PB85-917002 

NATIONAL 

T~tANSPORTATION 

SJ.\FETY 

BOARD 

WASHINGTON, D.C. 20594 

SAFETY REPORT 

GENERAL AVIATION CRASHWORTHINESS 

PROJECT: PHASE TWO - -

IMPACT SEVERITY AND 

POTENTIAL INJURY PREVENTION IN 

GENERAL AVIATION ACCIDENTS 

NTSB/SR-85/01 

UNITED STATES GOVERNMENT 

000001 
TECHNICAl REPORT DOCUMEHTATJOH PAGE ~. ~_eport Ho. 2.Government A~~esslon No. ].Recipient's Catalog No. 

NTSBiSR-85/01 PB85-917002 

lt. Tl t le and SubtItle Safety Report--General Aviation 5.Report Date 

Crashworthlness Project: Phase Two -- Impact Severity March 15, 1985 

&nd Potential InJury Prevention In General Aviation Accidents ~ 6.Performlng Organization 

Code 

7. Author (s) 8.Perlrorming Organization 

Report No. 

~. Performing Organization Name and Address lO.Work Unit No. 

3741A 

Natiohal Transportation Safety Board 11.Contract or Grant No. 

Bureau of Technology 

Washl~ton, D.C. 20594 13.Type of Report and 

l12. SponsorIng Agency Name 

Period Covered 

and Address 

Special Study 

NATIONAL TRANSPORTATION SAFETY BOAkD 1982 

Washington, D. C. 20594 )~.Sponsoring Agency Code 

15.Supplementary Notes 

l6.Abstract This report Is the second In a series of reports to be issued by the National 

Tro.nsportatlon Safety Board as a result of Its General Aviation Crashworthiness program. The 

purpuse of tttls program is to ptovlde lnCormation to support changes in crashworthiness design 

standards for seating and restraint systems in general avlat!on airplanes. A Phase One report 

presented a methodology for documenting Impact severity. This Phase Two report presents 

~Jt)eclfic data on survivable accidents. The data developed In this study suggest that the 

survivable envelope is defined by Impact speeds of 45 knots at 90 degrees of Impact angle, 

60 knots at 45 degrees, and 75 knots at zero degrees. Data are presented which demonstrate 

that If all occupants we!lr shoulde!' harnesses, fatalltle3 are expected to be reduced by 

20 percent &nd 88 percent of the seriously injured persons in survivable crashes are expected 

to experience significantly fewer lif~-threater.ing Injuries. Thirty-four ptrcent of the 

seriously Injured occupants of survivable llccldents are expected to be less seriously injured if 

energy-absorbing seats are available. 

17. Key We. rds general aviation accidents; f8.0istribution Statement 

crashworthlness; crashloads; This document is available 

accident investigation; crash pulse; to thP. public through the 

Impact severity; lapbf'lt; shoulder harness; National Tt>chnlcal Informsoccupant restraint; er; .-gy absorption; tion Service, 

Injury; seats; survivability Springfield, VIrginia 22161 

19.Securlty Classification 20. Security Classification 21 . No. of Pages 22 .Price 

(of this report) (of thIs page) 

UNCLASSIFIED UNCLASSIFIED 46 

NTS~ Form 1765.2 (Rev. 9/74) 000002 
INTRODUC'I10N • • 

MmJODOLOOY • • 

• • • 

• • • 

CONTBNTS 

• • • • • • • • • • 

I I I I I • • • • 

• • • I I I I I • • • • 

• • • • • • • • • • • • 

1 

3 

ANALYSlS . . . . . . . . . . . . . . .. I • • • • • • • • • • • • 4 

Impact Severity. . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Potential Benefits of Shoulder Harnesses and Energy-Absorbing Seats . • • 9 

Estimates or Shoulder Harness Benefits • • . . • • • • • • • • • • • • 12 

Estimates or Energy-Absorbing Seats Benefits . • • • • . • • • • • • • 15 

CONCLUSIONS. • • • • • • • • , • • • • • • • I I I I I I I I I I I I 15 

APPBNDIX~ . . . . . . . . . . . . . . . ' . . . . . . I • • • • • • 17 

Appendix A--National Transportation Safety Board General Aviation 

Crashworthiness Recommendations with Summaries of Federal 

A•Jiation Administration Responses and Safety Board Evaluations 

of these Responses • • • • . . . • • . . • • • • • • • . • . • • 17 

Appendix B--Comparison of Study Data with Natioraal Aeronautics 

and Space Administration Crash Test Data . • • • • . • • • • • • • 22 

Appendix C--Excerpts From the General Aviation Safety Panel Proposal 

to the Federal Aviation Administration . . • • • . • • • • • . • • 24 

Appendix D--Methodology • • • . • . • • . . • • • • . . • • • . • • 26 

Appendix E-- Five Accident Examples and Evaluation Results • • • • . • • 31 

ii 

00000.1 
NATIONAL TRAUSPORTATION SAPIITY BOARD 

W ASHINOTON, D.C. 20594 

SAPIITY RBPORT 

Ado?ted: March 15, 1985 

OBNBRAL AVIATION CRASHWORTHINESS PROJBCTz PHASB TWO--

IMPACT SBVBRITY AND POTENTIAL INJURY PP.BVBN'fiON 

IN GENERAL AVIA'nON ACCIDBHTS 

IMTRODUC110M 

In the years 1972 through 1981, 36,466 accidents occurred Involving general aviation 

airplanes. or the 73,596 occupants of these airplanes, more than 18,614 (25 percent) were 

killed or seriously Injured. The National Transportation Safety Board's Investigations or 

these accidents found that many of the fatal and serious Injuries could have been 

prewmted If the occupants had been usl~ shoulder harnesses and had been seated in 

energy-absorbing seats. 

The Safety Board began a General Aviation Crashworthlness Program in 1980 to 

gather data to be used to further support previous Safety Board recommendations for 

improved crashworthiness 1/ in general aviation airplanes. Two basic approaches were 

taken to compile these data. One approach was for a team of trained crashworthlness 

investigators to complete detailed onscene Investigations of selected survivable 

accidents 2/ to document the structural deformation of the airplanes, the Impact severity 

of tht' crash, end the resultant injuries to the occupants. Acceleration loads were then 

calculated for each accident. The methodology fer these analyses was described in the 

S'lfety Board's report, "General Aviation Crasltworthiness Project, Phase One". 3/ 

Analyses of these selected accidents will be presented later as part of a Phase Three 

rf'port. The other approach was to compile, beginning In 1982, more detailed kinematic 4/ 

and injury information for all general aviation accidents. This was thu information used 

as the basis for this report. 

This report places emphasis on, and provides support for, efforts to improve P1e 

crn<Jhworthiness of general aviation airplanes. It presents specific data which help to 

define survivable accidents, Including information on impact severity and estimates of the 

potential benefits that are expected to result from the use of shoulder ha1·nesses and 

energy-absorbing seats. In this report, "real world" occupants (actual survivors and 

potential survivors) define the limits or impact severity in survivable accid<mts. 

!I Crasfiworthiness refers t-:> the capability of a vehicle to protect its occupants rturing a 

crash. 

2/ A survivable accident is one in which the forces transmitted to the oceupant through 

the seat and restraint system do not exceed the limits or human tolerance to abrupt 

a-::celerations and i•t which the strueture In the occupant's Immediate environment remains 

substantially Intact to the extent that a livable volume is provided throughout the crash 

sequence. 

3/ "General Aviation Crashworthiness Project, Phase One," June 27, 1983 

n;·i'SB/SR- 83/01). 

4/ Kinematics is a branch or dynamfl'!s that deals with aspects ot motion apart from 

considP.ratlon of mass and force. 
-2-

Federal standards for occupant protection In general aviation airplanes essentially 

have remainei ·mchanged for the last 30 years. despite major advances in crashworthiness 

technology, many of which resulted from government/indut;try rt>senrch t\nd investigative 

projects which began in the late 1950's and et.rly 1960's. These projects, which includetl 

full-scale crash test!~ or a variety of alrcraf't, addressed all areas of crr.shworthlness, 

Including post crash fires, seats/restraints, cockpit/cabin environments, and crash 

E·.cceleratlon environments. However, the new technology has been used only in a verv 

limited way, primarily In agricultural apr!:cation airplanes. ~/ 

The Federal Aviation Administration (FAA) has been testing upgraded ~eat and 

restraint systems since 1970, but to date there has been only one substantive change in 

the relevant regulations for general aviation airplanes--shoulder harnesses have beP.n 

required on front seats of airplane~ manufactured After July 18, 1978, and on some older 

models used in commercial operations. 6/ Appendix A presents a synopsis of tile mor<: 

Important recommendations issued by the Safety ~o~rd to the FAA addressing various 

Issues of crashworthlness, and the F AAts responses to them. 

