**PREFACE**

This report presents statistical analyses of aviation accidents
conducted at the Volpe National Transportation Systems Center (Volpe
Center) to investigate possible factors related to
controlled-flight-into-terrain (CFIT) accidents. The conclusions drawn
from this paper will be used for two purposes: one, to guide further
analyses and two, to design experiments with electronic moving maps to
study what and how information needs to be displayed to improve pilots\'
understanding of, and ability to, avoid terrain.

The authors would like to thank their FAA sponsors, Dr. Maureen Pettitt,
Chief Scientific and Technical Advisor for Human Factors, and Dr. Thomas
McCloy, manager of the Cockpit Human Factors Program, AAR-100, for their
guidance and support of this work.

**EXECUTIVE SUMMARY**

This report describes the characteristics of general aviation (GA)
accidents and identifies factors related to the occurrence of
controlled-flight-into-terrain (CFIT) accidents in GA.

This study used the National Transportation Safety Board (NTSB) database
of 31,790 aviation accidents that occurred between 1983 and 1994,
inclusive. In the NTSB aviation accident database, 86.7% of these
accidents were GA accidents. This study analyzed the subset of accidents
involving GA airplanes and helicopters.

A controlled-flight-into-terrain accident (CFIT) is any collision with
terrain (or water) in which the pilot was in control of the aircraft but
was not aware of the airplane's altitude, the terrain elevation, or the
airplane's position in terms of latitude or longitude. This study
classified all GA accidents as occurring due to either CFIT or other
causes. Further analyses identified factors that were related
significantly to GA accidents due to CFIT.

These analyses show that 4.7% of GA accidents occur due to CFIT; these
accidents result in 1.4 fatalities per accident, compared with 0.33
fatalities in all other GA accidents. CFIT-type accidents account for
17% of GA fatalities. Instrument conditions and older pilots are factors
associated with CFIT-type accidents. Approximately one-third (32%) of
the GA accidents in instrument conditions are related to CFIT. Analyses
of this database provided insight into factors related to CFIT-type GA
accidents.

**TABLE OF CONTENTS**

**[Section]{.underline} [Page]{.underline}**

1.  BACKGROUND 1

    PURPOSE 2

    DESIGN AND PROCEDURE 2

    ANALYSIS 3

    1.  Distribution of General Aviation Accidents by Year 3

        Tests of Significance 4

    RESULTS 6

    CONCLUSIONS 7

    REFERENCES 9

APPENDIX A - Procedures for Keyword Queries 11

APPENDIX B - Analysis of All Aviation Accidents, 1983-1994 13

APPENDIX C - Analysis of Non-General Aviation Accidents, 1983-1994 17

**LIST OF FIGURES**

**[Figure]{.underline} [Page]{.underline}**

4-1 Trend in General Aviation Accidents, 1983-1994 3

**LIST OF TABLES**

**[Table]{.underline} [Page]{.underline}**

4-1 Frequency Distribution of General Aviation Accidents, 1983-1994 3

4-2 Incidence of General Aviation Accidents and Fatalities and CFIT
Accidents and

Fatalities by Visual Condition, Pilot, and Aircraft Characteristics,
1983-1994 4

4-3 Visual Condition, Pilot, and Aircraft Characteristics, and Incidence
of

CFIT-Type Accidents 5

4-4 Number of Aircraft Engines Versus Pilot Age 6

1.  **BACKGROUND**

A controlled-flight-into-terrain accident (CFIT) is defined as any
collision with terrain (or water) in which the pilot was in control of
the aircraft but was not aware of the airplane's altitude, the terrain
elevation, or the airplane's position in terms of latitude or longitude,
a definition similar to that described by Earl L. Wiener (1977).[^1]
Although Wiener's definition indicates that the pilot was in control of
the aircraft and impacted terrain, it does not mention the airplane's
position in terms of latitude and longitude. The custom data set created
for this study includes accident data involving only airplanes or
helicopters as our CFIT definition does not apply to other aircraft
(e.g., ultralights, blimps).

The introduction of Ground Proximity Warning Systems (GPWS) into the
U.S. air carrier fleet after the 1974 TWA crash at Washington Dulles
International Airport has led to a reduction in CFIT-type accidents.
GPWS has not completely eliminated CFIT-type accidents in air carriers.
Because radar altimeter looks only downward, GPWS can provide only a few
seconds' advance warning. GPWS can have false alarms which may affect
pilot response.

