Adaptation not useful when humans are placed in fast continuously moving
environment in the air – especially at night or in low visibility conditions
IV.
Vision (predominate sense)
A. Steady motion can induce illusions
1. Motion Induced Blindness
B. Day vision much better than night vision
1. Color only seen during day
2. Color vision cells provide much higher acuity (during day)
C. Foveal vision much better than peripheral vision
1. Only see clearly small area a few degrees around center of vision
2. Sense of permanence of other objects due to vague peripheral cues and
visual mental models
3. “See and avoid” concept for visual separation is problematic
i.
Eyes don’t focus naturally at correct distance
ii.
Objects on collision course do not change position only size
iii.
Difficult to detect objects against ground clutter
D. Experience important for perception
1. If you are not used to seeing it, you may not see it correctly
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V.
i.
Inverted faces -- Thatcher illusion
E. Depth perception depends on multiple cues
1. Convergence
i.
Eye muscles move so that eyes converge on object
ii.
Provides little information when objects far away
2. Binocular Disparity
i.
Each eye sees somewhat different area
3. Parallax
i.
When in motion, nearby objects appear to move relative to
farther objects
4. Size constancy – experience affects perception
i.
Objects of known size are seen as farther away not smaller
when farther away
ii.
Unknown objects may be seen as coming closer when growing
in size (e.g., gas cloud UFO)
iii.
Runway Illusions
a. Narrow runway – aircraft appears higher
b. Wide runway – aircraft appears lower
c. Up sloping runway – aircraft appears higher
d. Down sloping runway – aircraft appears lower
5. Brightness
i.
Dimmer objects are perceived as farther away
ii.
Objects seen through haze appear farther away
6. Direct perception of gradients
i.
When one moves over textured surface, texture appears to
move differently depending on difference in angle of motion
relative to surface and distance from surface
ii.
Difficult to perceive distance when texture cues absent; e.g.,
when dark or hazy
iii.
False horizon – without texture cues, cloud layers may be
interpreted as horizon
iv.
Autokinesis – without background cues, steady lights seen as
moving (due to saccadic movements of eyes)
Vestibular sense
A. Optimized for short movements of limited range
1. Running, jumping, swinging from trees
B. Semi-circular canals
1. Basic Morphology
i.
Three structures in inner ear at right angles to each other
ii.
Filled with fluid
iii.
Cilia in canals connected to neurons
iv.
Neurons connected to central brain
a. Yields fast, resilient, non-conscious processing
2. Effects of motion
i.
Detect yaw, pitch, and roll
ii.
Fluid moves when head moves
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iii.
Cilia move when fluid moves
iv.
Neurons detect motion in cilia
3. Illusions (somatogyral)
i.
With constant motion, cilia recover vertical position, brain
ceases to sense motion
ii.
The Leans
a. Description: Sensation of turning in level flight
b. Precipitating Event: Sudden return to level flight following
prolonged gradual turn
c. Cause: Adjustment of vestibular system to apparent
gravitational direction.
d. Effect: Illusion of bank in opposite direction; pilot may
initiate turn to regain sense of correct vertical posture.
iii.
Graveyard Spiral
a. Description: Sensation of level flight when in turn
b. Precipitating event: Unperceived steady turn in clouds
c. Cause: Adjustment of vestibular system to apparent
gravitational direction
d. Effect: Without additional power or pitch, aircraft altitude
will decay. Pilot detects loss of altitude and compensates
with increased pitch. However, because aircraft is banked,
increase in pitch increases rate of turn which causes
increased loss of altitude in a vicious cycle.
iv.
Graveyard Spin
a. Description: When a spin is entered, sensation of spinning
decreases as spin continues; if the spin is stopped, pilot will
sense spin in opposite direction.
b. Precipitating event: Spin entered in clouds.
c. Cause: Adjustment of vestibular system to yaw.
d. Effect: Pilot may enter spin and not understand indications
of altitude loss or alternately spin in one direction and then
the other.
v.
Coriolis Illusion
a. Description: Sensation of tumbling
b. Precipitating Event: Vertical movement of head during
turn.
c. Cause: Simultaneous stimulation of two semi-circular
canals after one has adjusted to apparent gravitational effect
d. Effect: Unbearable sensation that aircraft is tumbling; may
cause loss of control.
C. Otolith Organs
1. Basic Morphology
i.
Two structures at right angles in ear
ii.
Filled with fluid
iii.
Cilia in organs connected to neurons
iv.
Neurons connected to central brain
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a. Yields fast, resilient, non-conscious processing
2. Effects of motion
a. Saccule detects vertical motion
b. Utricle detects horizontal motion
c. Fluid moves when head moves
d. Cilia move when fluid moves
e. Neurons detect motion in cilia
3. Somatogravic Illusions
i.
With strong acceleration or deceleration, cilia move; motion
interpreted as change in position
ii.
Inversion
a. Precipitating Event: Ascent in high performance aircraft
followed by level off.
b. Cause: Acceleration
c. Effect: Sensation of aircraft rolling inverted
iii.
Heads-up illusion
a. Precipitating Event: Sudden acceleration in level flight
b. Effect: Sensation of aircraft pitching up
iv.
Heads-down illusion
a. Precipitating Event: Sudden deceleration in level flight
b. Effect: Sensation of aircraft pitching down
v.
Effect: Sensation of up or down motion even inversion; pilot
may pitch to recreate illusion of proper pitch.
VI.
VII.
Auditory sense
A. Optimized for detection, communication
B. Relatively poor at localization
Human Factors Intervention hierarchy
A. Key Ideas
1. Design – to accommodate human strengths and limitations
2. Train – what you can’t design
3. Select – people who are more capable if you can’t remove problem with
improved design or training.
B. Design
1. Technological solutions for dealing with limited visibility
i.
Attitude Indicator – provide pilot with visual indication of
attitude (orientation) of aircraft
ii.
Dynamic Stability – make aircraft less likely to change position
without pilot command and more likely to return to level flight
without pilot command
iii.
Autopilot – autopilot can fly aircraft with reference to
information in attitude indicator even if pilot is confused
iv.
Virtual VMC – provide pilot with computer-generated visual
representation of world hidden by clouds
2. Technological solutions for dealing with limited visual acuity
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Air Traffic Control radar (but doesn’t prevent all midair
collisions)
ii.
TCAS (Traffic Collision Avoidance System)
a. Resolve conflicts by direct commands
b. What if other aircraft doesn’t have TCAS?
c. TCAS only orders climbs and descents – what about headon collision? Why not turn?
d. Doesn’t prevent all midair collisions
3. Procedures
i.
Always fly on instruments until visibility clear
ii.
Always review runway descriptions before approach
iii.
Always use visual vertical guidance when available
C. Train
1. Avoidance
i.
Decision Rules
a. VFR-only pilot should not fly in marginal conditions
b. IFR rated pilot should fly IFR in marginal conditions
ii.
Information processing strategies
a. Use of weather information services
2. Recognition
i.
What does deteriorating weather look like
ii.
What do vestibular illusions feel like; when do they occur
iii.
What do visual illusions look like; when do they occur
3. Recovery
i.
Make the instruments read right despite the sensations
ii.
Can’t eliminate the sensations
i.
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