The National Af!ronautics nnd Space Administration (NASA) recently completed a 

program of crash testi~ general aviation airplanE'<: that began In 1973. Crashes of 24 

Instrumented ·~st airplanes with anthropomorphic dummies provided Jata on structural 

and occupant responses In specific crash sceMrios. In tnese crashes, survivability was 

determined by usin~ accelerometer data obtained from the test articles. (Ad1itional 

Information on this Important program is provided ir; appendix B.) 

During the last several years, there have been Increasing efforts to promote 

Improvement in general aviation crashworthiness. ln February 1983, a 

government/industry group, including representatives of the General Aviation 

Manufacturers Association (GAMA), met at NASA's Langley, VIrginia, facility to study 

Issues related to "l')neral aviation airplanes. The findings of the group regarding 

~rllshworthlness Included: 

o the mandatory availability and use or upp~r •orso rE.:straints (shoulder 

t:arnesses) in small 11ircraft could provide an Immediate Improvement in 

crashworthlness; 

o there currently is an adequate bc.dy of knowledge for the issuance of 

Initial rules pertaining to structural cra~hworthiness Cor small ail'planes; 

and 

o additional research is needed tu define a crash scenario representative of 

survivable accidents on which crashworthiness pet'forrnance standard•, 

ce.n be based. 

All GAMA airplane me.nuf'lcturers have pledged to Install voluntarily shoulder 

harnesses on all seats of newly manufactured airplanes. The organization has petitioned 

the FAA to require such installation on all small airplanes manufactured in tile United 

States. 

5/-WaiilO'lit,-- G.--:;:, "Crashworthiness Observations In Gentral Aviation Accident 

fnvestlgatlons--A StAtistical Overview", Aircraft CrashworthlneJS, University Press oC 

VIrginia, 1975. 

61 Tltte 14 r::ode of Federal Regulations (CFR), Section 23.785, published on June 16, 

1977 (4'2 FR 3('1503}. 

OUOOOti 
-3-

In February 1983, the General Aviation Safety Panel (GASP), an ini11lo:;try task for<!c 

convened at the Invitation of the FAA, issued a position paper conttlining several 

recommendations dealing with crashworthiness. Likt the earlier government/industry 

group, the task force ,.ecommended mandatory i'L'>tollation and use of shoulder harnesses 

as soon as practicable. Also, It recommended that the development of new 

crashworthlness design standards be expedited. One of the immP.diate goals of this 

recommendation was to '1, •• provide .:.. means for collecting meaningful accident data 

on the effectlveness of seat restraints and harnesses. Such 'real-world' data would be 

compared with experimental ~esults iil order to provide a broader b&sis for creatinrr design 

criteria." 

The Safety Board had b<!Cot gathering the "real-world" crashworthlness data since 

JaniJary 1982. With that data and the release of the GASP recommendations, the Safety 

Board approached both the manufacturers and the FA A and suggested that parties 

cooperate to resolve the technical stumbling blocks which had plagued past errorts to 

secure crashworthlness improvements. The FAA, manufacturers, and othe,. 

representatives from the industry responded by reconvening the GASP. 

Beginning In July 19R3, the GASP held a series of meetings to explore thP. general 

aviation crashworthiness issues. The Safety Board presented the data gathered in its 

crashworthiness program which supported heavily the GASP's efforts to develop its 

recommendations. As a result of the meetings, the GASP forwarded a proposal to the 

FAA on May 2, 1984, that detined standards for seats and scat restraints, Including 

requirements for the dynamic test.ing of seat/restraint systems to 26 G's in the 

longltuainal direction and provisions for energy managE'r'fiE"nt in the verticAl direction. Y 

ME'TIIODOLOGY 

To define the impact severity of survivable accidents and to estimate the benefits 

to be derived from the availability and use of shoulder harnesses and energy-absorbing 

seat:;, the Safety Board used data available in the investigative reports of 535 selected 

accidents that occurred in 1982 to perform a detailed analysis of crash kinematics and 

occupant injuries. Accidents selected as suitai.>lc for this examination were general 

aviation airplane accidents in which at least one occupant was fatally or seriously 

injured. 8/ Certain airplanes such as aerial application airplanes, homebuilt airplanes, and 

older airplanes or fabric and tube construction were excluded. The selected accidents 

also were limited to airplanes which are expected to continue to be m production and 

hence would be the most likely ean~idates for improved crashworthy designs. 

Data available concerning each of these accidents 'w'·ere evaluated by investigato.-s 

experh:nced in the analysis of ptttterns of injury causation in general aviation airplane 

accidents. A detailed analysis was made by examining completed io.vestigative forms, 

narratives, photographs, witness statements, and medical information in order to estimate 

7/Generai-Xviation Safety Panel, Proposal to the Federal Aviation Administration, 

~1ay 2, 1984. (For excerpts, see appendix C.) 

~/ Title 49 CFR 830.2 defines "serious injury" as any injui"y which: (1) RquirPs 

hospitalization ror more than 48 ho11rs, commencing within 7 days from the date the injury 

was received; (2) results in a fracture of any bone (except simf)le fractures of fingers, 

toes, or nose); (3) causes severe hemorrhages, nerve, muscle, or tendon damage; {4) 

involves any lnte~"nal organ; or (5) involves second- or third-degree burns, or any burns 

a(fectlng more than 5 percent of the body surfHce. 

ooouor; 
-4-

the extent to which ef:'ch accident was survivable and to compile Information on irnpact 

speeds and impact angles. For the purpose of this study, an accident was considered to be 

survivable when a livable cabin volume was maintained throughout the crash sequence and 

the forces transmitted to the occupant through the seat and restraint system did not 

appear to have or should not have exceeded the limits of human tolerance to abrupt 

accelerations. Therefore, an accidtnt was considered to be survivable when at least one 

occupant either survived or could have survived if shoulder harnesses or energy-absorbing 

seats had been used. 

A partially survivable accidtmt ~~a survivah1E" &cciO.:mt in which at least one fatality 

occurred that could not have be~:ii ~ re••t!nted. f'ot~Jntfal survivors were identified in each 

accident by examining accident dat& descl'''l:.g tl-te damage to the airplane and the 

in.lurics of eac!l occupant. First, the "livu~le volume" was evaluated fo~ each seat. 

Photographic documentation was the primary source of this information. To be 

considered livable, each space where an occupant was seated 11ad to have remained large 

enough for survival throughout thf! crash sequence. lndivt::fual locations consldeted 

nonsurvivahle were those wher(> the li•Jable volume had been reduced drastically or had 

bet-n destroyed. An example of a nonsurvivable accident is one in which the volum~ had 

been reduced during the crash by a crushing structure that had rebounded, thus giving a 

finul appearance of a livable volume. Se'!ondly, the injuries of (.ach of the occupants were 

evAlu~:ted separately, taking iitto account the availat:.ility and use of occupant restraints 

anf. ~he retention of seat structures in their normal positions, postc1ash fires, and other 

Important factors. An assessment was mP.de, wherever po~.sible, of the ~eg~·ee to which 

injuries cou!d have been les~ened by the use of shoulder ht messes or energy-absorbing 

seats. (A more detailed discussion of the procedures •Jsed is presented in appendix D. 

AppE!ndix E presents iive accident examt:-!es and the evaluation results.) 

ANALYSIS 

Th~ study group for this report is comprised of 535 accidents in..,olving 1,268 

occupants, of which 391 accidents resulted in at least one fatality. In these 391 

accidents, there were 859 fatalities, '!4 occupants who survived with serious injuri~s, and 

19 occupttnts wh" survived with minor or M injuries. All occupants were fatally injured in 

85 percent of the 391 fatal crashes. In 144 accid:mts in which no one was fatally injured, 

228 occupants were seriously injured and 87 o.:.."!upants rec~ived minor injuries. One 

occupant's injuries could not be determined. 

The analysis for this study groJp is presented in two sections: first, impact severitJ 

is discu~ed in terms of impact angles and impact speeds, and the impact severity 

envelope (referred to in this report as the survivable envelope) is determined for 

sur livable accidents. Second, the potential for injury prevention, made pos.;;lJ)e by 

shoulder harnesses and energy-absorbing seats, is presente1. 

Impact Severity 

Impact severity was defi,led in terms of impact angle and impsct speed, the most 

readily available parameters that c&n be related to the survivability of an acci:1P.nt. Each 

accident was determined to be survivable or nonsurvivable, and, for most of the accidents, 

impact speeds and impact angles were estimated. After the Impact se\·erity estimates 

were made, each accident and occupant wert represented on the polar (!lots which follow. 

The impact severity Increases with impact angle because the veloc;ty change during 

the principal impact becomes greate1· at increasinglv higher impact angles. At shallow 

OOOOU"i 
-5-

Impact angles, the airplane "hits and skips" with relatively small velocitJ changes. At 

high Impact angles, the airplane "hits and sticks," which results In a ~reater velocity 

change or a more severe Impact. 