As a result, manufacturers have developed improved Ground Collision
Avoidance Systems (GCAS) and Enhanced Ground Proximity Warning Systems
(EGPWS). These system upgrades to existing GPWS installations are
expensive for general aviation (GA) operators whose aircraft may lack
radar altimeters and integrated caution and warning systems; however,
there is strong evidence that these GPWS systems are important for
reorienting pilots who have lost situational awareness.[^2] Phillips
(1996) suggests that GA aircraft might also experience a reduced
incidence of CFIT due to the benefits of GPWS or GCAS systems. To meet
these concerns, commercial interest has begun to focus on developing
lower cost, stand-alone, GPS-based GCAS systems for GA use.

2.  **PURPOSE**

It is necessary to understand the factors associated with GA accidents
to improve alerting equipment for GA operations. Since GCAS and GPWS
systems alert for terrain avoidance, specific interest focuses on the
factors associated with CFIT accidents in GA flight. By examining a
database of aviation accidents it is possible to identify common
patterns in CFIT accidents which will be useful in designing or
modifying terrain alerting systems.

3.  **DESIGN AND PROCEDURE**

This study uses the National Transportation Safety Board's (NTSB's)
database of the 31,790 aviation accidents which occurred between 1983
and 1994, inclusive. GA accidents were identified using the "Regulation
Flight Conducted Under" code on the NTSB Report Form. GA accidents are
defined as "14 CFR 91 (*only*)" in this code. GA accidents were selected
from the database for further study. The GA subset of the NTSB database
of aviation accidents accounted for 86.7% of the NTSB database of all
aviation accidents.[^3]

The Volpe Center developed an operational definition for CFIT to
identify factors associated with this classification. The customized
data set was designed classifying each accident as a CFIT or
non-CFIT-type accident. Classifying the data as CFIT or non-CFIT
required several steps. First, the database was queried using keywords
to designate the majority of the accidents as due to causes other than
CFIT. Each of the remaining accidents were rated on an individual basis
to determine which were due to CFIT and which were due to other causes.
These steps are outlined in Appendix A. GA accidents classified as CFIT
represented 1,260 accidents in the GA database of 26,533 accidents.

4.  **ANALYSIS**

**4.1 DISTRIBUTION OF GENERAL AVIATION ACCIDENTS BY YEAR**

Figure 4-1 and table 4-1 show that, from 1983 to 1994, inclusive, the
proportion of CFIT-type accidents has remained relatively constant,
while the incidence of GA accidents due to all other causes has
declined.

![](media/image1.emf)

**Figure 4-1. Trend in General Aviation Accidents, 1983-1994**

**Table 4-1. Frequency Distribution of General Aviation Accidents,**
**1983-1994**

<table style="width:100%;">
<colgroup>
<col style="width: 14%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 7%" />
</colgroup>
<tbody>
<tr class="odd">
<td><strong>Year</strong></td>
<td><strong>1983</strong></td>
<td><strong>1984</strong></td>
<td><strong>1985</strong></td>
<td><strong>1986</strong></td>
<td><strong>1987</strong></td>
<td><strong>1988</strong></td>
<td><strong>1989</strong></td>
<td><strong>1990</strong></td>
<td><strong>1991</strong></td>
<td><strong>1992</strong></td>
<td><strong>1993</strong></td>
<td><strong>1994</strong></td>
<td><strong>Total</strong></td>
</tr>
<tr class="even">
<td><p>Total number</p>
<p>GA accidents</p></td>
<td>2,765</td>
<td>2,732</td>
<td>2,534</td>
<td>2,335</td>
<td>2,291</td>
<td>2,185</td>
<td>2,059</td>
<td>2,026</td>
<td>1,992</td>
<td>1,918</td>
<td>1,883</td>
<td>1,813</td>
<td>26,533</td>
</tr>
<tr class="odd">
<td>CFIT accidents</td>
<td>132</td>
<td>113</td>
<td>107</td>
<td>99</td>
<td>90</td>
<td>90</td>
<td>107</td>
<td>116</td>
<td>121</td>
<td>108</td>
<td>109</td>
<td>68</td>
<td>1,260</td>
</tr>
<tr class="even">
<td>Accidents due to other causes</td>
<td>2,633</td>
<td>2,619</td>
<td>2,427</td>
<td>2,236</td>
<td>2,201</td>
<td>2,095</td>
<td>1,952</td>
<td>1,910</td>
<td>1,871</td>
<td>1,810</td>
<td>1,774</td>
<td>1,745</td>
<td>25,273</td>
</tr>
<tr class="odd">
<td><p>% CFIT</p>
<p>accidents</p></td>
<td>4.77</td>
<td>4.14</td>
<td>4.22</td>
<td>4.24</td>
<td>3.93</td>
<td>4.12</td>
<td>5.20</td>
<td>5.73</td>
<td>6.07</td>
<td>5.63</td>
<td>5.79</td>
<td>3.75</td>
<td>4.75</td>
</tr>
</tbody>
</table>

2.  **TESTS OF SIGNIFICANCE**

This study analyzed the relationship between visual conditions, pilot
characteristics, aircraft characteristics, and the likelihood of a
CFIT-type accident. Table 4-2 presents frequency distributions for all
GA accidents, CFIT-type accidents, and for GA accidents due to all other
causes.

