carrying passengers with only a Student Pilot
Certificate, and two persons, including the air-
port operator, had urged him not to depart on
his fatal flight. A wing structure failed due to
excessive stresses during this flight.

A 54 year old Canadian pilot and his wife were
killed in the crash of their PA-24. The glucose
level.on sanguinous fluid from the thoracic cavity
was 36 mg %. Correspondence with Canadian
Department of National Health and Welfare
physicians revealed that a diagnosis of “diabetes
mellitus controlled by diet alone” had been made
on this pilot. Reports were submitted by his in-
ternist every six months verifying continued con-
trol by diet; the last report was submitted the
month prior to the accident.

Two pilots were found to have severe narrow-
ing of one or more coronary arteries but no evi-
dence of infarction. One of these, a commercial
pilot with over 20,000 hours, also had a 30 mg %
blood alcohol level. In two other accidents, the
pathologists reported coronary atherosclerosis,
and, in another, focal myocardial chronic inflam-
mation with fibrosis was reported:

A review of the medical records revealed that
25 wore corrective lenses, two had deficient color
vision, one had hypertension and diabetes melli-
tus treated by diet, one housewife-student pilot
had a history of emotional instability, one was
obese with gout, one had no speech or hearing,
one had weakness of one leg, one had a systolic
heart murmur after exercise, two had had pre-
vious surgery for kidney stones and three ad-
mitted a history of peptic ulcer.

Nineteen had had previous aircraft accidents.

Drugs. A pilot who flew straight into a hill-
side soon after take-off under VFR conditions
was found to be carrying Pro-banthine with
phenobarbital, Librium and Kolantyl. His wife,
who survived the accident, stated that he was
symptomatic and took medications but did not
know when he had last taken any of those he
carried. He had a known history of peptic ulcer
with profuse hemorrhage but had been issued a
Third Class Medical Certificate valid for six
months after he submitted a report that he had
no ulcer, was asymptomatic and was on no medi-
eations. No ulcer.crater, evidence of hemorrhage,
or pills were found in the gastrointestinal tract
at autopsy; no barbiturates, aldehydes, alkaloids,
or alcohol were found in the blood.

Liberal quantities of professional samples of
twelve drugs, a pair of contact lenses, an empty
contact lens container and a large bottle of
wetting solution were found together at the scene
of a BE-18 accident in which the physician-
AME-pilot and eight laymen were killed. Except
for three Eskatrol capsules,. all of the medica-
tions were comfort items which were understand-
able for the sole physician to be carrying on a
week-end outing with fifty others, A Second
Class Medical Certificate with a contact lens pro-
vision had been issued despite a waiver limited
to third class certificates. No evidence of any
physical condition or drug effect was found at
autopsy. Of chief concern in this accident was
the failure of two physicians and the coroner’s
representative to note the prominent array of at
least 200 pills and capsules, many of which, like
Tuss-Ornade, were contained in brightly-colored
packages of twos.

Two ATR pilots involved in fatal general avi-
ation accidents due to human factors were found
to have positive liver barbiturate levels. One,
with over 8000 hours, had a near-fatal accident
shortly before the fatal accident, had a liver
barbiturate level of 0.4 mg %, and was reported
to be on Dexamyl No. 2 for appetite control.
The other, with over 3000 hours, was found to
have a liver barbiturate of 0.7 mg %, of which
0.4 mg % was phenobarbital. No further infor-
mation was obtained regarding the identification
or purpose of the medication in this case.

Ethyl Alcohol. The blood ethyl alcohol levels
of the 17 pilots involved in fatal accidents found
to have levels > 30 mg % are shown in Table'1.

‘Taste 1, Blood ethyl alcohol levels in pilots involved
in fatal general aviation accidents. .

Blood ethyl alcohol level Number of fatal accidents

80-49 mg %
50-99 mg %
100-149 mg %
150-199 mg %
200-249 mg %
250-800 mg %

AON RR

There would seem to be little doubt of a causal
role in those with levels over 250 mg %. One
(4:45 a.m.; 278 mg %) was known locally to
drink and fly at night; one (270 mg %) had
the nickname of “Boozer”; and another (300 mg
%) had received four speeding tickets the past
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One-third of all of the accidents occurred at
night; two-thirds of those involving alcohol oc-
curred at night.

