Airspeed data in this report are in statute miles per hour.
Localizer and glide path data are in digital units representative of
needle deflections. Different amplification ratios were used for
localizer and glide path voltages in an effort to obtain maximum sensi-
tivity; figure 2 shows the digital values associated with cross-pointer
needle deflections in each axis. It will be noted that the values
associated with localizer deflections are twice those for equal glide
path needle deflections.

Procedural errors, as previously noted, are classified in three
categories according to seriousness. Carburetor heat errors, for reasons
noted below, are discussed separately.

Subjective comments regarding performance are discussed sepa-
rately and have not been reduced to scalar quantities or otherwise
modified for statistical analysis.

Figure 2
GLIDE PATH NEEDLE:

FULL SCALE: +1.25V.,1825 DU.
e +1.00V.,1460 DU.
ry + 50V, 730 DU.
+ .25V., 365 DU.
e e i. CENTER: OV, 0 DU

e LOCALIZER NEEDLE:
FULL SCALE: -1.40V.,2048 D.U.
-1.00V.,1460 DU.

e

-- .5OV, 730 DU.
CENTER: OV, O DU.

ILS CROSS-POINTER INSTRUMENT: SCHEMATIC

SHOWING AMPLIFIED VOLTAGES AND DIGITAL EQUIVALENTS
USED IN THIS STUDY

14


Subjective Data: Effects of Alcohol

Tabulation of procedural errors on a binary basis was carried out
by the safety pilot at the conclusion of each phase of the experiment.
The definitions used, and a few examples, have been presented above.
While these tabulations cannot be said to be free of potential observer
bias, since the safety pilot was aware of the alcohol levels prior to
each flight, a rigid attempt has been made to exclude value judgments
aside from those which impelled him to take control of the aircraft on
certain occasions.

Figure 13 summarizes the error data, partitioned by phase, type and
alcohol level. Errors in application or non-application of carburetor heat
are excluded from the figure for reasons noted below. Several facts are
immediately obvious. The number of minor errors differed significantly
across alcohol levels but not between phases. The number of major errors,
on the other hand, was larger in the inexperienced pilot group at all al-
cohol levels and became progressively larger in each group with each in-
crease in alcohol concentration. Neither group experienced a statisti-
cally significant number of catastrophic errors except at a blood alcohol
of 120 mg %, when a substantial number occurred.

Errors involving the carburetor heat control were tabulated sepa-
rately after it was noted by the investigators that a few pilots contri-
buted a disproportionate share of these errors, apparently without regard
to alcohol level. Most of those errors would have been classified as major,
since they involved either improper use of heat during takeoff and climb,
or failure to apply heat during descent at reduced engine power settings.
It is believed by the investigators that these errors were committed pri-
marily by pilots who normally fly aircraft equipped with fuel injection
engines. The trends in the data are not altered by the presence or ab-
sence of these errors, which are tabulated in table VI.

In summary: inexperienced pilots committed more procedural errors
than experienced pilots at each alcohol level; the difference between the
groups was significant. Both groups, taken separately or together, com-
mitted increasing numbers of progressively more serious errors with each
increase in blood alcohol concentration. The likelihood that the differences
occurred by chance is substantially less than 1%.

TABLE VI: PROCEDURAL ERRORS

7 Phase I Phase II
TYPE 0 40 80 120 0 40 80 120
Minor 18 33 40 45 32 25 30 45
Ma jor 5 19 33 53 30 46 65 80
Catastrophic| 0 1 3 11 0 1 1 5
Carb. Heat 9 20 23 10 26 24 27 29
TOTAL 32 73 99 119 88 96 123 159

35



In summary, the performance of highly experienced professional pilots
was minimally but significantly degraded by increasing levels of blood
alcohol, Less experienced pilots showed more and larger effects asso-
ciated with alcohol. There were considerable differences between the two
groups. Even at the highest alcohol level studied, the more experienced
pilots demonstrated an ability to control the aircraft more precisely as
they approached the middle marker. The less experienced pilots also demon-
strated this trend in their localizer tracking, though they compensated
less effectively. In glide path tracking, the comparatively inexperienced
pilots demonstrated progressive inability to cope with the task with in-
creasing alcohol levels. Figure 11 demonstrates these trends.

31



10.

ll.

12.

13.

BIBLIOGRAPHY

Leonelli, L. P.: Alcohol as it Affects the Task of Flying Small
Aircraft. M.Sc. thesis, unpubl., The Ohio State University, June,
1969.

Gerke, R. J., R. L. Wick, Jr., R. C. Chase and C. E. Billings:
Effects of Alcohol on Flying Skill during Instrument Approaches.
Presented at Aerospace Medical Assn. Meeting, St. Louis, Mo., April,
1970.

Wick, R. L., Jv., C. E. Billings and L. P. Leonelli: Effects during
Flight of Graded Doses of Alcohol on Professional Pilots. Presented
at Aerospace Medical Assn. Meeting, St. Louis, Mo., April, 1970.

Federal Aviation Agency: Alcohol and Aircraft Accidents. Medical
Newsletter, 3(7):7-8, July, 1962.

Harper, C. R., and W. R. Albers: Alcohol and General Aviation
Accidents. Aerospace Med. 35: 462-464, 1964.

Gibbons, H. L., and J. L. Plechus: Analysis of Medical Factors in
Fatal Aircraft Accidents. Texas J. Med. 61: 667-671, 1965.

Gibbons, H. L., J. W. Ellis and J. L. Plechus: Medical Factors in
1964/1965 Fatal Aircraft Accidents in the Southwest. Aerospace Med.
37: 1057-1060, 1966.

Gibbons, H. L. Personal communication, June, 1971.

Asknes, E. G.: Effects of Small Doses of Alcohol Upon Performance in
A Link Trainer. J. Aviation Med. 25: 680-688, 1954.

Fox, B. H., and J. H. Fox, eds.: Alcohol and Traffic Safety.
Washington, D.C.: USGPO (Public Health Service Publication No. 1043),
May, 1963.

Collins, W.E., R. D. Gilson, D. J. Schroeder and F. E. Guedry: Effects
of Alcohol on Tracking Performance During Angular Acceleration. FAA
Office of Aviation Medicine Report No. 71-20, 1971.

Gilson, R. D., W. E. Collins, D. F. Schroeder and F. E. Guedry:
Effects of Different Alcohol Dosages and Display Illumination on
Tracking Performance during Ventibular Stimulation. FAA Office of
Aviation Medicine Report No. 71-34, 1971.

Chiles, W. D., and A. E. Jennings: Effects of Alcohol on Complex
Performance. FAA Office of Aviation Medicine Report No. 69-14, 1969.

40


Initial Evaluation:

Prior to beginning the study, each subject was evaluated in the
laboratory to determine his metabolic degradation constant for alcohol
and to observe his behavior under the combined influence of 120 mg %
plood alcohol and mild hypoxia (produced by exposure to a simulated alti-
tude of 5,000' in an altitude chamber). The former study was done in
order to determine the size and frequency of maintenance doses of alcohol
necessary to maintain an essentially constant level of blood alcohol
throughout the 2-25 hour experimental flights; the latter study was per-
formed as a safety precaution.

During the first quarter of phase I, alcohol was administered as
a 50% solution of 80 proof (40% ethanol) Vodka in tomato juice. Thereafter,
at the request of the subjects, orange juice was used in place of tomato
juice. These beverages were thus 20% absolute alcohol solutions, a con-
centration previously found to promote optimal absorption of alcohol.

Metabolic decay constants were obtained by least squares regression
analysis of data obtained at ten-minute intervals over a 2-hour period
following administration of a priming dose calculated to produce a maxi-
mum blood concentration of 80 mg % alcohol. The primary doses were esti-
mated by the following formula:

Wx 3 ml/1lb x t 0 4, = Y ml of 20% alcohol solution,
in which W = the body weight of the subject in pounds.

As a check on the accuracy of the calculated rates, each subject
returned to the laboratory for the 120 mg % study at altitude. Although
this study was originally designed to detect individuals who might become
unruly at high levels of alcohol, it also served to eliminate several
candidates who became ill at this dose of alcohol.

Alcohol Analyses:

All blood alcohol levels were egtimated by alcohol analysis of ex-
pired air. A model 900 Breathalyzer @ (Stephenson Corporation, Red Bank,
New Jersey) was used to obtain these analyses. The accuracy of the ex-
pired air analyses was evaluated by studies on venous blood drawn concur-
rently and examined in two forensic toxicology laboratories using two
different analytic techniques. The correlation between breath analyses
and blood samples analyzed by steam distillation and colorimetric tech-
niques was +0.962; the correlation between breath analyses and blood
analyzed by gas chromatography was +0.936. Regression analyses yielded
linear data for metabolic decay (r =-.90 to-.98) with slopes which varied
from 11 to 22 mg % of blood alcohol per hour. Appendix 4 provides dosage
and decay data for each subject.

8




APPENDIX 3.

EXPERIMENTAL PROTOCOLS

EPRI

Phase I
1969 Unless Noted
Run # Run # Run # = Run # Run # Run # Run # Run #
subject 1 2 3 4 5 6 7 8
1 10/11/68 10/29/68 11/5/68 11/29/68 12/6/68 12/30/68 1/3 omitted
0 40 80 120 0 40 80
2 10/22/68 11/4/68 11/14/68 1/2 1/14 omitted 2/3 2/10
80 0 120 40 40 0 80
3 10/17/68 10/31/68 12/9/68 12/12/68 12/16/68 1/7 2/4 2/7
120 80 40 0 120 80 40 te)
4 10/12/68 11/1/68 11/8/68 12/2/68 12/10/68 12/19/68 1/10 1/13
40 120 O 80 80 0 120 40
5 2/4 2/21 3/7 3/14 3/21 4/4 4fu1l 4/15
iG 80 120 40 40 80 120 0
6 2/20 3/4 3/17 4/7 4/19 4/21 4/24 5/20
80 40 0 120 0 120 40 80
7 3/6 3/13 3/31 4/10 5/19 5/28 6/3 6/5
40 120 80 0 80 40 0 120
8 3/18 4/3 4/22 5/1 5/12 5/26 6/2 6/6
120 0 40 80 120 te) 80 120
Phase IL
1970 Unless Noted
Run # Run # Run # Run # = Run # Run # Run # Run #
Sub ject 1 2 3 4 5 6 7 8
1 1/30 2/2 2/10 2/16 2/20 3/2 3/6 3/30
120 80 40 0 120 80 40 0
2 2/3 2/13 2/15 2/19 2/23 2/26 3/1 3/10
0 40 80 120 0 40 80 120
3 5/19 5/21 5/26 5/29 6/1 6/7 6/12 6/19
40 120 (0) 80 80 0 120 40
4 5/28 6/2 6/4 6/8 6/11 6/18 T/T 6/23
80 0 120 40 40 120 0 80
5 8/6 9/11 9/15 9/20 9/22 9/25 9/29 10/1
0 120 80 40 40 80 120 0
6 8/2 8/7 8/13 9/18 9/21 10/2 11/3) (11/17
80 40 120 0 0 120 40 80
7 9/28 10/5 10/8 10/15 1/5 11/9 11/13 11/16
120 0 40 80 80 40 0 120
8 11/10 11/19 11/24 12/4 12/15 12/28 1/1/71 1/12/74)
40 80 0 120 120 oO 80 40

*Repeat run.

