ACCELERATION IN “9 UNITS

i {
2 te
TIME IN MILLISECONDS

Ficure 4. Picture and g-force curve of the energy attenu-
ator after a 25-ft/sec impact.

III. Conclusions.

Simple attenuators for reduction of head in-
juries in light-aircraft crashes have been de-
scribed, tested, and discussed. Such devices
could be installed on present aircraft with meager
weight and cost penalty and would save hundreds
of lives in survivable crashes.

REFERENCES

1. DeHaven, H.: The Site, Frequency and Dangerous-
ness of Injury Sustained by 800 Survivors of Light-
Plané Accidents. Department of Public Health and
Preventive Medicine, Cornell University Medical Col-
lege, New York, N.¥., July 1952.

2, Hasprook, A. H.: “Crash-Safe” Design Can Make
Many Accidents Survivable. Space Aeronautics:
79-80, 87, Sept. 1960.

3. Haynes, A. L., and Lissner, H. R.: Experimental
Head Impact Studies. Proceedings of Fifth Stapp
Automotive Orash and Field Demonstration Confer-
ence. Minneapolis: Uniy. of Minn., 1962, 158-170.

ACCELERATION IN “oT UNITS.

4 @. 2 16 20. 28
TIME IN MILLISECONDS

Fricure5. Test results of a 41.1-ft/sec head impact

a

10.

against a small semicylinder of 0.035 H-34
tempered aluminum filled with a erushable
foam,

Hvexe, D. F., Grxas, P. W., and Henpatx, R. C.:
Patterns of Injury in Fatal Automobile Accidents.
Proceedings of the Siath Stapp Oar Crash and Field
Demonstration Conference. Holloman Air Force
Base, New Mexico, November 1962, 44-58.

Marrow, D. J.: Analysis of Injuries of 1942 Persons
in 1422 Light Plane Accidents. CAA Medical Service
Records, Washington, D.C. Unpublished data, 1949.
Moore, J. O., Tourry, B.,.and Garnerr, J, W.: Study
of Crash Injury Patterns as Related to Two Periods
of Vehicular Design. Department of Public Health
and Preventive Medicine, Cornell University Medical
College, New York, N.¥., March 1955.

FeprraL AVIATION AGENCY: Sixth Annual Report:
Appendix B, Washington, D.C., January 1965.
Hanapy, Naseer E., FAA Administrator: Speech Be-
fore the ATC, Miami Beach, October 30, 1961.
Sweanincen, Jony J.: Tolerances of the Human Face
to Crash Impact. Office of Aviation Medicine Report
AM 65-20, July 1965.

Studies of high-speed movies taken of dummy flailing
in the 1964 FAA-AVSER crash test of a DO-7 aircraft.

U.S, GOVERNMENT PRINTING OFFICE:1966 O—~224-075



Figure 2, An oblique view of the cylindrical aluminum
energy attenuator used by one aircraft com-
pany on its aerial-applicator aircraft,

-160

gi

ACCELERATION IN "g" UNITS

sy

inna

rT reer
TIME IW MILLISECONDS

Fioure 3. View of energy attenuator after a 15-ft/sec
head impact with the instrumented dummy
head.

against a very small area of the head, perhaps not
more than 1% sq in. According to a previous study
by the author,? the forehead (the strongest part
of the face) cannot withstand more than 80g
on 1 sq in. without skull fracture. Hence, all
three tests on this panel would have produced fatal
head injuries in aircraft crashes.

Figure 2 shows an oblique view of a lightweight
semicylinder of aluminum that one company has
added to the top of its instrument panel (total
weight 114 aircraft pounds, probable installation
cost $50.00 or less). Figure 3 shows the g forces
produced when this cylinder was impacted with
our instrumented dummy head at 15 ft/sec. Note
by comparing Figure 1 and Figure 3 that the
attenuator dropped the peak g force from 165 to
30 in the 15-ft/sec impact and from 295 to 115 in
the 25-ft/sec impact (Figure 4). At the same
time, since the light metal deformed to fit the fore-
head, the area of the head taking the impact load
was increased from ¥% sq in. to approximately 8
sq in. The forehead can take over 200g if it is
applied to the contoured surface of 8 sq in. or
more.’ Thus, one can readily see the effectiveness
of this simple energy attenuator for decreasing
the number of deaths in light-aircraft crashes.

Since it has been established that head im-
pacts of 40 ft/sec occur in survivable crashes, an
energy attenuator similar to the one discussed
above but made of heavier aluminum and filled
with a crushable foam was fabricated in our lab-
oratory and impacted with the instrumented dum-
my head at 41.1 ft/sec (Figure 5). (Total weight
1% pounds, probable installation cost $50.00 or
less.) A comparison of the g force of the 40-
ft/sec impact shown in Figure 1 against an un-
protected panel with that shown in Figure 5 shows
a drop from 440g on a small surface to 100g on
a considerably larger contoured surface, bringing
the impact force well within the tolerable range
that under actual crash conditions would produce
no more than a few minutes of unconsciousness.




AM 66-12

INJURY POTENTIALS OF LIGHT-AIRCRAFT
INSTRUMENT PANELS

John J. Swearingen, M.S.

Approved by Released by

. oe
“0
Pp. V. Srsczt, M.D.

J. Rosert Dix, M.D.
Feperau Arr SURGEON

Cuter, Civ Azromepicat Insrrrure

April 1966

FEDERAL AVIATION AGENCY
Office of Aviation Medicine



Qualified requestors 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


INJURY POTENTIALS OF LIGHT-AIRCRAFT
INSTRUMENT PANELS

I. Introduction.

Many accident investigators have reported
that 70% to 80% of all deaths and injuries in
crash decelerations are from face or head injuries,
or both, caused by body flailing.* Most light
aircraft are not equipped with shoulder harnesses
or even feasible attachment points for them. With
only seat-belt restraint, pilots and passengers are
striking their heads on nonyielding instrument
panels, producing needless deaths in survivable
crashes. The death rate in light-aircraft crashes
(30) is five times greater than for automobiles
(6.4) based on 100,000,000 passenger miles.” The
total deaths in light-aircraft crashes is about 1,000
per year at the present time,’ but since light air-

.

craft are rapidly increasing in numbers—150,000
by 1975 *—one would expect this figure to con-
tinue to increase unless design features can
eliminate the needless loss of life caused by head
impact. Studies are underway at CAMI to deter-
mine feasible attachment points for shoulder-
harness retrofit in present light aircraft.

I.

Figure 1 shows the g-force curves obtained
by catapulting an instrumented dummy head
against a typical unprotected panel at 17.6, 26.7,
and 42.2 ft/sec. Even the lowest impact velocity
produced a peak g reading of 165 g, and, since it

Discussion.

did not deform, the edge of the panel was applied

Froure 1. A typical light-aircraft instrument panel showin:

g g-force curves obtained with head impacts of (1) 176

ft/sec, (2) 26.7 ft/sec, and (3) 42.2 ft/sec.

1