pilots who were involved in accidents, that 47
had no blood alcohol level, 18 were doubtful, 14
had a small trace, and 18 had levels of measur-
able degrees.

Interestingly, the flight surgeons’ guide for the
First World War, contains only the briefest
mention of the harmful effects of alcohol on flying
(“how foolish it is to go up in an aeroplane not
only in a condition of drunkenness, but even in
a state of excitation, which may falsify your sen-
sations and predispose you to foolish action”—
statement by the French Flight Surgeon, Dr.
Guilbert, p. 130).8 A later text of aviation medi-
cine contained essentially no reference to alcohol
and flying, either as a potential problem or a fac-
tor in accidents. A text published a little later,
however, devoted several pages to the subject.?°

It became apparent in the 1940’s that the addi-
tive and synergistic effects of alcohol on impair-
ment when combined with various factors such
as fatigue, drugs, hypoxia, illnesses, etc., were
quite marked. Dr. McFarland points out that
Committees of the American Medical Association
and the National Safety Council have concluded
that drinking drivers may be divided into three
rough groups with respect to impairment:

1. Up to 50 mg % blood al-

cohol ------------------ for driving, the finding is
(2 oz. whiskey or 2 bottles _ inconclusive.
of beer)

2. 50 mg % to 150 mg % ~-. for driving violations, the
(6 oz. whiskey or 6 bottles finding is relevant to
of beer) prosecution.

3. 150 mg % and higher -__ the finding is clear cut evi-
dence that driving be-
havior is significantly in
fluenced by drinking.

Illustration One presents the table used by Dr.

Kurt M. Dubowski, Director of Clinical Chem-

istry and Toxicology, of the University of Okla-

homa Medical Center, in assessing the impair-

ment of drivers at given blood alcohol levels.
It should be noted that this table is based on

the adult, neither aged nor ill, whose size is in

150 pound range, and who is neither an habitual

- drinker nor an alcoholic. It also assumes that the
individual is not fatigued or preoccupied by
heavy mental or emotional burdens.

IV. Analysis of the Flying Task
Illustration Two provides a diagram of certain
of the key factors involved in piloting a light

aircraft. These include roll, pitch and yaw move-
ments. There are such matters as “velocity never
exceed”, stalling speeds, drift movements, gusts,
and critical attitudes. The automobile presents
an extremely simplified control picture with re-
spect to the above points (as a matter of fact,
under most driving conditions, the automobile
has none of these considerations).

In addition, the light plane pilot must navigate,
must make appropriate control settings, must
coordinate, and must make critical adjustments
of the power, trim, mixture, propeller, etc., prior
to take-off, during climb, en route, during descent,
and when landing. He must exercise proper
judgments concerning “go” or “no go” in differ-
ent situations, a matter seriously compromised by
the effects of alcohol on the cerebrum and on the
emotional mechanisms.

The pilot must operate’ the aircraft in the air
at speeds many times those used by cars. When
he changes the position of one control, almost
certainly all of the other controls will be affected.
Weather factors in flying are far more crtical
than is the case with autos, and pilots must also
calculate how the barometric pressure and the air
temperature will influence his plane’s lifting ca-
pabilities at given airfield lengths and with given
weight loadings.

Visibility factors concerned with haze, dust,
rain or darkness, icing problems, and the occur-
rence of the unanticipated (head winds, fuel
shortage, engine or radio malfunction, etc.), must
be dealt with quickly, correctly, and skillfully.
The leeway concerning these factors for the auto-
mobile driver, as compared to the airplane pilot,
is great. In addition, automobiles have yet to
become involved in airport and en route radio
procedures.