The dlsttibutlons of Impact speeds and Impact angles for surviV9.ble accidents versus no~urvlvable accidents are presented in figur~ 1. 9/ Each data point represents one 

airplane. There were a significant number of surviVable occideo cs at impact speeds of 

less than 90 knots and at Impact angles of less than 45 degree-e. There were very few 

survivable accidents outside this range. In contrut, there ~~re proportionally fewer 

notllurvivable accidents at lrnpact speeds of less than 90 knc ts and at impact angles of 

less than 45 degrees. 

The occupants of the survivable accidents depicted ii~ fif!"~:-c 1 are plotted 

Individually In figure 2. The survivor plot (top) Includes all occupants who survived or 

who could have survived. 'fh~ nonsurvlvor plot (bottom) represents occuptlnts of partially 

survivable accidents who could not have survived even if they had been usinl shoulder 

harnesses and/or had been seated In energy-absorbing ~eats. These fatalities typical!y 

resulted from trP.e penetration at a specific stat location in the C'abin or from localized 

cabin disruptions. 

The occupants of the nonsurvlvable accidents depleted in figure 1 orr! plotted 

individually in figure 3. Relatively few occupants in nonsurvivable accidcnt1- Jre in the 

area defined as an Impact speed of less than 90 knots and an impaP.t angle of less thart 

45 degrees. Nearly all of the occupants who did not survive were i 1 accidents in which 

either one or both of ti,ose parameters were excet:rled. 

Figures 2 and 3 were compared to establish whether the difference between 

survivable accidents and nonsurvivable accidents wa~ one of impact severity. Any 

difference which ~ould be demonstrated would define the limits of the surviva~le 

env~lope. First, tl"!e density plots of figure 2 (top) and figure 3 were overlayed. In 

another comparison, the plots were redrawn as rectangular plots so that dot density of 

v&:lous sectors could be directly com!)ared. These rectangular plots also were overiP.yed 

for e.>mparlson. 

These comparisons produced a boundary, or visible difference, behveen the two 

group!. The dlfferencP. was most clear as a line which extends from 0 degrees at 75 to 

90 knots, to 45 t1egrees at SO knots, an~ to 90 degrees at 60 knots. A special effort was 

made to ev~tluate no~urvlvable accidents which fell Inside this limit and to evaluate 

survivable c;.ccldents which were outside this limit. 

Most of the latte~ accidents differed from tht other survivable or nonsurviveble 

accidents within their tespectlve severity ranges In some of the following ways. In the 

lower speed, survivable reglrn, nomur vivab~e accidents Included those Involving inverted 

crashes or direct treCJ or otht!r object strikes to single occupants. In the high-speed ar:jiur 

low-angle Impact region, a survivable accident would Include an airpl&ne cruisintt Into 

gP.ntly I·lslr.r terrain and sliding over some dlstar.ce to a stop without genet·ating 

slgnltlcant loads. 

9/ Comparisons o! the dot density of a sector In the low-speed range to the ~ot density of 

a sector In the high-speed range can be misleading. For example, i'l figure 1 between the 

Unes forml~ the angles of 30 end 45 degrees, the sector betwe(;•l 75 and 90 knots !s twice 

as larg\! as the sector between 30 and 4S knots, even though both repr~ent equal changes 

Jn velocity and anglP.. As a result, the relative dot density In differing speed ranges 

cannot be corr.pared directly. Compa. lsons of dot deMity for differing imi)act angles 

within a given speed range are valid, however, as are comparisons among tndividual 

secto~s from figure to figure In this report. OOOOOH 
. . . . . ' . 

. . . . . . . :p 

. . . . '·" . ' ·y· . . .·,~v . . . . 

. . . /'~~~ 1: t .$'. 

• • "'>o :o~ 

"'.t -·~ 

ro 

Survivable 

Accidents 

(216 Accidents) 

legend: INd> • "''"tsenll 

o-.e~t. 

5 

ro 

Nonsurvivable 

Accidents 

(219 Accidents) 

Figure 1.--lmpact angles and impact speeds: 

Survlvab!e versus nonsurvlvabla accidents. 

OOOOO~l 
IO 

Occupants Who 

Sur!ived or Who 

Could Have Survived 

(460 Occupants) 

Ugord: ..a. • f1IPO ... ott 

one~t. 

IO 

Or.cupants Who 

Could Not Be 

Expected To Survive 

(42 Occupants) 

Figure 2.--Jmpact angles ttnd Impact speeds In survivable accidents: 

Occupants who survived or could have survived 

versus occupants whose survival was not expected. 

000010 
. .·. . . . . . . . . . . . . . . . . . . . ·. . . . . . . . . . . . . . . . . . . . . ~ 

. ------- . • 

~-----

-8-

. . . . . . . . . . . . . . . . . . 

. . (568 Occupants} 

Figure 3.--Impact angles and impact speeds: 

Oc\!upants in r.t>nsurvivable s eel dents. 

As plotted, an lmpgct angle of 90 degrees appears to be the limit of the surviva'>le 

envelope for a 60-koot impact. However, examination of the ac1!ident reports shows that 

the survivable Impacts plotted In tlle 45- to 90-degree sector actually are diatributed 

much more closely to the 45-degree line than is shown by the even distribution of the p!ot. 

Since the data In that secto;· are biased more toward the 45-<.egree line, the survivable 

impact speed limit at an Impact angle of 90 degrees Is rnore nearly ·i5 knots. 

Similarly, many a<..-cldents in the Impact sp~.~ ran~e t>f 75 to 90 knots were only 

marginally survlvablP.. The survlva'.>le occupan• density d~pic~ed in figure 2 in the 75- to 

90-knot ~ectors probabl:· is actualiy aligned more closely with the 75-knot limit. 

The resulti~ boundary of the survivable envelope Is depleted in fiwue 4 by a line 

from zero degrees at 75 knots, to 45 degrees at 60 knots, and to 90 degraes at 45 knots. 

Figure 5 compares Impact severity for occupants who could have benefitted from 

using a shoulder harness with all occupants who actually survived. The top plot rep res( nts 

all oocupants who actually survived, some of whom were wearing a shoulder harness. The 

bottom plot Includes fatally and seriously Injured occupants who l!ould have oe~n les."' 

scrloa~;ly Injured had they worn a shoulder harness. That the two presentations ore so 

closely similar Indicates that the benetits to be gained from shoulder harness use may rot 

significantly expand the envelope In which accidents are survivable. Rather, the usc of 

shoulder harnesses will reduce Injuries and prevent fatalities In accidents which basicaily 

are survivable. The primary reason for this Is that the limiting factor In expanding the 

survivable envelope, to l~lude higher speeds, Is cockpit and cabin Integrity. The loss of 

cockpit/cabin Integrity results In the loss of a "livable volume" In high-speed, high-angle 

Impacts which precludes occupant survival regardle~ ot the Installation of shoulder 

000011 
Figure 4.-Survivable envelope for general aviation ,~cidents. 

harnesses and other protective systems. To significantly expand the survivable envelope 

to include higher speeds, the airframe would need to be designed to higher structural 

limits. 

Figure 6 depicts the impact severity for occupants whose injuries would have been 

less severe if energy-absorbing seats h&d been IJsed. •Yhile the number of occupants who 

would have benefitted from these seats is relatively small compared to occurants who 

would have benefitted from shoulder harnesses, the pattern of impact speeds and impact 

angles in which benefit is obtained is similar. As with shoulder harnesses, the potential 

lJene!it of energy-absorbing seats require~ the maintenance of a livable cockpit/c&bin 

vc•.ume. 

Potential Benefits of Shoulder Harnesres and Knergy-AbsorhlrJ{ Seats 

In addition to developing data on impact severity, an important part of this study 

wes to assess the magnitude ot the benefits that \!ould be eJ<pected from the use of 

shoulder harnesses and energy-absorbing seats. 

There were five survivable accidents in which shoulder harnesses w~re worn by only 

one of two front-seat occupants. A comparison was made of the relative injuries of each 

occupant. It was found In each case that injury severity was less for the occupant who 

wore the shoulder harness. The lmprct angles ranged from near zero degrP.es to 30 

degrees, 81"\d Impact speeds ranged from 30 to 7S knots. As expected, the higher speeds 

corresponded to Impact angles under 15 degrees, and the higher Impact angles (greater 

than 20 degrees) ~'Orresponded to the lower Impact speeds. None of the accidents involved 

postcrash fire. (See table 1.) 

000012 
-10-

IO 

15 

Occupants 

Who Actually 

Survived 

(321 Occupants) 

IO 

Occupants 

Who Would 

Have Benefittr.td 

from Shoulder 

Harnesses 

(330 Occupants) 

Figure 5.--Impact angles and Impact speeds: Occupanh who actuslly survlvr:d and 

occupants ot surv~vablo accidents who would have benefltte~ 

from using a shoulder harness. 