**Table 4-2. Incidence of General Aviation Accidents and Fatalities and
CFIT Accidents and Fatalities by Visual Condition, Pilot, and Aircraft
Characteristics, 1983-1994\***

![](media/image2.emf){width="5.999305555555556in"
height="6.077083333333333in"}

\* Source: National Transportation Safety Board Database of Factual
Aviation Report Forms.

Includes only airplane and helicopter accidents.

\*\* More flying time means pilots' total flight hours ranked in the
highest 25% of flight hours in the NTSB database.

Less flying time means pilots' total flight hours were in the lowest 25%
of flight hours in the NTSB database.

Tests of significance (chi-square) determined the relationship between
visual condition, pilot or aircraft characteristics, and the type of
accident. Table 4-3 reports statistically significant relationships. The
significant relationships were further analyzed using logistic
regressions to assess the relative contribution of variables measuring
visual conditions, pilot, or aircraft characteristics to the likelihood
of an accident occurring due to CFIT.

**Table 4-3. Visual Condition, Pilot, and Aircraft Characteristics, and
Incidence of CFIT-Type Accidents**

+------------------------------+-----------+--------------------------+
| **Characteristics**          | **C       | **Notes**                |
|                              | hi-Square |                          |
|                              | prob      |                          |
|                              | ability** |                          |
+------------------------------+-----------+--------------------------+
| [Weather                     | p = 0.000 | Accidents that happened  |
| conditions:]{.underline}     |           | in IMC were more likely  |
|                              |           | to be CFIT than          |
| VMC conditions versus IMC    |           | accidents in VMC.        |
+------------------------------+-----------+--------------------------+
| [Light                       | p \<      | Accidents that occurred  |
| conditions]{.underline}:     | 0.001     | on dark nights were more |
|                              |           | likely to be CFIT than   |
| Night: Bright night versus   |           | accidents that occurred  |
| dark night                   |           | on clear nights.         |
+------------------------------+-----------+--------------------------+
| Daylight versus night        | p \<      | Accidents that occurred  |
|                              | 0.001     | at night were more       |
|                              |           | likely to be CFIT than   |
|                              |           | accidents that occurred  |
|                              |           | during the day.          |
+------------------------------+-----------+--------------------------+
| [Cloud                       | p \<      | Accidents that occurred  |
| conditions:]{.underline}     | 0.001     | in cloudy conditions     |
|                              |           | were more likely to be   |
| Clear versus overcast        |           | CFIT than accidents that |
|                              |           | occurred in clear or     |
|                              |           | thin overcast            |
|                              |           | conditions.              |
+------------------------------+-----------+--------------------------+
| [Pilot age:]{.underline}     | p = 0.001 | Accidents that occurred  |
|                              |           | with pilots 50 or older  |
| Less than age 50 versus age  |           | were more likely to be   |
| 50 and over                  |           | CFIT accidents than      |
|                              |           | accidents that occurred  |
|                              |           | with pilots under 50.    |
+------------------------------+-----------+--------------------------+
| [Pilot gender:]{.underline}  | p = 0.002 | Accidents that occurred  |
|                              |           | with male pilots were    |
| male versus female           |           | more likely to be CFIT   |
|                              |           | accidents than accidents |
|                              |           | that occurred with       |
|                              |           | female pilots.           |
+------------------------------+-----------+--------------------------+
| [Pilot flight                | p \<      | Accident with pilots in  |
| time:]{.underline}           | 0.001     | the bottom 25% (fewer    |
|                              |           | hours) were more likely  |
| Pilots with more flying time |           | to be CFIT accidents     |
| versus pilots with less      |           | than accidents with      |
| flying time\*                |           | pilots in the upper 25%  |
|                              |           | .                        |
+------------------------------+-----------+--------------------------+
| [Pilot rating:]{.underline}  | p \<      | Accidents that occurred  |
|                              | 0.001     | with IFR rated pilots    |
| VFR rated versus IFR rated   |           | were more likely to be   |
|                              |           | CFIT accidents than      |
|                              |           | accidents that occurred  |
|                              |           | with VFR rated pilots.   |
+------------------------------+-----------+--------------------------+
| [Pilot rating in IMC         | p = 0.021 | Accidents that happened  |
| accidents:]{.underline}      |           | in IMC with VFR pilots   |
|                              |           | were more likely to be   |
| VFR rated pilots in IMC      |           | CFIT accidents than      |
| versus IFR rated pilots in   |           | accidents in IMC with    |
| IMC                          |           | IFR pilots.              |
+------------------------------+-----------+--------------------------+
| [Number of                   | p \<      | Accidents with multiple  |
| engines:]{.underline}        | 0.001     | engine aircraft were     |
|                              |           | more likely to be CFIT   |
| Single engine versus         |           | than accidents with      |
| multi-engine                 |           | single engine aircraft.  |
+------------------------------+-----------+--------------------------+

\* More flying time means pilots' total flight hours ranked in the
highest 25% of flight hours in the NTSB database. Less flying time means
pilots' total flight hours were in the lowest 25% of flight hours in the
NTSB database.

