An Analysis of Historical
Aviation Accident Data
Presented By:
Nastaran Coleman Ph.D.
FAA Investment Analysis and Operations Research
Outline
Safety’s Role in the FAA
Uses of Historical Data
Assumptions
Accident Rates Trends
Accidents by Categories
Weather Accidents
Accidents by Phase of Flight
Day/Night Accidents
Preventative Safety Programs
Safety
• Safety is the FAA’s primary
mission
• FAA’s GOAL - Achieve the lowest
possible accident rate and constantly
improve safety.
• Set the bar for aviation safety around
the world- Have done for almost a half century.
Safety- (Continued)
• Develop new technology to increase
safety
• Improve FAA’s risk management
practices
– collecting and analyzing data to identify
problems and prevent accidents from
occurring
• Improve runway safety
• Continue to partner with industry to
reduce the commercial accident rate
Claim
Use Historical Accident
Statistics To help FAA
Achieve its Goal…
Historical Data
• Historical accident statistics can be used
– to predict future accident rates for various
alternatives
– to evaluate the effect of a safety program by
comparing data before and after program
implementation
– to identify safety risks so that the return on
investment is maximized
Historical Data (continued)
• Historical accident data
– Can help derive the pool of safety benefits
– Can help establish the effectiveness of new
programs
Inputs and Assumptions
• Used the NTSB data base and included
– All accidents in or before 2001
– “Airplanes” and “helicopters”
– FAR Parts 91, 135 and 121
• Built categories of accidents using a
combination of NTSB “Cause-Factor”
codes, “Subject Modifiers,” and selected
keywords in brief reports
Examples of NTSB Cause-Factor Codes
Cause Code
OCC_DESC
ABRUPT MANEUVER
AIRFRAME/COMPONENT/SYSTEM FAILURE/MALFUNCTION
ALTITUDE DEVIATION, UNCONTROLLED
CARGO SHIFT
CountOfEVENT_ID
309
3822
155
12
COLLISION BETWEEN AIRCRAFT (OTHER THAN MIDAIR)
192
COMPLETE GEAR COLLAPSED
372
DECOMPRESSION
23
DITCHING
537
DRAGGED WING, ROTOR, POD, FLOAT OR TAIL/SKID
681
ENGINE TEARAWAY
13
EXPLOSION
27
FIRE
908
FIRE/EXPLOSION
119
FORCED LANDING
12940
GEAR COLLAPSED
1044
GEAR NOT EXTENDED
230
GEAR NOT RETRACTED
11
GEAR RETRACTION ON GROUND
25
HARD LANDING
4279
# of accidents
effected
by that cause
Accident Rates per Million Flights
40
35
30
rates
25
91(allacciden
121(all Accid
135(all accide
20
15
10
5
0
1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
years
Fatal Accident Rates per Million Flights
8
7
6
rates
5
91(Fatal Acc
121-Fatal Ac
135 Fatal Ac
4
3
2
1
0
1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
years
Fatality Rates per Million Flights
16
14
12
10
91 Fatality rate
121 Fatality Ra
135 Fatality Ra
8
6
4
2
0
1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
Years
Various Categories of Accidents
Taxi and Standing 121
0%
Taxi and Standing 135
0%
Taxi and Standing 91
3%
CFIT -121
0%
Mid air 91
0%
Other 91
4%
Other 121 Other 135
0%
0%
Weather 91
20%
CFIT -135
1%
CFIT -91
9%
Other A&L 135
1%
Weather 121
0%
Other A&L 121
