In-Flight Medical Incapacitation 

and Impairment of U.S. Airline 

Pilots: 1993 to 1998

Charles A. DeJohn 1

Alex M. Wolbrink 2

Julie G. Larcher 1

1

Civil Aerospace Medical Institute

Oklahoma City, OK 73125

2

American Airlines

Dallas Fort Worth Airport, TX 75261

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

October 2004

Final Report

This document is available to the public

through the National Technical Information

Service, Springfield, Virginia 22161.

 

Office of Aerospace Medicine

Washington, DC 20591

DOT/FAA/AM-04/16
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 thereof.
i

Technical Report Documentation Page 

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

DOT/FAA/AM-04/16 

4. Title and Subtitle 5. Report Date 

In-Flight Medical Incapacitation and Impairment of U.S. Airline Pilots: October 2004 

1993 to 1998 

6. Performing Organization Code 

 

7. Author(s) 8. Performing Organization Report No. 

DeJohn CA1, Wolbrink AM2, Larcher JG1

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

1

FAA Civil Aerospace Medical Institute 

P.O. Box 25082 

Oklahoma City, OK 73125 

2

American Airlines 

Dallas Fort Worth 

Airport, TX 7526

11. Contract or Grant No. 

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered 

Office of Aerospace Medicine 

Federal Aviation Administration 14. Sponsoring Agency Code 

800 Independence Ave., S.W. 

Washington, DC 20591 

15. Supplemental Notes 

16. Abstract 

Although it is not known when the first accident due to pilot in-flight medical incapacitation occurred, a 

recent survey showed that almost one-third of all pilots who responded had experienced an incapacitation 

requiring another crewmember to take over their duties, with safety of flight significantly threatened in 3% of 

cases. The importance of in-flight medical incapacitation and impairment can be better understood when it is 

realized that each in-flight medical incapacitation or impairment could potentially lead to an aircraft accident. 

We studied in-flight medical incapacitations and impairments in U.S. airline pilots from 1993 through 1998. 

We defined in-flight medical incapacitation as a condition in which a flight crewmember was unable to 

perform any flight duties and impairment as a condition in which a crewmember could perform limited flight 

duties, even though performance may have been degraded. We found 39 incapacitations and 11 impairments 

aboard 47 aircraft during the six-year period. All pilots were males. The average age for incapacitations was 

47.0 years (range 25 to 59 years). The average age for impairments was 43.3 years (range 27 to 57 years). The 

in-flight medical event rate was 0.058 per 100,000 flight hours. The probability that an in-flight medical event 

would result in an aircraft accident was 0.04. Incapacitations significantly increased with age, with more 

serious categories in the older age groups. The most frequent categories of incapacitation were loss of 

consciousness, cardiac, neurological, and gastrointestinal. Safety of flight was seriously impacted in seven of the 

47 flights and resulted in two non-fatal accidents. 

17. Key Words 18. Distribution Statement 

Incapacitation, Impairment, Aircraft Accidents, 

Diversions

Document is available to the public through the 

National Technical Information Service, 

Springfield, Virginia 22161 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 

Unclassified Unclassified 30

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 

iii

ACKNOWLEDGMENTS

We gratefully acknowledge Connie Peterman of AdvanciaTM for her technical support as the programmer for the Civil Aerospace Medical Institute Incapacitation Database and the hours spent in preparing and executing the many 

queries necessary to extract the data used in preparing this paper.

v

TABLE OF CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

In-Flight Medical Event Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Career Termination Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Simulator Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Questionnaire Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Epidemiological Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Summary of Incapacitation Study Methodologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Frequency and Rate of In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Probability of an Accident Due to an In-Flight Medical Event. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Age and Gender Distribution of In-Flight Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Categories of In-Flight Medical Incapacitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Categories of In-Flight Medical Impairments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Fatal In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Safety of Flight and In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

In-Flight Medical Events and Similar Medical Histories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Diversions Resulting From In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Aeromedical Certification Actions Resulting From In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . . 8

DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Frequency and Rate of In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Probability of an Accident Due to an In-Flight Medical Event. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Age Distribution of In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Categories of In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Fatal In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Safety of Flight and In-Flight Medical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

In-Flight Medical Events and Similar Medical Histories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Diversions Resulting From In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Aeromedical Certification Actions Resulting From In-Flight Medical Events. . . . . . . . . . . . . . . . . . . . . . 12

CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

APPENDIX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

1

IN-FLIGHT MEDICAL INCAPACITATION AND IMPAIRMENT

OF U.S. AIRLINE PILOTS: 1993 TO 1998

INTRODUCTION

The first fatal aircraft accident occurred in 1909, and 

by the end of 1910 there were 38 aviation fatalities. For 

some time, it was believed the first accidents attributed 

to pilot in-flight medical incapacitation occurred in 

1911; however, after reviewing these cases, Parmet and 

Underwood-Ground (28) believed that they were the 

result of pilot error. Therefore, the date of the first aircraft 

accident attributed to pilot in-flight medical incapacitation is still unknown. 

Over the years there have been many studies of airline 

pilot medical incapacitation (4, 6, 8, 19, 23, 24, 29, 30). 

Most studies can be classified as either direct studies of inflight medical events, career termination studies, simulator 

studies, questionnaire studies, or epidemiological studies. 

In addition, Li (22) recently performed a comprehensive 

review of pilot-related factors in aircraft accidents. 

In-Flight Medical Event Studies

In 1969, Buley (4) summarized three sets of airline pilot 

incapacitation data. First, he reported on the progress of 

a collaborative study initiated by the International Civil 

Aviation Organization (ICAO) and performed by the 

International Federation of Air Line Pilots Associations 

(IFALPA) and the International Air Transport Association 

(IATA). Buley examined in-flight deaths of airline pilots 

between 1961 and 1968. He found 17 reported cases 

of airline pilot deaths, all resulting from heart disease. 

Five of the 17 cases ended in aircraft accidents, four of 

which were fatal, resulting in 148 fatalities. Another five 

cases nearly resulted in accidents. Of the 17 events, seven 

occurred on the ramp, five while enroute, four during 

approach, and one during landing roll-out. Buley next 

reviewed 42 cases of non-fatal in-flight incapacitation 

in pilots of IATA-member airlines between 1960 and 

1966. In 24 of the 42 cases, causal organic disease was 

diagnosed. The most common categories of incapacitation 

were epileptiform manifestations (6), coronary occlusions 

(4), and renal/ureteric colic (4). 

In 1975, Raboutet and Raboutet (30) reviewed 17 

incidents of sudden incapacitation in French professional 

civil pilots between 1948 and 1972. They found five cases 

of myocardial infarction, three cases of angina pectoris, 

two cases of ischemic heart disease, two cases of epileptic seizures, and one case each of diabetes, pulmonary 

embolism, cerebral vascular accident, atrial fibrillation, 

and intestinal hemorrhage of unknown etiology. Fortunately, none of the cases resulted in aircraft accidents 

or the death of the pilot, and only two cases resulted in 

the complete incapacitation of the pilot due to epileptic 

seizures. Raboutet and Raboutet stated that for an incapacitation accident to occur, the incapacity must: (1) 

affect the pilot at the controls, (2) be sudden, (3) be total, 

and (4) take place during a critical phase of flight. 

Chapman reviewed IATA data and found 208 in-flight 

medical incapacitations between 1965 and 1977, which 

included 13 cardiac cases, or one cardiac incapacitation 

per year. He calculated the probability of an accident 

due to cardiac incapacitation to be about 10-10, assuming: (1) one accident per 400 incapacitations (i.e., one 

accident every 400 years), (2) 600 flying hours per pilot 

per year, and (3) subtle incapacitation during a critical 

phase of flight (7). 

Martin-Saint-Laurent and associates (23) found ten 

cases of sudden in-flight incapacitation out of a population of 1,800 Air France pilots and flight engineers from 

1968 to 1988. The most common causes of in-flight 

incapacitation were cardiac arrhythmias (2) and epileptic 

seizures (2). Two out of the ten flights diverted. The two 

pilots who suffered epileptic seizures and one pilot from 

the arrhythmia group who had an in-flight episode of 

atrial fibrillation (followed by a cerebral vascular accident 

with hemiparetic and epileptic seizure on the ground following the flight) were all permanently grounded. Five 

others were temporarily grounded. No action was taken 

against one pilot who experienced hypoxia and another 

who experienced CO2 intoxication. 

Career Termination Studies

Preston (29) followed 1,000 United Kingdom airline 

pilots and found that 73 were permanently grounded 

for medical causes between 1954 and 1965. Of the 73 

pilots, the most common causes for loss of employment 

were psychiatric (36), cardiovascular (8), respiratory (6), 

and diabetes (4). Preston attributed the low incidence of 

cardiovascular groundings to possible Anglo-Saxon racial 

differences between this group of pilots and other pilots, 

and the high incidence of psychiatric groundings to poor 

pilot selection procedures. 
2 

Lane (21) examined IATA loss of license insurance data 

and estimated the overall in-flight incidence of in-flight 

incapacitation to be 0.06 per 1,000 pilots per year. 

Kulak, Wick, and Billings (20) performed a similar 

study of career termination due to loss of licensure insurance in members of the U.S. Airline Pilots Association 

from 1955 through 1966. They found 891 cases of career 

termination: 229 due to accidents and 662 the result of 

disease. The rate of death and disability due to accidents 

was 2.07 per 1000 pilots per year, while the rate for disease 

was 8.05 per 1000 pilots per year. Although the overall 

rate for cardiovascular disease was only 2.91 per 1000 

pilots per year, the age specific rate ranged from zero for 

pilots under 30 years of age to 27.33 for pilots between 

55 and 58 years of age. Flying accidents accounted for the 

majority of career terminations for all age groups. Using 

the incapacitation incidence rates for termination due to 

disease by age and the age distribution of active ALPA 

pilots, the authors estimated the probability of serious inflight incapacitation by age. Their estimates ranged from 

1 per 58,000 pilots for the 30-to 34 -year age group to 1 

per 3,500 pilots for the 55-to 59- year age group. 

Simulator Studies

Harper, Kidera and Cullen performed two simulator 

studies, one dealing with obvious and maximal loss of 

function (14), and the other with subtle or partial loss 

of function (13). Although operationally interesting, 

discoveries were made. For example, the mean time to 

detect subtle incapacitation was 1.5 minutes, and 25% 

of the simulator sessions ended in “aircraft accidents” 

(13). The studies, however, were not designed to address 

medical causes of in-flight incapacitation. 

