Spatial Disorientation
16.400/16.453
Human Factors Engineering
Prof. L. Young Sept. 2011
1
SPATIAL DISORIENTATION IN FLIGHT
Formal Definition
“[A failure] to sense correctly the
position, motion or attitude of his
aircraft or of himself [herself]
within the fixed coordinate
system provided by the surface
of the earth and the gravitational
vertical.
In addition, errors in perception by the aviator of his position, motion or
attitude with respect to his aircraft, or of his own aircraft relative to other
aircraft, may also be embraced within a broader definition of spatial
disorientation in flight. -- Alan Benson (1978)
2
SPATIAL DISORIENTATION IN FLIGHT
Spatial Disorientation Types
TYPE I -- Unrecognized
• Pilot Does Not Consciously
Perceive Any Manifestation
of Spatial Disorientation
• Most Often Occurs When
Pilot Breaks Instrument
Cross-Check
• Most Likely to Lead to Controlled Flight
Into Terrain
3
SPATIAL DISORIENTATION IN FLIGHT
Spatial Disorientation Types
TYPE II -- Recognized
• Pilot Consciously Perceives A
Manifestation of Spatial
Disorientation but May Not
Attribute It to SD Itself
• Conflict between “Natural” and
“Synthetic” SD Percepts May
Occur
• Instrument Malfunction Is Often
Suspected
4
SPATIAL DISORIENTATION IN FLIGHT
Spatial Disorientation Types
TYPE III -- Incapacitating
• Experienced by 10-15% of
Aviators
• Vestibulo-Ocular Disorganization
(i.e., uncontrollable nystagmus)
• Motor Conflict (e.g., “Giant Hand”)
• Temporal Distortion
• Dissociation (“Break-Off”)
5
SPATIAL DISORIENTATION IN FLIGHT
Predisposing Perceptual Factors
• SD Is More Likely to Occur
at Night Or in Bad Weather
• Visual and Nonvisual Illusions
Contribute Equally to SD
• Sparse Terrain Is More
Challenging Than A Densely
Vegetated One
• Loss Of Other Aspects Of
Situation Awareness Can Lead
to SD
6
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
SPATIAL
ORIENTATION
SA in Good Weather
7
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
TACTICAL ARENA
SPATIAL
ORIENTATION
SA in Good Weather
8
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
TACTICAL ARENA
WEATHER
SPATIAL
ORIENTATION
SA in Good Weather
9
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
TACTICAL ARENA
WEATHER
SPATIAL
ORIENTATION
NAVIGATION
SA in Good Weather
10
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
TACTICAL ARENA
WEATHER
NAVIGATION
SPATIAL
ORIENTATION
OWNSHIP
INFO
SA in Good Weather
11
SPATIAL DISORIENTATION IN FLIGHT
Loss of Situation Awareness and SD
• Spatial Orientation is Part of Overall Situation Awareness
• SD Automatically Results in LSA
• Failure to Maintain Overall SA Can Lead to SD
• SA Is Especially Challenged in Poor Visual Conditions
TACTICAL ARENA
WEATHER
NAVIGATION
TACTICAL ARENA
SPATIAL
ORIENTATION
WEATHER
OWNSHIP
INFO
SA in Good Weather
NAVIGATION
12
SPATIAL
ORIENTATION
OWNSHIP
INFO
SA in Bad Weather
SPATIAL DISORIENTATION IN FLIGHT
Pilot-Specific Factors
• Experience
• Number of hours (no linear
relationship with age)
• Instrument proficiency
• Training experience
•
Type of Aircraft (100% SD in fighter pilots)
• Medical Conditions
• Alternobaric vertigo
• Positional nystagmus
13
SPATIAL DISORIENTATION IN FLIGHT
USAF Mishap Statistics and Costs
1980s
• SD and/or LSA Account for 27 Mishaps Per Year
• Approximately 43% of all USAF Class A mishaps
• 43 fatalities annually (85% of all operational-related)
• 8 SD mishaps annually ($100M per annum cost)
1990s
• SD and/or LSA Account for Over 15 Mishaps
Per Year
• Over 50% of all USAF Class A mishaps
• 5 SD mishaps annually ($80M per annum cost)
• SD/LSA mishaps decreasing in number
14
SPATIAL DISORIENTATION IN FLIGHT
USAF Mishap Rates
SD Class A Mishap Rate is Largely
Unchanged from 1970s!