0%
Weather 135
1%
Other A&L 91
19%
Loss of Control 91
19%
Loss of Engine 135
1%
Loss of Engine 121
0%
Loss of Control 135
1%
Loss of Control 121
0%
Loss of Engine 91
19%
Weather 91
Weather 121
Weather 135
Loss of Control 91
Loss of Control 121
Loss of Control 135
Loss of Engine 91
Loss of Engine 121
Loss of Engine 135
Other A&L 91
Other A&L 121
Other A&L 135
CFIT -91
CFIT -121
CFIT -135
Mid air 91
Taxi and Standing 9
Taxi and Standing
Taxi and Standing
Other 91
Other 121
Other 135
Fatality Counts By Category - Part 121&135
Other 121
9%
Taxi and Standing 135
0%
Other 135
2%
Weather 121
7%
Weather 135
12%
Taxi and Standing 121
0%
CFIT -135
18%
Loss of Control 121
15%
Loss of Control 135
10%
Loss of Engine 121
0%
CFIT -121
18%
Other A&L 135
4%
Other A&L 121
2%
Loss of Engine 135
3%
Weather 121
Weather 135
Loss of Control 121
Loss of Control 135
Loss of Engine 121
Loss of Engine 135
Other A&L 121
Other A&L 135
CFIT -121
CFIT -135
Taxi and Standing 121
Taxi and Standing 135
Other 121
Other 135
Preventive Safety Programs
• Commercial Aviation Safety Team (CAST)
addressing CFIT and Approach and
Landing (A&L) accidents
– TAWS
– Precision like approaches
– Pilot and controller training
• Capstone in AK
– Reduce weather and CFIT accidents in AK
Preventive Safety Programs (continued)
• System Approach for Safety Oversight (SASO)
– Increase the effectiveness of surveillance to reduce
maintenance related accidents
• Aviation Safety Knowledge Management
Environment (ASKME)
– Increase the effectiveness of oversight during aircraft’s
certification process to reduce related accidents.
• Various weather programs
• ASDEX and ASDE-3
– Surface Safety
Different Weather Categories
The categorization (part 1):
DENSITY ALTITUDE
HIGH DENSITY ALTITUDE
TEMPERATURE EXTREMES
NO THERMAL LIFT (gliders/sailplanes)
THERMAL LIFT (gliders/sailplanes)
TEMPERATURE, HIGH
TEMPERATURE, LOW
TEMPERATURE INVERSION
ICING
CARBURETOR ICING CONDITIONS
ICING CONDITIONS
ICE FOG
PRECIPITATION
RAIN
SNOW
WHITEOUT
DRIZZLE
FREEZING RAIN
PRECIPITATION STATIC CONDITIONS
Different Weather Categories (continued)
The categorization (part 2):
TURBULENCE
DOWNDRAFT
MOUNTAIN WAVE
TURBULENCE
TURBULENCE, CLEAR AIR
WIND/WINDSHEAR
CROSSWIND
GUSTS
HIGH WIND
TURBULENCE IN CLOUDS
HURRICANE
TURBULENCE (Thunderstorms)
TAILWIND
UPDRAFT
UNFAVORABLE WIND
TURBULENCE TERRAIN INDUCED
DUST DEVIL/WHIRLWIND
VISIBILITY/CEILING
VISBILITY/RVR
CLOUDS
FOG
HAZE/SMOKE
LOW CEILING
OBSCURATION
SAND/DUST STORM
VOLCANIC ASH
SUNGLARE
SUDDEN WINDSHIFT
VARIABLE WIND
WINDSHEAR
Weather Accidents 1982-2001
Wind/Windshear - 135
2%
Wind/Windshear - 121
0%
C&V - 091
14%
C&V - 135
1%
C&V - 121
0%
Density Altitude -91
7%
Density Altitude - 135
121
0%
Icing - 091
9%
Icing - 121
0% Icing - 135
1%
Wind/Windshear - 091
50%
Precipitation - 091
Thunderstorm - 091
4%
2%
Turbulence - 135
0%
C&V - 091
C&V - 121
C&V - 135
Density Altitude -91
Density Altitude - 121
Density Altitude - 135
Icing - 091
Icing - 121
Icing - 135
Precipitation - 091
Precipitation - 121
Precipitation - 135