A businessman-student pilot, who crashed a
Cessna 310 into his estranged wife’s bar in a
murder-suicide attempt, had a blood alcohol level
of 90 mg % and was known to be flying passen-
gers at night with only a student permit in an
aircraft that needed some engine maintenance.
No decrement in performance was noted prior to
take-off or during the flight to his predetermined
crash site. The influence of this alcohol level
upon his action is, of course, not known.

The frequency of accidents and alcohol involve-
ment by occupational groups is shown in Table 2.

Taste 2. Occupational groups of pilots involved in fatal
aircraft accidents, with and without alcohol involve-

ment.
No. (and %) with
Occupational No. of fatal blood alcohol level
group accidents > 30 mg %
Professional 16 0 (0%)
Businessmen “85 6 (17%)
Commercial pilots 21 4 (19%)
Mechanics 7 3 (48%)
All others 43 4 (9%)

A commercial pilot with over 20,000 hours was
fatally injured in a crash at 6:51 a.m. during
low-level flight. He had a blood alcohol level
of 130 mg %.

The reported flying time of pilots involved in
fatal accidents, with and without significant blood
alcohol levels, is shown on Table 3. The relation-
ship of age of the airman population, those in-
volved in fatal accidents in this series, and those
with alcohol involvement in this series are shown
in Figure 2, The amount of flying time, by age
group, is not known.

Taste 8. Relationship of fatal accident involvement,
alcohol and reported total flying time.

Total flying hours

reported at time No. with blood

of last physical No. of pilots alcohol > 30 mg
exam. %

0-40 19 (15.6%) 2 (11.8%)
41-100 11 (9%) 2 (118%)
101-200 5 (41%) 0 (0%)
201-500 16 (18.1%) 0 (0%)

501-1000 15 (12.8%) 4 (23.5%)
> 1000 87 (30.38%) 6* (35.3%)
Unknown 19 (15.6%) 3 (17.6%)

* Includes 1 with 14,000 hrs., 2 with over 20,000 hrs.

Carbon Monowide. Carbon monoxide levels
were routinely requested. Only four positive
levels in three accidents were reported. Levels
of 10% and 13% in two accidents were not con-
sidered significant. The direct and distractive
effects on a father and son with levels of 27.5%
and 40%, respectively, are felt to have caused one
accident which was fatal to both occupants.

Agricultural Chemicals, Three pilots were
killed during aerial application flying. One had
evidence of severe exposure to organic phospho-
rus insecticides, evidence of some exposure to
chlorinated hydrocarbon insecticides, and narrow-
ing of the left anterior descending coronary
artery to 10% of normal at one level. Another
had a low normal cholinesterase level and no
flying time seven months before his fatal acci-
dent. A third with reported “blackouts” had
evidence of brain damage from head trauma two
years before. A cholinesterase determination was
requested, but was not obtained, in the last. case.

All three were flying the same type agricultural
aircraft. This particular aircraft has no higher
accident rate than other “ag” aircraft but fatal-
ity rates are four times higher than other types.*

Miscellaneous. A commercial pilot with over
7500 hours was found to have crashed in nearly
level flight 57 miles off course. Investigation re-
vealed that he had been drinking the night before
and had obtained little, if any, sleep before his
5:00 a.m. departure, It is felt that the pilot went
to sleep in flight.

Discussion. Increased visits by physicians to
accident sites to determine the availability and
use of protective equipment, and crash-injury cor-
relations, are a major remaining need for success-
ful human factors investigations of general avi-
ation accidents.

An increased awareness of, and searching for,
the physical and chemical presence of drugs and
toxic materials are also indicated. The two possi-
ble human factors accidents involving very ex-
perienced pilots with reported liver barbiturate
levels are of particular interest. A relationship
of the liver to blood levels near unity can be
assumed when barbiturates are taken in divided
doses. The amounts of d-amphetamine and
amobarbital in one of the preparations reportedly
taken are sufficient, individually, to increase judg-
ment error. The levels involved in these cases
are not sufficiently elevated to permit one to
draw any conclusions, however. This may be be-


The role of drugs and alcohol in non-fatal
accidents is virtually unknown. Blood alcohol
levels on survivors are difficult to obtain.

Crash-injury correlations and the use of pro-
tective equipment in non-fatal accidents with
injuries can be coded for analysis but there is
practically no medically-oriented gathering of
this data.

Increased participation in the investigation of
these accidents by Regional Flight Surgeons and
Aviation Medical Examiners is indicated to deter-
mine the adequacy of current medical standards,
identify areas needing emphasis in airman edu-
cation (or regulation), and attain maximum avi-
ation safety. Coding of the data in the regional
offices will better identify missing facts and
promising leads.