Accidents with older pilots and accidents with multi-engine aircraft
were both more likely to be CFIT accidents than accidents with both
younger pilots and accidents with single engine aircraft. This
relationship may be the result of older pilots being more likely to fly
multi-engine aircraft than younger pilots. The statistical relationship
between the number of aircraft engines and pilots' age (table 4-4) is
significant. These two variables may interact to create a situation
where older GA pilots are more CFIT-oriented than younger pilots.

**Table 4-4. Number of Aircraft Engines Versus Pilot Age**

  ------------------------------- --------------- ---------------------------
  **Characteristics**             **Chi-Square    **Notes**
                                  probability**   

  Single/multi-engine versus less p \< 0.001      Accidents with multiple
  than/greater than 50 years old                  engine aircraft were more
                                                  likely to be flown by
                                                  pilots 50 years or over
                                                  than were single engine
                                                  aircraft.
  ------------------------------- --------------- ---------------------------

Using logistic regression, variables significantly related to the
incidence of CFIT accidents, e.g., pilot age, sex, total flying time,
rating, and weather condition, were analyzed to assess relative
contribution of each dichotomized variable to the likelihood of having a
CFIT-type accident. Weather condition and pilot age were the strongest
predictors of the occurrence of CFIT accidents.

Logistic regressions were also performed to unravel what factors
contributed to the significantly higher percentage of CFIT accidents
involving older pilots. Logistic regressions were performed for IFR and
VFR pilots to see how the variables of age and visual conditions were
related to CFIT. Weather conditions were significantly associated with
both IFR and VFR pilots in GA accidents. Pilot age, however, was only
significant for IFR-rated pilots in GA accidents. Pilot age is
statistically associated with the occurrence of CFIT only when the pilot
has an IFR rating.

**5. RESULTS**

The following conclusions are drawn from these statistical analyses:

ACCIDENTS:

-   CFIT-type accidents account for 4.7% of GA accidents.

-   CFIT-type accidents account for 32% of GA accidents in IMC
    conditions.

FATALITIES:

-   GA CFIT-type accidents result in an average of 1.4 fatalities per
    accident while GA accidents, due to all other causes, result in an
    average of 0.33 fatalities per accident.

-   CFIT accidents account for 17% of people killed in GA accidents.

-   Sixteen percent of the fatal GA accidents were due to CFIT.

ASSOCIATED CHARACTERISTICS:

-   IFR-rated GA pilots, age 50 and over, have significantly more
    CFIT-type accidents than IFR-rated GA pilots under age 50.

-   There were significantly more CFIT-type accidents during IMC
    conditions than during VMC conditions.

6.  **CONCLUSIONS**

CFIT-type accidents account for 17% of GA fatalities, which underscores
the need for further research into factors contributing to CFIT
accidents.

CFIT-type accidents represent 32% of the GA accidents in IMC conditions.
When looking at accidents in IMC weather conditions, other studies have
also indicated that CFIT-type accidents play a major role.[^4] Moving
maps with terrain displays may provide a way to better orient GA pilots
in low-visibility situations: electronic moving map displays may alert
pilots to avoid accidents before they occur.

Instrument conditions and older pilots are overrepresented in CFIT
accidents. IMC conditions may demand sensory or cognitive tasks which
vary with age. Other studies have indicated that older pilots with low
annual hours (a category that is primarily GA pilots) have a higher
accident rate overall.[^5] It has also been shown that CFIT rates are
higher in situations where pilots inadvertently fly from VMC to IMC
conditions.[^6] These issues, differential sensory and cognitive
capabilities, lower annual flight hours, and inadvertent flying into
altered conditions, seem to contribute disproportionately to the
incidence of CFIT accidents. Further examination of these relationships
is warranted.

Accidents in multi-engine planes are disproportionately represented in
the classification of accidents related to CFIT, and this relationship
needs more study. Older pilots may be more likely to fly multi-engine
planes. Alternatively, multi-engine aircraft may fly longer distances,
and over unfamiliar terrain more frequently.

In summary, analyses of this partitioned database provide a way to
identify factors that are associated with CFIT-type accidents.

