DOT/FAA/AM-95/1

Office ofAviation Medicine

Washington, D.C. 20591

A Review of Civil Aviation

Fatal Accidents inWhich

"Lost/Disoriented" Wis a

Cause/Factor: 1981-1990

William E. Collins

Civil Aeromedical Institute

Federal Aviation Administration

Oklahoma City, Oklahoma 73125

January 1995

Final Report

This document is available to the public

through the National Technical Information

Service, Springfield, Virginia 22161.

©

U.S. Department

of Transportation

Federal Aviation

Administration

19950210 071

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NOTICE

This document is disseminated under the sponsorship of

the U.S. Department of Transportation in the interest of

information exchange. The United States Government

assumes no liability for the contents or use thereof.
1. Report No.

DOT/FAA/AM-95/1

2. Government Accession No. 3. Recipient's Catalog No.

4. Title and Subtitle

A Review of Civil Aviation Fatal Accidents in Which

"Lost/Disotiented" Was a Cause/Factor: 1981-1990.

5. Report Date

January 1995

6. Performing Organization Code

7. Author(s)

William E. Collins, Ph.D.

8. Performing Organization Report No.

9. Performing Organization Name and Address

FAA Civil Aeromedical Institute

P.O. Box 25082

Oklahoma City, OK 73125

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

12. Sponsoring Agency name and Address

Office of Aviation Medicine

Federal Aviation Administration

800 Independence Avenue, S.W.

Washington, DC 20591

13. Type of Report and Period Covered

14. Sponsoring Agency Code

15. Supplemental Notes

16. Abstract

The National Transportation Safety Board (NTSB) analyzes circumstances and data from civil aviation accidents

and ascribes one or more causes and/or related factors to help explain each accident. Among the formally accepted

NTSB categories of accident causation is one termed "lost/disoriented;" that term generally differs from "spatial

disorientation" and refers more to a loss of geographic awareness and, perhaps, resulting confusion on the part of the

pilot. The present study was undertaken to provide information regarding the circumstances surrounding these fatal

general aviation accidents in recent years, and to define demographic and behavioral characteristics of the

"lost/disoriented" pilots. Those reports were examined and analyzed in terms of type of accident, age and experience

of pilots, actions of pilots, night or day, and other conditions. The computer search yielded a total of 120 accidents

in which "lost/disoriented" was among the findings rioted by investigators of general aviation accidents for the 10-

year period. Those accidents resulted in 169 fatalities. Related causes and circumstances associated with the

accidents were analyzed and categorized. "Lost/disoriented" accident frequency for the 1981-90 period peaked at 22

fatal accidents in 1985 and declined steadily thereafter. 75% of the pilots had no instrument rating, 64% of the

accidents were associated with adverse weather, and just over half occurred at night. Other analyses suggest that

educational efforts should continue to emphasize proper flight planning and the flight hazards of adverse weather

conditions so that the recently lowered rates of "lost/disoriented" accidents can be maintained or improved.

17. Keywords

Fatal Accidents, Lost/Disoriented,

Spatial Disorientation

18. Distribution Statement

Document is available to the public through the

National Technical Information Service,

Springfield, Virginia 22161.

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

10

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
A REVIEW OF CIVIL AVIATION FATAL ACCIDENTS IN WHICH

"LOST/DISORIENTED" WAS A CAUSE/FACTOR: 1981-1990

INTRODUCTION

The National Transportation SafetyBoard (NTSB)

analyzes circumstances and data from civil aviation

accidents and ascribes one or more causes and/or

related factors to help explain each accident. Among

the formally accepted NTSB categories of accident

findings is one termed "lost/disoriented;" that term

refers to a loss of geographic awareness and, perhaps,

resulting confusion on the part of the pilot. It differs

from "spatial disorientation" which refers to a false

perception ofdistance, attitude, or motion relative to

the plane ofthe earth's surface when a correct perception is necessary for controlling position, attitude, or

motion (6). The present study was undertaken to

provide information regarding the circumstances surrounding fatal general aviation accidents attributed to

"lost/disoriented" conditions in recent years, and to

define some demographic and behavioral characteristics of the "lost/disoriented" pilot.

METHODS

Special requests were made to the National Transportation Safety Board (NTSB) for computer printouts of report briefs of all lost/disoriented accidents

from 1981 through 1990. Although there have been

changes in format and content over time, these briefs

each contain certain standard information regarding

aviation accidents (e.g., statement of cause, nature of

injuries, etc.). Those reports were examined and analyzed in terms oftype of accident, age and experience

of pilots, actions of pilots, night or day, weather, and

other conditions.

