Taste I. Age Distribution of Pilot Population by Airman Certificate.
Midyear 1965.

16-29 30-44 45-59 60 and Over Total

Students 70,416 47,853 10,307 1,582 129,958
Private 34,854 97,358 47,857 5,917 185,984
Commercial 16,110 62,588 31,904 1,944 112,546
Air Transport 336 11,087 10,200 383 22,006
TOTAL 121,714 218,686 100,268 9,826 450,494

Nore: All figures are calculated by adding year-end figures 1964 and 1965; dividing
by 2 for average midyear 1965.

Taste II. Accidents Per 10,000 Pilots For The Year 1965
By Airman Certificate and Age

Certificate 16-29 80-44 45-59 60 and Over Total
Student 60 94 i 82 WT
Private 126 118 120 113 120
Commercial 254 146 109 123 152
Air Transport 298 118 59 104 93

TOTAL ACCIDENT RATE 106 121 109 110 14

Totals Excluding Students 167 128 109 115 129

Nore: This table consists of data based upon the actual accident figures adjusted
by division or extrapolation to populations of 10,000 individuals in accord-
ance with the following formula: number of accidents

—— a
Subject category for 1068 “1000

Taste III. Observed Versus Expected Number of Accidents By Age and Certification.

Total Acci-

16-29 30-44 45-59 60 and Over dents

Obsd. Eaptd. Obsd. Baptd. Obsd. Beptd. Obsd. Exptd. Obvsd. Exptd.

Students 426 541 450 872 14 80 13 10 1,008 1,008
Private 440 424 1,148 1,159 57 580 67 67 2,230 2,230
Commercial 409 237 915 950 848 475. 24 34 1,696 1,696

Air Transport 10 4 131 103 60 oF 4 4 205 205

The observed (Obsd.) number is the actual number of accidents (fatal and non-fatal)
experienced by the respective age and certificate groups during 1965.

The expected (Exptd.) number of accidents for each age and certificate group is
calculated by dividing the total number of pilots in a given age and certificate group by
the total number of pilots within each certificate group e.g.; student, private, ete, (Table
I) thus producing a percentage age representation, This calculated figure is then multi-
plied by the number of accidents yielding an expected number of accidents by age and
type of pilot certificate. ‘The expected number of accidents is essentially a pro-rated
figure based on pilot population and accidents.

3





statistical hypothesis is that occurrence of acci-
dents is independent of rating and age group of
pilots. That is, the rates in the table cannot be
regarded as different. We can reject this hypo-
thesis with a significance beyond the 0.005 level
(the likelihood ratio list gives the chi-square
approximation of 295 on 11 degrees of freedom).

The three pilot groups (private, commercial,
and ATR) were examined separately in a 2x4
contingency table (occurrence of accidents by
age groups). The calculated chi-square for the
private pilot was 1.198 on three degrees of free-
dom which supports the notion that age was not
an important risk factor in this group. In the
commercial pilot group the chi-square for the
accidents as occurring by age is 150.907 on three
degrees of freedom. This is a highly significant
result confirming the evident age differences in
accidents within the commercial group. To iso-
late the source of heterogeneity, the total calcu-
lated chi-square was partitioned into two addi-
tive components: one degree of freedom is
attributed to the difference between the rate for
those in the 45-59 year age groups against all
other (chi-square 51.939); and the remaining
two degrees of freedom are associated with dif-
ferences among the rates in the 16-29, 30-44,
and 60+ age groups (chi-square 99.515). We
concluded that the accident rate for commercial
pilots in the 45-59 age group was significantly
lower than the average for the other age groups
and the rates for the remaining three age groups
are heterogeneous.

The analysis for the 45-59 ATR group versus
the other age groups gives a chi-square of 24.230
on one degree of freedom. Comparisons among
the remaining three age groups give a chi-square
value of 11.640 on two degrees of freedom.

Further analysis was conducted in two parts.
One analysis included student pilots and one ex-
cluded the students. An expected accident rate
by category of certificate and age, assuming no
accident relationship with age, was calculated
for each pilot certificate and age group based on
10,000 pilots.

Student Pilots Included. Table TII shows
that the student pilots had more accidents than
would be expected in all age groups above 30
years of age. However, the small number of
accidents above the expected level in the 60 and
over age group proved not to be statistically sig-
nificant with a chi-square of 2.456 (at 0.05 level

of significance with one degree of freedom, the
chi-square would be 3.814). Table III shows
that private pilot accidents were remarkably con-
sistent among the age groups.