Owners handbooks for typical light single-
engine and four-place retractable-gear aircraft,
show 20 different pre-flight categories of items to
check out, 5 specific starting maneuvers, 10
ground check operations, 10 pre-take-off checks,
7 climb operations, 10 categories of en route op-
erations, 7 prelanding operations, 3 landing oper-
ations, and 8 shut-down categories of items. This
bare minimum of 80 essential items, all of which
must be individually ascertained to ensure a suc-
cessful flight accomplished with a reasonable level
of safety, makes an interesting comparison with
the 10 items listed in current automobile owner’s
manuals,



Levels of Alcohol in Relation to Signs and Symptoms

Reference: Kurt M. Dubowski, Ph.D., FAIC

University of Oklahoma
Medical Center

Oklahoma City, Oklahoma

Member, Committee on Tests for Intoxication

National Safety Council

ILLUSTRATION I

ETHYL ALCOHOL LEVEL
Per Cent by Weight

Blood

Urine

STAGE
OF
ALCOHOLIC
INFLUENCE

CLINICAL
SIGNS /SYMPTOMS

0.01-0,05
(10-50 mg %)

0,01-0,07

Sobriety

No apparent influence

Behavior nearly normal by ordi-
nary observation

Slight changes detectable by
special tests

0.93-0.12
(30-120 mgZ)

0,040.16

Euphoria

Mild euphoria, sociability, talk-
ativeness

Increased self-confidence; de~
creased inhibitions

Diminution of attention, judgment,
and control

Loss of efficiency in finer
performance tests

0.09-0.25
(90-250 mgz)

0,12-0.34

Excitement

Emotional instability; decreased
inhibitions

Loss of critical judgment
Impairment of memory and compre-
hension

Decreased sensitory response; in-
creased reaction time

Some muscular incoordination

0.18-0.30
(180-300 mg%)

0,24-0,41

Confusion

Disorientation, mental confusion;
dizziness

Exaggerated emotional states
(fear, anger, grief, etc.)
Disturbance of sensation (diplopia,
etc.) and of perception of color,
form, motion, dimensions

Decreased pain sense

Impaired balance; muscular inco-
ordination; staggering gait, slur-
red speech

0.27-0.40
(270-400 mg%)

Q.37-0.54

Stupor

‘Apathy; general inertia, approach-
ing paralysis

Markedly decreased response to
stimuli

Marked muscular incoordination; in-
ability to stand or walk

Vomiting; incontinence of urine
and feces

Impaired consciousness; sleep or
stupor

0.35-0.50
(350-500 mgz)

0.47-0,67

Complete unconsciousness; coma;
anesthesia

Depressed or abolished reflexes
Subnormal temperature
Incontinence of urine and feces
Embarrassment of circulation and
respiration

Possible death

0,45+

(450 mgz)

Death

Death from respiratory paralysis



dents). As seen in the accident case described
elsewhere in this paper, concerning an elderly
pilot who flew into a field which was usually un-
controlled, but which had a temporary control
tower in use on the day in question, unexpected
“coalitions” can occur, as described in the theory
of games, which can lead the pilot-player to lose
if he doesn’t make the right decision at the right
time. In the case in question, the evidence indi-
cates that the 35 mg % blood alcohol level was
sufficient to decrease the pilot’s ability to properly
respond to the red signal which the tower, in
‘coalition’ with the elements, gave him—results—
a lost game.

The interesting thing about the study of games,
is that statistics is not of the essence in game
theory. Thus, potential flying hazards can be
identified within the context of a given set of
circumstances, obviating the necessity of experi-
encing a series of tragedies which, in retrospect,
reveal what would be anticipated through game
theory.

V. Certain Accidents and Experiences

It is worthy of note that in both World Wars,
and during peace time, various pilots have accom-
plised amazing aerobatic maneuvers while under
the influence of alcohol. Certain air mail pilots
not infrequently undertook their scheduled flights
in the 1920’s following the consumption of con-
siderable amounts of alcohol.** However, warn-
ings begin to be found in lay aviation books in
the 1930’s and early 1940’s. In one book, the
statement is made that alcohol is “really a very
common” cause of aircraft accidents.“

In one midwest state and its nearby area, dur-
ing the period bounded roughly by 1963, half of
the ten fatal light airplane accidents involved
drinking pilots.*

One of these accidents involved a businessman.
who had consumed alcohol to the point that while
he was flying locally, he had markedly slurred
speech in his communications with the Flight
Service Station personnel. He made repeated
passes at a hard surfaced runway which was at
least 4000 feet long, but, even with the assistance
of these persons, was unable to land. He later
had a fatal crash when the airplane ran out of
fuel.