50


In consideration of the foregoing, I find that a grant of the exemp-
tion requested would not adversely affect safety and would be in the
public interest , provided appropriate conditions and limitations are
imposed. Therefore, pursuant to the authority contained in §§ 313(a) and
601(c) of the Federal Aviation Act of 1958, which has been delegated to me
by the Administrator (14 CFR 11.53), an exemption from FAR 91.11(a)(1) and
(b) is hereby issued to Ohio University Aviation Medicine Research Labora-
tory to the extent necessary to authorize designated persons to pilot a
Cessna 172 airplane, N530SU, while under the influence of intoxicating
liquor and to authorize the pilot in command of the airplane to permit such
intoxicated persons to be carried in the airplane in carrying out a research
project under a contract between the Ohio State University and the FAA Office
of Aviation Medicine, subject to the following conditions and Limitations:

1. Each pilot designated as a subject for testing and evaluation
shall have an instrument rating.

2, On each flight of the airplane there shall be on board, in addi-
tion to the designated subject pilot, a certificated instrument flight instruc-
tor who shall be the pilot in command of the airplane and occupy the right
seat, which shall have fully functioning dual controls. In addition, a
qualified flight surgeon shall occupy the rear seat of the airplane on each
flight.

3. The flight surgeon or pilot in command shall terminate any flight
of the airplane if it appears to either of them at any time that continua~
tion of the flight is likely to create a hazard to the safety of the Cessna
airplane andjits occupants or of other persons or property.

4, The flight surgeon on each flight of the airplane shall carry
medical and physical means to restrain the designated subject pilot in
the event such action becomes necessary.

5. The airplane shall be fully equipped for instrument flight,
with the necessary radio navigational aids appropriate to the area, and
with a stroboscopic anticollision light, all of which shall be in operable
condition during flight.

6. Each flight of the airplane shall originate and teminate at the
University's airport, and shall be conducted under VFR weather conditions.

7. Each flight of the airplane shall be conducted in accordance
with the instrument flight rules of the Federal Aviation Regulations
and during the course of each flight radio contact shall be maintained at
all times with local radar approach control.

8. Each flight shall be coordinated with the FAA local GADO and

subject to any additional conditions or limitations imposed by that office
in the interest of safety.

48


PRIMARY COMPUTER OUTPUT

APPENDIX 6

OUTPUT _BY APPROACHES.

IDENT= 412 DA= 324 SEC.
LOCALIZER GLIDESLOPE AIRSPEED
: Lo= 649 GO 2015 SO= 98
1 AL= 454.47 479.70 AG= 823.62 AGT= 1266.39 AS= 95.42 AST= 96.44
Vi= 329663 596299 vG= 293540  VGT= 129936 vs= 4 vst= 4
She 574.16 772.20 SG= 541.79  SCT= 360.54 S8= 2.05 SsT= 2.11
} DL= 621.89 DLT= 757.20 DG= 824.92  DGT= 1266.39 Ds= 4.59 DST= 3.62
I NDL= 1.48 NDLT= 1 NDG= 5.56 -NDGT=
4 ADL= 31.25 ADLT= 0.0 ADG= 92.14 ADGT= 130.40
AGL* -23.49  ACLT= 7.11 ACG# -50.79  ACGT= -71.93
AMLT= — -3.56 AMGT= 29.24
IM= 1356 GM= 847 SM= 98
DLO= 649. DGO= 2015 Dso= 2
' DIM= 1356 DoM= 847 DsM= 2
' HR= 88.81
\
i
DATA FOR EACH MINUTE OF APPROACH.
SEG DA AL SL DL AG sc DG AS ss DS RA HR
om (see)
6 24 102.90 356.20 292.93 | 1889.71 154.43 1889.71 | 98.06 1.07 1.94] 0.61 91 10
5 60 624.46 498.11 688.61 804.67 438.41 804.67 | 93.66 1.72 6.33 | 0.13 87.66
4 60. | 702.60 331.61 702.60 | 559.99 366,92 561-82 | 95.95 1.06 4.05 |-0.00 86.13
3 60 | 542,20 302.39 549.99 | 600.40 600.40 | 93.59 1.01 6.41 | 0.12 86 75
2 60 64.00 618.79 542.63 460.20 383.42 465.41 | 96.39 3.61 | 0.08 89 67
1 60 | 479,70 772.20 757.20 | 1266.39 360.54 1266.39 | 96.44 3.62 | 0.32 92.93
uM Tor 324 454.47 574.16 621.89 823.62 S41.79 824.92 | 95.42 2.05 4.59} 0.28% 88 81

correlation of rudder & ailerons.

54



ih

2

1s

AVERAGE LATERAL POSITION
DURING APPROACH

AVERAGE VERTICAL Position
DURING APPROACH

AVERAGE AIR SPEED
During APPROACH

AVERAGE LATERAL DEVIATIONS
DURING APPROACH

AVERAGE VERTICAL DEVIATIONS
DURING APPROACH

AVERAGE AIR SPEED DEVIATIONS
DURING APPROACH

VARIANCE OF LATERAL, TRACK
DURING APPROACH

VARIANCE. OF VERTICAL TRACK
DURING APPROACH

VARIANCE OF AIR SPEED
DURING APPROACH

AL

AG

AS

DL

BG

bs

VL

VG

VS

58

58

Fa

ary
Fue) (Zu)
my ne
Zc) (Fa)
n, ne


Ficure 18

RUNWAY IO LEFT ILS
J

om 35,200! |
~f J TT_"—__"" RWY.IOL
t "|
31,484 10, 716° |

I? Course Detection

at Outer Marker= 736"

| L000"

RUNWAY 28 LEFT ILS

OM '

32,683!

Ty Mm | awe

3.5° $
28, 883° 15,495!

(Course Deruection
at Outer Marner = 774

ar

| oF 1,600"

f—10,700'——

[INSTRUMENT LANDING SYSTEM GEOMETRY (not To scate)]

46


TABLE IV: ESTIMATED BLOOD ALCOHOL CONCENTRATIONS
(Number, Mean, Standard Deviation, Standard Error)
mg %
:
Phase I

40 80 120

16 16 14
Before 39.43 80.00 117.43
Flight 10.38 6.66 13.21
2.59 1.67 3.53

16 16 14
After Ist 39.94 78.63 118.79
Approach 6.06 5.20 3.56
1.52 1.30 0.95

16 16 13
After 4th 43,13 80.25 121.31
Approach 7.14 6.10 6.71
1.78 1.53 1.86

Phase IL

40 80 120

16 16 16
Before 34.06 72.88 114.31
Flight 6.32 7.67 10.49
1.58 1.92 2.62

16 16 16
After Ist 33.56 76.63 112.06
Approach 7.92 6.14 7.80
1.98 1.54 1.95

16 16 16
After 4th 38.25 82.69 120.19
Approach 4.67 3.14 7.47
1.17 0.78 1.87

18


DISCUSSION

With respect to the primary variable under consideration here,
there can be little doubt about the meaning of these data. If we assume
that instrument-rated pilots, flying ILS approaches, consider the job of
guiding their aircraft to a position from which a visual landing can
safely be made as their primary task, then it follows that the other, dis-
crete, procedures involved, while no less essential to safe operation, are
relegated to a secondary role. The evidence is clear that this is in fact
the hierarchy which exists. It is equally clear that as pilots are pro-
gressively affected by alcohol, they become progressively less able to
cope with the various facets of their task, and it is the secondary tasks
which suffer first and most.

This is not to say that the primary task escapes degradation. It
is interesting that the experienced pilots maintained their tracking ability
as well as they did, but the data from the less experienced pilots provides
some clues to the stratagems employed by the former group. We see, for
instance, virtually no effects of alcohol on glide path tracking. The
Cessna 172 has a fixed pitch propellor and thus has a degree of longitudinal
stability not found in more complex aircraft with constant-speed propellors.
The extraordinarily constant deviations and variability with respect to
glide path suggest that the experienced pilots recognized and made good use
of this stability, thus making more time and attention available for local-
izer tracking. Time-sharing is known to be affected by alcohol (13).

The effect of this is seen in the localizer data at the higher alco-
hol levels. The experienced pilots had smaller deviations, particularly
during the last minutes of the approaches, though their initial deviations
were only slightly less than those of the less experienced pilots, who
actually tracked the localizer more accurately when sober.

We also observe that the drift rates of the experienced pilots were
lower than those of the inexperienced group at all alcohol levels. This
may be due either to more rapid and frequent cross-checking of the instru-
ments or to better directional control by the former group. Whatever the
cause, they had more time in which to make corrections, which could be, and
were, of small magnitude.

The experienced pilots, then, appear to have allowed the airplane
to do a considerable part of their glide path tracking, while they concen-
trated on the localizer. Even when they were severely affected by alcohol,
they were able, because of this strategy and their greater experience, to
maintain lateral track fairly effectively.

The inexperienced pilots, possibly because they were not aware of
the longitudinal stability of the airplane, attempted to fly both axes of
the tracking task. When affected by alcohol, their performance decrements
were more marked in both axes as a result. The more sensitive task, glide
path tracking, suffered proportionately more, especially during the terminal

36


25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

41
42
43
4a
45
46
47
48
49
50

SUMMARY OF DERIVED VARIABLES (con't)

DGT

DST

vcT
VST
SLT
SGT
SST
NDL
NDG
ADL
ADG
ACL
ACG
NDLT
NDGT
ADLT
ADGT
ACLT
ACGT
DLO
DIM

AMGT ©

Average vertical error during last 60 seconds

Average airspeed error during last 60 seconds

Variance of lateral position during last 60 seconds

Variance of vertical position during last 60 seconds

Variance of airspeed during last 60 seconds

Std. dev.
std. dev.
Std. dev.
Number of

Number of

of lateral error during last 60 seconds
of vertical error during last 60 seconds
of airspeed error during last 60 seconds
deviations from localizer/minute

deviations from glide path

Average rate of drift (lateral)

Average rate of drift (vertical)

Average rate of correction (lateral)

Average rate of correction (vertical)

No. of deviations (lateral) during last 60 sec of apch

No. of deviations (vertical) during last minute

Avg. drift rate (lateral) during last minute

Avg. drift rate (vertical) during last minute

Avg. correction rate (lateral) during last minute

Avg. correction rate (vertical) during last minute

Abs. value of LO

= [in|
= |co

= on

Avg. lateral movement trend during last minute

Avg. vertical movement trend during last minute

67



ACKNOWLEDGMENTS

The authors wish to acknowledge the technical support provided
by Leo P. Leonelli, M.D., and Kenneth Babon, B.S. Invaluable coop-
eration was received from the Columbus facilities of the Federal
Aviation Administration. The Breathalyzer used in the studies was
made available by the Stephenson Corp., Red Bank, N.J. Technical
support was also provided by Richard Pfau, of the Columbus, Ohio,
Police Department. Finally, a word must be said in acknowledgment
of the excellent service provided by our subjects, who underwent
considerable discomfort without complaint.

iii





NOTATION IN FIGURES AND TABLES

Solid legends: .Phase I pilots: High experience

@: 120 mg % blood alcohol

a: 80 mg %
a: 40 m%Z " "
@: Om% " "

Open legends: Phase II pilots: Low experience

120 mg % blood alcohol
80 mg %
40 me% " "

O mg %

Performance Descriptors

SL: Variability on Localizer Course
sG: "Glide Slope

SLT: " "Loc, last minute
SGT: " "GS, last minute

DLO: Deviation from Loc at outer marker
DGO: " ¢ "on "
DL : Average Localizer error

3 "Glide path error
: (# refers to a specified minute)
:a non "
DLM: Deviation from Loc at middle marker
DCM: " "eg on " "

ADL: Average drift rate (lateral)

ADG: " " (wertical)
ADLT: " " " , last minute
ADGT: " " non "

(for complete descriptions, see pp. 56-67)

69





Average rate of drift from localizer (ADL) (figure 10) was nearly
significant with respect to alcohol in the experienced group. A similar
non-significant trend was noted in the inexperienced pilots, who also had
highly significant increases in drift rates from glide path associated
with alcohol, especially during the terminal minute of their approaches.
Average correction rates in both groups paralleled drift rates.

