Since the FAA had not conducted any research on the effects of smoking
on pilot performance and since we knew of no aircraft accidents in which
smoking or the resulting carboxyhemoglobin (COHb) levels have been found
to be the cause or a contributing cause, the submitted references were reviewed
and our only relevant data, the records of 2,660 fatal general aviation air-
eraft accidents that occurred in 1973 through 1976, were examined.

Several of the referenced studies were misleading. Only one of every
eight airline pilots responded to a questionnaire and, predictably, most were
nonsmokers. Some used nonsmokers as subjects. Reports sometimes failed to
give blood COHb, reporting only ambient CO corcentrations. Most used CO
without including the effects of nicotine. Measurement techniques for CC in
use before 1970 are now known to have had serious technical flaws and consid-
erable error. Spaces were occasionally smail and poorly ventilated, yet vaiues
were related to cockpits 5-10 times larger where the air is changed every 3-5
minutes. Performance tasks used frequently had a questionable relationship
te pilot tasks. It was assumed that perfect visual acuity, depth perception,
night vision, time and distance judgmont, and visual brightness threshold were
necessary for safe pilot performance. Decrements in time perception reported
at 50 ppm CO in one study (6) were not corroborated by other research groups
(12,14,15,16,22,23) nor by the original investigator (5). Our review of the
literature found that the cardiovascular effe-ts of 10% of COHb are insig-
nificant in healthy humans (20), smoking has beneficial effects on the psycho-
motor performance of smokers (7,13), withdrawal effects are real (19), and
the same investigator who is widely quoted as finding significant impairment
of visual thresholds at 22 to 4% COHb (11) did not find driving performance
seriously impaired at 17% CCHb (10).

Qur review of the petitioners’ report and several references did aot
support a ban on smoking in our opinion, and we thus proceeded to examine
our accident data.

METEOD

The FAA records of 2,660 fatal general aviation aircraft accidents that
eccurred in 1973-76 were examined. For 1,559 that contained toxicology reports,
COHb levels were determined in 1,197; of the latter, 817 accidents without
fire were separated into six categories (Table I).

For each accident, the location, date, time of day, weather, altitude,
type aircraft, pilot age, pilot medical conditions, type of accident, avail-
aole human factors details, autopsy and toxicology results, and performing
laboratory were documented. Any FAA statement about each accident's possibie
cause wes also documented, but the National Transportation ¢efety Board makes
the official determination and their reports were not readily available for
use.

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REFERENCES

Anderson, E. W., R. J. Andelman, J. M. Strauch, et al. 1973. Effect of
low level carbon monoxide exposure on onset and duration of angina pectoris.
Ann. Intern. Med. 79:46-50.

Aronow, W. S., et al. 1972. Effect of freeway travel on angina pectoris.
Ann, Intern. Med. 77:669-676.

Aronow, W. 5., and M. W. Isbell. 1973. Carbon monoxide effect on
exetcise-induced angina pectoris. Aon. Intern. Med. 79:392-395.

Ayers, S. M., S. Giannelli, Jr., and H. Mueller. 1970. Myocardial and
systemic responses to carboxyhemoglobin. Ann. NY Acad. Sci. 174:268-293.

Beard, R. R. 1970. Statement made during the discussion of his paper.
First Annual Conference on Environmental Toxicology, September 9-11.

Beard, R. R., and G. A. Wertheim. 1967. Behavioral impairment associated
with small doses of carbon monoxide. Am. 3. Public Heaith 55:2012-2022.

Frankenhaeuser, M., A. L. Myrsten, B. Post, and G. Johansson. 1971.
Behavioral and physiological effects of cigarette snoking in a monotonous
situation. Psychopharmecologia 22:1.

Grow, M. C., and H. GC. Armstrong. 1942. Fit to Fiy. New York, London,
D. Appleton-Century Co., Inc., p. 108.

Kafke, M. M. 1942. Flying Health. Harrisburg, PA, Military Service
Publishing Cco., pp. 95-96.

McFarland, R. A.
performance.

Low level expostre to carbon monoxide and driving
Heaith 27:355-359.

McFarland, R. A., F. W. Roughton, M. E. Hal
1944. The effects of carbon monoxide and 2

J. Aviat. Med. 15:381-394.

erin, and J. I. Niven.
ude on visual thresholds.

Mikuikxa, P., R. O’Dommell, P. Heinmig, and J. Theodore. 1970. The effect
of carbon monoxide on human performance. Ann. NY Acad. Sci. 174:4039-420.