Another of these involved the suicide of a
person who intentionally flew into a University
building after announcing his plans to do so over

Unicom to the local airport. The pilot had long
been troubled by emotional problems, and had,
as revealed by post mortem, a blood alcohol level
of 260 mg %. This level is not infrequently as-
sociated with the production of emotions of rage
and grief, and, in troubled individuals, can lead
to violent actions accompanied by potential or
actual self-destruction.

A third of these involved an elderly pilot
(seventy) who stalled out proceeding downwind
while initiating a 360 degree pattern turn after
receiving a red light from a temporary tower
during a windy day. The post mortem examina-
tion revealed a blood alcohol of 35 mg %, which,
in view of the circumstances of the accident, the
age of the pilot (aging decreases the resistance
of an individual to most pharmacologic agents,
including alcohol), and the other considerations
discussed previously in this paper, was felt to
have played a major role in bringing about the
accident.

It should be noted here, that the currency of a
given pilot (in terms of recent, flight experience),
the flight history of the pilot (in terms of quality
of training and over-all flight experience, know]-
edge and competency), and the familiarity of
the pilot with the aircraft and geographic area
involved, bear importantly on the degree of ad-
verse effects of alcohol on flight proficiency.

Those pilots who fly daily, as, for example, the
previously mentioned air mail pilots, become so
familiar with their aircraft, that they can com-
pensate up to a point for small amounts
of alcohol. For example, the famous Australian
pilot, Sir Charles Kingsford-Smith, reports that
during his 1931 attempt to set an Australia to
England speed record, he “took an occasional nip
of brandy—which kept me going”. Pilots who,
as often found in the business-man pilot and
pleasure pilot categories of general aviation, fly
one or two hours a month, or who have just
“stepped up” in aircraft class, are very suscepti-
ble to flight performance impairment through
alcohol. It is not unusual to find that in certain
of the latter two groups of pilots, each flight is
an adventure in the sober state, much less the
ethanolized state.

The paper by Drs. Albers and Harper bears out
this latter observation, in that they find that only
three of the 56 positive blood alcohol cases had
current instrument ratings. They also found
that the positive alcohol group peaked at 300



Obviously, flying, as described above, is con-
siderably more complicated than driving, and
offers eight times or more the opportunity for
error than is the case with driving.

The agile mind, unencumbered by alcohol, cer-
tain drugs, fatigue, or physical impairment, finds,
through practice, that mastery of the above mat-
ters pertaining to safe flight is accomplished with
surprising ease. However, as Dr. McFarland
points out in the above reference, alcohol, even
in small amounts, produces, among other things:

(1) A dulling of critical judgment;

(2) A decreased sense of responsibility ;

(3) Diminished skill reactions and coordina-
tion;

(4) Decreased speed and strength of muscular
reflexes (even after 1 ounce of alcohol) ;

(5) Twenty percent decrease in efficiency of
eye movements during reading (after 1 ounce of
alcohol) ;

(6) Significantly increased frequency of errors
(after 1 ounce of alcohol) ;

(7) Constriction of visual fields;

(8) Decreased ability to see under dim illumi-
nations;

(9) Loss of efficiency of sense of touch;

(10) Decrease of memory and reasoning abil-
ity;

(11) Increased susceptibility to fatigue and
decreased attention span;

(12) Decreased relevance of responses in free
association tests, with an increase in nonsensical
reactions;

(13) Increased self confidence with decreased
insight into immediate capabilities and mental
and physical status.