RESULTS

Tabulations over the 10-year period (1981-1990)

yielded a total of 120 accidents in which "lost/disoriented" was among the findings noted by investigators

offatal general aviation accidents (see Table 1). In all

but 7 cases, the finding that the "pilot became lost/

TABLE 1. Fatal Lost/Disoriented General Aviation Accidents

by Cause/Factor and Type ofInjury

Injuries (Fatal. Serious/Minor)

Attribution Pilots Passenge

Fatal

rs

Year Cause Factor Find ing Only Fatal S/M S/M

1981 12 0 0 11 1 14 0

1982 6 4 0 9 1* 10 0

1983 14 5 0 19 0 18 1

1984 10 2 1 12 1 14 1

1985 13 8 1 22 1* 20 0

1986 11 6 0 16 1 15 2

1987 7 5 0 13 0 19 0

1988 6 3 0 9 0 7 1

1989 0 0 3 3 0 3 1

1990 0 1 2 3 0 3 0

Totals 79 34 117 123

Minor
TABLE 2. Fatal Lost/Disoriented General Aviation Accidents, 1981-90, by Time (Day vs. Night)

and Weather (Instrument vs. Visual Meteorological Conditions)

and the Number ofInstrument Rated Pilots Involved

Instrument

Fatal

Accidents

Time YVeath«er Rated

Year Day Night IMC VMC Pilots

1981 12 5 7 5 7 0

1982 10 5 5 6 4 3

1983 19 11 8 11 8 2

1984 13 7 6 10 3 4

1985 22 14 8 13 9 7

1986 17 3 14 9 8 9

1987 12 7 5 5 7 5

1988 9 3 6 7 2 5

1989 3 0 3 2 1 0

1990 3 1 2 2 1 2

Totals 120 56 64 70 50 30

TABLE 3. Fatal Lost/Disoriented General Aviation Accidents in Which Flight into Instrument

Meteorological Conditions (IMC) Was Also a Cause/Factor

Fatal

Accidents

Flight Into IMC

Year Initiated Continued Inadvertent

1981 12 2 3 0

1982 10 3 4 1

1983 19 7 2 2

1984 13 6 2 0

1985 22 7 2 1

1986 17 5 4 2

1987 12 2 3 2

1988 9 5 1 0

1989 3 0 1 0

1990 3 0 1 1

Totals 120 37 23 9

TABLE 4. The Involvement of Pilots With and Without Instrument Ratings in

Fatal Lost/Disoriented General Aviation Accidents Involving

Visual vs. Instrument Meteorological Conditions

Instrument No.

Pilots

Accident Condition

VMC IMC

Find ngs: IMC Conditions

Rating Initiated Continued Inadvertent

Yes

No

Totals

30

90

120

12

38

50

18

52

70

7

30

37

2 1

21 8

23 9
TABLE 5. Age Groupings ofPilots in Fatal Lost/Disoriented

General Aviation Accidents, 1981-90

Age (in years)

Year <25 25-34 35-44 45-54 55-64 65+ Totals

1981 3 1 5 2 1 0 12

1982 0 3 2 1 2 2 10

1983 1 2 5 8 2 1 19

1984 0 5 3 3 2 0 13

1985 1 6 6 4 5 0 22

1986 1 4 6 3 3 0 17

1987 0 1 2 4 4 1 12

1988 0 2 2 2 1 2 9

1989 0 0 1 0 1 1 3

1990 0 0 0 2 0 1 3

Totals 6 24 32 29 21 8 120

disoriented" was later cited as one of the causes or

factors in the resulting accident. Two ofthe 7 exceptions included a case (1984) in which the accident was

attributed to pilot incapacitation due to carbon monoxide exposure and a case (1985) in which the aircraft

broke up in flight; both cases were retained in the

tabulations. Also retained were the 5 other exceptions

(all occurred in 1989 and 1990); for these cases, the

NTSB "causes" were listed but "factors" were not.

Ofthe remaining 113 cases, "lost/disoriented" was

considered one ofthe causes of79 ofthe accidents and

as one of the factors in the remaining 34 cases. The

120 accidents, each of which resulted in at least one

fatality, yielded a total of 240 deaths (117 pilots and

123 passengers), 9 serious injuries, and 2 minor injuries.