**7. REFERENCES**

AOPA Air Safety Foundation. (1996). *1996 Nall Report: Accident Trends
and Factors for 1995*. Frederick, MD.

Khatwa, R., & Roelen, A. L. C. (1996). An Analysis of
Controlled-flight-into-terrain (CFIT) Accidents of Commercial Operators
1988 through 1994. *Flight Safety Digest,* 15(4/5), 1-45.

Phillips, R. O. (1996). *Investigation of Controlled Flight into
Terrain* (Project Memorandum DOT-TSC-FA6D1-96-01). Cambridge, MA: U.S.
Department of Transportation, Volpe National Transportation Systems
Center.

Safety Analysis Division. (1982). *The Influence of Total Flight Time,
Recent Flight and Age on Class III Pilot Accident Rates*. Washington,
D.C.: Federal Aviation Administration.

Wiener, E. L. (1977). Controlled Flight into Terrain Accidents:
System-Induced Errors. *Human Factors*, 19(2), 171-181.

**APPENDIX A - PROCEDURES FOR KEYWORD QUERIES**

The NTSB database has four sections: 1) Narrative, 2) Causes, 3)
Sequence of Events, and 4) Core. The Narrative is a free-form
description of what occurred. The Causes and Sequence of Events are
compiled from pre-coded lists of causes and events. The Core section
contains the technical and objective information about the pilot,
passengers, aircraft dimensions, and weather conditions from the NTSB
accident report.

This study classified accidents due to the following causes as
non-CFIT-type accidents:

1.  Pilot loss of control due to mechanical problems or pilot error

2.  Intentional dangerous flying (aerobatics, crop dusting)

3.  Crashes in the runway environment

4.  Extreme weather affecting flight

5.  In-flight breakup

6.  Engine failure

7.  Pilot physical impairment

8.  Suicide

To designate accidents as due to causes other than CFIT, the Sequence of
Events section of the accident database was queried using keywords.
Keywords from the master list of Sequence of Events eliminated accidents
from the CFIT pool based on the chosen criteria. These words included:

1.  Physical impairment

2.  Midair collisions

3.  Aerobatics

4.  Buzzing

5.  Suicide

6.  Incapacitation

7.  Standing

8.  Taxi

9.  Fuel exhaustion

10. Fuel starvation

11. Aircraft control not maintained

12. Loss of engine power (total)

13. Loss of control

14. Alcohol

15. Impairment

16. Drug

17. Aerial application

It was not possible to identify all the non-CFIT accidents using
keywords. The remaining accidents were hand-rated by reading the
Narrative, Causes, and Sequence of Events sections for each accident and
designating the accident as due to causes other than CFIT if it met one
of these criteria:

1.  Crashes in the runway environment

2.  Extreme weather affecting performance

3.  In-flight breakup

4.  Intentional aerobatics

5.  Intentional buzzing (i.e., flying close to the ground)

6.  Total power loss

7.  Pilot loss of control

8.  Possible CFIT but evidence for other causes

9.  None of the above (but pilot aware of location/terrain)

The remaining accidents were classified as occurring due to CFIT.

**APPENDIX B - ANALYSIS OF ALL AVIATION ACCIDENTS, 1983-1994**

![](media/image3.emf)

**Figure B-1. Trend in All Aviation Accidents, 1983-1994**

**Table B-1. All Aviation Accidents by Year, 1983-1994**

  ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ------------
  Year        1983        1984        1985        1986        1987        1988        1989        1990        1991        1992        1993        1994        Total

  Total       **3,333**   **3,287**   **3,005**   **2,776**   **2,744**   **2,636**   **2,482**   **2,435**   **2,386**   **2,278**   **2,246**   **2,181**   **31,789**
  number of                                                                                                                                                   
  accidents                                                                                                                                                   

  CFIT        **144**     **122**     **121**     **113**     **102**     **99**      **127**     **136**     **135**     **130**     **126**     **78**      **1,433**
  accidents                                                                                                                                                   

  Accidents   **3,189**   **3,165**   **2,884**   **2,663**   **2,642**   **2,537**   **2,355**   **2,299**   **2,251**   **2,148**   **2,120**   **2,103**   **30,356**
  due to                                                                                                                                                      
  other                                                                                                                                                       
  causes                                                                                                                                                      

  \% CFIT     **4.32**    **3.71**    **4.03**    **4.07**    **3.72**    **3.76**    **5.12**    **5.59**    **5.65**    **5.71**    **5.61**    **3.58**    **4.51**
  accidents                                                                                                                                                   
  ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ------------

**Table B-2. All Aviation Accidents and Fatalities, 1983-1994,
Controlled-Flight-Into-Terrain (CFIT) Accidents, and Fatalities by
Visual Condition, Pilot, and Aircraft Characteristics\***

![](media/image4.emf)

\* Source: National Transportation Safety Board Database of Factual
Aviation Report Forms.