0000\~ 

. . . . ' ' ' 

I : -.,.., I .. ' 

' . . ~ ' • 4 ~ • 

. ' . • 1 '• .. 1 • , 
-11-

l-aend. ucll • 'il!l<_,ts 

one occvpent 

(93 Occupants) 

Figure 6.-lmpact angles and lmpcct speeds: Occupants who would have 

benefitted from energy-absorbing seats 

Table 1.--Side-by Side Injury Comparison 

Injury level Impact severity 

With Without 

shoulder shoulder Impact speed Impact angle 

Example harness harness (knots) (degrees) ---

1 Serious Se~lous 45-60 5-10 

2 Mlno:- Serious 60-75 0-5 

3 Minor Seriou& 45-60 0-5 

4 M!nor Serious 30-45 25-30 

5 Serious Fatal 45-60 0-5 

In each of these accidents, the occupant who wore a shoulder harness had fewer and 

less severe lnjl!l'les than the occupant who dld not. For e~:ample, In one accident each of 

two occupants sustained serious Injuries, but the pilot, wearing a shoulder harnt:ss, 

sustained a broken leg and a slight concussion while the passenger without a ~houlder 

harness sustained severe head Injuries. The differences In the Injuries In tht>se 

comparisons were related to head and upper body injuries. Those persons who wore 

shoulder harnesses had markedly fewer head Injuries. As would be expected, ahoulder 

harnesses dld not prevent Injuries to the lower torso or to the exttemltles. 

00001t1 
-12-

Estimates of Should£r Harness Benefits.--Sin<.'e this study did not evaluate accidents 

in whieh the injury levels were only mino.- and none, the estimates of shoulder harness 

benefits present.ed in this report are con~crvative. For example, there were a number of 

Sf:!'/ ere accidents in the 1982 data base in which .le<'Upants ret.!eived only rr inor or no 

injuries, because they were wearing shoul:1er harnesses. While an analy<;is of these 

accidents would havl:' further strE:ngthen~d this study, there was no timely way to isolate 

those accidents. Further, the estimates of benefit presented in thi-> report are based on 

the existing fleet .)f general nv;ation airplanes. Any improverne11ts in airframes which are 

incorporAtec1 in the fature that will result in i~iprovcd prcscrvntion of the "livable 

volume" will ir.r:rense the importance of sh0uldcr harness use. 

There are two important ~"lements whictt must be S3tisfied in order to realize the 

full beraefits of shoulder harnesses. First, the shouider harn<~s.s must be Available for use. 

Only 40 percent of all airplane occupants examined in this ~•tudy had shoulder harnesses 

avAilable. The second element is tttat (jf use; A shoulder harne;;s cL.nnot protect an 

occupant from injllty in a crash if it is not being worn. Of the 253 occupants whose 

shoulder harness use coul~ oc determined, c ·•lY 100 persons, Oi' 40 percent, actually used 

the available devices. (See f.gure 7.) Combining the availability rate (40 percent) a:Jd 

the usage rate (40 percenti indicates that 16 percent of the occupants were wen.-ing 

""oulr1er har·nesses. 

Oi the occupants examined in this study, 71 percent occupied front seats, And 

97 pl.'rcent of the 9ersons wearing shoulder harnesses were front-seal occupants. This 

indicates that the use of a shoulder harness is <:onfined almost entirely to front seats. 

Shoulder harness availability was determined for 771 of the 902 front-seat occupants. 

Fifty percent of those occupants (382 out of 771) had shoulder harnesses available. 

Shoulder harness use could be established for 240 of the 382 front-seat occupants. Forty 

percent of these occupants (97 out of 240) wore their shoulder harnesses. 

Shoulder 

Harness Not 

Available (843) 

or 

Availability 

Not 

Determined 

Use 

Unknown 

(172) 

Figure 7. --Shoulder harness availability and use. 

00001[; 
-13-

Fewer shoulder '.1arnesses were available for rear seat occupants. Availability was 

determined for 304 ol the 366 rear occupants. Fourteen percent of those occupants (43 

out of 304) had shoulder harness available. Shoulc~r harness use could be establi3hed for 

13 of the 43 rear seat 0ccupants. Only 23 percent of these occupants (3 out of 13) wore 

their shoulder harnesses. 

Many of the occupants who had shoulder harnessP.s available were not required to 

wear them. Although crewmembers are required to wear shoulder harnesses for takeoffs 

and landings, many did not. Some crewmembers forgot to put their shoulder harnesses 

ba~k on when it became evident that an in-flight emergency would lead to a crash. These 

issues will be addressed in the next report of this series. 

Each of the 1,268 occupants was evaluated separately. Potential benefits were 

established for 1,111 occupants. The potential for bene tit for the 157 remaining 

oc<'upants could not. be determined. Detailed data were collected on specific injuries and 

on the extent to which these injuries either could have been prevented or could have been 

less serious through the use of a shoulder harness. Of the 859 fatally lnjurl!d occupants in 

this study, the potential for benefit of shoulder harnesses could be established for 

800 persons. There were 163 occupants who could have survived but did not. It is 

estimated that at least 13 percent (106) of the 800 fatally injured person~ in these 

accidents would have been injured only seriously if they had been using shoulder harnesses 

and that an additional 7 percent (57) of the fatally injured persons would have had only 

minor or no injuries. The expected benefits are even more pronounced for those who were 

seriously injured. Fully 88 percent (201) of the 229 seriously injured persons who could be 

evaluated 1 r. this study probably would have received less severe head or upp~r llody 

injuries, (•:1;.y minor injui"ies, or no injuries at all if shoulder harnesses had been worn. (See 

figure 8 and table 2.1 

Minor/ 

Fatal Serious 

Actual 

Injuries 

800 229 

Projected 

Injuries 

637 155 319 

Figure 8.--Dlstrlbutlon of occupant Injuries as actually 

occurring and as expected with full shoulder harness use. 

None 

82 

000016 
-14-

Table 2.--Injury distribution as actually occurri~ 

and as prec.ilct,'<l given full shoulder harness U&e. 

Occupant Injury Original h;jury Predicted injuries level distribution with shoulder harnesses 

Fatal 800 637 

Serious 229 155 

Minor/none 82 319 

1,111 1' 111 

Percentage 

change 

-20 

-32 '-41) 

N .A. 

Table 2 presents the net benefits of shoulder harness use. The 163 fatally Injured 

occupsr.ts who would not have been Injured fatally if a shoulder harness had been worn 

would have received, Instead, serious, n,fnor, or no Injuries. Likewise, 180 of the persons 

(79 percent) who were Injured seriously without shoulder harnesses would have h11d only 

minor or no injuries with a shoulder harness. As a result, the n~t change Is a 20-percent 

reduction In fatRllties and a 32-percent reduction of serious Injuries. In addition to this 

benefit, 21 persons (9 percent) of the seriously injured occupants if1 this study, while still 

expected to have serious Injuries even with a shoulder harness, would have had 

significantly less serious head or chest Injuries. These additional benefits are presented in 

parentht'Ses in table 2. 

B~ause the data presented In table 2 include a large number or persons from 

nonsurvlvable accidents, the percentage change In benefits or shoulder harness use is not 

as graphic as would be the case If only survivable accidents are considered. Table 3 

presents the potential benefits of shoulder harness use for the occupants Involved in 

survivable accldent3 only. Por the purpose of this presentation, 584 of the fatally injured 

occupants were removed from the data base because they were involved in nonsurvivable 

accidents. Thus, in survivable accidents only, shoulder harnesses could have prevented 

75 percent (1G3) of the 216 fatelitles, and 79 percent of the 229 serious Injuries. Overall, 

of all occupants of survivable accidents who had fatal or serious injuries, 82 percent could 

be exp~ted to have received a significant benefit in terms of injury reduction through 

shoulder harness use. 

Or'glnal injury 

distribution 

Fatal 

Serious 

Total of Fatal 

and Serious 

Table 3.-oceNpanta tn survivable accidents: 

Potential benefita of ahouldel' harnese use. 

216 

229 

445 

Expected distrlbutlon 

with shoulder harnesses 

Fatal 

Serious 

Minor/none 

Serious 

Minor/none 

Total who 

benefitted 

53 

106 

57 

49 (21) 

180 

343 (364) !I 

Percentage 

25 

49 

26 

21 

79 

77 (82) 

1/ The number 364 (82 percent) Is complied from the 106 occupants coded 

fatal to serious, the S'7 occupants coded fatal to minor/none, the 180 

occupants coded serious to minor/none, and the 21 occupants out of 49 who 

were coded serious to serious but would have had less serious Injuries. 