Thunderstorm - 091
Thunderstorm - 121
Thunderstorm - 135
Turbulence - 091
Turbulence - 121
Turbulence - 135
Wind/Windshear - 091
Wind/Windshear - 121
Wind/Windshear - 135
Thunderstorm - 121
0%
Turbulence - 091
Precipitation
121
7%
0%
Turbulence - 121
Thunderstorm - 135
1%
0%
Precipitation - 135
1%
Weather Accidents 121&135
C&V - 121
2%
Wind/Windshear - 135
27%
C&V - 135
15%
Density Altitude - 121
1%
Density Altitude - 135
5%
Icing - 121
1%
Wind/Windshear - 121
2%
Turbulence - 135
6%
Turbulence - 121
19%
Icing - 135
8%
Precipitation - 121
2%
Precipitation - 135
10%
Thunderstorm - 121
1%
Thunderstorm - 135
1%
C&V - 121
C&V - 135
Density Altitude - 121
Density Altitude - 135
Icing - 121
Icing - 135
Precipitation - 121
Precipitation - 135
Thunderstorm - 121
Thunderstorm - 135
Turbulence - 121
Turbulence - 135
Wind/Windshear - 121
Wind/Windshear - 135
Recent Weather Accidents 121&135
1996-2001
C&V - 121
1%
Wind/Windshear - 135
21%
Density Altitude - 121
1%
C&V - 135
9%
Density Altitude - 135
4%
Icing - 121
0%
C&V - 121
C&V - 135
Density Altitude - 121
Density Altitude - 135
Icing - 135
10%
Wind/Windshear - 121
3%
Icing - 121
Icing - 135
Precipitation - 121
Precipitation - 135
Turbulence - 135
6%
Precipitation - 121
3%
Thunderstorm - 121
Thunderstorm - 135
Turbulence - 121
Precipitation - 135
9%
Thunderstorm - 121
1%
Turbulence - 121
31%
Thunderstorm - 135
1%
Turbulence - 135
Wind/Windshear - 121
Wind/Windshear - 135
Weather Accident Fatalities
Wind/Windshear - 091 Wind/Windshear - 121 Wind/Windshear - 135
10%
1%
Turbulence - 135
0%
0%
Turbulence - 121
0%
Turbulence - 091
hunderstorm - 135 7%
0%
C&V - 091
41%
Thunderstorm - 121
0%
Thunderstorm - 091
5%
Precipitation - 135
1%
Precipitation - 121
1%
Precipitation - 091
8%
C&V - 121
0%
Icing - 135
2%
C&V - 135
Icing - 091
3%
8%
Density Altitude - 091
Density Altitude - 121
7%
0%
Density Altitude - 135
1%
Icing - 121
3%
C&V - 091
C&V - 121
C&V - 135
Density Altitude - 091
Density Altitude - 121
Density Altitude - 135
Icing - 091
Icing - 121
Icing - 135
Precipitation - 091
Precipitation - 121
Precipitation - 135
Thunderstorm - 091
Thunderstorm - 121
Thunderstorm - 135
Turbulence - 091
Turbulence - 121
Turbulence - 135
Wind/Windshear - 091
Wind/Windshear - 121
Wind/Windshear - 135
Weather Accidents
• Accidents with more than 1 causal factor
are divided up equally among all causal
factors.
• Observations
– For part 121, turbulence has caused the most
number of accidents, but very few fatal injuries.
– A larger percentage of Ceiling and Visibility
accidents are fatal compared to other categories
Some Preventive Measures for
Weather Accidents
• Ground Based
– Low-Level Windshear Alert System (LLWAS), Terminal
Doppler Weather Radar (TDWR) and Weather Surveillance
Radar (WSR)
– Integrated Terminal Weather System (ITWS)
– Medium Intensity Airport Weather System (MIAWS)
– Weather and Radar Processors (WARP)
– Corridor Integrated Weather System (CIWS)
• Training Programs
• Airborne Systems
– Low-Altitude Windshear System Equipment Requirements.