REFERENCES

. Dovenerry, J. D.: Personal communication with the
authors.

. Gispons, H. L.: Personal communication with the

authors.

Gispons, H. L., and Piecuus, J, L.: Analysis of Medi-

cal Factors in Fatal Aircraft Accidents. Texas J.

Med. 61:667, 1965.

4, Harper, C. R., and ALBERs, W. R.: Alcohol and Gen-

eral Aviation Accidents. Aerospace Med. 35 :462, 1964.

a

i

sd

5. Outline of Procedures for FAA Aviation Medical Ha-
aminer Participation in Aircraft Accident Investiga-
tion. New York: Federal Aviation Agency, Eastern
Region, Office of the Regional Flight Surgeon, July,
1961.

Smirx, G. M., and Beecuer, H. K.: Drugs and Judg-
ment: Effects of Amphetamine and Secobarbital on
Self-evaluation. J. Psychol. 58:397, 1964.

a

67-3282



AM 66-27

HUMAN FACTORS IN GENERAL AVIATION ACCIDENTS

J. Robert Dille
Edward W. Morris

Approved by Released by
the [PU sege€ 0
J. R. Due, M.D. P. V. Sizcen, M.D.
Curr, Civ, Arromepican Instrrore Feperan Air SurGEoN
JULY 1966

FEDERAL AVIATION AGENCY
Office of Aviation Medicine





cause of the sustained release form of the prepa-
ration, to the time since the drug was taken or
to a combination of these two factors,

The alcohol involvement in this series is lower
than in other published studies ** but neverthe-
less remains an area needing corrective action.
The accident rates by age group and flying ex-
perience are similar to those reported by Gibbons
and Plechus.*

Of particular concern is the frequency with
which family, friends, and local officials knew
the habits, and physical and mental conditions,
of the pilots and tolerated the situation, Ab-
stainers who accompanied inebriated pilots on
their fatal flights exercised particularly poor
judgment. We are also aware of underreporting
of significant medical history by physicians who
do not understand or accept our medical stand-
ards.

Statistical evaluation of each pilots’ medical
history, physical condition, autopsy results, toxi-
cologic findings, use of protective equipment,
crash-injury condition, experience, time of day,
phase of flight, weather, type of aircraft, etc., is
performed for all fatal and non-fatal accidents
by the Accident Studies Branch, Aeromedical
Applications Division, and has not been at-
tempted for this series.

NON-FATAL ACCIDENTS

Medical Conditions. Late in this series the
medical records were obtained and reviewed for
accident repeaters and pilots involved in acci-
dents which, from the initial reports, seemed
likely to be due to human factors. No statistical
correlation of medical conditions and accidents
was planned or attempted at the regional level.
The first week of this extended program, three
accidents with possible medical significance oc-
curred in a period of three days. A 36 year old
male with amblyopia, left eye, struck the ground
with the left wing of his Aeronca Champion on
landing. The same day, a 39 year old male with
20/50 uncorrectable distant vision, left eye, made
a hard landing in a Cessna 182 with substantial
damage. Two days later, a 65 year old male
with bilateral aphakia, struck high bushes which
swung his TA-1 into a ditch when he landed on
a gravel road for refueling.

Ethyl Alcohol. A flight surgeon-pilot crashed
at 5:00 a.m. shortly after buzzing his residence.
The aircraft traveled over 1000 feet from the

point where it struck the ground, and the pilot
is calculated to have traveled 408 feet from the
point where he was thrown from the airplane.
His injuries consisted of a superficial head
wound, a concussion with amnesia for a three
week period, and fractures of the left foot. He
was refused additional drinks at a local bar 6
and 14 hours before the accident, was reportedly
observed to stagger and fall between his car
and the airplane at 4:45 a.m., and told the deputy
sheriff at the accident site that he was drunk.
No blood or breath alcohol level was determined.

One pilot who called “mayday” over the San
Francisco area was sentenced to three days in
jail and fined $22 for operating an aircraft under
the influence of alcohol.

Only one blood alcohol level was obtained on
a pilot involved in a non-fatal accident. He
was a spray pilot with a 130 mg % blood alcohol
level who explained that he and many such pilots
drank to keep the organic phosphorus insecti-
cides from making their pupils small and re-
ducing their vision.