Chapman (7) analyzed more than 1,300 simulator 

exercises in which the subtle incapacitation of the flying 

pilot was programmed to occur at a critical phase of flight. 

Two protocols were used. The first involved 500 exercises 

where major aircraft system failures were simulated as 

part of the drill. In 485 of the 500 cases, it was determined there would not have been any danger to an actual 

aircraft. In 15 cases, it was believed that safety of flight 

would have been at risk. In eight cases, it was considered 

that aircraft accidents would have resulted. The second 

protocol involved 800 exercises without simultaneous 

aircraft system failures. In this series, only ten out of the 

800 were felt to have represented a risk to safety of flight, 

and in two cases, the observers felt that an aircraft accident 

would have resulted. Again, these studies did not address 

medical causes of in-flight incapacitation.

There are inherent problems when simulator results 

are used to predict in-flight outcomes. Crews that 

“crashed” in the Harper, Kidera, and Cullen (13) study, 

for example, stated, “We wouldn’t let it happen in a real 

airplane.” Also, in addition to the obvious difficulty of 

attempting to predict possible in-flight outcomes from 

simulated data in the Chapman study, there was the 

added drawback of foreknowledge by the subjects, since 

they knew there would be an incapacitation at some time 

during each drill. 

Questionnaire Studies

Buley (4) reviewed the results of a questionnaire administered to pilots of IFALPA-member associations in 

1967, in which 27% of approximately 5000 respondents 

reported about 2,000 incidents of significant in-flight 

incapacitation. Safety of flight was affected in 4% of 

cases. Almost one-half of reported incapacitations occurred in the enroute phase of flight. Unfortunately, 

the IFALPA questionnaire was administered to actively 

flying airline pilots; therefore, pilots with more serious 

medical conditions, who may have suffered more severe 

types of incapacitation, had been previously eliminated 

and were not part of the study. This skewed the data by 

eliminating the potential for reporting more serious medical conditions while including the less serious conditions 

reported by actively flying pilots. In addition, most of the 

conditions addressed in the questionnaire were temporary 

in nature and would usually result in pilot impairment 

(i.e., nausea, vomiting, indigestion, etc.) rather than total incapacitation and would not likely be addressed by 

medical certification. 

In 1971, Lane (21) updated the 1967 IFALPA questionnaire data, analyzed by Buley (4), with IATA data for 

1962 through 1968 that was provided to ICAO. Lane 

added 51 additional, non-accident cases to Buley’s original 17 cases, for a total of 68 cases. He then calculated 

the probability of an incapacitating event resulting in an 

accident would be 5/68, or 0.074.

In 1991, James and Green (19) replicated Lane’s 

1967 IFALPA survey with similar results. Of 1,251 

respondents, 29% reported at least one incident of inflight incapacitation severe enough to require another 

crewmember to assume their duties. The most common 

causes of incapacitation were gastrointestinal (58.4%), 

earache due to a blocked ear (13.9%), and faintness or 

general weakness (8.5%). The most common phases 

of flight where incapacitations occurred were enroute 

(42.1%), followed by climb (18.4%), descent (17.3%), 

and on the ramp (11.4%). Safety of flight was felt to 

be potentially affected in 45% of cases and definitely 

affected in 3% of cases. Of those reporting that safety of 

flight had been affected, 43% stated the incapacitation 

event placed the remaining aircrew under maximum 

workload. As with the 1967 Buley study, the questionnaire was administered to actively flying airline pilots, 

again eliminating the potential for reporting more 
3

serious medical conditions. In addition, the study did 

not provide incapacitation rates which would allow for 

comparison with similar studies.

Epidemiological Studies

Castello-Branco and associates (6) found 13 deaths and 

eight medical incapacitations in a longitudinal evaluation 

of deaths and disease in 408 active Portuguese airline pilots 

between 1945 and 1983. The most common causes of 

death were accidents, myocardial infarcts, and cancer. By 

relating the number of deaths and incapacitations with 

the number of pilots at risk, they calculated incidence 

rates by age group. Death and incapacitation rates ranged 

from zero per 100 pilots at risk for the 20 to 24 year age 

group, to 3.64 per 100 pilots at risk for the 55 to 59 year 

age group. Although this is an excellent longitudinal study 

of airline pilots for an extended period and provides valuable insight into causes of death and disease, it does not 

directly reflect causes of in-flight incapacitation.

Summary of Incapacitation Study Methodologies

Most previous studies we reviewed did not use data 

from actual in-flight medical events. Instead, indirect 

measures, such as career termination due to permanent 

medical grounding or loss of licensure insurance data and 

general epidemiological data, were used to approximate 

the frequency of in-flight medical events. These studies 

provided information on the frequency and categories of 

in-flight medical events; however, they did not include 

incapacitation rates, making meaningful comparison 

between studies difficult. Although in-flight medical 

incapacitation rates can be inferred, these data are not 

directly based on in-flight medical events. 

The objective of this study was to provide incapacitation 

rates that could be easily compared with similar studies 

of in-flight medical incapacitation.

METHODS

Details of aircrew in-flight medical events aboard U.S. 

airlines between 1993 and 1998 were collected by the 

Federal Aviation Administration (FAA), Civil Aerospace 

Medical Institute’s (CAMI’s), Aerospace Medical Research 

Team (AMRT) and stored in a Microsoft Access 2000®

Database (Version 9.0). The official method of case notification was through the use of a Medical Case Alert 

Form (Appendix A, Table A-1); however, many cases 

were discovered through the FAA Administrator’s Daily 

Bulletin, telephone calls, news media, periodic searches 

of the National Transportation Safety Board (NTSB) and 

FAA accident databases, and direct interaction between 

the CAMI and the NTSB. 

Event data included incident, operational, pilot, and 

final disposition information. Incident information included a brief narrative and/or full report of the event 

when available, including injuries and/or fatalities. Operational information included the date, time, location, 

type of operation, accident or incident classification, phase 

of flight, airline, flight number, aircraft number, type of 

aircraft, origin, destination, and diversion details. Pilot 

information included the pilot’s name, social security 

number, age, gender, class of medical certificate, pilot 

certificate number, FAA medical history, aircrew position, occupation, and employer. NTSB numbers were 

recorded, and a unique CAMI Incapacitation Database 

number was also assigned to each case. The authors 

could not independently verify the validity of much of 

the information collected from sources outside of CAMI, 

including aircrew statements, airline records, and hospital 

records, etc. In most cases, this information had to be 

accepted without confirmation.

Cases were reviewed by the authors and classified as 

either an “impairment” or “incapacitation.” Individuals 

were classified as impaired when they could still perform 

limited in-flight duties, such as read checklists or perform 

radio communications, even though their performances 

may have been degraded. Examples of impairments include food poisoning, the use of monovision contact 

lenses, fatigue, and kidney stones. Individuals were considered incapacitated when they could no longer perform 

any in-flight duties. Examples of incapacitation include 

heart attacks and epileptic seizures. 

Cases were also classified as “possible,” “probable,” or 

“certain” depending on the degree of confidence in the 

supporting evidence. For airline events, the other aircrew 

members were witnesses to the occurrence, and reports 

were required by the airline. In addition, in cases serious 

enough to require further evaluation and treatment, the 

hospital record provided additional confirmation. 

Each case was also assigned to one of several broad 

medical categories. Incapacitation categories included loss 

of consciousness, cardiac, neurological, gastrointestinal, 

urological, vascular, medication, hypoxia, decompression 

sickness, and injury. Impairment categories included 

respiratory, cardiac, gastrointestinal, infectious disease, 

vision, and reaction to medication.

RESULTS

Frequency and Rate of In-Flight Medical Events

We found 39 incapacitations and 11 impairments of 

U.S. airline pilots on 47 flights during the period 1993 to 

1998 (More than one pilot was affected on three flights. 

See Table A-2, Case Summaries, in Appendix A.). During 
4 

this period, U.S. airlines flew a total of 85,732,000 revenue 

passengers hours (26); therefore, the rate of in-flight incapacitations and impairments was 0.04549 per 100,000 

hours (95% CI 0.04545, 0.04553) and 0.01283 per 

100,000 hours (95% CI 0.01281, 0.01285), respectively. 

A summary of the in-flight medical events is contained 

in Appendix A, Table A-2.

Probability of an Accident Due to an In-Flight 

Medical Event

There were two non-fatal aircraft accidents due to 

the in-flight medical impairment of the pilots. One was 

caused by the pilot’s visual impairment due to the use 

of monovision contact lenses during an approach. The 

other was caused by flight crew fatigue. Combining the 

39 incapacitations and 11 impairments gives 50 in-flight 

medical events on 47 flights; therefore, the probability 

that an in-flight medical event would be associated with 

an accident was 2 out of 50 events, or 0.04. 

There were 54,295,899 flights and 217 accidents 

involving U.S. Part 121 scheduled and non-scheduled 

airlines between 1993 and 1998 (25, 27). The probability 

of an aircraft accident for a pilot experiencing an in-flight 

medical event is summarized in Table 1.

The “law of rare events” states that the total number of 

events of interest will assume (approximately) the Poisson 

distribution if: (a) the event may occur in any of a large 

number of trials, but (b) the probability of occurrence in 

any given trial is small. Examples of events that follow a 

Poisson distribution are doctor visits, absenteeism in the 

workplace, mortgage pre-payments, loan defaults, bank 

failures, insurance claims, and aircraft accidents (5). Assuming that accidents involving pilot in-flight medical 

events can be described using a Poisson distribution, 

there is a statistically significant difference between the 

proportion of accidents given an in-flight medical event, 

compared with the proportion of accidents in the absence 

of such an event (z = 3.08, p < 0.001).

Age and Gender Distribution of In-Flight Medical 

Events

All pilots who had an in-flight event were males. The 

average age for incapacitations was 47.0 years (range 25 

to 59 years) while the average age for impairments was 

43.3 years (range 27 to 57 years). Figure 1 shows the age 

distribution for the percentage of U.S. airline pilots having in-flight incapacitations and impairments between 

1993 and 1998 based on the average age distribution for 

professional pilots (from a recent FAA 

study; Appendix A, Fig. A-1) (3).

Examination of Figure 1 suggests 

an increase in in-flight medical incapacitations with increasing U.S. airline 

pilot age.