Just over half of the 120 accidents (53.3%) occurred at night (Table 2); and 58.3% of all accidents

were associated with instrument meteorological conditions (IMC), but only 25% ofthe pilots had instrument ratings. Although 70 of the accidents were

designated as having occurred in IMC, various types

ofinclement weather (including haze) were present in

77 cases; in 3 other accidents, low ceilings (twice) and

heavy clouds with turbulence were noted. All of the

latter 3 occurred in daytime accidents along with 10

cases each ofrain and ofsnow, 9 offog, 3 ofhaze, and

9 accidents with combinations of those conditions.

Ofthe 64 nighttime accidents, fog was present in 10,

rain in 6, snow in 4, haze in 1, and various combinations ofinclement weather in 15 cases. Where weather

was not an issue in nighttime accidents, only 1 case

noted a "bright night;" all 27 others noted a "dark

night."

That pilots initiated, continued, or inadvertently

encountered flight into IMC was cited in 68 ofthe case

reports (Table 3). However, the influence of these

conditions is understated; for example, in some cases,

instrument rated pilots who initiated flights into inclement weather were not cited for that condition but,

rather, for poor planning/decisions. Table 4 shows the

involvement of instrument rated and noninstrument

rated pilots in visual meteorological conditions (VMC)

and IMC and the number of cases that cited inadvertent or intentional flight into IMC. Interestingly, the

proportions of accidents for the two pilot groups in

VMC and in IMC are almost identical to the ratio of

instrument to noninstrument rated pilots in the study

(i.e., about 3:1). A major difference is in the contribution to the accident of inadvertent encounters with

unfavorable weather - 8 of those 9 cases involved

noninstrument rated pilots. Moreover, over five times

as many noninstrument rated vs. instrument rated

pilots were cited for initiating or continuing flightinto

IMC.

The age of pilots involved in lost/disoriented fatal

accidents ranged from 17-78 years. A distribution of

accidents by age categories (Table 5) indicates very
TABLE 6. Total Flying Time Logged by Pilots in Fatal Lost/Disoriented

General Aviation Accidents, 1981-90

Total Hours Logged Flying Time

Year <100 100-199 200-499 500+ ? Totals

1981 4 3 3 2 0 12

1982 0 4 0 5 1 10

1983 3 3 5 6 2 19

1984 2 3 1 6 1 13

1985 2 2 6 12 0 22

1986 3 5 2 5 2 17

1987 0 2 1 9 0 12

1988 0 1 2 6 0 9

1989 0 0 1 2 0 3

1990 0 0 1 2 0 3

Totals 14 23 22 55 6 120

TABLE 7. Total Hours in Aircraft Type Logged by Pilots in Fatal

Lost/Disoriented General Aviation Accidents, 1981-90

Total Hours in Type

Year <25 25-49 50-99 100+ ? Totals

1981 3 4 2 3 0 12

1982 0 2 1 3 4 10

1983 4 1 2 4 8 19

1984 2 2 3 5 1 13

1985 2 1 4 9 6 22

1986 2 1 4 3 7 17

1987 1 0 2 4 5 12

1988 0 0 0 6 3 9

1989 1 0 1 0 1 3

1990 0 0 0 2 1 3

Totals 15 11 19 39 36 120

TABLE 8. Categories of Pilot Certificates and Altered States ofPilots Involved in Fatal Lost/

Disoriented General Aviation Accidents, 1981-90

Fatal

Accidents

Other Than Private Pilots

Year ATP Commercial Student Pilots in Altered States

1981

1982

1983

1984

1985

1986

1987

12

10

19

13

22

17

12

0

0

0

0

0

0

0

1

1

1

3

1.

2

4

1

0

1

2

1

2

1

1 (Cocaine, Amyl Nitrite)

1 (Alcohol)

2 (Alcohol)

1 (Carbon Monoxide)

2 (1-Alcohol, 1-Medication)

2 (Medication)

0

1988 9 1 2 0 0

1989 3 0 1 0 0

1990 3 0 2 0 0

Totals 120 1 18 8 9
TABLE 9. The Number ofUncontrolled Descents and the Involvement of Spatial Disorientation

in Fatal Lost/Disoriented General Aviation Accidents, 1981-90

Fatal Descent Spatial Disorientation

Year Accidents Controlled Uncontrolled Cause Factor ?