Myrsten, A. L., B. Post, T. Frankenraeuser, and C. Johansson. 1972.
Changes in behavioral ané physicliogical activation induced by cigarette
sucking in habitual smokers. Psychopharmacologie 27:305-312-

O'Donnell, R. D., P. Chikos, end J. Theodore. 1971. Effect of carbon
monoxide exposure on human sleep and psychomotor performance. J. Appl.
Physiol, 33:513-518.

O'Donnell, R. D., P. Mikulka, P. Heinig, and J. Theodore. i971. Low
level carboa monoxide exposure end human psychomotor performance.
Toxicol. Appl. Pharmacol. 18:593-502.

?



TABLE III. OTHER FINDINGS IN SELECTED FATAL GENERAL AVIATION ACCIDENTS

COHb, %

t
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23
26
33

WITHOUT FIRE WHERE PILOT CARBOXYHEMOGLOBIN LEVELS WERE ELEVATED

Other Findings
Age 65, 8,020 ft, poor weather, hx of MI 3 yr before.

9,900 ft, snow, area obscured by clouds.

Rain, fog, 200-ft ceiling, pilot reportedly “exhausted.”

Nighttime, 9,100 ft, age 55, blood alcohol (BA) level of 72 mg%, corcnary artery
bypass surgery, no medical certiticate.

Aerobatics, age 60, diabetic, arteriosclerotic vascular disease.

Age 67, pilot incapacitation due to disturbance of cardiovascular system.

Pentobarbital.

Dusk, BA level at 88 mg%.

Age 59, “stroke prior to impact," exemption for hx of MI.

Canyon, 11,100 ft.
Weather, struck pover lines, BA level of 188 mgZ.

In-flight MI, age 51, while planting rice.

BA level of 151 mg%, dusk.

Midair, two "ag” aircraft seeding the same field.

Dusk, fuel exhaustion, BA level of 216 mgt.

Night, low altitude, fog, marijuana transportation.

Diabetes, hypertension, BA level of 111 mg%, age 52, 2,000 ft.
BA level of 252 mg%, unauthorized use of aircraft.

4,700 ft, low-level maneuvers to impress girl friend.

3,050 ft, flying under low ceiling, struck ground.

BA level of 100 mgZ.

Age 61, coronary artery disease, suspected suicide.

Age 55, mild diabetic, possible pilot incapacitaticn.

7,500 ft, spin, flight instructor.

Struck cable.

Midair, age 62.

Age 67, disorientation, 10,500 ft.

Age 50, disorientation.

Age 63, stroke hx, laceration of descending aorta.

21,150 ft, 190 mg% BA level.

3,300 ft, 230 mgZ BA level, phenobarbital.

Student pilot flying over swamp in bad weather became disoriented.
Disorientation.

120 mgZ BA level.
Age 51, 6,000 ft, 1,600-£t cvercast, obscured mountain peaks, reportedly exhausted,
known to cruise on autopilot and nap when tired.

Plane began shedding parts before crash.

4,960 ft, student pilot carrying 3 passenger crashed on takeoff.

Stall-spin shortly after takeoff.

Age 23, obstructive atherosclerotic plaque of corcnary artery found on autopsy.

Burzing, night, 53 mgZ BA levei.

Attempted VFR flight in IFR weather despite advice not to.

Aerobatics, 6,000 ft, second pilot had 8% COHb. CO suggested as possible cause
in FAA report.

Midair, no sedical certificate.

Crashed after shallow descent, reduced power, wings level.

94 mg% BA level, other pilot 20% COHb, muffler had no detected 1c<1a.

Dual, studert training, practicing takeoffs and landings, student had 8.7% COHb-

Suspected incoordination and drowsiness due to CO causing crash while attexpting
a@ landing. Muffler was in good condition.

Cruising at 14,000 ft, icing, spin, age 53, Parkinson's Disease, Sinemet in
aircraft. "Probably significant CO” in FAA report.

Pilot bx of renal calculus. Aircvaft hx of induction fire, muffler inspection
found no ¢racks or holes, "CO powsibly contributory.”

Night, 5,700 ft, other pilot had 25% COBb, no muffler lesk found, “physiologically
at 17,000 ft.”

Night, 5,200 ft, passenger had 30% COdb, weather, poor judgment.