Table 1. The Probability of an Accident Given an In-Flight Medical Event.

Accident 

Yes No Total 

Yes 2 48 50 

In-Flight No 215 54,295,634 54,295,849 

Event Total 217 54,295,682 54,295,899 

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

25-29

30-34

35-39

40-44

45-49

50-54

55-59

Pilot Age Group (Years)

Percent of Incapacitated/

Impaired Pilots

Incapacitations

Impairments

Figure 1. Percent of U.S. airline pilot in-flight incapacitations and impairments as a 

function of age (1993 to 1998). 

Figure 1. Percent of U.S. airline pilot in-flight incapacitations and impairments as a function of 

age (1993 to 1998).
5

Figure 2 shows the percent of pilot in-flight medical 

incapacitations by age group. A linear regression of the 

data shown in Figure 2 indicates that the percentage of 

in-flight incapacitations increased with pilot age group 

(R2 = 0.69, p < 0.01). 

Categories of In-Flight Medical Incapacitations

All 39 in-flight medical incapacitations were classified 

as “certain.” The most frequent categories were loss of 

consciousness (LOC) (9), gastrointestinal (GI) (6), neurological (6), cardiac (5), and urological (3). Of the nine 

loss of consciousness cases, four were caused by vasovagal 

syncope, one was the result of neurogenic syncope, one 

was due to pain secondary to a duodenal bulb ulcer, 

one was the result of decompression sickness, and two 

were due to unknown causes. The six gastrointestinal 

cases included two cases of cholelithiasis, two cases of 

intestinal gas expansion with altitude, and two cases of 

possible food poisoning. Four of the six neurological cases 

were grand-mal seizures, one was an alcohol withdrawal 

seizure, and one was a petit mal seizure. Three of the five 

cardiac cases were fatal myocardial infarctions, and one 

was a fatal dysrhythmia, while one cardiac case involved 

a non-fatal coronary spasm. All three urological cases 

involved renal lithiasis.

Figure 4 shows the most frequent categories of inflight medical incapacitation by age. Examination of the 

figure suggests an increase in incapacitations with pilot 

age. Also, the data in Figure 4 suggest that more serious 

categories, such as loss of consciousness secondary to 

ulcers, cardiac events like myocardial infarctions, and 

neurological seizures occurred more frequently in older 

y = 0.0189x - 0.0071

R2

 = .6926

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

25-29

30-34

35-39

40-44

45-49

50-54

55-59

Age Groups (Years)

Percent of Pilots

Figure 2. Age distribution of in-flight medical incapacitations of U.S. airline 

pilots from 1993 to 1998. 

Figure 2. Age distribution of in-flight medical incapacitations of U.S. airline pilots from 

1993 to 1998.

Figure 3. Frequent categories of in-flight medical incapacitation. 

�

�

�

�

�

��

���

�������

������������

��

������ �����

���������

Figure 3. Frequent categories of in-flight medical incapacitation.
6 

pilots. At the same time, the less serious medical categories, 

such as gastrointestinal events due to gas expansion and 

food poisoning and loss of consciousness due to vasovagal 

syncope, occurred more frequently in younger pilots.

Less frequent causes of in-flight medical incapacitation included hypoxia (2), diabetes (1), decompression 

sickness (1), vascular (1), reaction to medication (1) and 

traumatic injury (1). The two hypoxia cases occurred on 

the same flight when the flight engineer inadvertently 

opened the outflow valve at altitude, accidentally depressurizing the aircraft. The diabetes case involved a second 

officer who had had two hypoglycemic episodes within 

a three-month period, one at the gate resulting in his 

removal from the aircraft prior to flight and another inflight. The decompression case occurred when a DC-8 

cargo captain ordered his crew to continue to climb to 

33,000 feet after it was determined that the aircraft could 

not be pressurized. Interestingly, the captain ordered the 

aircrew to use oxygen, believing that it would provide 

protection against decompression sickness at that altitude. 

The vascular case involved an Airbus captain with a history of chronic, controlled atrial fibrillation who decided 

to discontinue his digoxin and propranolol on his own 

and developed a temporoparietal cerebral infarct during 

landing. One pilot suffered heart palpitations that were 

attributed to an herbal medication he was taking for 

weight control; another suffered an injury when hydraulic 

fluid came into contact with his eye during an aircraft 

pre-flight inspection.

Categories of In-Flight Medical Impairments

All of the 11 in-flight medical impairments were 

classified as “certain.” Categories of in-flight medical 

impairment included respiratory (4), fatigue (2), vision 

(2), cardiac (1), gastrointestinal (1), and infectious disease (1). Three of the four respiratory cases occurred on 

the same taxiing DC-8 aircraft when carbon dioxide 

poisoning, caused by fumes from dry ice carried in the 

cargo compartment, impaired the captain, first officer 

and jumpseater. The fourth respiratory case was due to 

barosinusitis. The two fatigue cases occurred on a DC-8 

flight, resulting in an accident with three serious injuries. 

The captain had been awake 40 of the previous 66 hours 

and the first officer for 47 of the previous 66 hours prior 

to the accident. Of the two vision cases, one occurred 

when a B-737 captain looked directly into a laser that 

appeared to be tracking the aircraft from the ground, 

resulting in a temporary loss of night vision. The other 

occurred when an MD-88 struck the approach lights 

during an approach to a landing because of the captain’s 

use of monovision contact lenses, resulting in three minor 

injuries on evacuation of the aircraft. The cardiac case 

involved a 57-year-old L-1011 captain who had been 

experiencing retro-sternal chest pain since the previous 

day, which became more continuous in flight and began 

radiating to his left jaw and arm. Although the clinical impression of the attending physician was unstable 

angina, his electrocardiogram was normal on physical 

examination. One Embraer-120 captain was diagnosed 

with viral gastroenteritis and secondary dehydration, and 

an MD-88 first officer was found to have a viral infection 

that led to a vasovagal response.

Fatal In-Flight Events

Four pilots died as a result of their in-flight incapacitating event; however, no passenger deaths resulted from 

these incapacitations. No pilot deaths resulted from inflight medical impairments. The mean age of the four 

0

1

2

3

Frequency

25-29

30-34

35-39

40-44

45-49

50-54

55-59

Age Groups (Years)

LOC

Cardiac

Neurological

GI

Urological

Figure 4. Most frequent categories of in-flight medical incapacitation by age. 

Figure 4. Most frequent categories of in-flight medical incapacitation 

by age.
7

pilot fatalities was 53 (range 48 to 56 years). All four 

deceased pilots were pronounced dead because of cardiac 

events after being transported to the hospital. Three of the 

four deaths resulted from myocardial infarctions (MIs), 

while one was the result of a cardiac dysrhythmia. Two 

of the three pilots who suffered MIs and the pilot who 

died as a result of a fatal dysrhythmia had cardiac medical histories that were documented in the pilot’s FAA 

medical record. As a result, pathology codes, history 

codes, or both were assigned by the FAA prior to their 

in-flight medical events. Two of the three flights where 

the pilots suffered an MI and the one flight where the 

pilot suffered an arrhythmia diverted to alternate airports 

because of the in-flight medical events; however, the one 

flight that did not divert when the first officer suffered 

an MI was inbound to their final destination at the 

time. Cardiopulmonary resuscitation was attempted in 

all cases. Safety of flight was seriously affected only once 

temporarily when the first officer’s foot became lodged 

against the rudder pedal when he stiffened, requiring the 

captain to apply opposite rudder pressure until the foot 

could be dislodged. 

Safety of Flight and In-Flight Medical Events

Safety of flight is negatively affected during any inflight medical event; however, we considered safety of 

flight to be a factor during an event only when there 

was imminent danger of an aircraft accident resulting 

from the medical event. We found that on seven of the 

47 flights it was seriously affected. The mean age of the 

seven pilots involved in flights where safety of flight was 

seriously affected was 48.4 years (range 42-56, SD = 

4.5), and the mean age of the 41 pilots who were not 

involved in flights where safety of flight was seriously 

affected was 45.7 years (range 25-59, SD = 10.7). There 

was no significant difference in the mean age between 

the two groups. As previously discussed, two of the seven 

flights ended in aircraft accidents. The seven cases are 

summarized below.

 • A 45-year-old B-737 first officer experiencing an 

alcohol withdrawal seizure suddenly screamed, extended his arms up rigidly, pushed full right rudder, 

and slumped over the yoke during an approach. The 

aircraft descended to 1,000 feet above ground level in 

an uncoordinated turn to 25 degrees angle of bank 

before flight attendants could pull the first officer 

off the controls, allowing the captain to recover the 

airplane. “Mayday” calls were made, and the captain 

executed a missed approach before making a successful 

landing.

 • When a 48-year-old DC-9 first officer’s foot 

became lodged against a rudder pedal after he 

stiffened during a heart attack, the captain had to 

apply opposite rudder to control the aircraft until 

the foot could be dislodged.

 • A 44-year-old flight engineer and a 42-year-old 

captain lost consciousness when the flight engineer 

accidentally turned off a flow pack with the cargo 

heat outflow valve open, depressurizing their B-727 at 

33,000 feet. The captain and flight engineer regained 

consciousness only after the first officer donned his 

oxygen mask and made an emergency descent.

 • A 49-year-old captain stiffened so violently during 

an epileptic seizure after landing that he suffered a 

fractured shoulder and a lumbar compression fracture. 

At the same time, he applied such force to the rudder 

pedals that he caused the aircraft to turn sharply and 

stop suddenly. The first officer had to remove the captain from the controls to taxi the aircraft to the gate.

 • During an approach flown at higher than normal 

airspeed, a 56-year-old A-300 captain suffering a cerebral infarction did not ask for the landing gear to be 

extended and simply nodded agreement when the first 

officer questioned him about it. After touchdown, the 

captain used reverse thrust for longer than required 

and applied full take-off power on the taxiway. After 

the first officer reduced power, the captain again applied take-off power, and the first officer shut down 

the engines and called for assistance.

 • When a 48-year-old MD-88 captain wearing monovision contact lenses attempted to make a visual 

approach over water under reduced lighting conditions in rain and fog, he perceived the aircraft to be 

higher than it actually was. This resulted in a steeper 

than normal final approach, causing the aircraft to 

strike the approach lights. Although no one was hurt 

on impact, three passengers received minor injuries 

during the evacuation following the accident.