No significant effects of alcohol were noted in the airspeed data,
although deviations (DS,DST) from command speed were substantially higher
in the inexperienced group at 120 mg %. The lack of statistical signifi-
cance in these data may have been due to oversensitive instrumentation
and a consequent high noise level in the data,

29



RESULTS

This chapter is organized in two sections. The first presents the
results of computer analyses of the positional and air speed data recorded
continuously during all approaches. These data represent the pilot's
ability to direct his aircraft toward a desired landing spot on the run-
way at a given air speed. The second section describes the secondary
elements of the flying task in terms of the procedural errors observed
during the flights. Prior to these two sections, however, an introduc-
tion describes certain preliminary analyses which were performed in an
effort to ascertain whether the data from phases I and II could fairly
be combined.

Preliminary results:

The two phases of this experiment were performed as independent
experiments, utilizing samples of 8 subjects presumably drawn from two
different populations of instrument-rated aviators.

The first step in analyzing the data was to determine whether this
premise was correct. The mean data from all control (0 mgm %) flights by
the inexperienced group studied during phase II, a total of 64 approaches,
were compared with the comparable data provided by the more experienced
pilots during phase I. Table III and figure 3 summarize the data.

It was found that the inexperienced pilots, when sober, had average
localizer and airspeed deviations slightly smaller than those of the
experienced pilots. Their glide path deviations were slightly greater,
but this difference disappeared during the terminal minute of the approaches.
The inexperienced pilots showed greater tracking variability than the more
experienced men, and their average drift and correction rates were higher.
They were somewhat closer to localizer and thus runway centerline as they
crossed the middle marker, but they were substantially further from command
position on the glide path at the middle marker. The. inexperienced group
also committed more major errors than the experienced group during 0 level
flights.

A second preliminary study compared the first control flight of the
two phases with the second, in order to ascertain whether learning effects
may have been present. No systematic differences were seen in the data
provided by the experienced pilots. Some effects were observed, on the
other hand, in the inexperienced pilot data. These are discussed later in
the report.

Virtually all of the observed differences between the two groups
were in the expected direction. The presence of these differences suggested
that the data from the two phases should be analyzed separately, rather
than in one body, in order to allow observation of differences in modes of

15



Objective Data: Effects of Alcohol

All significant interactions were examined graphically to deter-
mine whether differences in subject responses to alcohol were a matter of
degree or whether they were qualitative in nature. As shown below in
figure 6, there were marked differences in subject responses; in the body
of the report, only those changes which were reasonably consistent are
discussed in detail. One difference between the experienced and inexper-
ienced pilots is immediately evident in table V: significant alcohol
effects were observed only in lateral control in the experienced pilots.
The inexperienced pilots, on the other hand, manifested significant alcohol
effects in many performance descriptors of vertical control as well. This
is discussed further below.

The subjects in each phase varied significantly among themselves in
tracking skill. Figure 5 shows composite averages for four measures:
variability on localizer and glide path (SL and SG) and deviations from
localizer and glide path centerlines (DL and DG), during all control
flights. It is obvious that there was much more within-group than between-
group variability under these conditions. Similarly, there was consider-
able individual variability in response to alcohol; figure 6 shows rela-
tive increments or decrements in the composite score for all alcohol
flights. This presentation is highly simplified, since a pilot who had
a performance decrement only at 120 mg % might show very little average
decrement when his 40 and 80 mg % data are included. The figure serves
only to illustrate the variability in response and the fact that the in-
experienced group, on the average, was degraded somewhat more by alcohol
than the more experienced group.

Looking at the composite scores by alcohol level, one obtains the
results shown in figure 7, which suggests progressive decrements in per-
formance with increasing alcohol levels, more pronounced in the inexper-
ienced pilots. These composite scores were not tested for statistical
significance in view of their synthetic nature, though it should be noted
that they are composed of four functionally independent measures of track-
ing precision. As such, they provide a useful summary of the observed data.

21



Figure 3

1000) © Puase T Prots
w © Poase IE Prots
= 900
—
a
5 800}
3
> 700}
2 coo 3
ti. 600}
3
= 500}
<
a 400,
a
D D D D
aa 6 gr
ol 94 3 2 TM To4 3 2 TM
LOCALIZER GLIDE PATH
600,
500}
> 400} =a
bE
2
@ 300 oot
a
< 200
S Ss $s s
100 p>————+8 @—3
0 4 3 2 T 4 3 2 T

COMPARISON OF EXPERIENCED (PHASE I) WITH INEXPERIENCED
(PHASE I) PILOTS DURING CONTROL FLIGHTS (NO ALCOHOL)



PERFORMANCE AT INDICATED ALCOHOL CONCENTRATION AS PERCENTAGE OF CONTROL

160
V4ol
120}
100
Bol
140,

120

Figure ll

PHASE I

OLO DL DLT DUM

L

PHASE I

eae

DLO DL DLT DLM

[DEVIATIONS FROM LOCALIZER CENTERLINE]

=

=

100
80!
160,
140)
120}

10

St SLT

o———a
—
SL SLT

[VARIABILITY IN LOCALIZER TRACKING]

2 40
3 80] mg % ALCOHOL
$ 120

80

160

140}

120

soe DG DGT DGM

L

DGO DG DGT DGM

[DEVIATIONS FROM GLIDE PATH]

A

Bol

SG SGT

SG SGT

[VARIABILITY IN GLIDE PATH TRACKING]

30


solo flight. Examples include leaving lights or radios on when shutting
down the aircraft, or failing to turn up the radio volume with resultant
inability to establish two-way contact.

2. MAJOR ERRORS: Errors which can result in a hazard to flight
safety or to the airplane if continued. These errors do not require
immediate intervention by the safety pilot, but they may shorten engine
life or degrade aircraft performance. No pilot would knowingly commit
such errors. Examples include taking off with full flaps, flying without
lights, taking off with carburetor heat on, turning the wrong way in re-
sponse to instructions from ATC, attempting to fly an approach while tuned
to the wrong ILS frequency.

3. CATASTROPHIC ERRORS: These errors require immediate interven-
tion by the safety pilot to prevent an imminent accident or damage to the
aircraft. In this experiment, the most common error of this type was an
error during landing in which the safety pilot was obliged to take control
to avoid striking the ground. Other examples included loss of control in
flight, or turns toward oncoming traffic of which the subject had just
been warned. Assessment of catastrophic errors did require a judgment by
the safety pilot as to the quality of the subject's performance.

These errors were analyzed by chi-square analysis assuming that if

the independent variable (alcohol) had no effect they would have occurred
randomly across experimental conditions.

Evaluation of Performance

A variety of statistical descriptors of pilot performance was made
available by the computer program used in this study. Each of the descrip
tors is defined rigorously in appendix 8. The descriptors discussed in
the remainder of the report are briefly described here for the convenience
of the reader. They are of three types.

1. MEASURES OF VARIABILITY: The measure of variability in trackin
i the standard deviation of position or air speed, symbolized by the pre-
fix (S).

2. MEASURES OF ERROR: The measure of error in tracking is the
deviation in either direction from commanded position or air speed; its
symbol in this report is (D).

3. ‘TREND MEASURES: Measures of average rate of drift away from, ¢
average rate of correction toward, commanded position are denoted by (AD),
the average rate of drift, or (AC), the average rate of correction. The
synthesis of these is the average rate of movement over a given time peric
(AM), which is positive if the trend is in favor of drift away from com-
manded position, and negative if the trend is in favor of correction to-
ward commanded position during a given time period.

12


APPENDIX 9

MEAN VALUES OF DEPENDENT VARIABLES

Ph.
VARIABLE ase I Phase IL

0 40 80 120 0 40 80 120
sL 505 557 584 673 603 591 645 774
SLT 445 443 476 512 474 422 493 538
SG 459 414 460 482 532 596 647 692
ScT 350 330 380 343 408 474 612 603
ss 9.7 6.1 7.7 7.9 9.8 9.8 8.8 9.9
SST 1.7 2.2 1.9 1.7 2.0 2.3 1.9 2.6
DLO 607 695 964 869 661 737 | 1007 985
DL 566 591 652 708 546 551 709 749
DLT 652 665 668 756 534 583 667 757
DLM 732 764 640 738 637 629 825 691
DGO 1072 | 1053 885 1004 925 989 | 1013 | 1033
DG 536 550 508 616 581 622 699 791
DGT 587 561 539 61l 567 654 799 879
DCM 609 588 676 639 778 813 993 | 1114
DSO 4.4 6.0 5.9 5.5 3.8 4.5 4.6 5.2
DS 3.8 4.2 3.7 3.8 3.6 3.3 3.1 6.0
DST 3.8 4.0 3.8 3.9 3.7 3.3 3.2 6.0
DSM 3.6 3.3 4.2 3.4 3.5 3.8 3.7 6.5
NDL +50 +46 -38 -40 -O1 +04 .20 +28
NDLT -38 42 31 +29 +02 +03 +22 .27
NDG 5.08} 4.90] 5.38} 4.76 4.79] 5.00] 4.22} 4.81
NDGT 4.59} 4.11) 5.05] 4.18 4.45) 4.14) 3.92 3.89
ADL 21.8 | 26.7 | 27.2 30.0 26.9 | 29.0 | 30.7 36.0
ADLT 13.3 | 18.5 | 11.8 | 13.5 17.2 | 15.6 | 25.2 | 19.0
ACL -22.0 |-23.6 |-23.8 |-26.8 -26.4 |-23.9 |-24.9 |-32.2
ACLT -13.0 |-13.9 |-12.2 |-12.3 -16.4 |-13.0 |-12.4 |-16.8
ADG 59.1 | 55.5 | 65.9 | 63.9 67.5 | 68.9 | 74.4 | 85.5
ADGT 61.5 | 64.7 | 79.7 | 66.6 68.6 | 76.4 |105.5 |100.2
ACG -59.4 |-57.9 |-64.6 |-62.4 ~65.2 |-69.2 |-76.6 |-88.6
ACGT ~65.3 |-59.6 |-76.7 |-76.3 ~73.7 |-83.5 $115.6 4116.5
AMLT 215 2.28 -.18 58 +39 1.29 6.37 1.06
AMGT -1.92 2.56 1.51] -4.85 -2.53] -3.55| -5.04] -8.15



APPENDIX 8

DERIVATIONS OF DEPENDENT VARIABLES

Let L be the digital representation of Localizer voltage (ch.1)

"gun oon " "Glide Path (ch.4)
"og onon " " " Air Speed " (ch.5):
no Aaonin " " " Aileron position  (ch.2)
Cr " " " Rudder " (ch. 3)
no powon " " "Elevator " (ch. 6)
sopomon " " “Throttle " (ch. 6)
Cs: " " " Electrocardiogram (ch.7)

"ty be a time at which the outer marker is passed at the beginning
of an approach; (30 sec. after the beginning of a 500 Hz signal)

"ty be the time at which the middle marker is passed at the end of
an approach; (6 sec. after the beginning of a second signal)

"np be the number of sample observations (digital) of some variable,

x, from time ty to time t,
"x; be the i-th value of a variable, x

Let S' be a speed, in miles per hour, corresponding to S and defined by
equations to be furnished.

S, isa digital representation of a calibration speed, S', which will
be provided at the beginning of each tape.

56




No significant effects of alcohol were found in glide path tracking
errors (DG,DGT,DGM) by the experienced pilots, nor was their mean tracking
variability (SG,SGT) affected. The inexperienced pilots, on the other
hand, demonstrated quite a different picture (figure 9). Except for
deviations from glide path at the outer marker (DGO), both deviations and
variability were significantly affected by alcohol, and the significance of
the deviations increased as the middle marker was approached.