See



TABLE I. EXPECTED EFFECTS AND RELATIONSHIP TO SMOKING
OF VARIOUS CARBOXYHEMOGLOBIN LEVELS

CcOHb Level
(%) Expected Effect
<2 Normal level for nonsmokers.
2-4.9 Significant changes in mental functions have been reported but
are controversial.
5-9.9 Performance effects have been reported.
<10 As reported. Unable to determine exact level.
10-20 Maximum levels found reported for smokers. Possible symptoms.
>20 Effects expected. Other sources of CO or laboratory error.
RESULTS ~

The COHb levels for the pilot fatalities in 817 general aviation acci~
dents without fire are shown for each of the 4 years and for each of six
ranges cf values in TABLE TI. None of the accidents involved carrying passen-
gers for hire.

TABLE II. CARBOXYHEMOGLOBIN LEVELS, PILOT FATALITIES,
GENERAL AVIATION ACCIDENTS WITHOUT FIRE

COHb (2)
Year <2 2-4.9 5-9.9 <10 10-20 >20 Total
1973 169 v7 13 3 6 2 210
1974 193 20 22 Qo 4 0 239
1975 i31 20 28 1 3 4 187
1976 1i5 28 34 it) & 0 181

Accidents frequently involved multiple factors such as altitude, alcohol,
advanced age, acrobatics, arteriosclerotic cardiovascular disease, other
medical conditions, fatigue, drugs, poor judgment, disorientation, darkness,
visual problems, weather, and stress (Table III).



st cor ns ysunviamcest

Patients with coronary artery disease have been found not to have 4 ner-
mal increase in coronary blood flow when they were exposed to low concentra~
tions of carbon monoxide sufficient to increase their COHb levels to 5%-9%
(1,2,3,4). The oxygen extraction ratio by the myccardium was increased, the
coronary sinus tension was decreased significantly, the lactate and pyruvate
extraction ratios were decreased, and exercise tolerance was reduced. At
least one author concludes that there may be no concentration of CO that does
not exert 4 significant stress on those patients with advanced cardiovascular
disease (21).

SUMMARY AND CONCLUSIONS

Although subject to considerable debate, it is possibie that smoking has
been a contributing cause to some general eviation fatal accidents in the
United States during 1973-76. However, the compcund factors that were often
found and the dire consequences are far less likely in air commerce situations.

Carboxyhemoglobin may have been elevated in many of the 1,101 accidents
for which toxicologic examinations were not performed. Increased COHb levels
due entirely or in part to smoking are also possible in 380 accidents with
fire, but these reports were not examined because of aaticipated difficulties
in determining the sources of the CO.

Despite the abundance of research on the effects of smoking, the authors
feel that additional studies of (i) smokers’ performance of realistic tasks
in an accurate environment, (ii) the effects of withdzawai, and (iii) aircraft
accidents and incidents are indicated before conclusions can be reached.

For some, withdrawal symptoms including tension, depression, irritability,
difficulty in concentration, decreased heart rate, a fall in blood pressure,
electroencephalographic changes, and impaired performance may occur and may
more than offset any benefits to aviation safety that are expected from a ban
on preflight and in-flight smoking.

Smoking cessation programs and puarmacologic approaches to nicotine
replacement or substitution are endorsed for improved health, maintained
levels cf performance, and safety.

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FAA-AN-80-11

THE EFFECTS OF TOBACCO ON AVIATION SAFETY
J. R. Dille and M. K. Linder
Civil Aeromedical Institute

Federal Aviation Administration
Oklahoma City, Oklahoma

ADA091510

AUGUST 1980

Document is available to the public through the
National Technicai Information Service,
Springfield, Virginia 22161

Prepered for
U.S. DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
Office of Aviation Medicine

rae
Washington, D.C. 20591

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18.

19.

20.

21.

22.

23.

24.

Orto, D. A., V- A. Benigus, and J. B. Preaek. 1979. Carbon monoxide and
human time discrimination: Failure to replicate Beard-Wertheim experiments.
Aviat. Space Environ. Med. 506:40-43.

Petition of the Airline Pilocs Committee of 76, Public Citizen's Heaith
Research Group, and the Aviation consumer Project. 1976. Smoking in the
cockpit, and smoking by flight crewmembers before commercial flight opera-
tions. Regulatory Docket No. 15614, filed April 2€, 1976, before the
Federal Aviation Administration, Washington, DC.

Robinson, S. A., and S. M. Wolfe. 197€. Smoking: Its adverse effects
on airline pilot performance. A report of Public Citizen's Health
Research Croup, Washington, BC.

Russell, M. A. H. 1971. Cigarette dependence: T—Neture and classifi-
cation. Br. Med. J. 2:330-331.