 • A cargo DC-8 crashed on approach because the aircrew’s judgment, decision-making, and flying abilities 

were impaired by fatigue. The 50-year-old captain had 

been awake for 40 of the previous 66 hours, and the 

54-year-old first officer had been awake for 47 of the 

previous 66 hours prior to the accident. The captain 

entered an approach turn stall and failed to recover, 

resulting in the accident, which caused serious injuries 

to himself, the first officer, and second officer.

In-Flight Medical Events and Similar Medical 

Histories

There are times when the airman’s FAA medical record 

contains coding that is similar to the category assigned to 

an in-flight event. While we found no pilots whose inflight medical impairments were categorized similarly to 
8 

the codes assigned in their FAA medical history, nine of 

39 incapacitations were categorized similarly to the codes 

assigned in the pilot’s FAA medical record, as shown in 

Table A-3. 

Diversions Resulting From In-Flight Medical Events

A flight diversion occurs whenever the aircraft lands at 

a destination other than the originally intended airport. 

Nineteen of the 39 flights involving incapacitated pilots 

and three of the 11 flights with impaired pilots diverted 

because of the in-flight medical event. The odds of a flight 

diverting is, therefore, 0.48 (95% CI 0.33, 0.64) in the case 

of an in-flight medical incapacitation and 0.27 (95% CI 

0.01, 0.54) in the event of an impairment. In three of the 

19 diversions (16%) for incapacitated pilots, the aircrewmember did not survive, while in all three diversions for 

impaired pilots the affected crewmember did survive.

Of the 19 diversions for incapacitated pilots, three were 

classified as cardiac cases, three as gastrointestinal, three as 

epileptic seizures, two as hypoxia, and eight due to other 

causes. Two of the three cardiac cases were fatal heart attacks, 

1 in a 48-year-old pilot and the other in a 56-year-old, and 

one was a fatal arrhythmia in a 55-year-old pilot. One of the 

gastrointestinal cases was due to food poisoning, 1 the result 

of intestinal gas expansion with an increase in altitude, and 

the third was suspected to be peritonitis. The two hypoxia 

cases occurred on the same flight when the flight engineer 

accidentally depressurized the aircraft at 33,000, and both 

the captain and flight engineer temporarily lost consciousness. The first officer eventually donned his oxygen mask 

and made an emergency descent. Eight cases classified as 

“other” included decompression sickness, unknown loss 

of consciousness, cholelithiasis, renal lithiasis, muscle 

cramps, chest pain of unknown origin, vertigo secondary 

to labyrinthitis, and vasovagal syncope.

The three diversions for impaired pilots included 1 case 

of cardiac chest pain in a 57-year-old pilot due to unstable 

angina, 1 case of viral infection leading to a vasovagal syncopal response in a 51-year-old, and 1 case of barosinusitis 

during climb in a 43-year-old. 

Aeromedical Certification Actions Resulting From 

In-Flight Medical Events

The 39 in-flight medical incapacitations led to 16 

medical certificate denials (Table A-2, cases 2, 5, 7, 9, 12, 

13, 18, 21, 37, 38, 39, 89, 96, 100, 175, and 178). In 

addition, a special-issuance code was assigned to 1 pilot 

(Table A-2, case 2), 16 history codes were assigned to ten 

pilots (Table A-2, cases 2, 5, 11, 12, 27, 32, 33, 73, 82, 

and 175), 37 pathology codes were assigned to 22 pilots 

(Table A-2, cases 2, 5, 7, 9, 10, 11, 12, 13, 14, 18, 21, 29, 

31, 32, 37, 38, 39, 73, 95, 96, 175, and 178), and four 

EKG codes were assigned to 1 pilot (Table A-2, case 12). 

Also, 11 pilot medical certificates were reaffirmed (Table 

A-2 ,cases 14, 20, 33, 34, 35, 39, 81, 82, 87, 95, and 98), 

five pilots were eventually re-certified (Table A-2, cases 2, 

5, 9, 18, and 73), and in two cases, no codes needed to be 

assigned (Table A-2, cases 16 and 17).

The 11 in-flight medical impairments led to three denials (Table A-2, cases 19, 218, and 219). In addition, six 

pathology codes were assigned to three pilots (Table A-2, 

cases 19, 218, and 219), three medical certificates were 

reaffirmed (Table A-2, cases 30, 74, and 86), and in five 

cases, no codes were assigned (Table A-2, cases 83, 84, 85, 

97, and 148). 

Figure 5 shows the trend in the number of aeromedical 

certification actions per in-flight medical event (incapacitations and impairments) for all types of actions, including 

the assignment of special issuance codes, electrocardiogram 

codes, history codes, pathology codes, as well as certificate 

denials, re-certification, and reaffirmation. As shown in the 

figure, there was a significant decrease in the number of 

aeromedical certification actions per event between 1993 

and 1998 (p<0.05).

Figure 5. The trend of FAA actions per in-flight medical events.

y = -0.8343x + 1667.5

R2

 = 0.7115

0

1

2

3

4

5

6

7

1993 1994 1995 1996 1997 1998

Year

FAA Actions/Event
9

DISCUSSION

Frequency and Rate of In-Flight Events

We found 39 in-flight medical incapacitations for a 

rate of 0.045 per 100,000 hours and 11 impairments 

for a rate of 0.013 per 100,000 hours on 47 U.S. airline 

flights between 1993 and 1998.It is interesting that there 

were approximately four times as many incapacitations 

as impairments, since impairments were generally less 

serious events and could be expected to occur at least as 

frequently as incapacitations. This is probably a reporting phenomenon. Incapacitated pilots were generally 

more seriously ill than impaired pilots. Consequently, 

incapacitations resulted in more declared emergencies, 

flight diversions, ambulance requests, and hospitalizations than impairments. Therefore, an incapacitation 

would probably have been better documented than an 

impairment. Since many of the impairment cases were 

less well documented, any record would have depended 

on pilot self-reporting, something that would probably 

be avoided by most pilots. 

Ironically, only two accidents resulted from pilot inflight medical impairments, while no incapacitations 

resulted in accidents. This may have been because of 

the insidious nature of the two impairment accidents. 

When a dramatic incapacitating event, such as a heart 

attack or epileptic seizure occurs, it is often obvious and 

can be dealt with by the unaffected crewmember. In the 

two impairments that ended in aircraft accidents, the 

pilots were probably not aware there was a problem. In 

one case, the pilot normally flew with monovision contact 

lenses. In the other, the pilots were probably aware they 

were fatigued but were not cognizant of how seriously it 

was impacting their performance at the time.

Martin-Saint-Laurent et al. (23) studied sudden 

in-flight incapacitation in Air France pilots and flight 

engineers from 1968 to 1988 and reported an incapacitation incidence of 0.044 per 100,000 flight hours. While 

this is very close to the rate found for incapacitations 

in this study, the Martin-Saint-Laurent et al. study 

included categories that would have been classified as 

impairments in this study; therefore, a more appropriate 

comparison would be to include incapacitations and 

impairments together. Combining incapacitations and 

impairments gives a total of 48 in-flight medical events 

and a rate of 0.059 per 100,000 flight hours, which is 

only slightly higher than the rate in the Martin-SaintLaurent et al. study.

A review of all U.S. Air Force (USAF) accidents coded 

for incapacitation, preexisting disease, or other acute illnesses between 1978 and 1987 yielded an incapacitation 

rate of 0.019 per 100,000 flight hours (24). This rate is 

less than half the rate in the Martin-Saint-Laurent (23) 

study and this study; however, the USAF study involved 

military pilots who may have been younger and in better 

physical condition, and it was restricted to events that 

resulted in aircraft accidents. We found that incapacitations rarely resulted in accidents; in fact, there were no 

accidents among the Martin-Saint-Laurent et al. cases and 

two accidents in this study, neither of which was fatal.

Two additional studies dealing with U.S. airline 

pilots were based on loss of licensure data, rather than 

in-flight events, and reported incapacitation rates based 

on the number of pilots incapacitated per year instead 

of flight time (20, 21); therefore, their results could not 

be compared with the results of this study in a meaningful way.

The two major airline pilot incapacitation studies that 

dealt with in-flight medical events provide only qualitative results (4, 19), which do not allow for meaningful 

comparison with other quantitative studies.

Probability of an Accident Due to an In-Flight 

Medical Event

Froom reported that less than 1% of all aircraft accidents 

are due to pilot in-flight incapacitation (11). Lane calculated a probability of 5/68 or 0.074 (21). However, Lane 

included categories that were classified as impairments in 

our study. Combining incapacitations and impairments 

in this study, we calculated the probability of an accident 

to be 2/50 or 0.04, about half of the probability found 

in the Lane study. The difference in proportions may be 

due to differences in the types of aircraft operations in 

the two studies. While we have included only U.S. airline 

pilot in-flight medical events, only two of the five flights 

in the Lane study were airline flights, and one of those 

was a positioning flight. Also, two of the five accidents 

in the Lane study involved cargo aircraft, and one was a 

Department of Defense charter flight. 

The proportion of military pilot in-flight medical incapacitations leading to accidents was much higher, probably due to the difference in the operational environment. 

Rayman reported that the probability of an accident was 

20/146, or 0.14, in one study of Air Force pilot incapacitations from 1970 to 1980 (32), and 28/59, or 0.47, in 

another Air Force study from 1966 to 1971 (31).

Although we found a statistically significant difference 

between the chance of an accident (given there was an inflight medical event), compared with flights where there 

was no in-flight medical event, this difference must be 

interpreted in terms of its operational significance. The 

in-flight events in the two accidents are not representative of most other in-flight events. In neither case was 

the flight crew acutely affected by a medical condition 
10 

in the same sense as a pilot who suffers chest pain from a 

heart attack or abdominal pain from a kidney stone, for 

example. These events might have ultimately led to an accident because they did not represent dramatic events that 

could have been detected and dealt with by the unaffected 

pilot. Some authors have made clear distinctions between 

obvious and subtle incapacitation (7, 14). Raboutet and 

Raboutet even asserted that an incapacitation needed to 

be complete for an accident to result (30). However, it is 

easy to imagine scenarios that involve: (1) incapacitation 

of the non-flying pilot, which increases the workload on 

the flying pilot to an unsafe level, (2) the subtle, insidious 

incapacitation of a crewmember that is not apparent until 

a critical phase of flight, (3) the partial incapacitation of 

a crewmember that degrades performance to an unsafe 

level, and (4) the incapacitation of a crewmember during a non-critical phase of flight that continues into a 

critical phase, resulting in an unacceptable increase in 

workload for the flying pilot. Any of these situations 

could result in an aircraft accident without meeting the 

Raboutets’ criteria. In addition, Crowley (8) also found 

the conditions described by Raboutet and Raboutet overly 

restrictive. Our findings suggest that a subtle, unperceived 

impairment might be more dangerous than an obvious, 

complete incapacitation. Although safety of flight was 

severely affected in seven of the 47 flights studied, accidents resulted in only two of those flights. In the other 

five flights, where the incapacitating event was not subtle, 

the unaffected pilot was able to recognize the emergency 

and prevent an accident, even in those situations where 

the event occurred on short final. 