MISHAP RATE
per 100,000 flying hours
2.00
Operations -- includes Loss of
Situational Awareness
Spatial Disorientation
1.00
0.00
1975
1990
15
2005
The Inner Ear and SD
16
Sensing Motion
Β̼ DΛΔ’θ F΍ϥ ̭ϥ θ͸̼ ͼ̼̠θ Λ͆ ͩϓΪ ͵̠Δθή
(or do we?)
16.400/423
MIT Fall 07
Prof. L. Young
17
The Giant Hand
18
The inner ear
Crus commune
Crista ampulla superior
Ampulla membranacea superior
Utriculus
Dachus endalymphaticus
Crista ampulla lateralis
Sacculus
Ampulla membranacea
lateralis
Scala tympani
Crista ampulla posterior
Ampulla membranacea
posterior
Ductus
cochlearis
Fenestra vestibuli
(Oval window)
Scala vestibuli
Helicotrema
Ductus cochlearis
Ductus reuniens
Fenestra cochleae
(Round window)
Image by MIT OpenCourseWare.
19
Slides on sensory signals removed due to copyright restrictions.
20
Slides on sensory signals removed due to copyright restrictions.
21
Slides on sensory signals removed due to copyright restrictions.
22
Slides on sensory signals removed due to copyright restrictions.
23
Slides on sensory signals removed due to copyright restrictions.
24
Slides on sensory signals removed due to copyright restrictions.
25
Slides on sensory signals removed due to copyright restrictions.
26
Slides on sensory signals removed due to copyright restrictions.
27
Slides on sensory signals removed due to copyright restrictions.
28
Slides on sensory signals removed due to copyright restrictions.
29
Slides on sensory signals removed due to copyright restrictions.
30
Slides on sensory signals removed due to copyright restrictions.
31
Slides on sensory signals removed due to copyright restrictions.
32
Slides on sensory signals removed due to copyright restrictions.
33
SPATIAL ORIENTATION IN FLIGHT
Vestibular Orientation Mechanisms
“΂͸̼ vestibular nerve occupies a
special position among the
senses. Its sensations do not
form part of our conscious
knowledge
of
the
world͙Whenever we perceive an
object we have the basic
knowledge about our body and
about the attitude of our body͙
Endolymph space
Perilymph space
Anterior vertical semicircular canal
Bony ampulla
Anterior vertical semicircular duct
Common crus
Poster vertical semicircular
canal and duct
Endolymphatic duct
Utricular and saccular nerves
Membranous ampulla
Horizontal semicircular
canal and duct
Cochlear nerve
Utricle
Endolymphatic sac
Cochlea
Saccule
Scala tympani
Ampullary nerves
Cochlear duct
Oval window
Vestibule
Round Window
Scala vestibuli
Image by MIT OpenCourseWare.
The vestibular apparatus with its influence on the muscle tone plays a part in every
Χ̼Ϊ̮̼ΧθͻΛΔ͙ ͩϓΪ ͻΓΧΪ̼ήήͻΛΔή ̮ΛΔ̮̼ΪΔͻΔͮ ΛϓΪ ̠θθͻθϓ̸̼ήͳ θ͸̼ ΧΛήθϓΪ̼ Λ͆ ΛϓΪ ̭Λ̸ϥͳ ̠Δ̸
θ͸̼ ΓΛθͻ΍ͻθϥ Λ͆ θ͸̼ ̭Λ̸ϥ͙ ͆ΛΪΓ θ͸̼ ̮ΛΔθͻΔϓΛϓή ̭̠̮ΊͮΪΛϓΔ̸ Λ͆ ΛϓΪ ̼ϤΧ̼Ϊͻ̼Δ̮̼ήͶ ΂͸̠θ this background is not in the full light of consciousness does not impair its
ͻΓΧΛΪθ̠Δ̮̼Ͷ” -- Paul
Schilder (1933)
34
VESTIBULAR ORIENTATION
Cardinal Principle of Vestibular Function
Semicircular Canals
• Designed to detect angular
accelerations generated
during terrestrial activity
Otolith Organs
• Designed to detect linear
accelerations generated
during terrestrial activity
• Signal head orientation relative
to gravity/gravitoinertial force
35
VESTIBULAR ORIENTATION Transduction in the Labyrinth
Otolith Organs
Semicircular Canals
Otoconia
Cupula
Endolymph
Utricle
(or Saccule)
Membranous
Ampulla
Otolithic
Membrane
Endolymph
Hair Cells
Crista Ampullaris
Ampullary Nerve
Macula Utriculi
(or Sacculi)
Image by MIT OpenCourseWare.
Hair Cells
Utricular
(or Saccular)
Nerve
Image by MIT OpenCourseWare.