Stewart, R. D. 1975. The effect of carbon zoncxide on humans. Ann.
Rev. Fhermacol. 15:409-423.

Stewart, R. D. 1976. The effect of carbon monoxide on humans. J. Cccup.
Med. 18:304-309.

Stewart, R. D., P. E. Newton, M. J. Eosko, anc J. E. Peterson. 1973.
Effect of carbon monoxide on tine perception. Environ. Heat:
27:155-160.

tewart, R. D., 5 E. Peterson, 2. D. Baretta, et al. 1970. Experimental
human exposure to carbon monoxice. Arch. Environ. 21:154-164.

U.S. Department of Health, Education, and Welfare, iblic Health Service.
i971. Health aspects cf smoking in transport aircraft. Report on a

joint study conducted ty the Federal aviation Administration, Department
of Transportation, and the National institute for Occupational Safety
ané Health.



No accident with COHb ievels clearly in the smoking range was ascribed
to CO in the medical and other FAA reports.

Carbon monoxide was listed as a possible cause in five accidents with
COHb levels of 12%, 21%, 23%, 26%, and 33%, but (i) a pathologist stated that
a 10.6% COHb* was probably due to heavy smoking and was not significant in a
pilot found on autopsy to have an “obstructive atherosclerotic plaque of the
circumflex coronary artery of a magnitude known to be associated with sudden
lethality," and (41) the report of a nighttime accident at 5,100 feet due to
poor *:dgment where the pilot had 36% COlb and the passenger had 30% COHb
states, "Post-accident medical examinations of the pilot disclosed nothing
significant with respect to causal facters of the accident." Thus, there is
evidence of underconsideration.

The mufflers were examined in four accidents where (uniess there were
gross laboratory errors) the occupants had nonsmoking COHb levels of i5% and
20%, 21%, 26%, and 33% and 25% COHb. Ail four mufflers were found to be free
of holes or cracks. Victims with the five highest reported COHb levels were
all flying in the same make and model of aircraft--but 13- te 17-year-old
models with normal mufflers--which raises questions about gaskets and seals
in aircraft of that vintage and about exhaust/air-intake reiationships.

DISCUSSION

Of necessity, the operations and accidents examined for this study are
not those that were addressed in the petition. Compared to the general avia-
tion pilots found involved in these accidents, pilots carrying passengers for
hire would often be younger aud healthier and would usually be more experi-
enced, better trained, better equipped, free of drug and alcohol effects, not
engaged in acrobatics, and backed up by one or two additional crewmembers.
Their margin of safety should therefore be considerably greater than thet
noted in any of our cases.

Impaired vision, reduced altitude tolerance, and increased fatigue,
which may have contributed to some of our accidents, have been reported for
light smoking. Alcohol, altitude, and CO are generally thought to be addi-
tive in producing tissue hypoxia. Pilots are taught that impaired performance
and errors in judgment may occur after 10-15 minutes at 12,900-15,000 feet.
Skill and judgment errors were seen at all COHb leveis in the accidents
reported here; no dose-response relationship was observed.

Of considerable interest are accidents where the pilects had rather low
COHb levels but were thought to have had a "disturbance of the cardiovascular
system" at 3.4% COHb, a "stroke pricr to impact” at 4.3% COHb, an in-flight
myocardial infarction at 5.5% COHb, “probably pilot incapacitation” at 8.5%
COHb, and “obstructive atherosclerotic plaque of the circumflex coronary

artery of a magnitude known to be associated with sudden lethality” at 3.0%
COHb.

*An error was later found in the pathologist’s summary. The true levei for
the pilot was 3.0% COHb; a passenger had the 10.6% COHb level.

5

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THE EFFECTS OF TOBACCO ON AVIATION SAFETY

INTRODUCTION

In 1976, the Federal Aviation Adrinistration (FAA) was petitioned by the
Airline Pilots Committee of 76, the Public Citizen's Health Research Group,
and the Aviation Consumer Action Project for rulemaking to amend Part 91 of
the Federal Aviation Regulations to (i) ban the smoking of any tobacco prod~
uct in the flight deck area during the operation of any flight in air com-
merce and (ii} ban any person acting as a flight crewmember on any flight in
air commerce within 8 hours of smoking any tobacco product (17).

One of the groups had reviewed the scientific literature on the effects
of carbon monoxide (CO) and smcking on mental and physiological functions and
submitted a report of their findings in support of the petition (18).