Variability on glide path was remarkably consistent across alcohol
levels in the more experienced group. The inexperienced pilots, on the
other hand, became more variable as they approached the middle marker, the
increases being proportional to the alcohol concentration.

27



33

34

35

36

LET L BE THE SmooTHED AND PROCESSED VARIANT OF L

LET G' GE THE SmooTHED AND PRacessep VARIANT oF G

NumGER OF CYcLIC
DEMATIONS FRom
LATERAL TRACK

NUMBER OF CYCLIC
DEVIATIONS FRom
VERTICAL TRACK

AVERAGE RATE OF DAFT
FRom LATERAL COMMAND
‘TRACK

AVERAGE RATE OF DRIFT

FRom VERTICAL CommAND
TRACK

No. oF cuances cll’ *60

OF SIGN OF
NOL = at
DA, Seconns
wears 26" 60
NDG =
‘DA, SEconps
n
>» el )
ADL s Edt A gg all 9
n dat
WHERE 1 © NO. OF POSITIVE VALUES
2)
ADG = ron lel, 9

dt

63



43

44

45

46

AVGRAGE RATE OF
CORRECTION TOWARD
LATERAL COMMAND TihcK

DURING TERMINAL ACLT =

PHASE OF THE APPROACH

AVERAGE RATE OF
CORRECTION TewaRD
VERTICAL COMMAND TRACK

DURING TERMINAL ACGT =:

PASE oF THE AFPROACK

WEIGHTED MEAN oF 41 (43:
SIGN AND MAGNITUDE

WEIGHTED MEAN oF 42 144;
SIGN AND MaGgnrTUDE

niente Saas

“)

h
2S
n

(‘ For dlu'| <0
dt

WHERE N= No, oF NEGATIVE VALUES

65

AmLT

AmMaT

For AIG'L eg
alt



SUMMARY OF DERIVED VARIABLES

RY EEE

VARIABLE SYMBOL DESCRIPTOR
1 LO Initial lateral position at outer marker
2 GO Vertical position at outer marker
3 so Airspeed at outer marker
4 IM Lateral position at middle marker
5 GoM Vertical position at middle marker
6 SM Airspeed at middle marker
7 AL Average lateral position throughout approach
8 AG Average vertical pos:.tion throughout approach
9 AS Average airspeed thrcughout approach
10 DL Average lateral error during approach
ln DG Average vertical error during approach
12 DS Average deviation from 90 mph IAS during approach
13 VL Variance of lateral position
14 VG Variance of vertical position
15 vs Variance of airspeed
16 SL Std. deviation of lateral position
17 sc Std. deviation of vertical position
18 ss Std. deviation of airspeed
19 DA Duration of approach in seconds
20 RY Runway used for approach
21 ALT Average lateral position during last 60 sec. of apch
22 AGT Average vertical position during last 60 seconds
23 AST Average airspeed during last 60 seconds
24 DLT Average lateral error during last 60 seconds

66


DEVIATION FROM CENTERLINE

VARIABILITY

Ficure_ 8

1000l. PHASE I L PHASE I
EXPERIENCED \ INEXPERIENCED
woo} \
way |
700} ‘ L
os 4
500} L
400, L
D D D D
De rs & rr 2
{ 04 3 2 TTM T04 3 2 TM
0
80
4 40
600. B B0| 79 % ALCOHOL
500 $ I20)
400} aa L
300}
200
s s sg
100 L L L L
4 3 2 7T 3 2 7T
()
LOCALIZER TRACKING DURING CONTROL ¢ ALCOHOL FLIGHTS

24



THE EFFECTS OF ALCOHOL ON PILOT PERFORMANCE DURING INSTRUMENT FLIGHT

INTRODUCTION

This research was initiated by the Federal Aviation Administra-
tion after receipt of an unsolicited proposal from the Aviation Medicine
Research Laboratory of The Ohio State University. Contract No. FA68AC-
6089-2 was signed in June, 1968 for a study of the effects of graded
doses of ethyl alcohol on the capability of experienced professional
pilots to fly light aircraft by reference to instruments. The study was.
later extended to include the effects of alcohol on less experienced
pilots.

This report is a formal description of the rationale of the study,
the methods used and the results obtained, with a discussion of their sig-
nificance. The data collected during the course of the study, some
27,395,000 computer words, and the first stage computer output, amounting
to 12,120 statistical descriptors of 501 instrument approaches, are not
included in the report; they are available for further study on request.
The report includes the results of all statistical analyses performed
on these data in summary form.

Portions of this research have already been presented at scien-
tific meetings or in publications (1,2,3). The pertinent material
summarized in the earlier reports is included here for the sake of com-
pleteness.

The report is constructed on conventional lines. Detailed de-
scriptions of the performance measures used, and equations for them, are
found in appendices. Another appendix summarizes all of the data, par-
titioned by experimental condition. .





All descriptor codes used in this report begin with one of the
above symbols: S, D, AD, AC or AM, or with (HR) when heart rates are
under consideration.

The tracking function being described is one of three; its symbol
follows the descriptors above.

1. All localizer tracking has the symbol (L). The commanded or
ideal position is attained when the localizer cross-pointer needle is
centered, indicating that the airplane is on the localizer centerline.
The angular width of the localizer course is 24° from center to full-
scale needle deflection in either direction.

2, Glide path tracking has the symbol (G). The commanded position
is attained when the glide path needle is centered, indicating that the
airplane is precisely on the command glide path. The vertical width of
the glide path is + 0.7° for a full-scale needle deflection.

3. Air speed tracking has the symbol (S). The command air speed
was 90 mph during phase I of this study; during phase II it was raised to
100 mph to minimize interference with other traffic.

DS thus connotes ‘deviation from command air speed; ADL connotes
average rate of drift away from localizer centerline.

The above descriptors may be modified by a suffix if the data
being presented do not refer to an entire approach. If no suffix is found,
as in the two examples just cited, the data cover all of the approach.
The suffixes are explained below.

The suffix (T) refers to the last, or terminal, 60 seconds of the
approach. The suffix (2) refers to the immediately preceding 60 seconds.
The suffix (3) refers to the next preceding 60 second period; (4) denotes
data collected during the next preceding minute. The suffix (0) refers to
data collected during the first four seconds of the approach, while cross-
ing the outer marker; similarly, (M) refers to the last four seconds of
the approach, while crossing the middle marker.

The sequence of data: DLO, DL, DL4, DL3, DL2, DLT, DLM, thus refers
to the airplane's average deviations (in either direction) from localizer
centerline when over the outer marker, during the entire approach, during
each of the four last minutes of the approach in order, and as it passes
the middle marker.

To simplify the reader's task, a brief list of the common perform-
ance descriptors and a summary of the notation used in figures is incorpor-
ated as a fold-out inside the back cover. This can be opened outward and
left extended for reference while reading the text.

13



any western nation? This research was designed to provide at least par-
tial answers to these questions.

Studies of man's performance under stress may be carried out
either in the laboratory, where uncontrolled variables may be minimized,
or in the field. The classic simulator study of Asknes (9) was the first
to relate alcohol to flight skills. Whether data obtained in simulated
environments are directly applicable to the real world is as yet an un-
answered question. On the other hand, studies in actual flight must be
constrained by considerations related to the safety both of the subjects
and of others in the flight environment, so that "total simulation" of
the stress situation is usually impossible even when the environment and
vehicle are real.

A great many prospective and retrospective studies of the role of
alcohol in automobile operation have been performed. An excellent review
and summary of this literature is available (10). Much less has been done
prospectively in aviation, though one laboratory study of the effects of
alcohol and acceleration has been completed recently (11,12).

A review of the extensive literature on the metabolism of alcohol
in vivo is beyond the scope of this report. It should be noted, however,
that many of the studies to date have evaluated performance after adminis-
tration either of a fixed dose of alcohol per unit of body weight, or after
bringing subjects to a desired level of blood alcohol; in either case, per-
formance has been studied while alcohol levels were declining at whatever
rates were characteristic of the subjects being studied. In the research
reported here, an attempt was made to circumvent this problem by providing
maintenance doses of alcohol at intervals while the subjects were under
study.



degradation under the influence of alcohol if such differences existed
to a significant degree.

Figure 4 and table IV summarize the results of alcohol analyses
during the data flights. Phase II alcohol levels were somewhat lower
than the phase I data, though it should be recalled that the second and
third values, taken during the data collection, are more important than
the initial value, taken immediately after the initial dosing period.

Note, in figures 3 and 4, the symbols which are used in all figures
in the report. Closed symbols signify data provided by the experienced
pilots (phase I), while open symbols signify the inexperienced pilots
(phase II). Alcohol levels are symbolized as follows: (00) 0 mg % -
control data; (A&) 40 mg %; (Gm) 80 mg %Z; (O@) 120 mg %.

Table V summarizes the results of analyses of variance performed
on the dependent variables, It is obvious that there were significant
interactions of subjects and treatments in nearly all of the variables.
Primary treatment effects were also observed; the differences between
the experienced and inexperienced pilots were considerable. They
raised the possibility that the effects of alcohol were different in the
two groups, a suspicion borne out in subsequent analyses. 5

Froure 4

f+ 144
rt

BEFORE AFTER AFTER
FLIGHT =—FIRST.-——_ FOURTH
HH APPROACH

g

‘
i

n
c)

ESTIMATED BLOOD ALCOHOL CONCENTRATION, mg %
o
Ss

RESULTS OF EXPIRED AIR ANALYSES|
MEANS AND STD. DEVIATIONS.

19



TECHNICAL REPORT STANDARD TITLE PAGE

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM-72-4

4, Title and Subtitle 5. Report Date
THE EFFECTS OF ALCOHOL ON PILOT PERFORMANCE January 1972
DURING INSTRUMENT FLIGHT %. Performing Organization Code

7. Authors) %. Performing Organization Report No.

Charles E. Billings,M.D., Robert L. Wick, Jr., M.D.,
Ralph J. Gerke, M.S., Robert C. Chase, M.S.

12,

. Performing Organization Name and Address 10. Work Unit No-

Aviation Medicine Research Laborator.

Departments of Preventive Medicine, Aviation TT
and the Computer Center
The Ohio State University

~ Contract or Grant No.

|__ Columbus, Ohio 43212 - 13. Type of Report and Period Covered
‘Sponsoring Agency Name ond Address
Office of Aviation Medicine OAM Report
Federal Aviation Administration
800 Independence Avenue, S.W. 14. Sponsoring Agency Code

Washington, D. C. 20590

. Supplementary Notes

This research was conducted under Contract No. FA68AC-6089~2, Project No.
RF-2626.

. Abstract

Sixteen instrument-rated pilots, eight of whom were very experienced
professional aviators, flew Instrument Landing System approaches in a
Cessna 172 under simulated instrument flight conditions while sober and
while under the influence of 40, 80, and 120 mg% of blood ethyl alcohol.
Each pilot flew four approaches to minimums on each of two occasions at
each alcohol level.

The data collected during these approaches included continuous measurement
of aircraft position with respect to localizer and glide path centerlines
and airspeed. Note was made of procedural errors committed during the flights.

The subjects showed significant and progressive decremental effects of alcohol
at all of the levels studied. The more experienced pilots maintained their
ability to guide the aircraft better than did the less experienced subjects,
particularly at high levels of blood alcohol. Both groups, however, demon-
strated progressive increases in the number and seriousness of procedural
errors with increasing levels of alcohol,

It is concluded that even 40 mg% of blood alcohol exerts decremental effects
on performance which are incompatible with flight safety.

17.