Thus, it becomes clear that in view of the con-
siderably increased complexity of flying over
that of driving, the effects of alcohol will be more
deleterious in the case of flying. In addition to
the increased complexity of flying, flight also
involves accelerations and decelerations around
the roll, pitch and yaw axes, and in the horizon-
tal, vertical and lateral directions, which stimu-
late the vestibular organs, the proprioceptive
system and other systems. Proper interpretation
(or proper disregard) for the sensations accom-
panying these accelerations must be made. Al-
cohol interferes with this interpretation.

It should be noted that in those aircraft simu-
lators which do not produce g’s, this critical fac-
tor in flight performance is not duplicated, a

matter simplifying the task of “flying” the sim-
ulator, and requiring careful interpretation of al-
cohol studies conducted with simulators. It
should also be noted that automobiles normally
have ‘accelerations which are under the control
of the driver in the longitudinal and the lateral
(turn) axes only. On icy or wet roads, yawing
about the vertical axis may be a complicating
control factor for drivers.

Critical to flying, is the effect of alcohol on
the “latent deviation of the eyes” (heterophoria).
A review of this subject reveals that with in-
creasing levels of blood alcohol, orthophoric (nor-
mal eye muscle balance) individuals gradually
become esophoric (tendency to be cross-eyed).??
Higher levels of alcohol produce esotropia (cross-
eyed) and a resulting diplopia (double vision) in
the primary position. A deterioration of “motor-
fusion” reserve occurs, and nystagmus appears
during, and remains long after (thirty six hours),
alcohol consumption.

One interesting consideration to be briefly
mentioned here, is that when a person undertakes
to pilot an aircraft from a point on the surface
of the earth, along a given course, to another
point on the surface, hundreds of decisions must
be made, some on the basis of incomplete informa-
tion, some on the basis of unexpected information
(adverse weather occurs, etc.). Proper maneu-
vers must be accomplished, and a return to the
home station, or a landing at an alternative point
may be judicious.

To a lesser extent, the above considerations ap-
ply also to local pleasure hops. The above facts
mean that the flying task is amenable to treat-
ment through the mathematical theory of games
as developed in 1928 by John Von Neumann.’*
Visual Flight Rules flying from uncontrolled
fields represents a two party (duopolistic) game,
in which one party is the pilot, and the opponent
is represented by ‘chance’ and the ‘laws of na-
ture’, The essential feature of a game is the
fact that the individual player has to do with
one or more opponents, and that only some of the
relevant variables are under the control of a
given player. To win (assuming survival as a
criteria of winning) the pilot has to return to
the surface of the earth in an’ intact status,

Now, it can be readily seen that anything which
impairs the pilot player’s ability to make succes-
sive decisions will lead to an increased number
of lost games (increased number of fatal acci-


VII. Conclusions

1. One ounce of whiskey or one beer ingested
during the period which immediately precedes
flight planning prior to undertaking a flight can
cause a significant impairment in airmanship.

2, Present evidence indicates that about one
third of the fatal accidents now being experi-

enced in civil light aircraft today are facilitated
directly or indirectly by ethyl alcohol ingestion.

8. Within the context of this paper, an ag-
gressive education program for general aviation
airmen is indicated, and represents one of the
major areas within which a substantial reduction
may be accomplished in the incidence of light air-
craft accidents.

REFERENCES

1, Scumipr, Worreana, Smart, Recrvatp G., and Pop-
HAM, Roperr E.: “The Role of Alcoholism in Motor
Vehicle Accidents”, Trafic Safety: 4-6, December
1962, p. 21.

Sarr, H. W., PopHaM, R. E.: “Blood Alcohol Levels

in Relation to Driving”, Journal of the Canadian

Medical Association: 65, 1951, pp. 325-828.