Agricultural Chemicals. The major attention
in the investigation of non-fatal accidents was
given to aerial application accidents. Two “ag”
pilots, who each had two accidents within a two
week period, were found to have reduced plasma
cholinesterase levels. They each struck wires one
time and the ground the other. Three other
pilots had single accidents and were found to
have reduced cholinesterase levels. One struck
large cables suspended between 100 foot steel
towers on his seventeenth pass over a field and
stated that he “did not know they were there”.

Discussion. The human factors investigation
of non-fatal accidents is still a relatively un-
tapped area which shows promise for consider-
able important data which could help prevent
future accidents. The incidence of various unsafe
acts (inadvertent landing gear retraction, for ex-
ample) by type of aircraft, pilot experience, time,
and phase of flight is being determined. The
correlations of these acts with various physical
defects reported on periodic physical examina-
tions are also being determined. Accident re-
peaters have been identified for evaluation of their
physical condition but there have been no signifi-
cant findings to date in this study. Emotional
and behavioral factors, which may play an im-
portant role, are rarely identifiable from reports
of routine physical examinations.


Ficure 1, The distribution of fatal general aviation accidents in the Western Region during a twelve month period.


HUMAN FACTORS IN GENERAL AVIATION ACCIDENTS

On September 17, 1908, Lt. Thomas Selfridge
was killed, and Orville Wright was seriously
injured, in the crash of the Army’s first airplane.
A Board of Inquiry determined that Lt. Self-
ridge suffered a fatal skull fracture when his
head struck part of the airplane structure on
impact. Attention was called to the need for the
crew and passenger to wear safety belts and
crash helmets in certain types of operations.
Military aircraft accident investigations have
been relatively complete since the first year of
Army aviation.

Since 1956 the Armed Forces Institute of
Pathology has provided the necessary aviation
toxicology and pathology support to the Civil

Aeronautics Board and the Civil Aeronautics,

Administration/Federal Aviation Agency. In
practice, this valuable service has been confined
mostly to air carrier accidents.

A Federal Aviation Agency Manual of Pro-
cedure on accident investigation, published in
October 1959, called for Regional Flight Surgeon
cooperation with the Flight Safety Foundation’s
Aviation Crash Injury Research division to deter-
mine what caused death or serious injury in sur-
vivable aircraft accidents, or prevented it in acci-
dents with severe destructive forces. Interest
was specifically disclaimed for the pilots’ back-
ground, competency, or physical condition.

In July 1961, Albers® published the first out-
line for Aviation Medical Examiners’ participa-
tion in light aircraft accident investigation. In
1964, Harper and Albers‘ published the first
statistics on the incidence of positive blood alco-
hol levels in pilots killed in general aviation
accidents. .

Aviation Medical Examiner participation in
accident investigation has increased rapidly.
There has been 100% coverage the past two years
in the Southwest Region.? The goal is medical
investigation of all aircraft accidents with serious
or fatal injuries to: 1) determine if human fac-
tors were primary or contributory causes of each
accident ; 2) establish the cause of death; 3) study

injuries and correlate them with structure, equip-
ment, and safety devices and recommend human
engineering design improvements when indi-
cated; and 4) identify the victims.

The results of this program the past year in
the nine states in the Western Region have been
reviewed and tabulated for this report.

FATAL ACCIDENTS

During the twelve months ending October 31,
1965, there were 122 fatal general aviation acci-
dents, with 236 fatalities, in which the wreckage
was located within one week and the Western
Regional Flight Surgeon’s office was notified.
The distribution of these accidents is shown in
Figure 1. Autopsies were requested for all of
the pilots and were performed in 86 of the acci-
dents. A blood alcohol determination was also
requested on each pilot and was obtained in 88
of the accidents Failures were attributable to
accidents with marked disintegration, delays in
communications, and remote locations. Burial
was at the scene in one accident included in this
study.

Medical Conditions. No accidents were found
to be definitely due to an existing medical con-
dition resulting in partial or complete incapaci-
tation; it is the probable cause in one, however.

An intern, who reported occasional bouts of
nervous gastritis during medical school and in-
ternship, was felt to be qualified for a Third
Class Medical Certificate by the AME, The
AME later learned that this physician had not
completed his internship, apparently due to psy-
chiatric problems, and reported this to the Re-
gional Flight Surgeon. A letter was sent to the
physician-airman directing him to return his
medical certificate. This letter was found in his
pocket at the time of his fatal accident ten days
later. A pistol was also found in the wreckage.
During the investigation it was found that six
instructors had refused to endorse his Student
Pilot Certificate and one had been threatened
with a gun to endorse it, he was known to be



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