Key Words TB. Distribution Statement

Alcohol Availability is unlimited. Document may

Pilot Performance lbe released to the National Technical

Instrument Flight Information Service, Springfield, Virginia
22151, for sale to the public.

19.

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

Unclassified Unclassified 74 $3.00

Form DOT F 1700.7 (s-69)



LOCALIZER

Ficure 15

GLIDE SLOPE AIRSPEED 20,

ex e
eM {
J 100 to $i

av

t
i

TYPICAL oak SIGNAL,
FOR INTEGRATED CIRCUITS

-
ian
~uf

MC hoo
torr;

Fm7 ALL AMPLIFIERS EXCEPT WHEN

Fi)
NOTED ARE RCA 3030A

Joma

v3] A Al a

EKG INPUT HY
10 10
tev 3 f
stl

“TYPICAL CALIBRATION SIGNAL
Ss FOR CONTROL CIRCUITS

ELEVATOR
THROTTLE
bh FM 6

aul

= ae (none
oe Te

Ga

ens

AUDIO:
HOLDING RELAY = ac
KHP ITD
= TIME DELAY RELAY. RESISTANCES IN KA
CdD 38-0003

CAPACITANCES IN jaf

[SCHEMATIC DIAGRAM OF MATING UNIT]

42


Table I: Subject

Data

Flight Instrument
Phase | # | FAA Rating Total Time Hours Flight Time Remarks
I 1 | Commercial & 6,500 350 Pilot Examiner
Instrument
2 | ATR 13,000 1,400 Pilot Examiner
3 | ATR 17,000 2,000 Chief Pilot
Photo Service
ATR 6,000 750 Pilot Examiner
Commercial & 4,000 850 USAF Instructor
Instrument Pilot
6 | ATR 12,000 1,350
ATR 12,000 1,400
8 | Commercial & 7,000 900 USA Standard-
Instrument ization Pilot
It 1 | Commercial & 1,000 60
Instrument
2 | Private & 230 50
Instrument
3 | Commercial & 605 45 Flight Instructor]
Instrument
4 | Private & 620 190
Instrument
5 | Commercial & 491 35
Instrument
6 | Commercial & 939 94
Instrument
7 Private & 400 89
Instrument
8 | Private & 340 85
Instrument



MATERIALS AND METHODS

Subjects:

This study was carried out in two phases. Phase I utilized as sub-
jects eight experienced professional pilots; pertinent data regarding these
volunteers are summarized in table I. Phase II was, insofar as possible,
a replication of phase I, utilizing relatively less experienced but still
instrument-rated pilots, whose data are also summarized in table I. Since
systematic differences were found between the two groups, their data are
presented separately throughout the report.

All of the subjects were social drinkers, though the extent of their
normal alcohol intake varied considerably. All subjects were known to the
investigators; none was believed to have emotional problems related to
alcohol or any degree of psychophysiological dependence on this or other
drugs.

Aircraft:

The airplane used in the experiments was a 1959 Cessna Model 172,
extensively modified as a research vehicle and carrying an experimental
category airworthiness certificate, The airplane's flight instrumenta-
tion included gyroscopic instruments powered by an engine-driven vacuum
pump, a navigation receiver and glide slope receiver, a marker beacon re-
ceiver and audio isolation amplifier, and two communications transceivers.
The aircraft equipment is listed in appendix 1.

Instrumentation:

Research instrumentation included temperature and humidity com-
pensated rotary potentiometers attached to the throttle and control cables,
a venturi system for airspeed assessment and pickups connected to the
pilot's cross-pointer instrument. These sensors were connected to an
interface unit; their outputs were amplified and connected to a 7-channel
FM instrumentation recorder. The pilot's electrocardiogram was also re-
corded, together with communications, the audio output from the marker
beacon, and audio event signals initiated by the safety pilot. Details
of the instrumentation are also given in appendix 1. Table II summarizes
the data available on the FM analog tapes.



APPENDIX 7

ANALYSIS OF VARIANCE
(LEAST SQUARES SOLUTION: ANOV WITH UNEQUAL CELL FREQUENCIES)

Source of Degrees of F Ratio
Variance Freedom * Test
Subjects (8) 7 S/e
Treatments (T) 3 T/SxT
Interaction (SxT) 21 SxT/e
Replications (e) 224

Total 255

*Note: Degrees of freedom for replications varied due to lost data:
Subjects I-1 and I-2 were flown only once at 120 mg % because
of incapacitating vertigo, and airspeed data were missing or
of inadequate quality in a number of flights. The actual
number of degrees of freedom for each phase are shown below:

ay
Phase I Phase IL
Air speed} All other Air speed All other
data data data data
Subjects 6 7 7 7
Treatments 3 3 3 3
Interaction} 18 21 21 21
Error 145 216 168 224
Total 172 247 199 255

55



The safety pilot in these experiments was an experienced flight in-
structor. While his summary comments are not susceptible to quantitative
evaluation, they are nonetheless valuable for the insight they provide as
to the type and degree of decrements we may expect in the pilot who, is
affected by ethyl alcohol.

The secondary tasks involved in instrument flight begin to be neg-
lected as pilots become less able to cope with all of the tasks at hand.
Our experienced pilots managed their primary task without observable
decrements at low levels of alcohol, but even at 40 mg % they no longer
coped satisfactorily with carburetor heat, radio frequency selection, flap
positions and ATC calls and instructions.

A very common error involved the misuse of carburetor heat. The
subjects would either neglect its use during flight at low power settings,
(a major error) or neglect to shut it off during ground taxi (a minor error).
Several took off and tried to climb at full throttle with full heat applied.
One 6,000 hour pilot examiner allowed the engine to ice to the point of
severe roughness and power loss before he took corrective action.

A second common error involved the flaps. In a number of instances,
flaps were not retracted after intermediate landings; shortly thereafter,
the subjects tried to take off with the flaps still down.

The catastrophic errors, while few, were very serious. In one case,
an experienced pilot became disoriented and lost control of the airplane.
The safety pilot restored the airplane to level flight for a few moments,
after which the subject was able to resume flying. In a number of cases,
subjects neglected the glide path and flew almost into the ground several
miles short of the runway threshold, requiring the safety pilot to take con-
trol. The third catastrophic error which was recurrent involved either ex-
cessive sink rates just prior to landing or attempts to land on the nose
gear (failure to flare). In three cases, subjects left the prepared surface
of runways or taxiways unintentionally.

The Cessna 172 is a simple, rugged, easy to fly airplane with the
least complex systems of any modern aircraft. Had the research vehicle
been a more complex machine, the number of errors in management of fuel
system, propellor controls, retractible landing gear and flaps would un-
doubtedly have been still larger.

38


00}
1ooor

= 900

PA

Ww 800

D

5
© 700

600)

z

DEVIATION FROM

400,

Figure 9

PHASE I
EXPERIENCED

PHASE I
INEXPERIENCED

600}
500
400
300

200,

VARIABILITY

100}

oe 08 DP Oe

lo (0)
80 mg % ALCOHOL

120

re)

$0
ADH

3.2

w
(0)

+@
AD

3.2

0

[GUIDE PATH TRACKING DURING CONTROL AND ALCOHOL FLIGHTS]

26


The system is operated by its own internal power supply, primarily
rechargeable sealed nickel - cadmium batteries. The system may be stored
and operated at temperatures of up to 120°F. The ideal temperature for
storage is room temperature.

The total system for data collection consists of the following
component parts:

1. Glide Slope and Localizer System consisting of a King KX160
nav/com unit, a King KI211 indicator, and a King KMA12 marker
beacon receiver - audio amplifier.

2. Control deflections are measured by Bourns 3510S-20-501
three-turn potentiometers driven by the control cables.

3. A flow meter measures air speed (the device used was a model
55Al Air Velocity Meter (Flow Corp.) powering a hot wire
anemometer over which air was drawn by a venturi mounted in
the slipstream).

4. A Lockheed Model 117 seven channel FM tape recorder,

5. A recorder mating box between the various pickups and the
tape recorder. A schematic of the mating unit is shown in
fig. 15.

6. A push-button device to signal when the aircraft is over the
outer and the middle markers.

The total system draws less than 1 ampere and does so only when all
component parts are connected and the device is in use.

43



Table V indicates that in the experienced pilots, significant
changes related to alcohol level were observed in only three dependent
variables (plus a fourth, not listed but discussed below). One of these
variables, SS (variability in air speed), appears to be spuriously sig-
nificant for reasons noted on p. 29. Another variable, ADL (the average
rate of drift with respect to localizer centerline) approached signifi- i
cance (F = 3.03; F.05 = 3.07).

A supplementary analysis indicated that deviations from localizer
centerline exclusive of the terminal minute were significantly related
to alcohol level (p<.05). The data shown in figure 8 show the localizer
deviations of the experienced pilots at the outer marker and during each
of the last four minutes of their approaches, terminating at the middle
marker. The data suggest a progressive decrease in differences related
to alcohol level, no systematic difference being apparent at the middle
marker. The inexperienced pilots performed similarly with respect to
localizer tracking, but decrements related to alcohol were larger, the
differences at the middle marker being highly significant.

Variability in localizer tracking (SL) was significantly related to
alcohol level in both groups of pilots. In both groups at all levels of
alcohol, localizer variability increased during the last minute of the
approach (SLT) but the means for the various levels did not differ signi-
ficantly. Figure 8 also illustrates this trend, which was observed in
virtually every pilot under all conditions.

25



Fluctuations during approach: explanatory note
When the airplane is drifting away from the command track, either laterally
(L) or vertically (G), the function d | or d |c| will be
“ae “at
positive. Conversely, when the airplane is returning toward command track,
the sign of the derivatives will be negative. If a smoothing routine is
applied to the data to minimize spurious slope changes, and a critical
slope rejection routine is applied to reject effects of transmitting over
the radio used for determination of L and G, the number of changes of sign
will indicate the ability of the pilot to detect drift (-) and correct it.
The average value of the function may also be useful. This may be different

when the sign is (+) than when it is negative (-).

Since initial position (variable 1) is not always under the control of
the pilot, high values of AL, DL, VL and SL may occur which are not
indicative of poor performance. The use of the functions defined below
will also aid in differentiating degraded performance from poor ground
control leading to defective positioning of the airplane at the outer

marker.

62


BACKGROUND

The role of alcohol as a contributing factor in general aviation
accidents has received considerable attention during the past decade.
An informal study in 1962 noted that during the three-year period 1957-60,
40-50% of accidents in which alcohol was known to be involved were fatal
(4). Only about ten percent of accidents in which alcohol was not in-
volved were fatal.

A subsequent study by Harper and Albers (5) suggested that
measurable levels of blood alcohol were associated with approximately
35% of all fatal general aviation accidents during 1963. Their estimate
was based on 56 positive alcohol findings in 158 fatal accidents in which
toxicological analyses were done, out of 477 fatal aircraft crashes in
that year. While the reliability of these data is open to some question
because of the different techniques used in handling and analyzing the
various specimens, other studies have also indicated that alcohol may be
involved in up to 40% of fatal accidents in some regions of the country
(6,7).

The National Transportation Safety Board has generally been rather
conservative about ascribing the cause of accidents to alcohol. This
drug has in the past been reported as the probable cause only when it has
been known to be present and other probable cause factors have not been
found, During recent months, however, the NISB has reexamined this policy
and has been listing alcohol as at least a contributing factor in fatal
accidents when levels greater than 50 mg % are found (8). During 1967-69,
the Board reported alcohol as a probable cause in 136 of 1942 fatal general
aviation accidents (74). Alcohol has been reported as the probable cause
of slightly less than 1% of all accidents in aviation, though the data in
non-fatal accidents are less accurate.