Includes only airplane and helicopter accidents.

\*\* More flying time means pilots' total flight hours ranked in the
highest 25% of flight hours in the NTSB database.

Less flying time means pilots' total flight hours were in the lowest 25%
of flight hours in the NTSB database.

**Table B-3. Visual Conditions, Pilot, and Aircraft Characteristics, and
Incidence of CFIT Accidents in the NTSB Aviation Accident Database**

+------------------------------+-----------+--------------------------+
| **Characteristics**          | **C       | **Notes**                |
|                              | hi-Square |                          |
|                              | prob      |                          |
|                              | ability** |                          |
+------------------------------+-----------+--------------------------+
| [Weather                     | p = 0.000 | Accidents that happened  |
| conditions:]{.underline}     |           | in IMC were more likely  |
|                              |           | to be CFIT than          |
| VMC conditions versus IMC    |           | accidents in VMC.        |
+------------------------------+-----------+--------------------------+
| [Light                       | p \<      | Accidents that occurred  |
| conditions]{.underline}:     | 0.001     | on dark nights were more |
|                              |           | likely to be CFIT than   |
| Night: Bright night versus   | p \<      | accidents that occurred  |
| dark night                   | 0.001     | on clear nights.         |
|                              |           |                          |
| Daylight versus night        |           | Accidents that occurred  |
|                              |           | at night were more       |
|                              |           | likely to be CFIT than   |
|                              |           | accidents that occurred  |
|                              |           | during the day.          |
+------------------------------+-----------+--------------------------+
| [Cloud                       | p \<      | Accidents that occurred  |
| conditions:]{.underline}     | 0.001     | in cloudy conditions     |
|                              |           | were more likely to be   |
| Clear versus overcast        |           | CFIT than accidents that |
|                              |           | occurred in clear or     |
|                              |           | thin overcast            |
|                              |           | conditions.              |
+------------------------------+-----------+--------------------------+
| [Pilot age:]{.underline}     | p = 0.000 | Accidents that occurred  |
|                              |           | with pilots 50 or older  |
| Less than age 50 versus age  |           | were more likely to be   |
| 50 and over                  |           | CFIT accidents than      |
|                              |           | accidents that occurred  |
|                              |           | with pilots under 50.    |
+------------------------------+-----------+--------------------------+
| [Pilot gender:]{.underline}  | p = 0.008 | Accidents that occurred  |
|                              |           | with male pilots were    |
| male versus female           |           | more likely to be CFIT   |
|                              |           | accidents than accidents |
|                              |           | that occurred with       |
|                              |           | female pilots.           |
+------------------------------+-----------+--------------------------+
| [Pilot flight                | p = 0.018 | Accident with pilots in  |
| time:]{.underline}           |           | the bottom 25% (fewer    |
|                              |           | hours) were more likely  |
| Pilots with more flying time |           | to be CFIT accidents     |
| versus pilots with less      |           | than accidents with      |
| flying time\*                |           | pilots in the upper 25%  |
|                              |           | .                        |
+------------------------------+-----------+--------------------------+
| [Pilot rating:]{.underline}  | p \<      | Accidents that occurred  |
|                              | 0.001     | with IFR rated pilots    |
| VFR rated versus IFR rated   |           | were more likely to be   |
|                              |           | CFIT accidents than      |
|                              |           | accidents that occurred  |
|                              |           | with VFR rated pilots.   |
+------------------------------+-----------+--------------------------+
| [Pilot rating in IMC         | p \<      | Accidents that happened  |
| accidents:]{.underline}      | 0.001     | in IMC with VFR pilots   |
|                              |           | were more likely to be   |
| VFR rated pilots in IMC      |           | CFIT accidents than      |
| versus IFR rated pilots in   |           | accidents in IMC with    |
| IMC                          |           | IFR pilots.              |
+------------------------------+-----------+--------------------------+
| [Number of                   | p \<      | Accidents with multiple  |
| engines:]{.underline}        | 0.001     | engine aircraft were     |
|                              |           | more likely to be CFIT   |
| single engine versus         |           | than accidents with      |
| multi-engine                 |           | single engine aircraft.  |
+------------------------------+-----------+--------------------------+

\* More flying time means pilots' total flight hours ranked in the
highest 25% of flight hours in the NTSB database. Less flying time means
pilots' total flight hours were in the lowest 25% of flight hours in the
NTSB database.

Accidents with older pilots and accidents with multi-engine aircraft
were more likely to be due to CFIT than accidents with younger pilots
and accidents with single engine aircraft. This relationship may be due
to older pilots being more likely than younger pilots to fly
multi-engine aircraft but the statistical relationship between the
number of aircraft engines and pilots' age (table B-4) was not
significant.