0 0 00 1 "/ 
\, r 

.. ·'• ' ' I L I t/ 

.. • •• , • 

' ' 

-15-

Estimates of Energy-AOs<>rhing Seats Benefits.--Energy-absorbing seats cannot he 

expected to prevent many fatalities since the predominant injuries which they can prevent 

are spinal injuries. These injuries rarely result in a fatality except when they prevent 

timely egress. However, they usul.!lly are severe, long-lasting, and costly. Evaluation of 

the data in this study indicated that about 2 pt>rcent or the fatalities could have been 

prevented if energy-absorbing seats had been available. Many serious back and neck 

injuries can be prevented if verti!!al energy management is considered during seat design. 

This study found that about 34 p<:rcent nf the occupants who had serious injuries could be 

expected to have had significantly fewer serious injuries if they had been seated in 

energy-absorbing seats. 

An importal"'t consideration In achieving these potential benefits Is that, in order for 

an energy-absorbing seat to provide occupant protection, the occupant must remain in an 

upright position and tile seat muc;t remain in place. This means that the c.ccupant must be 

restrained by a lapbelt and shoulder harness. Installation of improved seats, in the 

absence of shoulMr harness use, will not produce the improvements noted above. 

\toreover, it is important to note that nearly 27 percent of the seats in survivable 

accidents did not remain attached. 10/ When a seat does not remain securely attached to 

the floor, occupant injury protection 'lffered either by the scat or by the lepbelt and 

shoulder harness Is considerably reduced. 

To summarize the benefits that could be expected from the use of shoulder 

harnesses and energy-absorbing seats, it was established that 20 percent of all fatalities 

could have been prevented by the use of st;oulder harnesses and that 91 percent of the 

seriously injured occupants could have hart leJS serious head, upper body, and/or back 

injuries with the use of shoulder harnesses and energy-absorbing seats combined. Shoulder 

harnesses alone could have prevented or minimized the severity of the head and upper 

body injuries for 88 percent of the seriously injured occupants; energy-absorbing seats 

could have prevented or minimized the severity of back injuri<~s for 34 percent of the 

seriously injured occupants. 

CONCLUSIONS 

1. Shoulder harness use is the most effe~tive mdhod of reducing fatal ~tnd 

serious Injuries in general aviation airplane accidents. 

2. New crashworthy airframe design is the improvement which will most 

signi.'icantly expand th'~ survivable envelope to higher impact speeds. 

3. lmpnct severity, as defined by impact speed and impact angle, Is a principal 

determinant of a survivable ac~ident. 

4. The accidents reviewed in thi.l study generally were survivable within the 

envelope bounded by & line through an impact speed of 45 knots at an impact 

angle or 90 de<t{rees, 60 knots at 45 degrees, and 75 knots at zero degrees. 

5. A potential 20-percent reduction In fatalities could be realized if all occupants 

of general aviation airplanes were to wear shoulder harnesses. 

6. Potentially, 88 percent of seriously injured occupants could be expected to 

Incur significantly reduced Injuries If shoulder harnesses were used. 

lO/-A sea(aifachment failure is defined in appendix D under "Seat retention." 

. - . 

OOOOIH 

• • " 
'1 

•• 

8. 

9. 

10. 

-16-

A potential 2-percent reduction in fatalities could be realized wHh the 

installation of energy-absorbing seats. 

Potentially, 34 percent of seriouslt injured occupants could be expected to 

have significantly reduced injuries i energy-absorbing seats were etvailable. 

Where shoulder harness Availability and use could bt> determined, only 16 

pP.rcent of the occupants were wearing a shoulder harness at the time of the 

crash. Shoulder harnesses were available t.o 40 percent of the occupants and, 

when available, were worn 40 percent of the time. 

Tv.enty-seven percent of all seats in survivable accidents underwent some type 

of failure. 

BY TIIB NA'nONAL TRANSPORTATION SAPBTY BOARD 

:\iarch 15, 1985 

lsi JIM BURNETT 

Chairman 

lsi PATRICIA A. GOLDMAN 

Vice Chairman 

lsi G. H. PATRICK BURSLEY 

Member 

OOOOlB 
. . . 

• • ' . • r 

_. . . 

. . 

-17-

APPENDIXES 

APPENDIX A 

NATIONAL TRANSPORTATION SAFETY BOARD 

OHNRRAL AVIA110N (,RASHWORTHINKSS RHCOMMBNDATIONS 

WITH SUMMARIES OF FEDERAl, AVIATION ADMINISTRATION RJI..SPONSES 

AND SAFETY BOARD EVALUATIONS OF THBSB RRSPONSBS 

The Safet~· Board has issued a series of general aviation crashworthiness 

recommendations since 1970. A series of letters to and from the FAA discuss the variot·s 

fsgues and anticipated actions generated by those recommendations. The last formal FAA 

response to those recommendations was a letter to the Safety Board that was dated 

March 21, 1983. That response and the current FAA crashworthiness efforts resu:ted in 

the Safety Board issuing a letter to the FAA dated September 5, 1984, excerpts of \:hich 

follow. 

Recommendation CY-70-42, Part 4 

[Initiate] regulatory action ••• to raise· the "minor crash lAnding'' im .. rtia 

forces of 14 CPR 23.456 to o level comparable to those produced by a 

mode:ate-to-severe crash landing. Until a reasonable crash design condition is 

decided upon, Including a specific<! crash acceleration pulse, it is suggested 

that the longitudinal Inertia force be raised to 20 to 25 and the forces about 

other axes be similarly increased. 

The FAA has respooded that attempts at interim regulatory action without a 

technical d&ta base would not be productive, and that energy management must be fully 

assessed .iinc€ stronger seats have to be stiffer and thereby would transmit more crash 

loat1s to the occupant. Upon completion of its research activities concerning crash pulse 

definition and computer modeling, the FAA plans to initiate appropriate rulemaking. 

Since Its March 21, 1983, correspondence to the Safety Board, the FAA, at the 

GASP meeting of September 27, 1983, has made preliminary proposals for crast> 1ynfl mie 

standards which were considered by the GASP committee. A GASP proposal for ; at and 

restraint standards was agreed upon, and the proposal ha~ been forwarded to tl'c FAA. If 

adopted, it would fuUill the intent '.>f ::-'illfety Recommendation CY-70--12, Part '· for higher 

crash force requirements. 

In vlew of the present F AA/indu:1try effort tow&rd the development of crash landing 

design standards and other general a.-latlon crashworthlness requirements, the Safety 

Board has reclassified the status of Safety Recommendation CY -70-42, Part -1 from 

"Open--Unacceptable Action" to "Open-- Accepta~le Action" pending the outcome of 

these efforts. 

R~ommendation A-77-70 

Amend 14 CPR 23.785 to require installation c·f approved shoulder harnesses at 

all seat locations as outlined in NPRM (Notice of Proposed Rule ~,aking] 

73-1. 

oooo~o 
APPENDIX A -18-

The FAA forwarded to the Safety Board a copy of a cost-benefit analysii for 

shoulder harness installation, and the FAA intends to consider this cost-benefit analysis, 

GAMA ~ecommendations on shoulder harnesses, and the recommendati'lns from the "Smell 

Airpl8ne Stall Speed Si.udy" committee ir• determining what action to tAke on this issue. 

Safety Recommendation A-77-70 encompasses two specific areas: (1) installing 

shotJlder harnesses o'\ all seats on newly manufactured airplanes, and (2) requiring existing 

airplanes to be retrofitted. GAMA has petitioned the FAA to rP.quire shoulder harnesses 

on all seats of small airplanes manufactured after 1984. Also, GAM A and the Society of 

Automotive Engineers (SAE) are working on shoulder harness design requirements which 

will facilitate such installations. Industry reprt.•sentatives also t:ave voiced support ror 

voluntary efforts to retrofit the curreilt fleet with shoulder harnesses at most seats. 

The recommendation for shoulder harness retrofitting at all seat locations should be 

addressed, and the GASP forum is an ideal one in which to discuss this is~ue. The Safety 

Board recognizes that the current GASP task of defining dynamic testing and installation 

requirements must b~ resolved first. The Board has sut.>mitted data to the GASP which 

clearly show that many lives can be saved if the current airplane fleet is equipped with 

shoulder harnesses. Until the FAA responds on the retrofit issue and takes action on the 

GAM A petition to require shoulder harnesses on all seats, the status of Safety 

Recommendation A-77-70 will remain in an "Open--Unacceptable A~tion" status. 

Recommendation A-80-125 

Require that those general aviation aircraft manufactured to include 

attachment points for shoulder harnesses at occupant seats be fitted with 

shoulder ha1·nes.<;es no later than December 31, 1985, and, iil the interim, 

require this moJification as a requisite for change in FAA registration. 

The FAA stated that Safety Recommendation A-80-125 was addressed in its costbenefit analysis and that it will be evaluated with Safety Recommendation A-77-70. 