8. Bert, Paut: Barometric Pressure, 1877, Translation
by Hitchcock, M. A. and Hitchcock, F. A., College
Book Company, Columbus, Ohio, 1943, pp. 1-1055.

4, Harper, Crarves R., and AvBers, WiltIaM R.:
“Alcohol and General Aviation Accidents”, Aerospace
Medicine, 35:5, May 1964, pp. 462-464.

5. Federal Aviation Agency: “Alcohol and Aircraft Ac-
cidents”, Medical Newsletter, Volume 8, Number 7,
July 1962, pp. 7-8.

._Kuvasrorp-Sairx, Sm Cuartes: My Flying Life, The

Aviation Book Club, London, 1939, p. 210.

Hess, Herman A.: “Drugs—Alcohol—and Flying”:

The Flying Physician, Volume 8, Number 1, January

1964, pp. 11-15.

8 War Department: Air Service Medical, U.S. Govern-
ment, Printing Office, 1919, pp. 1-446.

9. ArmsTrone, Harry G.: Principles and Practice of
Aviation Medicine, Bailliere, Tindall and Cox, Lon-
don, 1939, pp. 1-496.

N

2

a

10. Karka, M. Martyn: Flying Health, Military Service
Publishing Company, Harrisburg, Pennsylvania, 1942,
pp. 1-248.

11. McFartanp, Ross A.: Human Factors in Air Trans-
portation, McGraw-Hill Book Company, Inc. New
York, 1953, pp. 1-830.

12, Masrers, Ricuarp L.: “The Hffects of Alcohol and
Hypoxia on the Heterophorias”, Aeromedical Re-
views, Review 2-64, U.S.A.F, School of Aerospace
Medicine, February 1964, pp. 1-22.

18. Smrru, Drawn C.: By the Seat of My Pants, Little,
Brown and Company, Boston, 1961, p. 141.

14, JorpaNorr, Assen: Safety in Flight, Funk and Wag-
nalls Company, New York, 1941, p. 127.

15. Contry, Crame: “Five Drinking Pilots Died in
Crashes Last Year”, The Daily Oklahoman, January
8, 1964, p. 12.

16. Vaspa, S.: “Theory of Games”, The World of Mathe-
matics, Volume II, Simon and Shuster, New York,
1956, p. 1285.

17. Federal Aviation Agency: “General Operating and
Flight Rules”, Code of Federal Regulations, Part 91,
Title 14, January 1, 1963.

18. Gorpsretn, Leon G.: “Human Variables in Traffic
Accidents: A Digest of Research”, Trafic Safety,
Volume 8, No. 1, March 1963, pp. 26-81.



AM 66-29

RECENT FINDINGS ON THE
IMPAIRMENT OF AIRMANSHIP BY ALCOHOL

Stanley R. Mohler, M.D.

Approved by Released by
pom Pag 7 ahs , “ [Usege€ mo
James L. Harris P. V. Srzczn, M.D.
Cur, ArromepicaL Epucation Feprray Aim Surceon

Division

September 1966

FEDERAL AVIATION AGENCY
Office of Aviation Medicine





WEIGHT

ILLUSTRATION IL

Depicted above are certain key features of flight that determine the
nature of the pilot's tasks. Three dimensional travel requires considera-
tions beyond those specific to driving or yachting. : For example, the pilot
must watch his stall speed, red line speed, wind drift, and navigation pro-
cedures. He must coordinate roll, pitch and yaw, and manage various
controls, including mixture and flaps. He must exercise a high degree of
judgment, especially with respect to weather conditions, and must remain
at a level of alertness sufficient to meet emergencies. These various re-

quirements are adversely affected by acutely ingested alcohol.

6763294



hours, a relatively low flight experience. Sixteen
percent had 100 hours or less, a factor two times
that for the 100 hours or less pilot experiencing
a fatal accident not involving alcohol. The al-
cohol group also had twice as many cases at
night than did non-alcohol groups. Also, more
than half of the accidents involved “loss of con-
trol,” including stall-spin accidents, and twenty
percent involved “struck object” accidents.