1981 12 7 5 3 0 0

1982 10 7 3 1 1 0

1983 19 12 7 2 0 3

1984 13 6 7 0 0 2

1985 22 6 16 4 1 4

1986 17 4 13 1 1 2

1987 12 3 9 3 2 2

1988 9 6 3 0 2 0

1989 3 3 0 0 0 0

1990 3 2 1 1 0 0

Totals 120 56 64 15 7 13

small proportions at the lowest (< age 25) and highest

(65+) age brackets. Most of the pilots involved in

those accidents were betweerf 35-55 years of age with

a mean age of 44.7 years; the mean age for all second

class and third class airmen during that 10-year period

ranged from about 37-39 years (1,2). Moreover, nearly

half(45%) ofthe pilots had 500 or more hours oftotal

logged flying time and an additional 18% had between 200-499 hours of flying experience (Table 6).

Data on "hours in type," i.e., in the type of aircraft

that was involved in the accident, are less clear due to

the fact that those data were not available in 30% of

the cases (Table 7). However, of the remaining 84

cases, just over 46% (N=39) of pilots were credited

with 100 or more hours in type (Table 7).

Table 8 shows the number of pilots who held other

than private certificates at the time of the accidents

and the number of pilots who were flying under

"altered state" conditions (e.g., alcohol). Only 8 ofthe

pilots were classified as students; their ages ranged

from 17-51 years. Only 1 pilot held an air transport

rating while 18 others held commercial certificates; all

19 of these pilots were instrument rated. Nine pilots

(none ofwhom were students) were in "altered states"

during the accident; toxicological studies indicated

that 4 had notable blood alcohol levels (0.038%,

0.054%, 0.124%, and 0.171%), 3 had used medications (Tenormin and Librium; Valium and Darvon;

and an unidentified barbiturate), one had used cocaine and "amyl nitrate" (sic; probably amyl nitrite),

and one suffered from carbon monoxide exposure

during flight (the pilot and his 3 passengers had CO

levels ranging from 22-44%).

Spatial disorientation (Table 9) was considered to

be a cause (N=15) or a factor (N=7) in 22 ofthe 120

cases. However, there were at least 13 more cases

where the described circumstances of the accidents

seemed to suggest very strongly that spatial disorientation was involved. Of these 35 total cases only 9

pilots were instrument rated. Moreover, the substantial number of"uncontrolled descents" noted in Table

8 suggest additional possibilities for involvement of

spatial disorientation; the available data for many of

these accidents are insufficient to draw firmer conclusions.

DISCUSSION

The number of fatal accidents attributed to the

pilots' becoming lost/disoriented has declined steadily

since 1985. This decline reflects, to some degree, both

the steady improvement in general aviation accident

statistics (Table 10) and recessionary economic conditions that may have contributed to the reduction in

the number of active pilots and the number of hours

flown; with respect to the latter, the number declined

from 36.8 million hours in 1981 to 30.8 million in
TABLE 10. The Numbers ofActive Airmen, Airmen With Instrument Ratings,

Overall Aviation Accidents, and Fatal Accidents, 1981-90

No. No. No.

Active Instrument No. Fatal

Year Airmen Ratings Accidents Accidents

1981 764,182 252,535 3,500 654

1982 733,266 256,073 3,233 591

1983 718,004 254,271 3,075 555

1984 722,376 256,584 3,011 543

1985 709,640 258,559 2,737 497

1986 709,118 262,388 2,576 473

1987 699,663 266,122 2,464 431

1988 694,016 273,804 2,369 434

1989 700,010 282,804 2,216 424

1990 702,659 297,073 2,187 435

1990 (5). Another influence for improvement maybe

the FAA's Accident Prevention Program and the Pilot

Proficiency Award Program (Wings) (3) which have

recorded increasing participation by pilots in recent

years. Of particular relevance are the "Back to

Basics" seminars introduced in 1986 as part of the

Accident Prevention Program; these seminars specifically address the 12 most prevalent causal factors in aviation accidents.

Table 10 also indicates substantial growth in the

number ofpilots with instrument ratings, and in their

proportion relative to the total number ofactive pilots

(4,5). While that growth is highly desirable, it is also

reflective of changes in the airman population. Specifically, while the total number of active airmen has

been declining over the past decade, the number of air

transport pilots (ATPs) has been increasing. Since all

ATPs have instrument ratings, the proportion of

private pilots with instrument ratings is not as high as

might be inferred from Table 10 data. By correcting

for ATPs, the proportions of "other than ATPs" with

instrument ratings increased from 27% in 1981 to

32% in 1990. That increase may also represent a

contribution to reduced general aviation accidents.