Therefore, pending further evaluation by the FAA of the retrofit issue and in view of thr 

close relationship of this recommendation to Safety Recommendation A-80-127, the 

Safety Board will change the status of Safety Recommendation A-80-125 from 

"Open--Acceptable Action" to "Ope'l--Unaccept'lble Action." 

Recommendation A-80-126 

Develop, in coordination with airframe manufacturers, detailed, approved 

inslalla~ion instru\~tions for installing shoulder harnesses at each seat location 

in current models snd types of general av:,tion aircraft in which shoulder 

harness attachment points werE: not provided as standar<' equipmerat. Publish 

and provide these instructions to owners or those aircraft by December 31, 

1982. 

The FAA st'ltes that design functions are the responslb!lity of the manufacturers or 

owner .. and that the provisions or Safety Reeommendaticn A-80-126 are not within the 

scope of the FAA's responsibility. 

000021 
-19- APPENDIX A 

As stated in its November 5, 1982, letter, the Safety Board recognizes that the FAA 

does not perform detailed desigr, work; however, the FAA, on an almost dailv basis, tests 

and evaluates crashworthiness designs at the Civil Ae.•omedical Institute :CAMI). The 

s•arr at CAMI has b~en constructive In suggesting imi>rOVE.ll1ents in seat and restraint 

designs developed by manufacturP.r~. It is that type of ccordination to which the Board 

refers. Members of GAMA are voluntarily invoived in pursuing the intent of this 

ree:ommendat!on. GAMA has stated that the three ma)or manufacturers now have 

FAA-approved kits to :-etrofit shoulder harnesses to old~r airplanes and that tt intends to 

promote the retrofitting or such restraint devices. The Safety Board recognizes that 

there may be some older alr!)laneo; in which retrofitting is not possihle, but the majority cC 

the fleet now can be retrditted with ex~sting kits. However, to be most eCCective, this 

effort will require FAA support If shoulder tlarnesses are to be installed in a large number 

or airplanes. The FAA has informed the GASP committee that it ir.tends to pHblish !in 

Advisory Circular to assist designers in developing bPtter restraint and seat systems, and 

that it will promote the inst11Hation and use of shoulder harnesses in gener3l aviation 

airplanes. The Safety Board considers the proposed FAA action as fulfilling the intent or 

Safety Recommendation A-80-126. Tt.erefore, Safety Recommendation A-80-126 has 

been reclasshied from "Open--Una<'ceptable ~ction" to "Open--Acceptable Alternate 

Action." The Board encourages the FAA to expedite the develcmment of the Advisory 

Circular, and it requests that the FAA provide the Board its plans to support the voluntary 

retrofit effort as announced at the GASP meeting. 

Recommendation A-80-127 

Require that those general aviation ail'craft for which FAA-approved harness 

installation instructions have been developed be fitted with shoulder harnesses 

at each seat location no later than December 31, 1985, and, in the interim, 

require this modification as a requisite Cor change in the FAA registration. 

The FAA stated that Safety Recommendation A-80-127 was addressed in the costbenefit analysis and that it will be evaluated with Safety Reco:nmendation A-77-70. 

Therefore, pending FAA':o; further evalu&tion of Safety Recommendations A-77-70 and 

A-80-125, the status of Safety Recommendation A-80-127 also will remAin 

"Open--Unacceptable Action." 

Recommendation A-80-128 

At established intervals, extend the application of all newly established 

occupant protection provisions of 14 CFR 2~ to all newly manufactured 

general aviation aircraft. 

The FAA has responded that the broad general scope or such a recommendation 

makes it difficult to determine what occupant protection provisions the Safety Board is 

addressing. The FAA believes that periodic Part 23 regulatory reviews, now part of its 

regular process, adequately address the Intent of Safety Recommendation A-80-128. 

Moreover, retroactive application of new regulations must comply with Executive Order 

12291 and cost-benefit analysis, "illustratu tt.at retrofit schemes are t)opically very 

costly, with little Identifiable benefit." 

It was not the Intent of Safety Recommendation A-80-128 that airplanes already 

manufactured be retrofitted. Rather, its intent was to eliminate the "grandfather" clause 

under which airplanes type-certificated many years ago still can be manufactured today 

without lncorpo~·ating known safety improvements. Manufacturers repeatedly introduce 

000022 
APPENDIX A -20-

significant new features !n aircraft during yearly model changes using the same type 

certificate. The Beech Bonenza, Cor exampJ~, has had many new seat designs during the 

35 years since its type certificate was issued. 

The Safety Board believes that newly established occupant protection provisions, 

such as improved seat designs in newly certificated airplanes or in new models of existing 

alrplsnes, ~hould be extended by regularly scheduled Part 23 t1esign reviews to all newly 

manufactured airplanes. Pending further FAA review, the -;tatus of Safety 

Recommendation h-80-128 will remain "Open-Unacceptable Action." 

Recommendation A-80-129 

Revise 14 CfR 23. 785(J) to incorporate performance standards and test 

criteria to lmure that ttn acceptable level of occupant safety is achieved 

through cabin "delethslization." 

The FAA has restated its belief that it Is not feasible to o!"oceed in accordance with 

Sa~ety Recommendatlon A-80-129 because of its broad general :..~~cpe. Moreover, the FAA 

suggest3 that advisory material developed In the FAA general aviation crash dynamics 

program will be sufficient to supplement regulatory actions. 

Both Safety Board and FAA acddent investigations have identified numerous areas 

where present cabin delethsllzation ml•asures did not work. No standarlis exist to define 

acceptable methods to prove that the delethalization designs perform as intended. The 

Safety Boar<' is not attempting to limit the many ways in which these problems can be 

solved; it only seeks to limit the manufacturing of aircraft with inadequate safety 

provtstons. If the FAA wiU not specify test and performance standards that ensure 

adequate safety designs, so called "delethalized airplanes" th3t cause Injury will continue 

to be manufactured. Since the FAA will not act on this recommer.daHon, Safety 

Recomme1dation A-80-129 has been placed in a "Closed-Unacceptable Action" status. 

Recommendation A-80-130 

devise current standards for seat and restraint systems to Incorporate needed 

crashworthiness improvements identified in FAA Research Project reports. 

Although the FAA concuta td with the intent of St.fety Recommendation A-80-130, 

it planned no definitive action without specific information ~llncernlng crashworthinest 

improvements. Since this response, the Safety Board has learned informally that the FAA 

is In the process or developing an Advisory Circular tor crashworthy seat design because 

investigations have disclosed that there are deteriorated seat pans in the fleet which rip 

easily when a tear starts. Although the FAA's staff has stated that Part 23 will never 

provide the standards to solve crashworthiness problems, the Board believes that seats and 

restraints need to be designed to standards other than just strength req~.&!r~ments. 

However, based on the FAA staff's proposed development of an Advisory Circular to 

establish broader guidance, the status of sarety Recommendation A-80-130 has been 

changed from "Open--Unacceptable Action" to "Open--Acceptable Alternate Action." 

The Board encourages the FAA to expedite the development of the Advl~ry Circular and 

would like to receive a tlm~table for Its development as well as an C'ltUre of its proposed 

content. 

00002 :~ 
-21- APPENDIX A 

h~commendatiOil A-80-131 

Estab!ish standards for the dynamic testing of occupant protection devices 

required in general aviation aircraft. 

The FAA stated in a response of April 3, 1982, that it was waiting to determine 

dynamic load characteristics, end it asked the Safety Board to identify other "devices" to 

which it might have had reference. Based on the Safety Board's further clarification in its 

letter of November 5, 1982, the FAA stated on :\1arch 21, 1983, that it appears that the 

intent of Safety Recommendation A-80-131 would require testing of all immediate 

components of the cockpit/cabin environment without sufficient rationale or justification. 

The FAA concluded that testing would be an enormous undertaking and inconsistent with 

the Regulation by Objective concept the FAA was then advocating, and that the Safety 

Board should reconsider its position. 

The Safety BMrd recommended that dynamic t~sting of occupant protection devices 

be required in general aviation aircraft. The reason the word "devices" was used is that 

there are many ways to protect occupants. The most straightforward approach led to the 

design of the seats and seatbelts and shoulder harnesses as we know them today. 

l!owever, in the future, a manufacturer may opt f.o use energy-absorbing cabin structures 

to reduce O<!cupant crash loads. Such energy-absorbing devices should be proven by 

dynamic testing. For instance, an effective enm·gy-absorption device could be a better 

landing gear design. 

A manufacturer's representative at the GASP meeting agreed that standards for 

dynamic testing are needed. The CAMI has been testing full-scale fuselages for years, 

and many deficiencies have been found in occupant protection .1evices thnt would not have 

surfaced except for dynamic testing. This type of testing of new aircraft models would 

not be an enormous undertaking; it is the only valid way to test the effectiveness of 

devices that are to function in a dynamic environment. 