Drs. Albers and Harper conclude that alcohol
adversely affects flying performance at levels con-
siderably below those which adversely affect
driving. They use 15 mg % as the critical level
where adverse effects may begin to appear. Pre-
liminary analyses of a current series of studies at
the Civil Aeromedical Research Institute, confirm
the critical nautre of the 15 mg % level. Also,
the combination of small amounts of alcohol with
various hypoxia levels (starting at 8,000 feet) is
under scrutiny. The tests used determine fine co-
ordination, decision capabilities, flicker fusion
levels and involuntary eye movements (nystag-
mus). An interdisciplinary team consisting of
psychologists, physiologists and physicians, is
accomplishing the studies, which are conducted at
CARI with special apparatuses in a large alti-
tude chamber.

It is to be stressed that the great majority of
general aviation pilots are mature and dependable
individuals, and operate their aircraft safely.
However, through lack of understanding, or
proper education, or character, a small number
of the total pilots, undertake flights while under
the influence, and a certain percent of these have
accidents. A certain number of episodic drinkers
become pilots, and, sooner or later, some of these
undertake to fly during a spree. Also, a minute
number of pilots, as is true in all groups, be-
come true alcoholics, and some of these sooner or
Jater decide to make a flight while drinking. In
the interest of safety, alcoholism is disqualifying
for an airman’s medical certificate as issued by
the FAA.

VI. Selected Comments

Part 91 of the Federal Aviation Regulations,
“General Operating and Flight Rules”, provides
that no person may act as a crewmember (or pilot
in command) of a civil aircraft while under the
influence of intoxicating liquor.” The enforce-
ment of this regulation is difficult, and its ulti-
mate impact must derive from the individual

pilot. It should be noted that the individual pilot
must be alert to sources of ethyl alcohol other
than liquor (cough medicine, tonics, etc.). A
good rule to follow is that if one is sick enough
to require these substances, he is too sick to fly at
the time.

Another matter of concern, is the possibility of
“endogenous alcohol” being formed in the tissues
during the period following death.” Also, one
must be certain that the laboratory accomplish-
ing the blood alcohol test is using a reliable
method.

Since the days of the English Admiral, Ed-
ward Vernon, who wore a grogram coat and was
known as “old Grog” (who ordered the sailor’s
rum diluted, an event leading to any intoxicating
liquor called “grog’), it has become increasingly
apparent that we will live with machinery, par-
ticularly vehicular machinery, and specifically
aircraft, much better if we go easy with alcohol.
A good rule is to allow twenty four hours from
“bottle to throttle”, although fifteen should be
sufficient following light indulgence (3 ounces).
Eight hours is the minimum time allowed by the
Federal Aviation Agency for its own pilots be-
fore flight can be undertaken following alcohol
consumption (Flight Standards Handbook 4040.1,
Paragraph 2.111). This rule has worked with
apparent safety, within the context of FAA
flight activities and through the exercise of
judgment by FAA pilots.

A recent article on automobile accidents, is con-
sistent in its conclusions concerning drivers with
the conclusions in this paper concerning pilots."*
The article reports that 50 mg % blood alcohol
levels and lower have a deleterious effect on
driving performance and that alcohol is a con-
tributing or critical factor in 25 to 50% of fatal
automobile accidents.

An active and agressive airman education pro-
gram concerning the potentially disastrous. con-
sequences of mixing alcohol and flying, even at
very low levels of alcohol, can potentially result
in a significant reduction in the annual toll of
life taken through light aircraft accidents. For
those who would consider combining flying with
drinking, it should be emphasized that the beauty
of flight, and the pleasures of flying, are, of them-
selves, sufficiently satisfying (for many even ex-
hilarating), to preclude any necessity of combin-
ing alcohol with flying.


while the third, who, among other things, had
“drunk rum abundantly” was the only one who
remained awake.