The commercial pilots had a worse record than
might have been expected in the 16-29 age group
(Table III). We feel it should be mentioned
that one cannot obtain a commercial license until
he is at least 18 years old. Also, there was no
way to separate the agricultural pilots from
other commercial pilots by age groups. Thus,
the inclusion of this relatively high-risk group
of pilots may have distorted the figures some-
what and points up the need for valid “exposure
index” data under these circumstances. Among
ATR rated pilots, there is an excessive number
of accidents over the expected number in the
16-29 age group (Table III), and slightly more
than expected in the 30-44 group. Fewer acci-
dents than expected occurred in the 45-59 age
group. The over sixty group had identical
numbers of observed and expected accidents.

Students Eacluded. As in the students in-
cluded analysis, the table of rates shows consid-
erable heterogeneity which indicates that acci-
dents, certification, and age are associated. When
the source of this heterogeneity was tested for
the private pilot group, it showed that age was
not an important risk factor. However, in the
commercial and ATR groups, only the 45-59
age group indicated that age was not an im-
portant risk factor. Excluding student pilots
(Table II), the total accident rates are higher
for all age groups with the exception of the
45-59 year old group.

Il. Discussion

If one excludes the student pilots from the
analysis, the 60 and over age group appears to be
slightly more hazardous than the 45-59, consid-
erably safer than the 16-29, and about as haz-
ardous as the 30-44 year age group. However,
when the student group is included, it appears
that there is not a significant difference between
any of the age groups. Thus pilot certifica-
tion has more effect on the accident rates than
does the age of the pilot. Where individual
rates are compared by type of pilot certificate,
the rate differences do stand out.

Analysis of the accidents involving pilots over
sixty showed that more than 51% of the acci-
dents occurred during the landing phase of op-


erations. Taxiing accidents comprised 8% and
take-off accidents accounted for 15%. Twenty-
two percent occurred inflight and were attributed
to proceeding into adverse weather, disorienta-
tion, fuel exhaustion, and improper flight plan-
ning. Approximately 4% were due to undeter-
mined causes.

For purposes of this paper, accidents requiring
FAA investigation were included. Approxi-
mately ten percent of the total number were
fatal.

In the over sixty group, there were four fatal
accidents: in which cardiovascular problems were
cited as contributory. This compares with six
such accidents for the under sixty group. There
were six pilots over sixty with known cardio-
vascular conditions involved in nonfatal acci-
dents. The pilots were properly certificated in
that it had been earlier decided by competent
authority that the specific conditions did not
constitute a hazard to aviation safety. None of
the six nonfatal accidents were felt related to
the pilots’ cardiovascular conditions.

In the over sixty group, all but two of the 108
pilots involved in accidents had some kind of
limitation on their medical certificates for vision.
These visual acuity conditions were not felt to
be definitely related to the accidents.

Fatal accidents comprised about 10% of all
general aviation accidents. With respect to age,
the fatal accidents compared with the nonfatal
accidents in the following manner:

Including Student Pilots

1965 Total pilots over 60:
dents: 17; Percent: 0.19

1965 Total pilots under 60: 440,668; Fatal ac-
cidents: 526; Percent: 0.12

9,826; Fatal acci-

Excluding Student Pilots

1965 Total pilots over 60:
dents: 16; Percent: 0.19

1965 Total pilots under 60:
cidents: 454; Percent: 0.11

Described. another way, the older pilot ex-
perienced about sixteen percent fatal accidents
within all accidents for the over sixty group.
For all pilots, the older pilot. included, the total
fatal accident rate compared to the total accident
rate was 10%. However, if the older pilot acci-
dent group is subtracted from the total number
of accidents (5134—108=5026) and the percent
of fatal accidents excluding the over sixty group
(543—17=526) is obtained (526+5026x100) we
see a 12% fatal accident rate for the under sixty
group.

We see, then, that the fatal to nonfatal acci-
dent ratio for the over sixty group is 16%, and
for the under sixty group is 12%. These two
numbers are sufficiently close for the 1965 acci-
dents to preclude any inferences that older pilots
in general are likely to have more fatal
accidents in proportion to nonfatal accidents
than is the case with the under sixty age group
of pilots. For the year 1965, however, pilots
over sixty did have a proportionately higher
number of fatal accidents. It is possible that
the well-known greater ability of younger per-
sons to recover from traumatic injuries, as com-
pared to that of older persons, is reflected in a
somewhat lower proportion of fatal accidents
within the former group.2*+

8,244; Fatal acci-

312,292; Fatal ac-

IV. Summary

An analysis of the accident record of older
general aviation pilots (over sixty) for 1965 re-
veals that this age group has an accident record
essentially comparable, and in some cases su-
perior, to that of the younger pilot group. Es-
pecially for the private pilot group, the age and
accidents were not significantly related.