Again. with the formation of the GASP crashworthiness committee, the upcoming 

Par! 23 regulatory review, and the FA A's crashworthiness program plan, the Safety Board 

looks forw.ud to progress in increased occupant protection in generAl aviation airplanes. 

Therefore, in view of tt.ese positive steps, the status of Safety Recommendation A-80-131 

has been changed from "Open-Unacceptable Action" t'> "Open--Acceptable Action" 

pending the results of these activities. 

000024 
-22-

APPBNDIX B 

COMPARISON OF STUDY DATA 

WITH NATIONAL AERONAUTICS AND SPACR ADMINISTRATION 

CRASH TEST DATA 

In 1973, the National Aeronautics and SPflce Administration (N AS.A.i initiated 

full-scale crash testing of general aviation airplanes in an effort to define the dynamic 

response of airplane structure, seats, and occupants during survivable crashes. The 24 

tests, which wt-re concluded in 1982, WE're accomplished by cushing airplanE's into 

concrete ot dirt under controlled flight conditions. The impact angles and Impact speeJs 

for the tests were chosen to closely approximate impact speeds and angles of actual 

general aviation airplane crashes. These tests provided data about structural and 

occupsnt response which are useful to designers involved in the development and tesdng 

of new crashworthy systems. A comparison of the NASA data with data from the actual 

crashes of general aviation airplanes described in this report is useful in confirming that 

the tests were representative of actual survivable accidents. The current Safety Board 

study of impact data confirms that the NASA testing scriPs represented real-world 

general aviation survivable crashes. Impact severity data presented in NASA Tect.nical 

Paper 2083 !!I was compared with the data in this study. 

The 24 sets of impact speeds and impact anrles generated by the NASA tests are 

shown In figure 9. This figure shows that most of the NASA tests fall within the impact 

severity envelope of survivable accidents presented in this study. The thr~t tests outside 

the envelope were consi~c:red survivable because the impacts to concrete ;.;;suited in small 

velocity changes and small accelerations. One test within the survivablE- envelope 

(45 degrees and 52 knots) was only partially survivable because of the crust.ing in the 

cockpit area. Another test within the survivable envelope was considered nonsurvivable 

because of the high accelerations and extreme crushing (loss of a livable volume). That 

test consisted of an airplane impacting soft dirt. The dirt impact resulted in an abrupt 

stop and high acceler'ltions instead of the typical impact and slide exhibited in other tests 

·.vhich impacted concrete. 

In summary, the NASA tests end the results of this Safety Board crashworthiness 

study combine to provide a foundation for future crashworthiness design efforts. The 

present SafP.ty Board study has yielded real-world data conC(!rning the limits or the 

impact severity envelope of survivable eccidents, and the NASA test results provide the 

precise engineering dP.ta which are the basis Cor the mathematical models needed for 

desig!ling better crashworthy equipment. 

11/Nationaf-Aeronautlcs and Space Administration (NASA) Technical Paper 2083. 

"Correlation and Assessment of Structural Airplane Crash Data with Flight Parameters at 

Impact, 19~2." 

oooo2~) 
~----~ 

--

ro 

~: _, . ...,.._, .. oneiMCIWI 

APPENDIX 8 

- Ropr-'llh t<>Mvable 

limila M do!er~ by the study 

Figure 9.-Impacc angle aoo Impact speed: 

Comparison of NASA tellt crashes and Umlts of the survivable envelope. 

00002h 
I ( I . ' I 

I 

·. ' ' 

/ 

I ' I '1.-

• , 

0 . 

I r . ·- . ;,! \ ·' • . ... 

-24-

APPHNDlX C 

KXCnttPTS PROM THE 

GRNERAL AVIATION SAPIITY PANEL 

PROPOSAL TO TIIB 

FEDERAL AVIATION ADMINISTRATION 

' 

Dynamic:: Testing of Seftt.s 

Recommer1ded seat criteria for small general aviation aircrnft &pplying fer initial 

type certifi.!ation after December 31, 1985, for operations with fe~1er than 10 passenger 

seats. 

(a) Each seat, bench or other device for crew or passenger occupancy must 

succfllsfully complete dyne.mic tests with an occupant weight of 170 pounds in Accordance 

with each of the conditions stated beiow. 

(1) A change in velocity of not less than :!1 feet r"r seccnd when the 

seat, bench or other seating device is oriented in its nornin.1l position with 

respect to thE; aircraft's reference system and the aircrdft's longitltdinal axis is 

canted upward 60 degrees with respect to the impact velocity vecto.· ond the 

aircraft's laterdl axis is perp~ndicular to a vertical plane containing the 

impact velocity vector and th~' aircraft's longitudinal axis. For the aircraft's 

first row of seats, peak deceleration must occur in not more tha'l .OS seconds 

after impact and must reach a minim urn of 1 g g's. For all othe;o seats, peak 

decleration must occur in not more than .06 seconds after imoal!t Anti muc:t 

reach a minimum of 15 g's. 

{2) A change in velocity of not less than 42 r~et per second when the 

seat, bench or other seating device is oriented in its nominal position with 

respect to the aircraft's refErence system and the aircraft's longn\ldinol axis is 

yawed 10 degrees either right or left of the impact velocity vcPtO!' (but in such 

a way as to cause th~ greatest loari on the upper to~so restraint system), the 

aircraft's lateral axis is contained in a horizontal plane containing the impact 

velocity vector and the oircrdft's vertical axis is perpendicular to a horizontal 

plane containing the impact velocity vector. For thP. aircraft's first rov• of 

seats, peak deceleration must occur in not more thsn .05 second~ a(t«·r impact 

and must reach a minimum of 26 g's. For all other seats, peal. deceleration 

must occur in not more than .06 seconds after impact and must reach a 

minimum or 21 g's. 

(Note: The aircraft's reference system is defined as consisting of three 

mutually perpendicular axes where the vertical axis is perpendicular to a 

waterline reference system of the aircraft and parallel to the station 

reference system and the ltlngitudinal ftxis is perpendicular to the station 

reference system. The velocity change shaH be pure translation wltit no 

angular accelera tlon considered.) 

(3) The floor ralls used to attach the seating device to the airframe 

must be •nisallgned with respect to each other by &t least 10 degrees vertlc&Uy 

(I.e. out of parallel), with the direction at the option or the manufacturer, to 

account for noor warp. 

· . . . 
-25- APPENDIX C 

(4) Dynamic tests in accordance with the conditions stated in 

paragraph (a), subparagraphs (1), (2) and (3) are considered to be successfully 

completed when the performance measures (4a) through (4n are demonstrated. 

(4a) Loads in individual upper to.-so straps do not exceed 1,750 pounds. 

If dual straps are used for retelning the upper torso, the total strap loads do 

not exceed 2,000 pounds. 

(4b) The maximum pelvic load as measured in a 11 CFR 572 dummy 

does not exceed 1,50') pounds. 

(4c) The occupant's upper torso strap or straps remain on or in the 

immediate vicinity of the occupant's shoulder during the impact. 

(4d) The lap belt remains on the occupant's pelvis during the impact. 

(4e) the occupant's head either does not contact any portion of the 

cockpit or cabin or if it does, the head Impact does not exceed d Head Impact 

Criteria (HIC) of 1,000, as determined by the test procedures defined in SAE 

J921. 

(4() The attachment between the seating device and the aircraft's 

structure remains intact (although the structure can have exceeded its limit 

load) and tha restraint !>ystem remains intact (although it also can have 

experienced separation that is Intended as part of its de.slgn) as long as the 

conditions contained in (4a), 4b), (4c), (4d) and (4e) are met. 

(b) In a<ldition to the dynamic tests and criteria defined in paragraph 

(a) and its subparagraphs (1) through (4f), all seats, benches, or other seating 

devices and its supporting structure must be designed to withstand the static 

loads Imposed by a 215-pound occupant when subject to the aircraft's design 

loads as defined in the aircraft's approved flight/ground envelope. 

(c) Paragraphs (a) and (b) above specify a minimum standard for new 

aircraft with application Cor type certification dated after December 31, 19S5. 

An applicant for a type certificate has the option to depart from th£> criteria 

presented in paragraphs (a) and (b} above provided a'l alternate approach that 

achieves the same or equivalent level of occupant crash tolerance can be 

substantiated on A rAtionAl 1-,asis. 

Mandatory Equipage of Shoulder Harnesses 

The General Aviation Safety Panel affirms its earlier recommen<! .... tlon that all PAR 

Part 23 general aviation aircraft menufactured after December 31, 1984 be equipped with 

upper torso restraint systems. We further recommend that the the FAA consider ways to 

facilitate the installation of upper torso restraint systems In older general aviation 

aircraft, and that the FAA work with the SAr. Upper Torso Restraint Committee to 

formulate acceptable standards for harness material and attachments to be used In 

aircraft manufactured after December 31, 1985. 