It becomes apparent that traveling through
the air beneath a balloon is a matter considerably
removed in complexity from traveling by other
means, The balloonist has control of one para-
meter of his vehicle: the vertical dimension, and
the time parameter is essentially that bounded by
the speed of the wind. Of course, the passive
balloonist, usually not called upon for great
physical exertion “at altitude”, would not notice
the effects of alcohol as soon as the mountain
climbers described by De Saussure.

Similarly, it is clear that when great-grand-
father climbed into his buggy and started out
across the countryside, he delegated a fair share
of the operator task to the horse, which, as
previously mentioned, had no blood alcohol level.

It is not uncommon for yachtsmen to habitu-
ally drink while piloting their craft, apparently
with a fairly respectable degree of safety. In
the following sections, the task of yachting, will
be compared with that of driving, and, subse-
quently, with that of flying. First, a brief pres-
entation of pertinent considerations relative to
alcohol in the context of this paper will be made.

III. Relevant Considerations

In the recent analysis covering 1963, startling
information concerning the extent to which al-
cohol is associated with fatal light airplane ac-
cidents is revealed.* The authors, who operated
the Fedral Aviation Agency’s medical investiga-
tion program relative to U.S. civil aircraft acci-
dents, have found that for the year 1963 there
were 477 general aviation fatal accidents in which
899 persons died (the term general aviation en-
compasses all civilian private, business, corporate
and commercial flying, excluding air lines opera-
tions—scheduled and unscheduled).

The above study shows that toxicological ex-
aminations were performed on the pilots involved
in 158 of these accidents. Fifty six, or 35.4 per-
cent, of the examinations showed 15 mg % (15
milligrams alcohol per 100 milliliters of blood,
or 0.015 percent) or higher blood or tissue ethyl
alcohol concentrations. The average blood alcohol
for the group was 145 mg % (0.145 percent).

As the authors point out, this is the first time
that objective evidence indicates that one-third of
the fatal accidents in general aviation are associ-
ated with alcohol. Due to the absence of alcohol

determinations, they excluded ten fatal accidents
where the history established alcohol as a key
factor, and they also excluded cases where the
examinations showed levels below 15 mg %.

‘When four ounces of pure alcohol are consumed
by an average man four hours prior to an acci-
dent, a blood alcohol level of 40 mg % (0.04 per-
cent) or more will be found at the time of the
accident.1_ Consequently, it appears from the
above analysis that a significant number of gen-
eral aviation pilots are undertaking to pilot air-
craft shortly after indulging in alcohol, and that
an aggressive airman education program regard-
ing the incompatibility of alcohol and flying is
indicated.

In 1962, the Federal Aviation Agency notified
its five thousand Designated Aviation Medical
Examiners that an analysis of general aviation
accidents for the years 1957 to 1960 showed that
forty to fifty percent of the accidents in which
the investigation report mentioned alcohol were
fatal, while only ten percent of the accidents in
which alcohol was not mentioned were fatal.®

Dr. McFarland has pointed out that .over
ninety percent of the ingested alcohol is metabo-
lized at a fixed rate by the liver, and that if 163
grams of ethyl alcohol are rapidly ingested
(equivalent to 5.5 ounces of ethyl alcohol, 7-8
beers or 5 to 6 shots of whiskey), blood alcohol
levels will reach more than 250 mg % in about
two hours? Even eighteen hours later, the de-
clining blood alcohol will still be in the 50 mg %
range. Taking the same amount of alcohol over
a four hour period will result in a lower peak
blood alcohol level (220 mg % at four hours),
but the eighteen hour blood alcohol level will be
almost the same as noted above, due to its fixed
rate of metabolism by the liver.