AM 67-22

AIRCRAFT ACCIDENTS BY OLDER PERSONS

Stanley R. Mohler, M.D.
Rowland H. S. Bedell, M.D.
Alan Ross, Ph.D.
Everett J. Veregge, B.S.

Released by Approved by
’ oe
James L. Harris P. V. Srecen, M.D.
Curer, ArromepicaL EpucatTion ~ Feperat Arr Surcron
Division

October 1967

FEDERAL AVIATION ADMINISTRATION

Office of Aviation Medicine



REFERENCES

1. FAA Statistical Handbook of Aviation. Federal 3. Moyer, C. A.: “Aging and Mortality from Thermal

Aviation Agency. U.S. Government Printing Office, Injury”, Journal Gerontolog, 7: 456-461, 1954.
‘Washington, D.t 1966 Edition. , 4, Humpnrey, G. M.: “Remarks on Repair of Wounds

2. Srrenter, B. L.: The Biology of Aging, Comment and Fractures in Aged Persons”, British Medical
by Comfort, A., American Institute of Biological Journal, 2: 55-56, 1884,

Sciences, Washington, D.C. 1960, pp. 24.

3564



Qualified requesters may obtain Aviation Medical Reports from Defense Documentation
Center, The general public may purchase from Clearinghouse for Federal Scientific and
Technical Information, U.S, Dept. of Commerce, Springfield, Va. 22151


AIRCRAFT ACCIDENTS BY OLDER PERSONS

I. Introduction

There is no upper age limit for general avia-
tion pilots, General aviation pilots in the United
States may continue flying as pilot-in-command
so long as they hold a valid medical certificate.
Airline pilots are required to retire from air
carrier flying at age sixty, but many of them
continue to fly in general aviation for years after
retirement. During the time covered by this
study, the oldest active pilot in the United States
was a ninety-three year old physician.

The number of persons over sixty holding
valid medical certificates is increasing each year.
Between August 1965 and December 1965, the
number jumped from 7,401 to 11,317. With the
large increases in pilots over the age of sixty,
an analysis was undertaken of the accident ex-
perience of the older pilot. Their accident ex-
perience was then compared with that of pilots
in all age groups.

All pilots with a given class of medical cer-
tificate meet essentially the same medical stand-
ards. There are three classes: Class I, having
the strictest physical standards, is primarily for
air transport pilots; Class III is for private and
student pilots; and Class II, intermediate be-
tween I and III in strictness, is designed for
commercial pilots (instructors, etc.).

II. Methods and Findings

The pilot population data was divided into
four age groups." (See Table I.) These groups
start with age 16 since that is the minimum age
for soloing powered aircraft. The pilots were
also divided according to the type of airman
certificate held. In most cases, the student and
private pilots hold Class III certificates, com-
mercial pilots hold Class IT certificates, and air-
line transport (ATR) pilots hold Class I cer-
tificates. In a small number of cases, a student,
private, or commercial pilot will hold a medical
certificate of a class higher than that required
for the pilot certificate. The converse may also

be true of some air transport and commercial
rated pilots.

Accident rates (per 10,000 pilots) for the four
major classes of pilots and age groupings are
summarized in the table of accident rates (Table
II). The numerators for the rates are reported
accidents by age and rating of the pilot operat-
ing the aircraft at the time of the accident. The
denominators are the midyear 1965 pilot popu-
lation figures ranked by age and certification.
Because of the special circumstances of student
flying, the data are presented showing both the
inclusion and exclusion of the student group.
It is recognized that the general aviation popu-
lation is constantly changing in dimensions of
certification and age. Thus, a midyear figure
of the pilot population was calculated from the
FAA Statistical Handbook using 1964 and 1965
year-end figures. The 1965 aircraft accidents
which had been received, reviewed, and coded
by February 1966 (5,134) were used since data
for this year was the most comprehensive avail-
able.

Out of a computed midyear population of
450,494 pilots, there were 9,826 (or 2.2%) over
60 years of age. These same pilots had 108 air-
craft accidents (or 2.1%) out of a total of 5,134
accidents during that year. As illustrated in
Table III, calculations show considerable dif-
ferences between accidents, certification, and age.
Chi-square calculations show that general avia-
tion accidents are associated with both age and
certification. Also (it is here noted that all air-
line accidents were deleted from these data),
general aviation accidents are associated with
age in the student, commercial, and airline trans-
port rated groups, but not in the private pilot
group. Table II shows the same differences.
Statistically, a likelihood ratio test of the hypo-
thesis that rating, age, and occurrence of acci-
dents are mutually exclusive gives a chi-square
approximation of over 9,550 with 17 degrees of
freedom. This is for the 3x4x2 table rating by
age of occurrence of accidents. A pertinent