36
VESTIBULAR ORIENTATION Semicircular Canal Function
Away from
Kinocilium
Toward
Kinocilium
Neutral
Position of
Cilia
Kinocilium (1)
Head acceleration
Stereocilia
(60-100)
Hair cell
Vestibular
afferent nerve
ending
Vestibular
efferent nerve
ending
Action potentials
Hyperpolarized
Depolarized
Normal
Polarization
of hair cell
Lower
Higher
Resting
Frequency of
action potentials
Image by MIT OpenCourseWare.
37
VESTIBULAR ORIENTATION Functioning of the Otoliths
Shearing
Acceleration
Saccular Macula
Utricular Macula
Superior
r
Posterior
io
er
Medial
r
rio
te
s
Po
Anterior
t
An
Lateral
Inferior
Image by MIT OpenCourseWare.
Image by MIT OpenCourseWare.
38
VESTIBULAR ORIENTATION
Vestibular-Ocular and -Cervical Reflexes
Vestibular Nystagmus
Right
Leftward
head acceleration
• Compensatory movement of eyes
opposite to head motion (slow-phase)
Angular Acceleration
Motion On
Left
39
Time
VESTIBULAR ORIENTATION
Vestibular-Ocular and -Cervical Reflexes
Vestibular Nystagmus
Right
Leftward
head acceleration
• Compensatory movement of eyes
opposite to head motion (slow-phase)
Angular Acceleration
• Designed to stabilize retinal inputs
• Can be driven by canals or otoliths
Motion On
• Gain of nystagmus is highest in frequency
range of natural head movements
Left
Time
• Nystagmus ceases in long-rotation turn; decays
gradually thereafter
Head
Control
• Nystagmus, along with vestibular- cervical
reflexes controlling the head, help provide a
stabilized space while locomoting in the
environment
40
W/graviception
WO/graviception
VESTIBULAR ORIENTATION
Canal Limits in Sustained Turns
Sustained
Perceived
Angular
Velocity
+
0
-
Cupular
Deviation
+
0
-
Angular
Velocity
+
0
-
Angular
Acceleration
+
0
-
0
4
0
15
30
45
Time (seconds)
60
VESTIBULAR ORIENTATION
Canal Limits in Sustained Turns
Sustained
In brief turns,
canals effectively
integrate angular
acceleration into
velocity signal!
Perceived
Angular
Velocity
+
0
-
Cupular
Deviation
+
0
-
Angular
Velocity
+
0
-
Angular
Acceleration
+
0
-
0
4
0
15
30
45
Time (seconds)
60
VESTIBULAR ORIENTATION
Canal Limits in Sustained Turns
Sustained
Perceived
Angular
Velocity
+
0
-
Cupular
Deviation
+
0
-
Angular
Velocity
+
0
-
Angular
Acceleration
+
0
-
0
4
0
15
30
Time (seconds)
45
60
VESTIBULAR ORIENTATION
Canal Limits in Sustained Turns
Perceived
Angular
Velocity
In prolonged
Cupular
turns, canals onlyDeviation
detect
Angular
acceleration;
Velocity
velocity is
consequently
Angular
misperceived!
Acceleration
Sustained
+
0
-
+
0
-
+
0
-
+
0
-
0
4
0
15
30
45
Time (seconds)
60
VESTIBULAR ORIENTATION
C̠Δ̠΍ “͵̼Ϊ̮̼Χθ” DϓΪͻΔͮ ͼϓήθ̠ͻΔ̸̼ ΂ϓΪΔͻΔͮ
1. “Straight-and- level” flight:
Cupula in neutral position
3. Sustained turn to left:
Cupula returns to neutral
ΧΛήͻθͻΛΔ ̠ή ̼Δ̸Λ΍ϥΓΧ͸ “̮̠θ̮͸̼ή
ϓΧ”ʹ ΔΛ θϓΪΔͻΔͮ ̸̼θ̼̮θ̸̼
2. Initial turn to left: Cupula deviated
by endolymph inertia; leftward
acceleration detected
+
4. Return to “straight- and - level” :
Cupula deviated by endolymph
momentum, gradually restored;
rightward turn perceived
_
VESTIBULAR ORIENTATION
C̠Δ̠΍ “͵̼Ϊ̮̼Χθ” DϓΪͻΔͮ ͼϓήθ̠ͻΔ̸̼ ΂ϓΪΔͻΔͮ
1. “Straight-and- level” flight:
Cupula in neutral position
3. Sustained turn to left:
Cupula returns to neutral
ΧΛήͻθͻΛΔ ̠ή ̼Δ̸Λ΍ϥΓΧ͸ “̮̠θ̮͸̼ή
ϓΧ”ʹ ΔΛ θϓΪΔͻΔͮ ̸̼θ̼̮θ̸̼
2. Initial turn to left: Cupula deviated
by endolymph inertia; leftward
acceleration detected
+
4. Return to “straight- and - level” :
Cupula deviated by endolymph