It is clear that there is not a simple, definitive,

biodemographic description of pilots who become

lost and geographically disoriented as part of a sequence of events that leads to a fatal accident. Over

the 10-year period of this study, the average age of

pilots who were involved in fatal lost/disoriented

accidents was 6-7 years older than the average age of

all pilots who did not hold air transport (ATP) ratings.

With regard to experience, 46% ofthe deceased pilots

had 500 or more hours of total flying time and only

14% had less than 100 hours. Although there was

considerable (30%) missing data for tabulating "hours

in type" of the aircraft involved in the accident, the

category with the largest representation was that of

"100+ hours."

However, common to many ofthe lost/disoriented

accidents are concepts associated with planning, judgment, and decision making. Although the cited findings regarding these accidents do not always trace a

consistent path, the fact that pilots without instrument ratings make decisions to initiate or continue

flight into adverse weather or that instrument-rated

pilots disregard weather briefings or advice, or that

flights are initiated without weather briefings or flight

plans support the need for targeted training such as

that in the FAA's "Back to Basics" and "Back to Basics

II" programs regarding the importance offlight planning and decision making, and the recognition of

individuallimitations. Related to this notion ofproper

preparation is the advisability for general aviation

pilots to have a reasonable idea of the terrain along

their proposed routes and particularly within some

significant radius ofthe destination airport to reduce

the possibility that a "lost" pilot might cruise into

elevated terrain while seeking to locate a nearby airport.
However, the "lost/disoriented" pilot is often faced

with the additional problem ofspatial disorientation.

The 22 cases in which spatial disorientation is attributed as a cause or factor by the NTSB represents 18%

of the "lost/disoriented" accidents; if the 13 additional (circumstantial) cases noted by the author are

included, the proportion reaches 29%. Itis important

for general aviation pilots to recognize that becoming

lost or geographically disoriented is only part of the

problem and that dark nights and unfamiliar routes

can hold potent hazards related to spatial disorientation irrespective of clear weather. An indistinguishable horizon, especially on a dark night, effectively

constitutes IMC for the pilot even if the weather is

VMC.

And finally—and particularly related to spatial

disorientation—good instrument skills are essential

to many adverse conditions encountered in flight.

CONCLUSION

Fatal general aviation accidents from 1981-90 that

include findings ofpilots becoming "lost/disoriented"

have declined markedly since peaking in number

during 1985. The decline is coincident with the

decline in number of all fatal general aviation accidents and may be attributable both to economic

conditions affecting the aviation community and to

the success of FAA safety programs.

Neither age, general experience, nor student status

appears to define characteristics ofpilots who become

involved in fatal "lost/disoriented" accidents. However, some lack ofgeographic knowledge ofthe route

and destination airport, limited or no instrument

skills, poor or incomplete flight planning, and poor or

questionable judgment regarding the advisability of

initiating or continuing a flight into adverse conditions seem to characterize many of these accidents.

Continued emphasis in safety and training programs

regarding proper flight planning and the flight hazards of adverse weather conditions will be needed to

maintain or improve these lowered rates of "lost/

disoriented" and related spatial disorientation accidents.

REFERENCES

1. Department ofTransportation, Federal Aviation Administration, 1992. Aeromedical Certification Statistical Handbook, 1992. Civil Aeromedical Institute, Oklahoma City, OK.

2. Department ofTransportation, Federal Aviation Administration, 1981. Aeromedical Certification Statistical Handbook, 1981. Civil Aeromedical Institute, Oklahoma City, OK.

3. Department ofTransportation, Federal Aviation Administration, 1991. Pilot Proficiency Award Program, Advisory Circular No. 61-91F, (AFS-20),

March 6 1991, Washington, D.C.

4. Department ofTransportation, Federal Aviation Administration. U.S. Civil Airmen Statistics: Calendar Year 1981. Washington, D.C.

5. Department ofTransportation, Federal Aviation Administration. U.S. Civil Airmen Statistics: Calendar Year 1991. Washington, D.C.

6. Gillingham, K.K. and J.W. Wolfe. 1985. Spatial

orientation in flight. USAFSAM-TR-85-31. USAF

School ofAerospace Medicine, Brooks, AFB, TX.

£U.S. GOVERNMENT PRINTING OFFICE: 1995 - C60-067/Ö0069