Age Distribution of In-Flight Medical Events

Some studies examining the Age 60 Rule for airline 

pilots have focused on pilot performance and aircraft 

accident data (3, 16, 17, 18). Hyland et al. studied all 

accidents involving pilots with Class I medical certificates and found a decrease in accident rate with age (16, 

17, 18). Broach et al. found a “U”-shaped curve with a 

decrease in accidents with increasing age, followed by a 

slight increase in older age groups for professional pilots 

holding Class I or II medical and ATP or Commercial 

pilot certificates (3).

Other researchers have suggested that replacement of 

older, experienced pilots by younger, inexperienced pilots 

could adversely affect flight safety, and it may be preferable 

to grant waivers to experienced pilots with an increased 

incidence of disease-related, in-flight sudden incapacitation than to replace them with younger, inexperienced 

pilots (2, 11). Froom reported that inexperienced pilots 

have a two to three time increased incidence of pilot errorrelated accidents and cautioned that the estimated risk of 

in-flight medical incapacitation needed to be balanced 

by a consideration of pilot experience (11).

We found a significant increase in the percentage of 

incapacitations with age among the most frequent categories of in-flight medical incapacitation for U.S. airline 

pilots; however, we did not find a significant difference 

between the mean age of pilots where safety of flight was 

seriously impacted and those pilots where safety of flight 

was not seriously at issue. 

Categories of In-Flight Medical Events

Although many studies have dealt with pilot medical 

incapacitation, few have analyzed in-flight medical events 

(6, 7, 13, 14, 19, 21, 29). Studies of in-flight medical 

events had different results or categorized cases differently, 

making comparison between studies difficult; however, 

we found no significant differences between four in-flight 

studies (4, 24, 31, 32) when they were compared by 

categorizing cases with the same classification scheme 

used in this study and compared using a Krushal-Wallis 

ANOVA.

Fatal In-Flight Medical Events

Only three in-flight medical incapacitation studies 

reported fatalities (24, 30, 31); however, it was not always clear when fatalities occurred or how many fatalities 

occurred in several other studies. Rayman reported 24 

fatalities in a six-year study of sudden in-flight incapacitation in USAF pilots, or four fatalities per year (31). In 

addition, in a ten-year study of in-flight incapacitation 

in USAF pilots, McCormick and Lyons (24) found one 

pilot was fatally injured in the crash of his single-seat 

aircraft after suffering a myocardial infarction in-flight, 

for a rate of 0.1 fatalities per year, while Raboutet and 

Raboutet (30), in a 25-year investigation of professional 

French pilots, found that one pilot suffered a massive 

pulmonary embolism in-flight and died about one month 

post-crash, yielding a rate of 0.04 fatalities per year.

We found four deaths in our six-year study, which 

equates to 0.67 fatalities per year. The wide range in 

fatality rates per year from 0.04 to four in other studies 

can be partially explained by the fact that pilot fatalities 

resulting from in-flight medical incapacitation are very 

rare, random events; therefore, exposure time should be 

considered in evaluating them. Fatality rates based on 

flight-time exposure were not provided in earlier studies; 

therefore, comparisons were not possible. Accounting 

for flight-time exposure, we calculated a fatality rate of 

0.00467 per 100,000 flight hours (95% CI 0.00465, 

0.00468). 
11

Safety of Flight and In-Flight Medical Events

Chapman (7) analyzed over 1,300 simulator exercises 

using two protocols. In the first protocol, the authors determined that safety of flight was at risk in 15 out of 500 

(3%) of the cases, and it was felt that an accident would 

have resulted in eight (1.6%) cases. In the second protocol, 

ten out of 800 (1.25%) were felt to have represented a risk 

to safety of flight; in two (0.25%), the authors believed 

aircraft accidents would have resulted.

A survey by the International Federation of Airline 

Pilots Associations conducted by Bennett (1) showed 

that the pilots surveyed considered that safety was only 

significantly threatened in 3% of the incidents because 

there was time available to warn the other pilot of the 

problem .

Buley (4) reviewed IFALPA in-flight incapacitation 

questionnaire data and reported that 40% of responding 

aircrew members felt that safety of flight was not affected, 

56% believed it was potentially affected, and 4% were 

convinced that safety of flight was actually affected. 

Our data showed that safety of flight was severely 

impacted in 15% (7 out of 47) of the flights we studied. 

This figure is higher than those reported by Chapman, 

Bennett, or Buley. Differences in the percentage of 

flights where safety of flight was impacted might be due 

to differences in methods among studies. In our study, 

we reviewed actual in-flight events and judged whether 

the circumstances would have severely impacted safety 

of flight. In the studies conducted by Chapman, the 

researchers were required to determine if what was done 

in a flight simulator would have affected safety of flight 

in the aircraft under similar circumstances. The Buley 

study was the only one that collected safety of flight 

data directly from aircrew members; however, Buley’s 

study would have relied on the ability of pilots to recall 

details of events that may have occurred many years 

earlier. Stone and Shiffman (34) recently reported that 

retrospective assessments may be prone to recall bias and 

distortion. In addition, Hunter (15) recently reported that 

exposure to hazardous aviation events may be associated 

with risk misperception by pilots. These factors suggest 

why pilots in the Buley study might have perceived the 

risk to safety of flight for a past event as being less than 

it actually was.

In-Flight Medical Events and Similar Medical 

Histories 

There are times when the airman’s FAA medical record 

contains coding that is similar to the category assigned 

to an in-flight event. We found no pilots whose in-flight 

medical impairments were categorized similarly to the 

codes assigned in their FAA medical record. However, 

nine of 39 incapacitations were categorized similarly to 

the codes assigned in the pilot’s FAA medical record as 

shown in Table A-3. It should be noted that the similarities between the assigned incapacitation categories and 

the corresponding FAA medical codes do not necessarily 

imply a cause-and-effect relationship and do not, in any 

way, suggest the airman should not have been medically 

certified because of the documented pre-existing condition. For example, an airman with hypertension controlled 

with medication may be assigned a pathology code of 

485 and issued a valid medical certificate. If the airman 

then suffers a stroke in-flight, it might be argued that 

there could have been a relationship between the airman’s 

hypertension and the stroke, since hypertension is a risk 

factor for stroke. However, the stroke could also have 

resulted from an undiagnosed cerebral aneurism.

In addition, an FAA medical code does not necessarily 

imply the airman should have been disqualified. Airmen 

often have codes assigned (pathology codes, history codes, 

or EKG codes) to indicate the presence of medical conditions that are not disqualifying. 

Diversions Resulting From In-Flight Medical 

Events

Diversions for medical purposes represent a significant 

problem for commercial air carriers (9). Delay to original destination, passenger inconvenience, increased risk 

to safety, and cost factor into the complexity of aircraft 

diversions (12). The exact cost of a medical diversion typically ranges between approximately $3,000- $100,000, 

depending upon whether fuel needs to be dumped before 

landing and whether or not passenger overnight accommodations are arranged (33). Landing weight is also a 

consideration, and valuable fuel may have to be jettisoned 

to attain a suitable landing weight for a premature touchdown. While it is more difficult to put a dollar amount 

on safety of flight, this is perhaps the most important 

consideration in any diversion situation. If the unaffected 

pilot is forced to proceed via an unplanned route to an 

unexpected destination and perform an unfamiliar instrument approach, this could reduce the margin of safety 

still further in an already hazardous situation.

Nineteen of the 39 flights involving incapacitated pilots 

and three of the 11 flights with impaired pilots diverted. 

The diversion rate for all in-flight medical events was 22 

out of 47, or 46.8% of flights. This is over twice the 20% 

diversion rate reported by Martin-Saint-Laurent et al. 

(23) in a study of in-flight incapacitation in commercial 

aviation in Air France pilots and flight engineers from 

1968 to 1988. Since the methodologies of the two studies 

are very similar, the difference in percentages of diverted 

flights are probably due to other factors. One reason 
12 

might be differences in the corporate culture between U.S. 

airlines in the 1990s and Air France in the 1960s that 

might have influenced the flight crews’ decision whether 

to divert. Another reason could be differences in the type 

of operation between the U.S. domestic airlines and Air 

France. For example, if many of the Air France flights 

were international flights, diversions for medical events 

may not have been practical because continuing to the 

destination would often be as appropriate.

Aeromedical Certification Actions Resulting From 

In-Flight Medical Events

The pathology, history, and EKG codes assigned as a result of FAA Aeromedical Certification Division (AMCD) 

action become part of the airman’s FAA medical record 

and have been incorporated into the new computerized 

Document Imaging and Workflow System (DIWS). It 

must be noted that more than one type of action was 

taken in some cases. For example, a pilot may have been 

assigned a pathology code, been denied as a result of an 

in-flight medical event, and then eventually re-certified 

with a special issuance medical certificate. 

Although there was a significant decrease in the number 

of certification actions per in-flight medical event with 

time, it did not appear to reflect any change in FAA 

aeromedical certification policy, nor did it appear to be 

a function of the frequency of in-flight medical events. 

In fact, the frequency of events increased with time, and 

the effect of frequency was accounted for in Figure 5. 