It is difficult to ascertain exactly where the truth lies in this
area. Harper and Albers used 15 mg % (0.015%) as their lower limit of blood
alcohol. The NTSB until recently has been reluctant to impugn alcohol as
a cause factor if levels have been below 150 mg % (0.15%), a concentration
at which a prima facie finding of intoxication may be made under the law in
46 states, Many states now define intoxication as being present at 100 mg %,
however, and Utah uses 80 mg %, as do the United Kingdom and several
European nations. The average blood alcohol reported by Harper and Albers
was 147 mg %, a value close to the most liberal of the values defined by.
state laws in this country.

There is little question about the role of high levels of blood
alcohol in either aircraft or motor vehicle accidents. A much more sub-
stantial question arises when lower blood alcohol levels are found. If it
is assumed that there is some low level at which alcohol ceases to be a
factor, what is the level? In particular, is alcohol a problem of any
magnitude in aviation when it is present at levels below 80 mg %, the low-
est value at which intoxication is presumed to be present by the laws of

2


TABLE ILI: COMPARISON OF SUBJECT GROUPS: CONTROL (NO ALCOHOL)
—= ————— a
Variable I II Variable I II II/t
SL 505 603 sc 459 532 1.16
SLT 445 474 SGT 350 408 1.17
DLO 607 661 DGO 1072 925 86
DL 566 546 DG 536 581 1.08
DLT 652 534 DGT 587 567 +97
DLM 732 637 . DEM 609 778 1.28
ADL 21.8 26.9 ADG 59.1 | 67.5 1.14
ADLT 13.3 17.2 ADGT ° 61.5 | 68.6 1.12
ACL -22.0 |-26.4 ACG -59.4 |-65.2 1.10
ACLT -13.0 |-16.4 ACCT -65.3 |-73.7 1.13
AMLT +15 39 AMGT -1.92 | -2.53 1.32
ACL/ADL 1.01 +98 ACG/ADG 1.01 97 96
ACLT/ADLT +98 95 ACGT/ADGT| 1.06) 1.07 1.01
Variable I IL IL/t
ss 9.7 | 9.8 1.01
SsT 1.7 | 2.0 1.18
DSO 4.4 | 3.8 +86
DS 3.8 3.6 95
DST 3.8 | 3.7 397
DSM 3.6 | 3.5 97
I: Phase I: Experienced Pilots

II: Phase IL: Inexperienced Pilots

16


Sample Narrative Summary
ALCOHOL PROJECT REPORT

Subject: Air: Smooth
Date: Altitude: 30.12
Alcohol: 120 mgm % Runway: 28L

Temperature: 36°

Wind: 180-9

Preflight Activities: Satisfactory, but the initial takeoff was
made with full heat, although it was quite obvious the aircraft required the entire
length of the runway and then just barely got into the air. The subject then left
the landing light on.

First Approach: Missed one radar vector completely. No
carb heat on the approach. Air speed varied from 85 - 110 mph, but the landing
was satisfactory,

Second Approach: No mag or carb heat check prior to takeoff.
The subject overshot the localizer and just kept on going making no attempt to turn
to the runway center line. The approach ultimately, however, was satisfactory after
I steered him back to the centerline. The turn on the missed approach, however,
was a bad slipping turn,

Third Approach: The subject climbed with full carb heat on.
We overshot our target altitude by about 300 feet. We then missed one radar vector
and cruised with carb heat on. The approach, however, was made without carb heat
and terminated with a diving turn to the left from which the subject eventuall
recovered just prior to my taking control. .

Fourth Approach: The subject left the landing light on.
Airspeed reached 115 mph, the approach was satisfactory as was the landing, but
the subject then turned off the runway onto the grass instead of the taxiway. We
taxied with flaps down and carb heat on.

Flight Back to Don Scott: The subject shut off the nav lights, but
the rest of the flight back was satisfactory as was the shutdown procedure.

53



al

22

23

24

2

26

LeT mn, BE THE First DATUM DURING THE FINAL MINUTE

OF THE APPROACH

AVERAGE LATERAL Position
DURING THE TERMINAL
PHASE OF THE APPROACH

AVERAGE VERTICAL Position
DURWG THE TERMINAL
PHASE OF THE APPROACH

AVERAGE Aig SPEED DURING
THE TeaminaL VHASE
OF THE APPROACH

AVERAGE LATERAL DEVIATIONS
DURING THE TERMINAL
PHASE OF THE APPROACH

AVERAGE VERTICAL DEVIATIONS
DURING THE TERMINAL
PHASE oF THE AFPROACH

AVERAGE AIR SPEED DEviaTions
DURIWG THE TERMINAL
PHASE OF THE APPROACH

AST . Sts —__
nye (nae)

re
2 tui]
Aen

Dur s
nyn Cae!)

me
G.
ver. SIS
me nat!)

60


Heart rates during the approaches were directly related to alcohol
levels. This was noted in both groups of pilots. The data are summarized
in figure 12. It is interesting that the effect of alcohol was rather
more pronounced during the first replication of the experiment than during
the second in each phase. Tests for significance were not carried out
on these data, but the small and consistent standard errors suggest that
the differences associated with alcohol were statistically significant.

33



APPENDIX 10

DESCRIPTION OF COMPUTER PROGRAMS

A series of Fortran IV (G) computer programs has been written and
used to reduce continuous analog data to a series of 51 parameters which
are used as input to statistical programs.

At the time of conversion of the analog tape, the record number
representing the beginning of the approach (outer marker), position at
the middle marker, and time of landing or go-around is recorded and subse-
quently key punched as input data for the programs. Appendix 8, pp. 66-67,
lists the parameters which are measured for each approach. The parameters
in general are smoothed (average) values for: the entire approach, the
last minute of the approach, or sequential increments of the approach, In
addition, the variance and standard deviation of selected variables are cal-
culated.

The main program reads the cards containing the information on the
proper approach, time at markers, alcohol level, and subject identification
and searches the master data tape until the proper data are found. A series
of subroutines is then called to perform the appropriate analysis for the
parameter in question. The use of these subroutines enables one to modify
various parts of the programs with ease and to write common code for a large
number of the 51 parameters. Among the subroutines are:

1. a data smoothing routine

2. one which counts course reversals

3. heart rate

4. multichan - separates two variables which have been recorded
on one FM Channel

5. a routine to pass data from record to record
6. a slope routine

7. a summing routine

8. an absolute value routine

9. a mean and sta. deviation routine

73



ERROR FREQUENCY

20,

80

60

40}

20

40

20)

Figure 13

CATASTROPHIC ERRORS

es.

MAJOR ERRORS

\\

40 80 120
BLOOD ALCOHOL CONCENTRATION, mg %

of

MINOR ERRORS Tell

[PROCEDURAL ERRORS|

34


This exemption shall terminate one year from its effective date
or upon completion of the research project involved, whichever occurs
first, unless sooner superseded or rescinded,

[anu fide

Director
Flight Standards Service

Issued in Washington, D.C., on far « 1968

49



Hy

Figure 5

2 PHASE I: EXPERIENCED PILOTS. PHASE Il: INEXPERIENCED PILOTS
5 |
a
© 600;
2
a L
ra
© 400
3
us
Dd
8 200
a
=
co)
cs)
oLlL7 sities] 4+ sla; ;sj}si4ajel{i|7jale
[COMPOSITE PERFORMANCE SCORES DURING CONTROL FLIGHTS (NO ALCOHOL)]
Figure 6
40|%
20
+ 4 8 efs{[s;7; ital oe 2ef7]ila]alsie
fo) — —

[RELATIVE CHANGE IN COMPOSITE SCORES DURING ALL ALCOHOL FLIGHTS]

22



APPENDIX 5

Au

Analog strip chart recording of an ILS approach
terminating in a landing.

52


at

28

29

30

31

32

VARIANCE, OF LATERAL
POSITION DURING TERMINAL

V“T
PHASE OF THE APPROACH L

VARIANCE OF VERTICAL,
POSITION DURING TERMINAL
PHASE oF THE APPROACH

V@T

VARIANCE OF AIR SPEED
DURING TERMIAL PHASE
OF THE APPROACH

VST

STANDARD DEVIATION OF LATERAL
Position DutmG TERMINAL
PUASE oF THE APPROACH

STANDARD DEVIATION OF VERTICAL
POSITION DURING TERMINAL
PHASE OF THE APPROACH

STANDARD DEVIATION OF AIR SPEED
DURING TERMINAL PHASE OF
THE APPROACH

61

_ ge

ct, ne

Ree) 7

(Ru)

(nef)

> (62) (26 y

: bine tang
release) (my-Enst])”
* 2
” (si¥ ( s\)
- Wah _ Vi

ne rar!) (ny Cae ])® j

SLT = Jvir

Scr + ver

SST = {VsT



Il.
IIL.
Iv.

VI.

LIST OF TABLES

Subject Data

Data Available on Tape

Comparison of Subject Groups (Control Condition)
Estimated Blood Alcohol Concentrations

Analyses of Variance: F Ratios

Procedural Errors

LIST OF FIGURES

Schematic of Data Acquisition, Reduction, Evaluation
Schematic of ILS Cross-pointer Instrument
Comparison of Experienced with Inexperienced Pilots
Results of Expired Air Analyses

Composite Performance Scores (No Alcohol)

Relative Changes During All Alcohol Flights

Scores & Decrements at Each Alcohol Concentration
Localizer Tracking during Control & Alcohol Flights
Glide Path Tracking during Control & Alcohol Flights
Effects of Alcohol on Average Drift Rates

Relative Decrements in Individual Measures

Heart Rates during Instrument Approaches

Procedural Errors

Attenuation of Alcohol Effects by Replication
Schematic Diagram of Mating Unit

Approach Chart: Runway 10 Left

Approach Chart: Runway 28 Left

ILS Geometry

Li


APPENDIX 1

AIRCRAFT INSTRUMENTATION

The Cessna 172 used in this research contains the following flight

equipment:

A. Instruments (lighted)

1. Air speed indicator
2. Turn and bank indicator
3. Altimeter
4. Rate of climb indicator
5. Directional gyro
6. Artificial horizon
7. King KI-211 VOR-LOC-GS cross-pointer indicator
8. Tachometer
9. Oil temperature gauge
10. Oil pressure gauge
11. Fuel quantity gauges
12. Vacuum gauge
13. Ammeter
B. Lighting
1. Cockpit instruments
2. Observer (rear) station
3. Navigation lights
4, Tail-mounted stroboscopic unit (white)
5. Landing and taxi lights

The electronic system in the research vehicle (Cessna 172) provides

a method of collecting the following data:

Localizer tracking
Aileron movements
Rudder movements
Glide slope tracking
Airspeed

Throttle movements
Elevator movements
EKG

Voice communications

4l



SUMMARY AND CONCLUSIONS

This experiment involved exposure of 16 instrument-rated pilots to
four blood concentrations of ethyl alcohol, 0, 40, 80 and 120 mg %, and
observation of their ability to fly a light aircraft by reference to in-
struments. Objective data were collected on tape during instrument ap-
proaches to ILS minimums; subjective data were collected by a safety pilot
throughout the flights. Blood alcohol levels were estimated by analysis
of the alcohol content of expired air.

The following conclusions are drawn from these data:

1. When sober, the inexperienced pilots were less proficient in
glide path tracking and were more variable. They also committed more
procedural errors.

2, At the lowest level of alcohol studied, 40 mg %, both groups
demonstrated significant increases in the number and potential seriousness
of their procedural errors. Minor decrements in ILS tracking were observed
in the inexperienced pilots at this level.

3. At higher alcohol levels, performance decrements were observed
in both groups; these were minor in the experienced pilots but became sub-
stantial in the less experienced pilots whose ability to track the vertical
component of the ILS suffered severely. The number of major procedural
errors continued to rise almost linearly in both groups.