Day/Night Accidents
All Accidents
Night- Part 91
12%
Night - Part 121
1%
Fatal Accidents
Night - Part 135
2%
Night- Part 91
20%
Day - Part 121
1%
Night - Part 121
0%
Night - Part 135
3%
Day - Part 135
4%
Night- Part 91
Night - Part 121
Night - Part 135
Day - Part 121
Day - Part 135
Day- Part 91
Day - Part 121
0%
Day - Part 135
4%
Day- Part 91
73%
Day- Part 91
80%
Night- Part 91
Night - Part 121
Night - Part 135
Day - Part 121
Day - Part 135
Day- Part 91
All Accidents By Phase of Flight
TAXI OTHER
2%
3%
TAKEOFF
14%
APPROACH
9%
CLIMB
2%
CRUISE
8%
STANDING
1%
MANEUVERING
7%
DESCENT
16%
LANDING
38%
APPROACH
CLIMB
CRUISE
DESCENT
LANDING
MANEUVERING
STANDING
TAKEOFF
TAXI
OTHER
Fatal Accidents By Phase of Flight - Part 121&135
TAKEOFF
11%
TAXIOTHER
0% 4%
APPROACH
19%
STANDING
2%
CLIMB
5%
MANEUVERING
12%
CRUISE
17%
LANDING
7%
DESCENT
23%
APPROACH
CLIMB
CRUISE
DESCENT
LANDING
MANEUVERING
STANDING
TAKEOFF
TAXI
OTHER
Observations
– Most accidents happen during daylight
however, the rate of fatal accidents is greater in
the absence of daylight.
– Approach, Landing, and Descent are the most
dangerous phases of flight.
Summary
Through the analyses of
historical accident data, such
findings can contribute to
efforts in preventive safety in
order to reduce aviation
accidents.
BACK UP SLIDES
Various Categories of Accidents – Part 121&135
Other 121
Taxi and Standing 135 2%
Other 135
5%
Weather 121
7%
7%
Weather 135
18%
Taxi and Standing 121
7%
Loss of Control 121
1%
CFIT -135
12%
Loss of Control 135
10%
CFIT -121
0%
Other A&L 135
14%
Loss of Engine 121
1%
Other A&L 121
3%
Loss of Engine 135
13%
Weather 121
Weather 135
Loss of Control 121
Loss of Control 135
Loss of Engine 121
Loss of Engine 135
Other A&L 121
Other A&L 135
CFIT -121
CFIT -135
Taxi and Standing 121
Taxi and Standing 135
Other 121
Other 135
Various Categories of Fatal Accidents
Taxi and Standing 135
0%
Taxi and Standing 121
0%
Taxi and Standing 91
1%
CFIT -135
2%
Other 91
8%
Other 121
0%
Other 135
0%
Mid air 91
0%
Weather 91
23%
CFIT -121
0%
Weather 121
0%
CFIT -91
21%
Weather 135
2%
Other A&L 135
0%
Other A&L 121
0%
Other A&L 91
3%
Loss of Engine 135
1%
Loss of Control 91
30%
Loss of Engine 121
0%
Loss of Engine 91
7%
Loss of Control 135
1%
Loss of Control 121
0%
Weather 91
Weather 121
Weather 135
Loss of Control 91
Loss of Control 121
Loss of Control 135
Loss of Engine 91
Loss of Engine 121
Loss of Engine 135
Other A&L 91
Other A&L 121
Other A&L 135
CFIT -91
CFIT -121
CFIT -135
Mid air 91
Taxi and Standing 91
Taxi and Standing 121
Taxi and Standing 135
Other 91
Other 121
Other 135
Categories of Fatal Accidents - Part 121&135
All Categories-FATAL Accidents
Other 121
1%
Taxi and Standing 135
1%
Other 135
5%
Weather 121
3%
Taxi and Standing 121
2%
Weather 135
21%
Loss of Control 121
3%
CFIT -135
32%
Loss of Control 135
18%
CFIT -121
1%
Other A&L 135
5%
Loss of Engine 121
0%
Other A&L 121
1%
Loss of Engine 135
7%
Weather 121
Weather 135
Loss of Control 121
Loss of Control 135
Loss of Engine 121
Loss of Engine 135
Other A&L 121
Other A&L 135
CFIT -121