One possible explanation for the trend was the chance 

distribution of events. An examination of the events 

showed those which occurred between 1993 through 

1995 generally required more certification actions, while 

the events from 1996 to 1998 generally required fewer 

certification actions. Between January 1, 1993, and December 31, 1995, there were two cases of fatigue resulting 

in an aircraft accident with serious injuries, an alcohol 

withdrawal seizure, three cardiac events, three neurological events, a vasovagal syncopal episode, two episodes of 

loss-of-consciousness, and two miscellaneous events. The 

average number of FAA certification actions per event for 

this group was 3.6. In contrast, between January 1, 1996, 

through December 31, 1998, there were two neurological 

cases, three cardiac cases, four cases of vasovagal syncope, 

five gastrointestinal cases, three cases of carbon dioxide 

poisoning, two cases of hypoxia, three cases of renal 

lithiasis, two cases of unknown losses of consciousness, 

and two miscellaneous cases. In addition, there was one 

case each in the following categories: endocrine, vascular, 

vision, trauma, laser illumination blindness, medication 

use, and respiratory. The mean number of FAA aeromedical certification actions per event for the post-1996 

group was 1.7, which is about half that of the pre-1996 

group. Therefore, the decreasing trend in the number of 

certification actions with time appears to have been due 

to random causes and not any purposeful change in FAA 

aeromedical certification policy.

In-flight medical incapacitation and impairment cases 

are regularly reviewed at CAMI medical staff meetings 

attended by physicians from the Aerospace Medical Certification and the Aerospace Medical Research Divisions. 

Details of the in-flight event, as well as the pilot’s medical 

history, are evaluated in deciding what action to take and 

which codes to assign. This process is very important 

because it may affect future aeromedical certification decision-making, should the airman develop future medical 

problems or experience another in-flight event.

It is important to note the FAA actions taken in the 

39 in-flight medical incapacitation cases and 11 impairment cases we studied represent action after the fact. In 

many instances, the FAA Aerospace Medical Certification Division denies medical certification applications for 

airline pilots, possibly preventing many serious in-flight 

events. One FAA study (10) reported an overall denial 

rate for medical reasons of 4.3 per 1,000 active aviators 

for calendar years 1987 and 1988. The highest age-specific 

denial rate was for the 55-to-59 age group, and the most 

significant causes for denial for all age groups were coronary 

artery disease (8.5%), disqualifying medications (6.2%), 

psychoneurotic disorders (6.1%), myocardial infarction 

(5%), and disturbance of consciousness (4.4%).

CONCLUSIONS

In-flight medical events in U.S. airline pilots were very 

rare; resulting aircrew deaths were even more rare, and resulting aircraft accidents were extremely rare. Fortunately, 

in the six years and nearly 86 million flight hours covered 

by this study, there were no passenger fatalities caused by 

pilot in-flight medical events. The two aircraft accidents 

resulted in serious injuries to three aircrew members and 

minor injuries to three passengers. 

One study, focusing on professional pilot performance and aircraft accident data, found a curvilinear 

relationship between pilot age and performance (3). 

Still, other researchers have argued that replacement 

of older, experienced pilots by younger, inexperienced 

pilots could adversely affect flight safety. We found a 

significant increase in the percentage of incapacitations 

with age. However, there was no difference between the 

mean age of pilots involved in flights where safety of 

flight was seriously affected and the mean age of pilots 

not involved in such flights.
13

Although there was a significant difference between 

the probability of an aircraft accident, given an in-flight 

medical event, this result must be interpreted in its 

operational context. Both accidents involved the subtle 

impairment of the pilot in ways that are not classically 

thought of as medical incapacitation, and it may be that 

subtle impairment of a pilot is more dangerous than 

obvious medical incapacitation.

The most important factor that appears to be responsible for the exceptionally good U.S. airline safety record 

associated with in-flight medical incapacitations is the 

presence of a second pilot. In five out of the seven cases 

where safety of flight was considered to be severely impacted, the aircraft was taken over by the unaffected pilot 

who made a successful landing. In the two cases where 

the affected pilot remained at the controls after subtle 

impairment, both resulted in an aircraft accident.

Aeromedical studies on incapacitation have been few 

in number, retrospective, and less detailed than most 

other scientific studies. There is a lack of high-quality 

data, which has led to a lack of adequate research and 

inadequate information and recommendations. To be 

most valuable, future research needs to be based on actual in-flight medical events and should be normalized 

to a useful denominator, such as flight time, to allow 

for meaningful comparison between studies. Since the 

most frequent categories of incapacitation were loss of 

consciousness, cardiac, neurological, and gastrointestinal 

(occurring mostly in older pilots), future research should 

be directed toward these areas.

REFERENCES 

1. Bennett G. Medical-cause accidents in commercial 

aviation. Euro Soc Card 1992; 13 (Supplement 

H):13-15.

2. Bennett G. Pilot incapacitation and aircraft accidents. 

Euro Heart J 1988; 9 (Supplement G):21-4.

3. Broach D, Joseph, KM, Schroeder DJ. Pilot age and 

accident rates report 3: An analysis of professional 

air transport pilot accident rates by age. Oklahoma 

City, OK: Federal Aviation Administration, Civil 

Aerospace Medical Institute. 2003: OAM Research 

Task AAM-00-A-HRR-520. 

4. Buley LE. Incidence, causes and results of airline pilot 

incapacitation while on duty. Aero Med 1969; 40 

(1):64-70.

5. Cameron A, Trivedi P (1988). Regression analysis of 

count data. New York, NY: Cambridge University 

Press.

6. Castelo-Branco A, Cabral-Sa A, Borges JC. Comparative study of physical and mental incapacities among 

Portuguese airline pilots under and over age 60. 

Aviat Space Environ Med 1985; 56:752-7.

7. Chapman P. The consequences of in-flight incapacitation in civil aviation. Aviat Space Environ Med 

1984; 55:497-500.

8. Crowley J, Campbell J, Johnson P, Powell JA. Coronary artery disease and in-flight incapacitation. 

U.S. Army Medical Department Journal 2000; 

(July-September):17-22.

9. Davies G, Degotardi P. In-flight medical emergencies. 

Aviat Space Environ Med 1982; 53(7):694-700.

10. Downey L, Dark S. Medically disqualified airline 

pilots in calendar years 1987 and 1988. Washington, DC: Federal Aviation Administration, Office of 

Aviation Medicine. 1990; DOT/FAA/AM-90/5.1

11. Froom P, Benbassat J, Gross M, et al. Air accident, 

pilot experience, and disease-related in-flight sudden incapacitation. Aviat Space Environ Med 1988; 

59:278-81.

12. Goodwin T. In-flight medical emergencies: An overview. BMJ 2000; 321:1338-41.

13. Harper C, Kidera G, Cullen J. Study of simulated airline pilot incapacitation: Phase II. Subtle or partial 

loss of function. Aero Med 1971; 42 (9):946-8.

14. Harper C, Kidera G, Cullen J. Study of simulated 

airline pilot incapacitation; Phase 1 – obvious and 

maximal loss of function. Aero Med 1970; 41 (10):

1139-42.

15. Hunter DR. Risk perception and risk tolerance in 

aircraft pilots. Washington, DC: Office of Aerospace 

Medicine. 2002; DOT/FAA/AM-02/17.1

16. Hyland D. Experimental evaluation of aging and 

pilot performance. 7th International Symposium 

on Aviation Psychology. 1993; Columbus, OH.

17. Hyland D, Kay E, Deimler J, et al. Age 60 rule research, Part II: Airline pilot age and performance – A 

review of the scientific literature. Washington, DC: 

Federal Aviation Administration, Office of Aviation 

Medicine. 1994; DOT/FAA/AM-94/21.1

1

This publication and all Office of Aerospace Medicine technical 

reports are available in full-text from the Civil Aerospace Medical 

Institute’s publications Web site: http://www.cami.jccbi.gov/aam400A/index.html
14

18. Hyland D, Kay E, Deimler J. Age 60 rule research, Part 

IV: Experimental evaluation of pilot performance. 

Washington, DC: Federal Aviation Administration, 

Office of Aviation Medicine. 1994; DOT/FAA/

AM-94/23.1

19. James M, Green R. Airline pilot incapacitation survey. 

Aviat Space Environ Med 1991; 62:1068-72.

20. Kulak LL, Wick RL, Jr., Billings CE. Epidemiological 

study of in-flight airline pilot incapacitation. Aero 

Med 1971; 42 (6):670-2.

21. Lane JC. Risk of in-flight incapacitation of airline 

pilots. Aero Med 1971; 42 (12):1319-21.

22. Li G. Pilot-related factors in aircraft crashes: A review 

of epidemiologic studies. Aviat Space Environ Med 

1994; 65:944-52.

23. Martin-Saint-Laurent A, Lavernhe J, Casano G, et 

al. Clinical aspects of in-flight incapacitations in 

commercial aviation. Aviat Space Environ Med 

1990; 61:256-60.

24. McCormick TJ, Lyons TJ. Medical causes of in-flight 

incapacitation: USAF experience 1978-1987. Aviat 

Space Environ Med 1991; 62:884-7.

25. NTSB. http://www.ntsb.gov/NTSB/query.asp#query 

_start 10/24/02.

26. NTSB. Accidents and accident rates by NTSB classification, 1982 through 2001, for U.S. air carriers 

operating under 14 CFR 121, http://www.ntsb.gov/

aviation/Table2.htm on 10/30/02.

27. NTSB. Accidents, fatalities, and rates, 1982 through 

2001, for U.S. air carriers operating under 14 CFR 

121, scheduled and nonscheduled service (airlines), http://www.ntsb.gov/aviation/Table5.htm 

on 2/24/02.

28. Parmet A, Underwood-Ground K. Reported in-flight 

incapacitation: The early birds of 1911. Aviat Space 

Environ Med 1987; 58:276-8.

29. Preston FS. Twelve year survey of airline pilots. Aero 

Med 1968:312-4.

30. Raboutet J, Raboutet P. Sudden incapacitation encountered in flight by professional pilots in French 

civil aviation, 1948-1972. Aviat Space Environ Med 

1975; 46 (1):80-1.

31. Rayman R. Sudden incapacitation in flight: 1 Jan 1966 

- 30 Nov 1971. Aero Med 1973; 44 (8):953-5.

32. Rayman R, McNaughton GB. Sudden incapacitation: 

USAF experience, 1970-80. Aviat Space Environ 

Med 1983; 54 (2):161-4.

33. Rodriguez A, Golaszewski R. (2004). Some preliminary evidence on the costs to airlines and passengers 

of schedule disruptions: working paper. Jenkintown, 

PA, GRA Inc.

