Spatial Disorientation in
Military Aviation
LT Kelly R. Johnson, Ph.D.
15 November 2000
What is Spatial Disorientation?
• SD occurs when
– “the aviator fails to sense correctly the position,
motion, or attitude of his aircraft or of himself
within the fixed coordinate system provided by
the surface of the earth and the gravitational
vertical.”
• This includes
– “the erroneous perception of the aviator’s own
position, motion, or attitude to his aircraft, or of
his aircraft relative to another aircraft.”
Why do
aviators
become
…and other misconceptions
Previous Mishap
Research
Gillingham, K.K. (1992). The spatial disorientation
problem in the United States Air Force.
Journal of Vestibular Research, 2: 297 - 306.
Total
Mishaps
Fatalities
Cost
(US$)
Operations
related
633
356
795
515
4,452M 2,558M
SD
related
81
115
539M
LSA
related
SD/LSA
related
263
270
425
437
2,012M 2,045M
Bellenkes, A. et al. (1992). Spatial disorientation in
Naval aviation mishaps: A review of class A
incidents from 1980 - 1989. Aviation, Space,
and Environmental Medicine, 63: 128 - 131.
All mishaps
Helo
Prop
Jet
# SD mishaps
33
11
1
21
Fatalities
37
28
0
9
Fatalities/mishap
1.12
2.55
0.00
0.43
Mean flight hours
1458.6
1945.2
1164.0
1266.6
Braithwaite, M.G. et al. (1998). Spatial disorientation
in U.S. Army rotary-wing operations. Aviation,
Space, and Environmental Medicine, 69: 1031 1037.
Factor
T otal num ber of accidents
% of all accidents
% of class A accidents
T otal cost of accidents
Average cost per accident
T otal lives lost
Average lives lost per accident
M ean height above ground at em er.
M ean airspeed at tim e of em ergency
SD Accidents
N on-SD Accidents
299
694
30.8
69.2
36
18
$46.79 m illion
$49.95 m illion
$1.62 m illion
$0.74 m illion
110
93
0.38
0.14
65 ft
455 ft
28 knots
44 knots
Naval Safety Center: FY90 - FY96
Aircraft
SD
Fatalities
Cost
58
Total
aircraft
64
All aircraft
88
$956.93 M
Tacair
32
37
26
$778.57 M
Rotary
23
23
30
$88.02 M
Fixed Wing/
non-ejection
3
4
32
$90.34 M
NAMRL Mishap Research
• Mishap review
– US Navy and Marine Corps
– Class A flight Mishaps
– Fiscal Years 90 through 98
• 392 mishaps (USN-248; USMC-146)
• Methods
– Braithwaite et al. SD
categorization
Categorization of the Spatial
Disorientation Accident
Category
Definition
1
4
SD was the “major” component of the accident
sequence (all other contributory factors would
normally have been overcome without mishap)
SD was a “subsidiary” component of the accident
sequence (other contributory factors would have
led to a mishap in any case, but SD made the
accident sequence more difficult to deal with or
the outcome more severe)
SD was an “incidental” component (SD occurred
but did not affect the outcome)
SD did not occur
5
The role of SD was unknown
2
3
Naval Safety Center Reports:
FY90 - FY98
SD mishaps
Non-SD mishaps
51
341
% of total mishaps
13%
87%
Fatalities
104
267
Fatalities/mishap
2.04
0.78
Mean flight hours
1730.25
1606.78
Mean hours in type
662.8
742.91
8
22
# mishaps
NVG’s in use
Mishaps (SD & Non-SD) per Year
FY90
FY91
FY92
FY93
FY94
FY95
FY96
FY97
FY98
Total
65
60
55
53
28
34
36
27
36
USN
38
39
38
34
17
21
21
15
25
USMC
27
21
17
19
11
13
15
12
12
Class A Mishaps: FY90 - FY98
70
# M isha ps
60
50
65
60
55
53
40
30
34
20
28
36
36
27
10
0
FY90 FY91
FY92 FY93
Ye a r
FY94 FY95
FY96
FY97
FY98
Spatial Disorientation (SD) vs.
Non-SD Mishaps
50
49
# Mishaps
40
38
40
36
30
27
20
20
19
10
12
12
16
27
21
18
13
Non-SD
7
0
6
9
7
FY90 FY91
FY92 FY93
SD
FY94 FY95
FY96 FY97
FY98
Year
Percentage of mishaps
SD vs. Non-SD mishaps:
Phase of flight
74
80
70
62.8
60
50
SD
40
30
20
8.9
16.8
14.7
22.5
10
0
Takeoff
Inflight
Phase of flight
Landing
Non-SD
SD vs. Non-SD Mishaps:
Time of day
81.6
P e rce nta ge of m isha ps
90
80
70
60
50
56.4
43.6
SD
Non-SD
40
30
20
10
18.4
0
Day
Night
Tim e of da y
SD vs. Non-SD Mishaps:
Type of aircraft
68.3 69.3
P e rce nta ge of m isha ps
70
60
50
40
SD
25.7 26.3
Non-S D
30
20
5.9 4.4
10
0
Helo
P rop
Type of a ircra ft
Jet
# Mishaps
SD mishaps: Aircraft type and
time of day
43
50
40
30
20
26
18
8
5
Helo
Prop
10
Day
Night
1
0
Type of Aircraft
Jet
Meteorological Conditions for All
SD Mishaps
VM C
67%
IM C
33%
USN and USMC Mishaps:
FY90 - FY98
38 39
40
38
# Mishaps
34
30
20
27
17
21
10
17
FY92 FY93
Year
25
21
15
19
11
0
FY90 FY91
21
13
15
12
USN
11
USMC
FY94 FY95
FY96 FY97
FY98
Spatial Disorientation Mishaps:
USN vs. USMC
12
# Mishaps
10
9
12
11
8
8
8
8
6
3
4
2
3
4
4
4
6
4
5
4
3
USN
0
2
3
FY90 FY91
USMC
FY92 FY93
FY94 FY95
FY96 FY97
FY98
Year
SD mishaps in the Navy and Marine
Corps: Type of aircraft
73.8
Percentage of Mishaps
80
70
60
52.2
45.7
Helo
50
Prop
40
7.7
20
10
Jet
18.5
30
2.1
0
USMC
USN
Branch
Overall Findings
Factor
SD
Non-SD
# mishaps
101
276
% Mishaps
26
70
Total Lives
172
168
Avg lives/Acc
1.70
0.61
Mean flight hours
1690.3
1494.9
Mean hours in type
686.1
611.2
20
10
NVG’s in use
Conclusions
• Spatial disorientation plays a larger part in military
aviation mishaps than previously indicated
• Mishaps due to spatial disorientation claim nearly
three times more lives than non-SD mishaps
• Pilots-at-controls are often very experienced
aviators
• The influence of Night Vision Devices appears to
be under reported in aviation mishaps.
– Further research into training methods and HUD
symbology may be warranted
Thank You
To Contact:
LT Kelly R. Johnson, Ph.D.
Naval Aerospace Medical Research Lab
51 Hovey Road
Pensacola, FL 32507-1046
Ph.: 850-452-2048 (DSN: 922)
Fax: 850-452-9290
Email: [email protected]