4. At a level of 120 mg % of blood alcohol, catastrophic failures
began to occur. The safety pilot was required to take control of the air-
craft on 16 occasions during 30 flights at this level. Two pilots became
incapacitated in flight as a result of severe vertigo, nausea and vomiting
while flying by reference to instruments.

5. It is concluded that significant degrees of performance impair-
ment exist in qualified pilots under the influence of 40 mg % blood alcohol,
half the minimum level accepted by any jurisdiction as evidence of intoxi-
cation. We have not determined a blood alcohol level at which no signif-
cant impairment exists in flight.

39



31

38

34

4|

42,

CORRECTION TOWARD ACL
LATERAL COMMAND
TRACK

BAe: el)
AVERAGE RATE OF ) For Jel <0
dt

WHERE WENO, OF NEGATIVE VALUES

a ale
AVERAGE RATE OF R For ale ¢o

CORRECTION TOWARD
VERTICAL COMMAND
TRACK

NUMGER OF CYCuc

DEVIATIONS From LATERAL
TRACK Dung Termine «=| NDUT = NO: OF CHANGES ge From nto my
PRASE OF THE APPROACH OF SIGNS oF dt

Symes oF CYeLIG No. OF CHANGES dc!
DEMATIonS FAOM VERTICAL - la. Of

Taacn ouning Terminal  NDGT = oF sians oF From mato my
PHASE OF THE APPROACH dt

AVERAGE RATE OF DRIFT 2 (aut)

FRom LATERAL COMMAND dt : ‘
TRack DuamG Teta, ADLT = + +———"__ For ile't >o
Puase oF THE Arrroacn n dt

WHERE M=NO. OF POSITIVE VALUES

AVERAGE RATE OF DRIFT

ew

'
Fenvemrens cme pyc r, Grvdt A peg All 5
PWASE OF THE APPROACH n dt

64


Flight Protocol:

A standard protocol was used for all data collection flights. On
the day of a flight the subject ate his normal breakfast and went about his
usual activities during the day. He ingested only soup and other rapidly-
digested liquids for lunch. At least 3 hours after lunch and 2% hours
prior to takeoff time, the subject reported to the field laboratory. Under
supervision of a physician or technician, the subject drank a previously
prepared alcohol mixture at a rate approximating 5 ml. of mixture (thus
1 ml of absolute alcohol) per minute. The total volume of beverage pro-
vided the subject was divided into three equal parts. If 120 mg % was
desired, all three contained 20% alcohol; if 80 or 40 mg % were desired,
either the third, or the second and third, portions contained only enough
alcohol to maintain the desired level, the total volume being maintained
by distilled water.

The first portion of the beverage contained some alcohol even on
days when 0 mg % was desired, in a largely successful effort to confuse
the subjects. The amount of alcohol on control days was small enough to
allow its complete metabolism prior to flight.

Five minutes after finishing his priming dose, the subject rinsed
his mouth thoroughly with water, then provided an expired air sample to
confirm that the desired alcohol level had been reached. He then went to
the aircraft. Previously affixed chest electrodes were connected to the
instrumentation unit. (The airplane and instrumentation pre-flight inspec-
tions had been conducted in advance by the safety pilot and the technical
observer). The Breathalyzer was placed in the airplane, ready for later
use, Thereafter, the subject performed all of the duties of pilot-in-
command, with one exception: the safety pilot responded to radio communi-
cations regarding other traffic in proximity to the experimental aircraft,
since the subject was flying entirely by reference to instruments.

Takeoff time was normally scheduled for 40 minutes after sunset.
The subject started the engine, taxiied, operated all radios, conducted
the engine run-up, and took off. After take off, he donned an instrument
hood, and then called Columbus approach control to request radar vectors
to an ILS approach and full-stop landing. Approximately 2% miles prior to
outer marker passage, the tape recorder was activated by the technical
observer, acting on instructions from the safety pilot who occupied the
right front seat. Upon passing the outer marker, the safety pilot acti-
vated his event marker. A second event mark was placed on the tape upon
passing the middle marker at minimum altitude. The subject then removed
the hood and landed the aircraft. The tape recorder was turned off.

The subject taxiied back to the departure end of the runway and
parked the aircraft. A second expired air sample was taken and analyzed,
to allow the technical observer to calculate the volume and frequency of
successive maintenance doses, which were administered as required during



APPENDIX 4

METABOLIC DEGRADATION OF ALCOHOL

/_n iE
Correlation
[Phase # Weight, 1b. | Coefficient Regression Equation Slope (mg %/hr)
rT 1 185 0.94 y = 77.89 - 0.29 x 17.69
2 150 -0.97 y = 67.22 - 0.37 x 22.14
3 176 -0.97 y = 76.28 - 0.37 x 21.92
4 176 -0.95 y = 69.25 - 0.27 x 16.02
5 157 -0.91 y = 83.50 - 0.30 x 17.96
6 170 -0.96 y = 71.79 - 0.33 x 19.94
7 225 -0.91 y = 72.63 - 0.25 x 14.90
8 160 -0.95 y = 83.09 - 0.30 x 17.94
‘ae 1 170 -0.90 y = 93.62 - 0.29 x 16.74
2 160 -0.92 y = 111.33 - 0.18 x 10.68
3 155 -0.95 y = 84.64 - 0.28 x 16.56
4 220 -0.98 y = 67.89 - 0.32 x 19.20
5 155 -0.97 y = 113.56 - 0.26 x 15.48
6 155 -0.93 y = 85.21 - 0.31 x 18.36
7 210 -0.97 y = 83.56 - 0.32 x 17.96
8 220 -0.96 y = 80.54 - 0.23 x 13.92

51



MEASURES OF PERFORMANCE BASED oN AIRPLANE PosiTion AND SPEED

VARIABLE DESCRIPTION SYMBOL DEFINITION
=
Ls
| INITIAL LATERAL lo =;
Position 100
100
INITAL VERTICAL Gq aS
2 PosiTion ° * 100
Mad
1
2 S:
3 INITIAL AIR SPEED Kye) >
loo
=
bi
4 Fiveu LATERAL LM = ieagioe
Position “Too
ne
LD &
5 FINAL VERTICAL GM . itm wo
PoSiTion = loo
Me
'
Ds
6 FINAL AIR SPEED smog ee
too

57



cruising flight. The subject then received departure instructions,

took off, and after donning his hood requested vectors for three more
ILS approaches. The entire sequence was repeated except that the second
and third approaches were terminated by missed approach procedures; the
subject landed after the fourth approach, when a final breath alcohol
determination was made. He then took off and returned to the Ohio State
University airport under visual flight conditions, landed, parked and
conducted the prescribed shut-down procedures. He was then driven to
his home by the technical observer. This was done regardless of the
alcohol level to maintain insofar as possible the "blind" conditions of
the experiment.

Processing of Data:

The data tapes were reproduced on a strip-chart recorder the
following morning to insure that all aircraft equipment was operating
correctly. Processing of the tapes thereafter is described below.
Since the taped data were not subject to observer bias, they are referred
to hereafter as the "objective" data. Subjective data were also col-
lected by the safety pilot during each flight; a narrative description
of the flight was either dictated or transcribed within 12 hours of its
termination. To minimize observer bias, the subjective observations
were binary wherever possible. Note was made of all procedural errors
committed by the subject, as well as of his affective responses to the
alcohol and any unusual features of the flight. A copy of the strip-
chart readout of one approach is shown in appendix 5, together with a
representative narrative summary prepared by the safety pilot.

The objective (tape) data were processed according to the scheme
noted in figure 1. The tapes were converted to digital format and pro-
cessed by an IBM 360-75 computer. A variety of statistical descriptors
was derived for each approach; the annotated output from one such approach
is shown in appendix 6. The statistics shown therein were also punched
on IBM cards, which were then processed further by the computer, using
analysis of variance to discern effects of the variables in the experi-
ment. A summary of the results of these analyses is contained in the body
of the report; the analysis of variance matrices are shown in appendix 7.

The narrative summaries of the flights were reviewed by the safety
pilot after each phase of the experiment was completed. At that time, he
compiled a tabulation of errors of omission and commission for each flight,
and classified these errors into four categories: errors involving the
use or non-use of the carburetor heat control, and other errors, classi-
fied in one of three mutually exclusive categories,

1. MINOR ERRORS: Errors which do not affect the safety of the

flight materially, but which are mistakes which a student pilot would not
be expected to make upon reaching the degree of competence required for

11



TABLE OF CONTENTS

ABSTRACT
ACKNOWLEDGMENTS iii
INTRODUCTION 1
BACKGROUND 2
MATERIALS AND METHODS 5

Subjects 5

Aircraft 5

Instrumentation 5

Environment 7

Experimental Design 7

Initial Evaluation 8

Alcohol Analyses 8

Flight Protocol 9

Processing of Data 11

Evaluation of Performance 12
RESULTS 15

Preliminary Results 15

Objective Data 21

Subjective Data 35
DISCUSSION 36
SUMMARY AND CONCLUSIONS 39
BIBLIOGRAPHY 40

LIST OF APPENDICES

1. Aircraft and Research Instrumentation 41
2. Approach Charts; ILS Geometry; FAA Exemption 44
3. Protocols for Phases I and II 50
4. Metabolic Degradation of Alcohol: Regression Analyses 51
5. Sample Analog Chart; Sample Narrative Summary 52
6. Sample of Computer Output 54
7. Analysis of Variance Matrices 55
8. Definitions of Dependent Variables 56
9. Mean Values of Dependent Variables 71

10. Description of Computer Programs 73



Figure l2

4s PHASE I PHASE IL
no
ul
=
>
Zz
= 105 a a ae
~
P
Z | ge
40
100 Bo |mg” ALCOHOL
< $ 120
Es
95+
[ HR HR
4 3 2 T 4 3 2
fe)

MINUTES PRIOR TO REACHING THE MIDDLE MARKER

HEART RATES DURING INSTRUMENT APPROACHES

32



The reduced data is printed for visual verification and review
and is additionally punched on cards to be used as input to the statis-
tical analysis programs. Appendix 6 (p. 54) contains samples of the
output obtained for each approach. While the data could be written on
tape, it is somewhat easier to recombine and sort the data from cards
for subsequent analysis.

An analysis of variance program similar to BMDO2V but utilizing
weighted means to compensate for unequal cell sizes has been employed to
perform the bulk of the statistical analysis. It utilizes Dwyer's
square root algorithm and includes as output:

1. cell frequencies

2. cell, marginal, and grand totals and means

3. a summary of the analysis of variance

Individual analysis of variance problems are run on 32 selected
parameters from Appendix 8. Significant results from these analyses are

combined with the narrative output and the resulting data interpreted.
The resulting interpretation has been presented elsewhere in this report.