34. Stone A, Shiffman S. Capturing momentary, selfreport data: A proposal for reporting guidelines. 

Ann Behav Med 2002; 24 (3):236-43.
A1

0

5

10

15

20

25

LE 29

30-34

35-39

40-44

45-49

50-54

55-59

GE 60

Age Group (Years)

Percent of Pilots

Figure A-1. Average age distribution of U.S. professional pilots from 1993 to 1998 (3). Inclusion 

criteria included: air transport pilots or commercial pilots, class-I or -II medical certificate,

occupation professional pilot, employer CFR Part 121 or 135 operator, 200 recent flight hours and at 

least 1500 total flight hours.

APPENDIX A
A2 

Table A-1. Medical Case Alert Form. 

MEDICAL CASE ALERT 

(Including incapacitations, special medical circumstances, etc.)

1. AIRCRAFT 

ACCIDENT/INCIDENT 

1A. DATE 1B. TIME 1C. LOCATION 1D. 

NUMBER/TYPE 

1E. NUMBER OF PERSONS ON 

BOARD 

1F. PILOT FATALITY

 YES NO 

1G. COPILOT FATALITY

 YES NO 

2A. OCCUPANT 

STATUS 

X Pilot Cabin Crew

CoPilot Passenger

2B. FULL NAME 2C. SEX 

 Male Female

3. MEDICAL CLASS 

 I II III

3A. SOCIAL SECURITY NUMBER (Airmen Only) 

3B. ANY KNOWN MEDICAL CONDITIONS (ex: SODA, SI, Undisclosed medication or condition, Path Codes) 

4. INJURY STATUS 

5. ESTIMATED ROLE OF 

INCAPACITATION NONE POSSIBLE CERTAIN 

6. ESTIMATED ROLE OF 

IMPAIRMENT 

 NONE POSSIBLE CERTAIN 

7. POSSIBLE FACTORS INVOLVED IN 

THE MISHAP

7a. Medical condition 

7b. Medication 

7c. Alcohol 

7d. Marijuana/Illicit drug 

7e. Carbon Monoxide 

7f. Pesticide 

7g. Hypoxia 

7h. Spatial disorientation 

7i. Fatigue 

7j. Emotional Stress 

7k. Other (specify) 

8. TOXICOLOGICAL 

DATA 

PERFORMED BY: 

Address 1: 

Address 2: 

City: State: Zip Code: 

Phone: 

FINDINGS: 

9. AUTOPSY DATA 

PERFORMED BY: 

Address 1: 

Address 2: 

City: State: Zip Code: 

Phone: 

COMMENTS: Pending 

10. FAA/NTSB IIC 

FEEDBACK 

PROVIDED BY: 

Address 1: 

Address 2: 

City: State: Zip Code: 

Phone: 

11. NARRATIVE COMMENTS: (Elaborate on any of the above, or other significant factors. Use a separate sheet if additional space is needed.)

Medical person completing form: (Name) (Phone) DATE: 
A3 Table A-2. Case Summaries. Case Summaries Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) Case Year Age Safety of Flight Issue Deceased Event Category CAMI Narrative 2 1994 45 Yes No Incapacitation ALCOHOL WITHDRAWAL SEIZURE The first officer suddenly screamed, extended his arms up rigidly, pushed full right rudder and slumped over the yoke. Aircraft descended to 1,000 feet before flight attendants pulled the F/O off the controls. "Mayday" calls were made and the captain made a full missed approach before making a successful normal landing. Oxygen was administered for about 7 minutes. F/O had another grand mal seizure at the hospital. 3 1994 52 No Yes Incapacitation CARDIAC Aircraft was on approach with the first officer flying when his left arm slid off the throttles and the airman lay back in the seat. CPR was performed. It appeared to be a heart attack. 4 1994 55 No Yes Incapacitation CARDIAC The captain became limp at the controls. CPR was performed. The second officer moved into the captain's seat, the F/O declared an emergency and the flight diverted where an uneventful, overweight, 

landing was made. The captain was transported to hospital where he was pronounced dead. 

5 1995 59 No No Incapacitation VASOVAGAL The captain lost consciousness and slumped across the center 

pedestal. Oxygen was administered and the captain regained consciousness in 30 to 40 seconds. However, he passed out again, and recovered again. First officer landed the aircraft; captain taxied to the gate. 

6 1995 48 Yes Yes Incapacitation CARDIAC The first officer complained of heartburn, profuse sweating, 

tingling in both of his arms and nausea. His appearance was described as ashen gray. The captain assumed control. Symptoms passed and he resumed flying. First officer complained that the heartburn pains were returning so the captain assumed control and diverted. First officer eventually lost consciousness, began twitching and stiffened, and loudly exhaled. CPR was performed. The first officer's left leg had became lodged against the left rudder when he stiffened, requiring the captain to apply right rudder to control the aircraft until the F/O’s leg was dislodged. 
A4 

Case Summaries 

Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) 

Case Year Age Safety of 

Flight 

Issue 

Deceased Event Category CAMI Narrative 

7 1995 57 No No Incapacitation NEUROLOGICAL During descent from cruise, the captain failed to respond to a 

heading from Air Traffic Control and did not respond to the first officer. What was described as a grand mal seizure followed. The F/O landed the aircraft and the captain was taken to local area hospital. (Hospital suspected a brain tumor of the left temporal lobe). 

9 1995 56 No No Incapacitation LOSS OF 

CONSCIOUSNESS 

GASTROINTESTINAL 

The captain became nauseated, stomach became bloated and uncomfortable then he lost consciousness. The flight was diverted. Upon landing the captain was taken to hospital. 

10 1995 41 No No Incapacitation MISCELLANEOUS The first officer experienced severe back pain soon after take-off. 

The captain declared an emergency, and the flight returned to its place of origin. 

11 1996 37 No No Incapacitation GASTROINTESTINAL The first officer became medically incapacitated inflight, and the 

flight diverted. The F/O was admitted to hospital for treatment of possible peritonitis. He remained in hospital for two days and was sent home by train. The first officer had had an appendectomy two months previous to the incident. 

12 1996 56 No No Incapacitation VASOVAGAL 

GASTROINTESTINAL 

The captain experienced severe abdominal pains and became medically incapacitated in flight. He was taken to hospital, where workups including CTscan, gastro consultation, and treadmill tests concluded event as probable gastroenteritis with vasovagal response. He had a near-syncopal episode during treadmill. Neuro and gastrointestinal work-ups were within normal limits. 

13 1996 43 No No Incapacitation ENDOCRINE The second officer became hypoglycemic. He was on oral antihypoglycemic agents and had a similar episode six weeks prior at 

the gate. This resulted in the airman being removed from the aircraft prior to the flight. Medical certificate was surrendered by the airman. 

14 1996 47 No No Incapacitation VASOVAGAL 

GASTROINTESTINAL 

Take-off was aborted due to the first officer’s incapacitation. F/O had slumped over in the cockpit but "recovered" as they were taxiing back to the gate. He appeared pale and was sweating profusely. The F/O was taken to hospital and held overnight. The airman reported eating a bad sandwich the day before. 
A5 Case Summaries Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) Case Year Age Safety of Flight Issue Deceased Event Category CAMI Narrative 16 1996 44 Yes No Incapacitation HYPOXIA The aircraft experienced decompression at 33,000 feet. The first officer made an emergency descent. It appears the flight engineer may have turned off the right flow pack with the cargo heat outflow valve open. Cabin altitude increased toward 33,000 ft and the first officer donned his mask. The captain, flight engineer, and flight attendant lost consciousness but regained during descent. Oxygen masks deployed for all passengers. The captain took over the aircraft and landed. 17 1996 42 Yes No Incapacitation HYPOXIA The aircraft experienced decompression at 33,000 feet. The first officer made an emergency descent. It appears the flight engineer may have turned off the right flow pack with the cargo heat outflow valve open. Cabin altitude increased toward 33,000 ft and the first officer donned his mask. The captain, flight engineer, and flight attendant lost consciousness but regained during descent. Oxygen masks deployed for all passengers. The captain took over the 

aircraft and landed. 

18 1996 31 No No Incapacitation VASOVAGAL While the aircraft was climbing through 28,000 feet the first officer 

went limp and slumped to left side of seat. Attempts to revive him were unsuccessful. After approximately 20 to 30 seconds he started to stir a little, then abruptly started flailing about. The flailing lasted about 10 seconds, knocking off the captain's glasses and turning on the deice switches on the overhead panel. The F/O then came to. Over a period of about five minutes the airman regained full consciousness, but was drenched in sweat, and “as white as my shirt.” Airman became fully coherent with complete situational awareness. The flight then proceeded normally to the alternate airport. Initial evaluation was negative and electrocardiogram was normal. 

19 1996 57 No No Impairment CARDIAC In-flight, the captain began experiencing chest pain. The airman 

reported experiencing intermittent retrosternal chest pain since the previous day, which was becoming more continuous with radiation to his left jaw and left arm. The flight diverted, the captain taxied the aircraft to the gate. The clinical impression was chest pain with possible unstable angina. 
A6 

Case Summaries 

Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) 

Case Year Age Safety of 

Flight 

Issue 

Deceased Event Category CAMI Narrative 

20 1996 41 No No Incapacitation MISCELLANEOUS The captain experienced chest pains during flight. A nurse who was 

on board stated that he appeared pale and anxious; the flight diverted. Upon landing the airman was taken to the hospital for treatment. The captain was admitted and kept overnight for observation. Electrocardiogram was performed; he was without chest pain upon entry to the emergency room, stress test performed and enzymes tested. All studies were normal. 

21 1996 56 Yes No Incapacitation VASCULAR A scheduled domestic passenger flight was stopped on the taxiway 

after landing when the captain became incapacitated. The first officer stated that the captain was flying the aircraft, and during the approach the captain did not ask for the landing gear to be extended. The approach to the runway was flown at a higher than normal speed and after touchdown the captain used reverse thrust for a longer than normal time. After exiting the runway onto the taxiway the captain applied takeoff engine power. The first officer closed the engine power levers, the captain again tried to apply takeoff engine power. The F/O realized the captain was incoherent and closed the engine power levers and shut down the engines. He then called for assistance from the flight attendants and asked the air traffic controller to send out rescue personnel. 

27 1997 37 No No Incapacitation GASTROINTESTINAL While enroute, the first officer experienced severe stomach pain. 

The captain decided to divert. Paramedics took the first officer to hospital. Diagnosis: severe intestinal gas blockage. 