CFIT -135
Taxi and Standing 121
Taxi and Standing 135
Other 121
Other 135
Fatality Counts for All Accident Categories
Taxi and Standing 135
0%
Other 91
6%
Taxi and Standing 91
Taxi and Standing 121
0%
0%
Mid air 91
0%
CFIT -135
3%
Other 121
2%
Other 135
0%
Weather 91
23%
CFIT -121
3%
Weather 121
1%
Weather 135
2%
CFIT -91
20%
Other A&L 135
1%
Other A&L 121
0%
Other A&L 91
2%
Loss of Engine 135
1%
Loss of Engine 121
0%
Loss of Engine 91 Loss of Control 135
5%
2%
Loss of Control 91
25%
Loss of Control 121
3%
Weather 91
Weather 121
Weather 135
Loss of Control 91
Loss of Control 121
Loss of Control 135
Loss of Engine 91
Loss of Engine 121
Loss of Engine 135
Other A&L 91
Other A&L 121
Other A&L 135
CFIT -91
CFIT -121
CFIT -135
Mid air 91
Taxi and Standing 91
Taxi and Standing 121
Taxi and Standing 135
Other 91
Other 121
Other 135
Fatal Weather Accidents
Wind/Windshear - 121
0%
Turbulence - 135
1%
Wind/Windshear - 135
1%
Wind/Windshear - 091
14%
Turbulence - 121
0%
Turbulence - 091
8%
C&V - 091
43%
Thunderstorm - 135
121
0%
Thunderstorm - 091
5%
Precipitation - 121
0%
Precipitation - 135
1%
Precipitation - 091
Icing - 121
9%
0%
Icing - 135
1%
C&V - 121
0%
Density Altitude - 121
0%
Icing - 091
8%
Density Altitude - 135
0%
C&V - 135
2%
Density Altitude - 091
7%
C&V - 091
C&V - 121
C&V - 135
Density Altitude - 091
Density Altitude - 121
Density Altitude - 135
Icing - 091
Icing - 121
Icing - 135
Precipitation - 091
Precipitation - 121
Precipitation - 135
Thunderstorm - 091
Thunderstorm - 121
Thunderstorm - 135
Turbulence - 091
Turbulence - 121
Turbulence - 135
Wind/Windshear - 091
Wind/Windshear - 121
Wind/Windshear - 135
All Day/Night Accidents – Part 121&135
Night - Part 121
8%
Night - Part 135
23%
Night - Part 121
Night - Part 135
Day - Part 121
Day - Part 135
Day - Part 135
55%
Day - Part 121
14%
Fatal Day/Night Accidents – Part 121&135
Night - Part 121
5%
Night - Part 135
38%
Day - Part 135
52%
Day - Part 121
5%
Night - Part 121
Night - Part 135
Day - Part 121
Day - Part 135
Fatal Accidents By Phase of Flight
TAKEOFF
9%
STANDING
1%
TAXI OTHER
4%
0%
APPROACH
12%
CLIMB
3%
CRUISE
15%
MANEUVERING
20%
LANDING
5%
DESCENT
31%
APPROACH
CLIMB
CRUISE
DESCENT
LANDING
MANEUVERING
STANDING
TAKEOFF
TAXI
OTHER
SASO’S Contribution to Part 121 Accident Avoidance
Other 44%
5%
39%
19%
In Flight Collision
23%
4%
1%
3%
14%
2%
Loss of Engine Pow er 4%
10%
3%
Loss of Control 17%
Airfram e/Com ponent
Malfunction 12%
Accidents by Category
Weather 91
Weather 121
Weather 135
Loss of Control 91
Loss of Control 121
Loss of Control 135
Loss of Engine 91
Loss of Engine 121
Loss of Engine 135
Other A&L 91
Other A&L 121
Other A&L 135
CFIT -91
CFIT -121
CFIT -135
Mid air 91
Taxi and Standing 91
Taxi and Standing 121
Taxi and Standing 135
Other 91
Other 121
Other 135
Sum
Sum 121&135
Fatal
Fatality
All Accidents Accident
Counts
9616
1847
4080.75
202
15.5
217.25
541.5
125.5
383.5
9111
2380
4380
33
17
487
313
104
327
9161
533
909
31
2
6
396
43
94
8936
236
419
103
8
70
444
32
138
4157
1658
3533
12
5
585
374
186
599
36
0
0
1652
64
55
208
14
4