**Table B-4. Number of Aircraft Engines Versus Pilot Age for All
Aviation Accidents**

  ------------------------------- --------------- --------------------------
  **Characteristics**             **Chi-Square    **Notes**
                                  probability**   

  single/multi-engines versus     p = 0.657       not significant
  less than/greater than 50 years                 
  old                                             
  ------------------------------- --------------- --------------------------

Using logistic regression, variables significantly related to the
incidence of CFIT accidents, e.g., pilot age, sex, total hours, and
rating, along with weather condition were analyzed. Weather condition
(VMC vs. IMC) and pilot age (\<50 and ò50) most strongly predicted the
incidence of CFIT accidents.

Logistic regressions for pilot age and weather examined the possibility
that the significantly higher percentage of CFIT accidents with older
pilots was due to the higher percentage of older pilots with IFR
ratings, who were therefore, in IMC conditions more frequently. Two
logistic regressions were performed, one with IFR pilots only, and one
with VFR pilots only to see how age and weather condition contribute to
CFIT.

The results of these regressions found that weather condition was
significantly related to incidence of accidents for both IFR and VFR
pilots. However, pilot age was only significantly related to accidents
for IFR-rated pilots. Pilot age is associated with the occurrence of
CFIT-type accidents when the pilot has an IFR rating. The relationship
with age was not established for VFR-rated pilots.

**APPENDIX C - ANALYSIS OF NON-GENERAL AVIATION ACCIDENTS,**

**1983-1994**

![](media/image5.emf)

**Figure C-1. Trend in Non-GA Accidents, 1983-1994**

**Table C-1. All Non-GA Accidents by Year, 1983-1994**

  ----------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- -----------
  Year        1983       1984       1985       1986       1987       1988       1989       1990       1991       1992       1993       1994       Total

  Total       **563**    **548**    **460**    **438**    **446**    **435**    **404**    **380**    **370**    **330**    **334**    **334**    **5,042**
  non-GA                                                                                                                                          
  accidents                                                                                                                                       

  CFIT        **12**     **9**      **14**     **14**     **12**     **9**      **20**     **19**     **12**     **22**     **17**     **10**     **170**
  accidents                                                                                                                                       

  Accidents   **551**    **539**    **446**    **424**    **434**    **426**    **384**    **361**    **358**    **308**    **317**    **324**    **4,872**
  due to                                                                                                                                          
  other                                                                                                                                           
  causes                                                                                                                                          

  \% CFIT     **2.13**   **1.64**   **3.04**   **3.20**   **2.69**   **2.07**   **4.95**   **5.00**   **3.24**   **6.67**   **5.09**   **2.99**   **3.37**
  accidents                                                                                                                                       
  ----------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- -----------

**Table C-2. Non-GA Accidents and Fatalities and
Controlled-Flight-Into-Terrain (CFIT) Accidents and Fatalities by Visual
Condition, Pilot, and Aircraft, 1983-1994\***

![](media/image6.emf)

\* Source: National Transportation Safety Board Database of Factual
Aviation Report Forms.

Includes only airplane and helicopter accidents.

\*\* More flying time means pilots' total flight hours ranked in the
highest 25% if flight hours in the NTSB database.

Less flying time means pilots' total flight hours were in the lowest 25%
of flight hours in the NTSB database.

**Table C-3. Visual Conditions, Pilot Characteristics, and Aircraft
Characteristics and Incidence of CFIT Accidents for Non-GA Accidents**