29 1997 54 No No Incapacitation TRAUMATIC INJURY While the first officer was performing the pre-flight check, a drop 

of hydraulic fluid (Skydrol) entered into his eye. The airman was then taken to the local hospital where the eye was washed out. 

30 1997 34 No No Impairment LASER ILLUMINATION 

BLINDNESS 

The captain was on the controls when he noticed a green light illuminating the aircraft. He reported that his exposure to the light caused a minimal, yet persistent loss of night vision. 

31 1997 58 No No Incapacitation UROLOGICAL First officer declared an emergency due to the incapacitation of the 

captain. An onboard doctor determined it was a stomach related problem. The captain was vomiting, had pain in stomach, and was very weak. The first officer landed the aircraft. The captain was taken to hospital, and kidney stones were passed. 
A7 Case Summaries Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) Case Year Age Safety of Flight Issue Deceased Event Category CAMI Narrative 32 1997 51 No No Incapacitation GALL BLADDER Enroute, the first officer developed severe abdominal pains. The captain radioed that the F/O had "gas pain with significant discomfort" and requested paramedics meet the aircraft, an emergency was declared. The F/O was taken to hospital. Diagnosis was gallbladder attack; subsequently surgery was performed. 33 1997 53 No No Incapacitation GASTROINTESTINAL The captain became ill with flu-like symptoms, nausea, vomiting and diarrhea during a transatlantic flight. An onboard physician said the captain was suffering from acute gastroenteritis, secondary to food poisoning. 34 1997 54 No No Incapacitation GALL BLADDER The flight declared an emergency and made an unscheduled landing because the flight engineer had a suspected heart attack. The airman was transported to hospital in stable condition. Working diagnoses was cholelithiasis. 35 1997 30 No No Incapacitation MEDICATION An emergency was declared after the first officer experienced chest pains. The pilot was taken to the local hospital. Preliminary reports 

indicated the chest pains were not cardiac related. 

37 1998 38 No No Incapacitation NEUROLOGICAL 

(SEIZURE) 

The first officer was on a break, and asleep when a flight attendant noticed he was bleeding from his mouth and tongue. The airman was awakened and appeared disoriented. It was assumed the F/O had a seizure while sleeping. The airman was taken to a hospital and had a seizure while having an ECG.

38 1998 48 No No Incapacitation UNKNOWN LOSS OF 

CONSCIOUSNESS 

The captain experienced severe abdominal pain during flight. He collapsed in his seat and was unresponsive. The captain reported eating at a Cuban restaurant. Complaints were diarrhea, vomiting, sweating, panting, and abdominal pain. The hospital found him to be dehydrated and administered approx 31⁄2 liters of fluid. 

39 1998 50 No No Incapacitation UNKNOWN LOSS OF 

CONSCIOUSNESS 

The first officer was found unresponsive and an onboard physician was called to attend him. He appeared to have had a seizure and appeared to be unconscious for 30 minutes. He walked through the airport and refused medical attention from the paramedics who had been sent to meet him at the gate; he also refused to be checked at a hospital. 
A8 

Case Summaries 

Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) 

Case Year Age Safety of 

Flight 

Issue 

Deceased Event Category CAMI Narrative 

72 1998 56 No Yes Incapacitation CARDIAC The first officer told his captain that he was not feeling well shortly 

before suffering an apparent heart attack. He was observed slumped over in his seat. The flight diverted. CPR was given. Paramedics were waiting at the gate six minutes after the F/O collapsed, but they were unable to revive him. 

73 1998 50 No No Incapacitation UROLOGICAL During flight, the captain suffered severe back pain. The flight 

diverted. The pain went away after landing but returned on the way to the hospital. An IVP at the hospital revealed dilation at the left utethral-vesticular junction, most likely due to a kidney stone. 

74 1998 51 No No Impairment VASOVAGAL The first officer had what was thought to be indigestion before 

departure. After the F/O stretched and raised an arm, the airman stated that it felt "heavy" and that a weakness was felt in the arm. The F/O broke out into a cold sweat. 

81 1998 47 No No Incapacitation UROLOGICAL The first officer was having chest and abdominal pains. Hospital 

diagnosed kidney stones. 

82 1998 56 No No Incapacitation CARDIAC The captain became intensely nauseated during the flight and 

developed severe anterior chest heaviness, along with aching discomfort without radiation. The captain broke out into a sweat and it appeared the airman was having a heart attack. The captain was treated onboard by two physicians; given four tablets of nitroglycerin that produced decreased chest discomfort but gave him a headache. 

83 1998 55 No No Impairment CARBON DIOXIDE 

POISONING 

The aircraft was taxiing to takeoff when all four occupants became short of breath. All occupants donned oxygen masks, and the captain taxied the airplane back to the ramp. The crew were transported to hospital. Diagnosis was physical impairment resulting from an accumulation in the cockpit of carbon dioxide fumes produced by dry ice, a hazardous material, carried in the main cargo compartment. 
A9 Case Summaries Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) Case Year Age Safety of Flight Issue Deceased Event Category CAMI Narrative 84 1998 28 No No Impairment CARBON DIOXIDE POISONING The aircraft was taxiing to takeoff when all four occupants became short of breath. All occupants donned oxygen masks, and the captain taxied the airplane back to the ramp. The crew were transported to hospital. Diagnosis was physical impairment resulting from an accumulation in the cockpit of carbon dioxide fumes produced by dry ice, a hazardous material, carried in the main cargo compartment. 85 1998 27 No No Impairment CARBON DIOXIDE POISONING The aircraft was taxiing to takeoff when all four occupants became short of breath. All occupants donned oxygen masks, and the captain taxied the airplane back to the ramp. The crew were transported to hospital. Diagnosis was physical impairment resulting from an accumulation in the cockpit of carbon dioxide fumes produced by dry ice, a hazardous material, carried in the main cargo 

compartment 

86 1998 29 No No Impairment GASTROINTESTINAL 

DEHYDRATION 

The captain had been feeling ill all day. On approach he began to vomit, which continued for a few minutes. Local clinic diagnosed gastroenteritis. 

87 1998 31 No No Incapacitation MISCELLANEOUS The first officer experienced dizziness when getting up to go for 

aspirin for an earache. LOC was initially reported, although this was not confirmed. 

89 1998 49 Yes No Incapacitation NEUROLOGICAL 

(SEIZURE) 

The aircraft had just landed when the captain apparently had a seizure episode for over a minute and a half. The captain’s body became stiff, the back arched, and the captain bit his tongue, and dislocated/fractured the left shoulder, also sustaining a lumbar compression fracture. The captain caused the aircraft to turn right and come to a sudden stop due to the stretched position. The airman regained consciousness shortly thereafter. The first officer removed the captain from the controls and taxied to the gate. 

95 1998 25 No No Incapacitation LOSS OF 

CONSCIOUSNESS 

CARDIAC 

During flight the F/O lost consciousness for less than one minute. After regaining consciousness, the F/O was able to fully perform some duties and the flight continued to destination. 
A1

0 

Case Summaries 

Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) 

Case Year Age Safety of 

Flight 

Issue 

Deceased Event Category CAMI Narrative 

96 1994 57 No No Incapacitation NEUROLOGICAL 

(SEIZURE) 

During a transatlantic flight, the captain lost consciousness. The aircraft diverted. The captain was in the jump seat at the time, the episode was described as an out-of-body sensation with the head jerking to the right. The captain passed out and became wedged in between the cockpit seats. The captain was unresponsive with arms folded across the chest. The captain was stiff, and did bite the tongue. However, he regained his senses in less than one minute and did not describe any significant postictal phase. 

97 1998 43 No No Impairment RESPIRATORY On departure, the F/O experienced increasing pain and pressure in 

the sinuses and right inner ear. The pain became worse as the aircraft ascended; pressure increased and was accompanied by numbness. Flight diverted, the pain subsided on descent and was tolerable at sea level. 

98 1998 34 No No Incapacitation GASTROINTESTINAL The flight diverted after the F/O became ill. It was reported the F/O 

had flu-like symptoms, cramps and vomiting, but did not lose consciousness. 

100 1994 59 No No Incapacitation MISCELLANEOUS Inflight, the captain’s performance was poor and inattentive, with 

portions of his speech being unrecognizable. The first officer assumed all flight deck duties but the captain wanted to participate and to avoid a confrontation the F/O allowed the captain to assist, but the duties became very difficult for the captain to accomplish. After landing, the captain assisted in parking the aircraft but was unable to respond intelligently. 

148 1996 48 Yes No Impairment VISION The airplane struck the approach light structure and the end of the 

runway deck during the approach. Because of the captain's use of monovision contact lenses, the airman was unable to overcome the visual illusions resulting from the approach over water in limited light. These illusions led the captain to perceive that the airplane was higher than it was during the visual portion of the approach, and thus, to his unnecessarily steepening the approach during the final 10 seconds before impact. 
A11

Case Summaries 

Shaded sequential cases occurred on the same flight (i.e. cases 16-17, 83-85, and 218-219) 

Case Year Age Safety of 

Flight 

Issue 

Deceased Event Category CAMI Narrative 

175 1993 33 No No Incapacitation NEUROLOGICAL 

(SEIZURE) 

First officer experienced LOC in-flight, and experienced feeling disorientated, presyncopal and "numb all over" for 10 seconds prior to the LOC. The F/O was witnessed to have a 5-minute episode of tonic-clonic convulsions, with a postictal state accompanied by confusion. 

178 1994 52 No No Incapacitation LOSS OF 

CONSCIOUSNESS 

DECOMPRESSION 

SICKNESS 

During climbout, the crew was unable to pressurize the airplane. The crew donned oxygen masks and climb was continued to FL330. Shortly after level-off, the captain became incapacitated from decompression sickness. The flight diverted. 

218 1993 54 Yes No Impairment FATIGUE Additional factors contributing to the cause were the inadequacy of 

the flight and duty time regulations applied to 14 CFR, PART 121, Supplemental Air Carrier, International Operations, and the circumstances that resulted in the extended flight/duty hours and fatigue of the flight crew. 

219 1993 50 Yes No Impairment FATIGUE Additional factors contributing to the cause were the inadequacy of 

the flight and duty time regulations applied to 14 CFR, PART 121, Supplemental Air Carrier, International Operations, and the circumstances that resulted in the extended flight/duty hours and fatigue of the flight crew.