Dr. Herman Heise has reported to the Flying
Physicians’ Association that individuals tested
for judgment, sensory and motor functions, prior
to and shortly after the consumption of alcohol,
showed deterioration at blood alcohol levels in the
range of 50 mg.%.’ Two shots (two ounces) of
whiskey or two beers will produce a 50 mg %
blood alcohol level in a 150 pound man.

He also stresses the fact that the potential after
effects of alcohol, as found 24 hours later (hang-
over, nystagmus*, etc.), can be detrimental to
flying, and discusses the interesting finding in 92
post mortem examinations of Swedish Air Force

* Involuntary oscillation of the eye balls.


RC /05Y¥

US HY

ia
BIOLOGY ©
LIBRARY

RECENT FINDINGS ON THE
IMPAIRMENT OF AIRMANSHIP BY ALCOHOL

Stanley R. Mohler, M.D.*

I. Introduction

Evidence indicates that ethyl alcohol was as-
sociated in 1963 with one-third of the fatal gen-
eral aviation accidents An aggressive airman
education program on these findings appears to
represent a major means of accomplishing a
significant dent in the accident rate.

Does ethyl alcohol in small quantities really
impair airmanship? Many people apparently get
away with driving and drinking—cannot they do
so with flying? To find answers to these ques-
tions, the following studies and analyses have
been undertaken.

“Taking one for the road” became a tradition
in the horse and carriage era of transportation.
The indications are that no significant increase
in the accident rate accompanied this practice
(although the statistics are sketchy). Also, it
was helpful that the horse had no blood alcohol
level. .

As the automobile came into being during the
early twentieth century, a carryover occurred with
respect to the custom of driving in various states
of intoxication. Physicians and law-enforcement
officers began to see an apparent relationship be-
tween alcohol and driving accidents, but con-
flicting experiences clouded the picture.

As pointed out by Dr. Wolfgang Schmidt and
his colleagues, a great deal of confusion has re-
sulted because of a failure on the part of in-
vestigators to differentiate between (1) the im-
pairing effects of alcohol on proficiency with
respect to a given task, and (2) the character of
the individual who drinks alcohol sufficiently to
be clasified as an alcoholic? This paper is con-
cerned with the degree of short term impairment
which follows the recent consumption of alcohol.

*Dr, Mohler is Chief, Aeromedical Applications Division,
Office of Aviation Medicine, Federal Aviation Agency, Wash-
ington, D.C.

The following information represents an at-
tempt to summarize the present knowledge with
respect to the significance of alcohol as a pre-
cipitant or predisposing factor in light aircraft
accidents. The physician, flight surgeon, and
aviation educator, armed with the facts, can
serve more effectively in their respective roles as
promoters of flight safety and improved public
health.

II. Base-line Knowledge

A survey of the general driving population of
one large community revealed that 23 percent of
the persons involved in automobile accidents had
blood alcohol levels of varying amounts? Studies
in other communities have indicated both higher
and lower proportions of automobile accidents
involving alcohol. A true assessment of the role
of ethyl alcohol in vehicular accidents is often
complicated by (1) incomplete investigations of
many accidents, (2) absence of blood or breath
alcohol determinations, (8) lack of accurate “non-
alcohol” involved accident data for a given en-
vironment, and (4) undetermined operator char-
acteristics (non-alcoholic, alcoholic, physically im-
paired, emotionally unstable, etc.).

Curiously, although De Saussure warned as
early as 1786 that there is an incompatibility be-
tween enduring the low barometric pressure en-
vironment found on high mountains and the con-
sumption of wine or liquor, two balloonists of
the era thought otherwise? Robertson ascended
jn a balloon from Hamburg in 1803, and upon
reaching a height equivalent to twelve inches of
pressure (304.8 mm Hg, or roughly equivalent to
98,000 feet), records that only with the aid of a
little fortifying wine did he succeed in “finding
intervals of mental clarity and power”. The
same year, Zambeccari and two colleagues as-
cended from Bologna, and reported that at high
altitude two of the aeronauts fell in a torpor,



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