+------------------------------+-----------+--------------------------+
| **Characteristics**          | **C       | **Notes**                |
|                              | hi-Square |                          |
|                              | prob      |                          |
|                              | ability** |                          |
+------------------------------+-----------+--------------------------+
| [Weather                     | p \<      | Accidents that happened  |
| conditions:]{.underline}     | 0.001     | in IMC were more likely  |
|                              |           | to be CFIT than          |
| VMC conditions versus IMC    |           | accidents in VMC.        |
+------------------------------+-----------+--------------------------+
| [Light                       | p = 0.048 | Accidents that occurred  |
| conditions]{.underline}:     |           | on dark nights were more |
|                              | p \<      | likely to be CFIT than   |
| Night: Bright night versus   | 0.001     | accidents that occurred  |
| dark night                   |           | on clear nights.         |
|                              |           |                          |
| Daylight versus night        |           | Accidents that occurred  |
|                              |           | at night were more       |
|                              |           | likely to be CFIT than   |
|                              |           | accidents that occurred  |
|                              |           | during the day.          |
+------------------------------+-----------+--------------------------+
| [Cloud                       | p \<      | Accidents that occurred  |
| conditions:]{.underline}     | 0.001     | in cloudy conditions     |
|                              |           | were more likely to be   |
| Clear versus overcast        |           | CFIT than accidents that |
|                              |           | occurred in clear or     |
|                              |           | thin overcast            |
|                              |           | conditions.              |
+------------------------------+-----------+--------------------------+
| [Pilot rating:]{.underline}  | p \<      | Accidents that occurred  |
|                              | 0.001     | with IFR rated pilots    |
| VFR rated versus IFR rated   |           | were more likely to be   |
|                              |           | CFIT accidents than      |
|                              |           | accidents that occurred  |
|                              |           | with VFR rated pilots.   |
+------------------------------+-----------+--------------------------+
| [Pilot rating in VMC         | p = 0.050 | Accidents that happened  |
| accidents:]{.underline}      |           | in VMC with IFR pilots   |
|                              |           | were more likely to be   |
| VFR rated pilots in VMC      |           | CFIT accidents than      |
| versus IFR rated pilots in   |           | accidents in VMC with    |
| VMC                          |           | VFR pilots.              |
+------------------------------+-----------+--------------------------+
| [Second pilot                | p = 0.012 | Accidents without a      |
| present?:]{.underline}       |           | second pilot present in  |
|                              |           | the aircraft were more   |
| yes versus no                |           | likely to be CFIT than   |
|                              |           | accidents with a second  |
|                              |           | pilot present.           |
+------------------------------+-----------+--------------------------+
| [Pilot relationship to       | p \<      | Accidents with aircraft  |
| aircraft:]{.underline}       | 0.001     | not owned by the pilot   |
|                              |           | were more likely to be   |
| owner versus non-owner       |           | CFIT than accidents with |
|                              |           | aircraft owned by the    |
|                              |           | pilot.                   |
+------------------------------+-----------+--------------------------+
| [Number of                   | p = 0.004 | Accidents with multiple  |
| engines:]{.underline}        |           | engine aircraft were     |
|                              |           | more likely to be CFIT   |
| single engine versus         |           | than accidents with      |
| multi-engine                 |           | single engine aircraft.  |
+------------------------------+-----------+--------------------------+

\* More flying time means pilots' total flight hours ranked in the
highest 25% of flight hours in the NTSB database. Less flying time means
pilots' total flight hours were in the lowest 25% of flight hours in the
NTSB database.

The statistical relationship between the number of aircraft engines and
pilots' age (\<50 or ò50).

**Table C-4. Number of Aircraft Engines Versus Pilot Age for Non-GA
Accidents**

  ------------------------------- --------------- --------------------------
  **Characteristics**             **Chi-Square    **Notes**
                                  probability**   

  single/multi-engines versus     p \< .01        Accidents with single
  less than/greater than 50 years                 engine aircraft were more
  old                                             likely to be flown by
                                                  pilots over 50 years than
                                                  accidents with multiple
                                                  engine aircraft.
  ------------------------------- --------------- --------------------------

[^1]: Wiener, E. L. (1977). Controlled Flight into Terrain Accidents:
    System-Induced Errors. *Human Factors,* 19(2), 171-181. Wiener
    defines CFIT as, "\...those \[accidents\] in which an aircraft,
    under the control of the crew, is flown into the terrain (or water)
    with no prior awareness on the part of the crew of the impending
    disaster."

[^2]: Khatwa, R., & Roelen, A. L. C. (1996). An Analysis of
    Controlled-flight-into-terrain (CFIT) Accidents of Commercial
    Operators 1988 through 1994. *Flight Safety Digest,* 15(4/5), 1-45.

[^3]: Note: In addition to the analysis of GA accidents, this study
    analyzed all the aviation accidents in the database, which includes
    both GA and non-GA accidents. The results of these analyses are
    presented in Appendix B. Because GA accidents account for 86.7% of
    all aviation accidents, the results of the statistical analyses on
    the encompassing database mirror the results reported for the GA
    accidents.

    The remaining 13.3% of the accidents (non-GA) were also analyzed in
    a similar manner to the other two groups. These results are
    presented in Appendix C. Because this sector of the database is
    defined as being all accidents "other than" GA, there is variability
    in the profiles of pilots and aircraft, producing a slightly
    different picture than the other two analyses.

[^4]: AOPA Air Safety Foundation. (1996). *1996 Nall Report: Accident
    Trends and Factors for 1995.* Frederick, MD.

[^5]: Safety Analysis Division. (1982). *The Influence of Total Flight
    Time, Recent Flight and Age on Class III Pilot Accident Rates* .
    Washington, D.C.: Federal Aviation Administration.

[^6]: Khatwa, R., & Roelen, A. L. C. (1996). An Analysis of
    Controlled-flight-into-terrain (CFIT) Accidents of Commercial
    Operators 1988 through 1994. *Flight Safety Digest,* 15(4/5), 1-45.