74


Table V

ANALYSES OF VARIANCE: F RATIOS

ns
VARIABLE Phase L f Phase IL
Alcohol Interaction Alcohol Interaction
F P F P F P F P

sL 3.75 .05 | 2.65 | .O1 3.86 .05 2.05 O01
SLT <1 2.30 O01 2.59 1
SG <1 3.60 -O1 3.45 05 2.04 -01
scT <1 3.18 | .01 4.84 05 2.18 01
ss 3.26 05 1.49 <1 <i
SST <1 10.85 | .01 1.10 2.81 01
DLO 5.62 -O1 1.35 4.31 -O1 1.56
DL 2.05 3.73 -O1 2.57 3.64 01
DLT <1 2.22 OL 1.80 3.18 01
DLM <1 1.76 05 1.67 <1
DGO <1 3.00 -O1 <1 2.27 O01
DG 1.41 3.78 -O1 3.66 -05 2.10 OL
DGT <1 2.84 -O1 8.92 -01 1.36
DGM <1 2.32 -O1 4.38 01 <1
DSO <1 1.92 05 <1 4.02 01
Ds <1 4.63 -01 2.60 3.64 01
DST <1 6.07 01 1.86 3.60 -O1
DSM <1 7.08 | .O1 1.85 3.17 -O1
NDL <1 4.53 -O1 2.06 5.57 -O1
NDLT <1 3.34 -O1 2.47 2.52 -01
NDG 1.02 3.86 .O1 5.15 -O1 1.49
NDGT 2.33 1.44 1.42 1.30
ADL 3.03 2.79 .O1 1.77 2.30 01
ADLT <1 1.87 | .05 1.66 1.04
ACL 1.24 2.30 | .O1 2.57 2.35 O01
ACLT <1 1.42 <1 <1
ADG 1.24 3.45 -01 11.19 +01 1.20
ADGT 1.43 2.55 -O1 5.07 -O1 2.56 -O1
ACG <1 3.03 01 10.03 .O1 1.79 05
ACGT <1 7.10 -01 4.54 +05 2.52 OL
AMLT <1 1.71 -05 2.92 +05 <1
AMGT <1 2.97 -O1 <1 1.00

20




APPENDIX 2

Figure 16
PORT COLUMBUS INTERNATIONAL

ILS RWY 10L AL-94 (FAA) COLUMBUS, OHIO

COLUMBUS

119.0 279.6

‘COLUMBUS TOW!

120.5 257.8

GND CON

121.9 348.6

ASR

2500 996

Glide slope 2.63°

enon 4 ~

FLeV 816

amen GRANDVIEW LOM 1 ide 335
ithin 10 NM MISSED APPROACH 1
" Climb to 2700 to CM LOM Bo 7
& and hold. Rwy 23 Ig 3900"
Ou Rwy 13 Idg 3683’
Rwy 31 Idg 3792'

MM

FETT
CATEGORY A 8 [ c
SAUS-101 1014724 (200-4) ie
S-10C101 1300/24 486 (500-4) 1a cat sf
1320-1 | 1380-2 | Rwy 1-19 45 898
CIRCLING 1320-1 504 (600-1) 3551 x 150
504 (600-1a) | 564 (600-2) Rwy 523 HIRL Rwys 10R-281,
Vv 4483x150 and 10L-28R
13-31 REIL Rwys TOR
5001 x150_and 28R
TOM fo Locolizer Missed Apch 5.6 NM
Knots [_70 [100 ] 125 [150 [165
[Min:Sec| 4:58 [3:29 |2:47 | 2:19 [2:07

APPROACH CHART:

RUNWAY 10 LEFT

44


AVERAGE DRIFT RATE

AVERAGE DRIFT RATE

Fisure_1O

50,
PHASE 1 PHASE I

40|. EXPERIENCED INEXPERIENCED
30} L

20}

10} L

ADL ADLT ADL ADLT

fe}

EFFECTS OF ALCOHOL ON DRIFT RATE FROM LOCALIZER

Or eg
a
2 50 mg% ALCOHOL
a
oo. 2 120
" —.
—
sol ——
40}
7 p06 ADGT ADG ADGT
0

EFFECTS OF ALCOHOL ON DRIFT RATE FROM GLIDE PATH]

268


phases of the approaches. The higher variability suggests as well that
these pilots were working considerably harder, but they consistently lost
rather than gained by their greater effort. That they had less time to
devote to the secondary tasks is quite obvious in the error data.

It is especially noteworthy that there were no marked differences
in tracking between the two groups during control flights. The differ-
ences became obvious when the pilots were operating under stress. The
heart rate data reinforce this view. It is also instructive to note that
no very marked learning effects were apparent in the inexperienced group
during control flights. There were some considerable differences, however,
in the decrements caused by alcohol between the first and second replica-
tions of the experiment (figure 13). It would appear from these data that
these pilots benefitted considerably from their first exposure to the ex-
periment; again, the heart rates support this interpretation.

Figure 14

m 1000, [ 20
Fy | * 40 Ig % ALCOHOL
# ;
5 s00 ° 120 |
8
=
@ 600]
2
S
2
z DL

4 4 3 2T

MINUTES PRIOR TO REACHING THE MIDDLE MARKER

o

===

°
+
w
n
4

DEVIATIONS FROM
COMMAND AIR SPEED
-

lo

loo,

HEART RATE.

PHASE I PHASE I
FIRST TRIAL SECOND TRIAL

90

[ATTENUATION OF ALCOHOL EFFECTS BY REPLICATION]

37



COMPOSITE SCORE

PERCENT CHANGE FROM CONTROL

800

600

400

200

30

20}

Fieure 7

© PHASE I PILOTS -EXPERIENCED
© PHASE II PILOTS - INEXPERIENCED

BLOOD ALCOHOL, mg%
40 ” 80 120

MEAN SCORES AT EACH ALCOHOL CONCENTRATION

BLOOD ALCOHOL ,mg %

° 40 80 120

[RELATIVE DECREMENTS ASSOCIATED WITH ALCOHOL

23



TABLE Il: DATA AVAILABLE ON TAPE

1. Position with respect to localizer course
2. Position with respect to glide path
3. Air speed, indicated

4. Throttle position

5. Elevator position

6. Aileron position

7. Rudder position

8. Electrocardiogram (subject)

9. Radio communications

10. Marker beacon audio output

11. Event marks (observer)

Environment:

All flights were conducted in the Columbus, Ohio, terminal area
under radar observation by the Columbus air traffic control facility. Two
ILS installations at Port Columbus International Airport were used for
approaches. Appendix 2 reproduces approach plates for these two installa-
tions and diagrams of their geometry. Since aircrew members are not allowed
to fly under the influence of alcohol, an exemption was obtained to permit
the conduct of the experiment; this is also reproduced in appendix 2. A
special aircraft call sign was used during data collection flights; ATC
personnel were briefed in advance regarding the study, though they were not
aware of the alcohol level on any individual flight. All flights were con-
ducted at night under normal traffic control procedures.

Experimental Design:

Each phase of the experiment was a single-blind replicate study
utilizing a complete randomized block design. The protocols are shown in
appendix 3. Two flights were omitted in the second half of phase I because
two pilots were unable to tolerate the highest level of blood alcohol.

No flights were lost in phase II.

Each pilot (with the two exceptions noted above) flew on two nights
at each of four levels of blood alcohol: 0, 40, 80 and 120 mg %. During
each flight, four approaches to ILS minimum altitude (200' above field
elevation) were completed. A minimum of 48 hours separated successive ex-
perimental flights to eliminate carryover effects. Prior to the start of
data collection, each subject was allowed to fly the research aircraft
until he was satisfied with his own performance. The experienced pilots
used in phase I required an average of less than two hours to reach this
self-imposed level of familiarity; the inexperienced pilots required about
three hours of familiarization.



STANDARD DEVIATION oF LATERAL Ww
1G Rack DURING APPROACH SL =VVL

STANDARD DEVIATION OF VERTICAL

v Track DURING APPROACH SG = VG
STANDARD DEVIATION OF AIR SPEED

18 Dunmg aPPRoAeH SS +Vvs

NOTE! VARIABLES 7-18 DEFINE BENAVIOR OVER THE ENTIRE
PERIOD OF STUDY, DA,

Ty oss.

19 DURATION OF APPROACH DA = —t wn seconns
soos, /sec,
20 RUNWAY RY: ErtHee tot
OR BL

NOTE: ‘THE FowloWiNG VARIABLES DESCRIBE AIRPLANE BEHAVIOR
DURING THE LAST 60 SECONDS OF EACH APPROACH.

59



Figure 17

PORT COLUMBUS INTERNATIONAL

ILS RWY 28L ALIA (FAA) COLUMBUS, OHIO
‘COLUMBUS APPROACH CONTROL

119.0 279.6

COLUMBUS TOWER 1:

120.5 257.8 as

tao sa :
a :

ATIS 109.1

2700 NoPT to CM LOM.
via APE R186 and CMH
Localizer course (17.2)

LOM:
221 CB Sist*

‘SUMMIT
MISSED APPROACH — STATION LOM Remain
Climb te 2500 direct to within 10 NM.

==) 0.6 mIT
CATEGORY A I B I c I D
SHS 281 1014/24 (200-4)
Pera 1260/24 446 (500-%4) 4s 200%)
1320-14 1380-2
crane 13201 2041600) _| soa oo.nit | 504 (6002 4483x150 IRL Rwys 10R-28L

‘Glide slope point of touchdown opproximately 1600 feet in from approach end | Rwy 13-31 and 1OL28R
runway:

v IR
[LOM to Lecalizer Misted Apch5 NM
[ene | 90 [150 [asf so tae]

Min:Sec|4:38]3:14[2:36] 2:10]1:58

APPROACH CHART: RUNWAY 28 LEFT

45



Exemption No. 821,

UNITED STATES OF AMERICA
FEDERAL AVIATION ADMINISTRATION
DEPARTMENT OF TRANSPORTATION

WASHINGTON, D. GC.

RRR Re RR RR
*
In the matter of the petition of *
*
OHLO STATE UNIVERSITY *
AVIATION MEDICINE RESEARCH LABORATORY » Regulatory Docket No. 8895
*
for an exemption from section 91.11(a)(1)*
and (b) of Part 91 of the Federal *
Aviation Regulations *
*

RRR te Re ek ee ee RRR eR
GRANT OF EXEMPTION

The Director, Ohio State University Aviation Medicine Research
Laboratory has requested a waiver of FAR 91.11(a)(1) and (b) in order
to undertake a research project,

FAR 91.11(a) and (b) prohibit a person from acting as a crewmember
of a civil aircraft while under the influence of intoxicating liquor
and, except in an emergency, prohibit the pilot of a civil aircraft from
allowing a person who is obviously under the influence of intoxicating
liquors or drugs (except a medical patient under proper care) to be
carried in the aircraft.

The Ohio State University Aviation Medicine Research Laboratory has
entered into a contract with the FAA Civil Aeromedical Institute, Office
of Aviation Medicine, to determine the effects of low blood alcohol con=
centrations upon pilot performance.

Specifically, the research project would produce in certain pilots
various blood alcohol levels up to, but not beyond, the lower limit
(150 mgm %) considered sufficient to support a legal determination of
drunkeness on a prima facie basis in most states for automobile drivers.
These pilots would then fly a Cessna 172 airplane in accordance with a
prescribed program and their performance would be measured objectively
by on-board recording devices. The program will require an instrument
flight, followed by a number of ILS approaches at the Port Columbus
International Airport, during the course of this evaluation of pilot
performance,

2242 47



Figure |

SUBTEC ELECTROCARDIOGRAM.

FLIGHT CONTROLS
NAV.CROSS-POINTER

AIRCRAFT Iain SPEED TRANSDUCER!

COMMUNICATIONS

ANALOG TAPE

MAGNETIC

OBSERVER|—-[EVENT MARKER

[NARRATIVES

ERROR COUNTS}—

STRIP CHART FOR

QUALITY CONTROL

ANALOG TO DIGITAL (A-D)

ICONVE Si0W 7 TRACK

7 TO9 TRACK D-D
CONVERSION

INITIAL DATA REDUCTION

PUNCHED CARD

PRINTED OUTPUT]

OUTPUT

FOR REVIEW

SECONDARY DATA REDUCTION;
STATISTICAL PROCESSING

PRINTED OUTPU'

[INTERPRETATION

OF DATA]

IREPORT

FOR EVALUATION

SCHEMATIC OF DATA ACQUISITION, REDUCTION, EVALUATION AND REPORTING =

RF 2626

10