In FAA medical education and physiological training programs for ¢light
instructors and other pilots, we regularly mentien the possible adverse
effects of CO and nicotine from smoking on altitude tolerance, vision, and
performance. Yet, we have had ao research or accident data to verify these
concerns. However, a causal roie is not likely to be ascribed if it is not
looked for, considered, and understood. Margins obviously exist, pilots are
usvally heaithy, and adaptation and compensation occur. We also recognize
that smoking may provide useful sedative effects; furnish oral gratification;
occupy the hands to reduce anxiety and tension; and maintain and even enhance
performance, allay fatigue, and increase alertness from the stimulating
effects of nicotine. Some classic texts on aviation medicine conclude that
smoking in flight is not dangerous and, except for fire danger and possible
distraction, is even probably beneficial (8,9).

The chronic effects of smoking on the health of smokers are not ques~
tioned by the authors. Health effects were not the primary issue for the
petition and are not considered in this paper.

The acute effects of the CO in tobacco smoke on healthy, sedentary non-
smokers in a weli-ventilated environment are not considered a safety hazard.
Irritation, distraction, and possible allergic reactions of nonsmoking flight
crewmembers are an issue that has not been studied and remzins unresolved
(except that it has never been cited as the contributory cause of an accident
or incident to our knowledge).

In 1970 and 1971, the FAA and the U.S. Public Health Service did make
enviromental measurements and determined passengers’ feelings about in-flight
smoking on 14 domestic and 20 Military airlift Command In:ernational flights
(24). The average levels of carbon monoxide, particulates, ammonia, and
ozone that were found were below the accepted safe limits and did not repre-
sent a known health hazard to nonsmoking passenges. (Humidity was also
measured and was found to range from 26% to 16%.) However, because of odor
and irritation to the eyes, nose, and throar, up to 73% of the nonsmoker
passengers suggested corrective action. Separate areas for smokers and non-
smokers were established on air carrier aircraft in 1973.

1

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Technica! Report Documentation Page

‘4. Title and Subtitle

marae VC A) a ngy 510

JTRE EFFECTS OF TOBACCO ON AVIATION SAFETY, . FE Bonlooming Organization Sodar=
a a eS }

and

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5. R./oitte amtem. KX. hinder /
4. Performing Orgonization Name ond Address

FAA Civil Aeromedical Institute
P.O. Box 25082

Oklahoma City, Oklahoma 73125

-= _[8. Performing Organization Report No.

10. Work Unit No. (TRAIS)

Vi. Contract or Grant No.

13. Type of Revert and Period Covered

12. Sponsoring Agency Name ond Address 7
Cffice of Aviation Medicine i
Federal Aviation Administration |
800 Independence Avenue, S.W. F
Washingtoa, D.C. 20591 i

15. Supplementary Notes

14" Sponsoring Agency Code

1976, the FAA was petitioned to issue regulations that would prohibit all smoking
in the cockpit during commercial fiigat operaticns and prohibit preflight smoking by
flight crewmembers within 8 hours before commercial flight operations.

A review of the literature was conducted to determine the effects on pilot perfcrn-
ance of carbon monoxide (CO), nicetine, and smoking withdrawal. The literatuze is
ccnfusing because it frequently contains the results of studies using nonsmokers, CO
only, estimated carboxyhemoglobin (COHb) levels, smali and poorly ventilated cham-
bers, and discrimination tasks where spare capacity is not a factor. Some frequently}
quoted results cannot be duplicated. Significant changes in psychomotor and cardio-
vascular performance with COHb leveis® 10 percent are doubtful.

“eesg tS
The records of 2,660 fetal general aviation aircraft accidents that occurred in 1973
through 1976 have been examinei. Toxicology reports are contained in 1,559 records,
and 225 without fire had COHb levels G1 percent. Smoking was not identified as a
causal factor but may have contributed to the cause of some of these accidents. How-!
ever, the compound factors that were often found and the dire consequences are far
less likely to cccur in air commerce operations.
Ape.
For some, withdrawal symptoms may occur and more than offset any benefits to aviation!
safety that are claimed for a ban on preflight end in-flight smoking.

Pilot performance

Virginia 22161.

Wi. Key Words | 18. Distribution Stotement a
Snoking Aircraft accident | Document is available to the public
Tobacco investigation | through the National Technical

i Carbon monoxide Toxicology | iaformation Service, Springfield,

i

T 2. Security Chats tel as page) | 2@ No. of Poses [22 Price
| Unclassified i &
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Form DOT F 1700.7 (8-72) Reproduction of completed page cutherized Gf, L44
eproduction of campleted peg iz ALFIE

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