CGAR STATISTICAL ANALYSIS FOR FATAL GENERAL AVIATION ACCIDENTS Ken Knopp, FAA Massoud Bazargan, ERAU

1
CGARSTATISTICAL ANALYSIS FOR FATAL GENERAL
AVIATION ACCIDENTSKen Knopp, FAAMassoud
Bazargan, ERAU
2
Scope of the Project

• Analyze existing data on General Aviation
  accidents resulting in fatalities.
• Identify associations and patterns between flight
  elements and fatalities

3
NTSB Database

• Every accidents/incidents receives a record
  (event ID). Each aircraft involved in the
  accident receives an NTSB report number.
• 600 MB
• Around 60,000 events accidents/incidents (total).
• 50,000 events relate to GA. (83 of all
  accidents).
• 9200 events 9380 aircraft fatal GA accidents
  (18.4 of total GA events).

4
GA Fatal Accidents
5
GA Accidents Accidents per 100,000 flight hours
(est.)
6
Phases I II

• Phases I II analyzed and reported 5, 10 and 20
  year fatal accidents.
• Identified patterns for national and nine regions
  as defined by the FAA (a summary presented at UND
  and UAF).
• Provided statistical analyses on single factors
  for national and 9 regions (75 factors).

7
Some General Statistics Phase III
8
Time of Accidents (1983-1992)National
9
Time of Accidents (1993-2002)National
10
Time of Accidents (1983-1992)Arizona
11
Time of Accidents (1993-2002)Arizona
12
Arizona vs. National (1983 1992)
Differences across the categories are NOT
SIGNIFICANT
13
Arizona vs. National (1993 2002)
Differences across the categories are NOT
SIGNIFICANT
14
Pilot Hours of Experience(1983-1992) National
15
Pilot Hours of Experience(1993-2002) National
16
Pilot Hours of Experience(1983-1992) Arizona
17
Pilot Hours of Experience(1993-2002) Arizona
18
Pilot Gender Fatal Accidents (1993-2002)Nationa
l
19
Pilot Gender Fatal Accidents (1993-2002)Arizona
20
Pilot Age Fatal Accidents (1993-2002)National
21
Pilot Age Fatal Accidents (1993-2002)Arizona
22
Analyses

• Primary causes
• Statistical analyses

23
Primary Causes

• The NTSB reports up to 5 occurrences for each
  accident.
• Each occurrence has up to 10 sequence of events
  showing chronologically what happened at each
  occurrence.
• We searched for the primary cause that triggered
  all the events.

24

• First Causes

More than 400 causes
25
Fatal GA Aircraft Accidents

• Nationwide Analysis of 5-Year Periods
• Top 10 primary causes
• 1983 1987
• 1988 1992
• 1993 1997
• 1998 2002

26
56 of all fatal accidents
27
50 of all fatal accidents
28
53 of all fatal accidents
29
57 of all fatal accidents
30
Comparison of 5-Year Periods
Categorized as Aircraft Handling
31
Primary Cause Aircraft Control
NTSB Code 24566
32
Primary Cause Airspeed
NTSB code 24506
33
First Primary- VFR flight into IMC
NTSB code 24015
34
Non-Fatal GA Aircraft Accidents
35
Pattern among Fatal and Non-Fatal GA Aircraft
Accidents
36
Risk Factor Comparison
Rank First Cause 83-88 88-92
93-97 98-02

1. Aircraft Control 2.792 3.586 4.200 2.497
2. Airspeed 1.667 2.120 2.865 2.7
   00
3. VFR Flight Into IMC
   16.818 18.415 17.416 15.666
4. Altitude
   4.306 4.080 5.242 5.199
5. In-flight Planning 1.778 1.380
   0.865 1.334
6. Visual Lookout 1.393
   1.400 1.561 1.357

37
General Aviation Accident Analysis

• Part 91 GA accidents analyzed in 5-year periods
• 1983 1987
• 1988 1992
• 1993 1997
• 1998 -- 2002

• Single engine aircraft analysis separated by
  engine horse-power
• Quartile 1
• Less than 150 HP
• Quartile 2
• 150 200 HP
• Quartile 3
• 200 300 HP
• Quartile 4
• Greater than 300 HP

38
Comparison of 5-Year PeriodsSingle engine
reciprocating lt150HP
Categorized as Aircraft Handling
39
Comparison of 5-Year PeriodsSingle engine
reciprocating 150-200 HP
Categorized as Aircraft Handling
40
Comparison of 5-Year PeriodsSingle engine
reciprocating 200-300 HP
Categorized as Aircraft Handling
41
Comparison of 5-Year PeriodsSingle engine
reciprocating gt300 HP
Categorized as Aircraft Handling
42
Statistical Analyses on combined multi-Factors
Contributing to Fatalities in General Aviation
Accidents
43
National Analyses

• Sample 35,960 GA airplane accidents
• From 1983 to 2002.
• More than 420 data fields
• 28 variables related to pilot and airplane
  characteristics selected.
• Sample was meticulously screened for
• accuracy,
• missing variables,
• outliers,
• Absence of multicollinearity problems

44
National AnalysesVariables Included

• FATAL is the fatal accident (dependant variable)-
  Binary Logistic Regression
• VFR flight plan
• Light condition
• Instrument meteorological condition
• Cross-country flight
• Wind velocity in the area
• Retractable landing gear

45
National Analyses Variables Included

• engines
• Pilots type rating variable
• Second pilot on board
• Seat belt
• Shoulder harness
• Medical certificate

46
National AnalysesVariables Included

• Gender
• Age
• Pilots total flight experience
• Phase of the flight (taxi, takeoff, climb,
  descent, ..)
• YEAR of the accident

47
National Analyses

• Please Pay Attention You will have a test on
  the following equation after this!!

SPSS Logistic Regression
48
National AnalysesOnly those significant

• Only 10 variables found to be significant
  (combined).
• Lighting Condition positive and significant,
  indicating that darker environment - increased
  probability of an accident to be fatal
• Instrument Meteorological Condition (IMC)
  significant, highest odds ratio.

49
National Analyses

• Cross Country Flight positive and significant
• Wind Condition negative and significant -higher
  wind velocity - decreases the probability of the
  accident to be fatal !!
• Literature also reports that stronger winds lead
  to more GA accidents, but these accidents most
  commonly result in aircraft damage and minor
  injuries

50
National Analyses

• Retractable Landing Gear positive, significant.
  
• Second Pilot Onboard Positive, significant
  (?!!!).
• More than 13 percent of the accident airplanes in
  the sample had a second pilot on board.

51
National Analyses

• Conventional wisdom suggests that an extra pilot
  on board would help the flying pilot in case of
  unexpected emergency.
• However, for this help to be constructive, GA
  pilots should understand how to properly use
  human resources in flight.

52
National Analyses

• U.S. airlines have implemented Crew Resource
  Management (CRM) training with an emphasis on
  principles and concepts that improve crew
  performance and flight safety,
• A typical GA pilot has never taken a CRM course.
  Our results imply that such a course would
  decrease the number of fatal GA accidents.

53
National Analyses

• Seatbelts significant
• Phase of flight CLIMB and DESCENT significant
• Pilots flight time over the last 30 days
• less than 5 hours (rusty!) significant
• More than 100 hours (tired!) significant
• Year Negative and significant

54
Research in Progress

• Machine learning approaches to find patterns
  among fatal/non-fatal accidents
• Continue with logistic regression for all 9
  regions.
• Text processing analysis.
• Finalize phase III.
• Start phase 4 on statistical analyses on
  rotorcraft and helicopters.

55

• Thank you
• Q/A