momentum, gradually restored;
rightward turn perceived
_
VESTIBULAR ORIENTATION
C̠Δ̠΍ “͵̼Ϊ̮̼Χθ” DϓΪͻΔͮ ͼϓήθ̠ͻΔ̸̼ ΂ϓΪΔͻΔͮ
1. “Straight-and- level” flight:
Cupula in neutral position
3. Sustained turn to left:
Cupula returns to neutral
ΧΛήͻθͻΛΔ ̠ή ̼Δ̸Λ΍ϥΓΧ͸ “̮̠θ̮͸̼ή
ϓΧ”ʹ ΔΛ θϓΪΔͻΔͮ ̸̼θ̼̮θ̸̼
2. Initial turn to left: Cupula deviated
by endolymph inertia; leftward
acceleration detected
+
4. Return to “straight- and - level” :
Cupula deviated by endolymph
momentum, gradually restored;
rightward turn perceived
_
VESTIBULAR ORIENTATION
C̠Δ̠΍ “͵̼Ϊ̮̼Χθ” DϓΪͻΔͮ ͼϓήθ̠ͻΔ̸̼ ΂ϓΪΔͻΔͮ
1. “Straight-and- level” flight:
Cupula in neutral position
3. Sustained turn to left:
Cupula returns to neutral
ΧΛήͻθͻΛΔ ̠ή ̼Δ̸Λ΍ϥΓΧ͸ “̮̠θ̮͸̼ή
ϓΧ”ʹ ΔΛ θϓΪΔͻΔͮ ̸̼θ̼̮θ̸̼
2. Initial turn to left: Cupula deviated
by endolymph inertia; leftward
acceleration detected
+
4. Return to “straight- and - level” :
Cupula deviated by endolymph
momentum, gradually restored;
rightward turn perceived
_
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
Upright Resting
Backward Head Tilt
+
Acceleration
Net Gravitoinertial Force
Forward Acceleration
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
+
Forward Acceleration
Backward Head Tilt
Acceleration
Net Gravitoinertial Force
50
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
Backward Head Tilt
Forward Acceleration
Acceleration
Net Gravitoinertial Force
51
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
Forward Acceleration
Backward Head Tilt
Acceleration
Net Gravitoinertial Force
52
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
Forward Acceleration
Backward Head Tilt
Acceleration
Net Gravitoinertial Force
53
VESTIBULAR ORIENTATION
Otolith Ambiguity In Sustained Acceleration
+
+
Forward Acceleration
Backward Head Tilt
Acceleration
Net Gravitoinertial Force
54
SPATIAL ORIENTATION IN FLIGHT
Somatosensory Mechansims
Golgi Tendon
Organ
Muscle Spindle
Organ
Free Nerve
Ending
Pacinian
Corpuscle
© source unknown. All rights reserved. This content is excluded from our Creative
Commons license. For more information, see http://ocw.mit.edu/fairuse.
55
SPATIAL ORIENTATION IN FLIGHT
Motor Systems
Lateral System
Ventromedial System
Lateral corticospinal
tract
Medial longitudinal tract
Lateral reticulospinal tract
Vestibulospinal tract
Rubrospinal tract
(a)
Medial reticulospinal tract
Tectospinal tract
Ventral corticospinal tract
Intermediate zone
Ventral zone
(b)
Interneurons
Motor neurons
Fingers
Arms
Body
(c)
Image by MIT OpenCourseWare.
56
SPATIAL ORIENTATION IN FLIGHT
Cognitive Factors
Somatosensory
•
•
•
•
Attentional Factors
Sensory Integration
Interpretation Based on Experience
Interpretation Based on Expectancies
Visual
Vestibular
57
Motor
SUMMARY • Spatial orientation relies on three major sensory
systems
• Ambient vision, along with the vestibular system,
determines the spatial orientation frame-of-reference
• Focal vision is not optimal for maintaining spatial
orientation; too attention-demanding
• The vestibular system is not well-suited to detecting
sustained accelerations and rotations
• Control of spatial orientation is not normally under
voluntary cortical motor control
• Spatial orientation is ultimately a cognitive construct
58
MIT OpenCourseWare
http://ocw.mit.edu
16.400 / 16.453 Human Factors Engineering
Fall 2011
For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.