222
8
8
1953
645
1121
66
6
313
159
28
80
47726.5
7957
17809.5
3104.5
594
3311.75
Weather
Weather All accidents
C&V
Density Altitude
Icing
Precipitation
Thunderstorm
Turbulence
Wind/Windshear
Grand Total
091
1423.547619
712.0833333
967.7857143
409.9452381
176.85
696.8190476
5214.969048
9602
Sum of TOT_FATALITY FLTCNDCT_CODE
wx_CODE
091
121
C&V
1905.295238
Density Altitude
337.8833333
Icing
358.0333333
Precipitation
388.0119048
Thunderstorm
233.1333333
Turbulence
348.55
Wind/Windshear
489.8428571
Grand Total
4060.75
121
135
11.64
3.833
7.333
14.78
9.917
139.3
15.19
202
PUBU
114.7285714
37.7
58.05
73.81190476
7.926190476
45.82142857
203.4619048
541.5
135
10.66666667
0.666666667
148
55.25
2
0.666666667
217.25
4.666666667
1.5
1
1.333333333
0
2
3.5
14
PUBU
140.8571429
32.66666667
83.6
41.24047619
22.86666667
19.42380952
42.8452381
383.5
Grand Total
1555.081746
755.1166667
1034.169048
499.868254
194.6928571
883.9460317
5437.125397
10360
Grand Total
11.33333333 2068.152381
3.5 374.7166667
589.6333333
3.666666667 488.1690476
256
369.9738095
1.5 534.8547619
20
4681.5
Weather- Continued
Weather after 1996
C&V
Density Altitude
Icing
Precipitation
Thunderstorm
Turbulence
Wind/Windshear
Grand Total
091
121
252.8333333
150.8333333
214.1666667
61.91666667
35
129.5
1357.75
2202
135
2.333333333
2
1
6.5
2.5
64.5
6.166666667
85
PUBU
19.83333333
7.833333333
20.33333333
19
2
12.16666667
43.83333333
125
Grand Total
3.5
1
1
0.5
0
1
2
9
278.5
161.6666667
236.5
87.91666667
39.5
207.1666667
1409.75
2421
Phase of Flight
APPROACH
CLIMB
CRUISE
DESCENT
LANDING
MANEUVERING
STANDING
TAKEOFF
TAXI
OTHER
All Accident Fatal Accidents
121&135 only
3767.405
1070.738095
116.5333333
747.8833
291.4333333
29.36666667
3525.348
1366.17381
107.8166667
7122.35
2744.509524
143.7833333
16534.18
427.6928571
43.31666667
3155.217
1753.1
77.15
579.7333
44.83333333
11
5905.824
814.7238095
68.5
1427.917
13.66666667
1.666666667
807.1429
373.1285714
21.86666667
Day/night
Night- Part 91
Fatal Accidents
All Accidents Fatal Accidents All Accidents
1531
3992
19.77%
11.60%
Night - Part 121
28
192
0.36%
0.56%
Night - Part 135
Day - Part 121
Day - Part 135
Day- Part 91
212
28
295
5650
556
342
1365
27967
2.74%
0.36%
3.81%
72.96%
1.62%
0.99%
3.97%
81.27%
Accidents
Annual Average
All accident
Fatal Accident
Fatality counts
91
2065.85
424.5
794
121
32.2
3.45
152.55
135
116.8
29.2
84.65
Accidents
Weather 91
Weather 121
Weather 135
Loss of Control 91
Loss of Control 121
Loss of Control 135
Loss of Engine 91
Loss of Engine 121
Loss of Engine 135
Other A&L 91
Other A&L 121
Other A&L 135
CFIT -91
CFIT -121
CFIT -135
Mid air 91
Taxi and Standing 91
Taxi and Standing 121
Taxi and Standing 135
Other 91
Other 121
Other 135
Sum
Sum 121&135
All Accidents
Fatal Accident Fatality Counts
9616
1847
4080.75
202
15.5
217.25
541.5
125.5
383.5
9111
2380
4380
33
17
487
313
104
327
9161
533
909
31
2
6
396
43
94
8936
236
419
103
8
70
444
32
138
4157
1658
3533
12
5
585
374
186
599
36
0
0
1652
64
55
208
14
4
222
8
8
1953
645
1121
66
6
313
159
28
80
47726.5
7957
17809.5
3104.5
594
3311.75