000028 
General 

-26-

APPBNDIX D 

MBTHODOLOOY 

In 1982, the Safety Board began collecting substantially more detailed informatioa 

on general aviation accidents than it had in the past, which could be used to define crash 

severity and Injury causation factors. For the first time, more comple'.·~ Information on 

airplane speed, Impact angles, and terrain condition was available for analysis as was 

more complete documentation of seats, restraint systems, and occupant injuries. 

In order to select accidents particularly suited for a study on the potential for injury 

reductlon, the Safety Board's most recently completed general aviation data base (1982) 

was examined. A subset of accidents in this data base was selected which represented 

only flxed-wi~ airplanes In which at least one occupant sustained fatal or serious injuries. 

From this subset, certain accidents were eliminated: principally those which involved 

older airplanes of fabric and tube construction, home-built airplanes, and agricultural 

application airplanes (crop dusters). Also eliminated from this study were aircraft 

involved In on-ground collfsions. The remaining airplanes were those which are or could 

continue In production and which would not be expected to be eliminated from the general 

aviation neet in any substantial numbers in the next few years. 

The resulting set of 535 accidents was evaluated by Safety Board investigators 

experienced in •.t.e patterns of Injury causation in general aviation accidents. All records 

pertaining to each of these accidents were collected, including reporting forms, 

narratl.,es, photograp~~. witness statements, and medical Information. A detailed analysis 

was made of this Information and qulllitative estimates wer~ made of the extent to which 

the accident was survivable. The Injuries of each of the 1,268 occupants were evaluated 

separately, taking lntn occount the availability and use of occupant restraints, the 

retention of seat st. uctures in their precrash position, postcrash fires, and other 

important features. The formats used for recording the occupant injury and airframe 

Impact severity lnforma·don are presented on the ner.t two pages. 

Potential survivors were identified by examining injuries and airplane damage. This 

examination was applied on a seat-by-seat basis for each occupant in each airplane. First, 

it was determined whether a livable volume was available aroun•J t:!\ch seat. Each space 

where an occupant was seated had to • emaln esentially unconpromised throughout the 

crbSh sequence. Photographic documentation was the primary St.'urce of this Information. 

Seat locations considered nonsurvlveblc were those where the iivablc volume had been 

destroyed or where , ~l volume had been violated severely during the crAsh by a crushing 

structure that had rebounded, thus giving a final appearance of a livable volume. Some 

spaces were considered nonsurvivable while tt ~ rest of the airplanr. was t-nnsidered 

survivable. For example, a tree lrnpinging into one seat lCJCatlon may render that position 

nonsurvivable whlle other seat locatlons are not affected. Proximity of an occupant to 

the crush line (fiat spot on the airplane caused by ground contact) also affects 

survlvablUty. Investigative experience has shown that an occupant located near or below 

the crush liM normally will receive fatal accelerative Injuries. 

00002~1 
0 

0 

0 

0 

w 

0 

• 

~1n~~at1es Study - Alr~lan~ Oata Page 13~7 

--~-----~---~~~----~--~--------~---~----~--------------~--------------------

fil~ oat~ Loeat1on Injuries l>aol·a~e "'i'l•·r 

~·at s~r ~in NOn Unk ... 0 ~ •: 

lb03 Auq-21-19t12 APf,.;uf.l p;(l 0 () 0 4 0 0 1:." ~U(II,~.) 

"· 2 v ~ 

Aeeident HUrnber j.)t'last> Fire ~ot A'-'Plieable t./1. F..t-ason Initl. Ot:t~~820A17CJ LA:\i u ... ~. --- ---------- - -

F'l1QI'\t Patl'l Terrain liiiP«tC'l 

Fire Angle AnQlt" Velocity 

--- ----- ----- -------- 1. Yt;~ 1 • liP 1. UVSL.OPE 1. 1.1 - 1~ 

:l. NG 2. L'N 2. "'~1\.Sl.O.,.E 2. 1~ - 3 t.• 

J. U·•F<t..LATt.O 3. () - 5 J. . ·. - s 3. )\,I - 45 

4. ~ .. 10 4. 5 - 10 4 • 4~ - Ml 

:>. 1(1 - 15 ~- 10 - 15 ~- t){l - 7~ 

t>. 1~ - 20 6. 15 -20 b. 75 - ':10 

7. 2•} - 25 7. 2v - 25 7. 9\.1 - 120 

8. 2: - 30 s. 1~ -)0 tt. 1:eo- 1~() 

9. 30 - 4~ ~- 30 - 45 9. 150- ll:j (1 

1u. 45 - (i (I lv. 45 - ~0 l(,. 1 b (i• 

• 

·--------------------------------~----------------------------------· ~otes : 

----------------------. --------------------------~-----------------------------------------~------ __________ _, ___________ ·-----------·---.. ------ --~-----------·-----------~-----------------------------~-------------.. ------ -------~---~---------------·---~------·-------------._._._ ____ _ -------------------------------·----·-----------

-;:J 

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In 

en 

-

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APPENDIX D -28-

Kinematics Study- Occupant Data 

File 

Region of 

Injury 

Initials 

Notes 

O:cupant 

Position 

Sloulder 

Available 

1. Yes 

2. fb 

3. lhk. 

Harr.ess 

Used 

1. Yes 

2. fb 

3. Ulk. 

Seats llier~w 

Absorber 

1. Yes 

2. tb 

3. U1k 

Stayed 

in Place 

1. Yes 

2. !b 

3. llik. 

Rerluced by Table of injury improvanents 

Harness FA Sloulder Harness Seat (FA~ Retention) 

yes no yes no 

1. Fatal to Fatal 1. Fatal to Fatal -- -- 2. Fatal to Serious 2. Fatal to Serious -- -- 3. Fatal to t1inor 3. Fatal to flinor -- -- 4. Fatal to tbne 4. Fatal to None -- -- 5. Serious to Seriouc; 5. Serious to Seriou .. o:; 

-- -- 6. Serious to ttinor 6. Serious to Hioor -- -- 7. Serious to None 7. Serious to NonP 

8. Minor to ttinor 8. Hi nor to Minor 

9. 11inor to None 9. Hi nor to None 

10. tbne to None 10. fbne to None 

11. Fatal to Unl<Jlor..ln 11. Fat~l to Ln~n 

12. Serious to U1J<noo..n 12. Serious to Unkno ... ·n 

13. Mioor to Unl<nown 13. Mimr to lJnknoo,.Kl 

00U03.l 
-29- APPENDIX D 

Injury Information came primarily from medical reports and autopsies. Injuries that 

could h!ve beet: reduced or eliminated by the use of shoulder harnesses or energyabsorbing seats \';ere noted. The evaluator then attempted to determine whether the 

occupant could ha\·e survived If the inJuries had been less severe or eliminated. 

Each accident was evaluated by examining OC!cupant injury and evidence supporting 

estimates of impact speed and impact angle. Data were documented that detailed 

shoulder harness availability and use, seat retention, and shoulder harness and energyabsorbing seat ~tre~tiveness. These data were recorded on an occupant injt •. •y form and 

an airplane Impact severity form. 

An occupant Injury form was completed for each occupant even if the Injuries of 

that occupant were minor or none. 

Shoulder harnesses available.--3houlder harnesses were considered avaU,\ble If the 

accident report so stated or for front seats of airplanes manufactured after July 18, 1978. 

AU seats on Beechcraft airplane models from 1975 on were considered to be equipped with 

shoulder harnesses. While some models of general aviation airplanes had shoulder 

harnesses lnstrlled as options before 1978, the number was considered to be small. Data 

recorded frorn the older airplanes confirmed that few older airplanes had shoulder 

harnesses. 

Shoulder harness use.--In many cases it could not be determined whether shoulder 

harnesses were used. Determinations were made predominantly on the strength of written 

documentation of the investigation and on occupant or rescue personnel statements, when 

available. 

Energy-absorbing seats.--The only seats that were com:ictcred energy absorbing were 

Piper's "S" tube seats. In fact, other seat designs, such as the Beel'h Musketeer seats, can 

absorb significant amounts of energy, but they were not coded as energy absort)ing since 

energy absorption wcs not a part of the seat design concept. 

Seat rttentlon.--Ir a seat separated from its r. ttachment points, or If seve rill of the 

seat feet or legs became detached, the seat was classified as loose. A seat that Is loose, 

even If it stays close to Its normal position, offers little protectlon. Loose seats were 

C~>ded as "not staying In place." 

Aetual Injuries Versus Predicted Injuries 

Tf.t.'Jle of predicted lnjurles.--These data were compiled under the assumption that 

shouldei' harnesses were not worn and energy-absorbing seats were not available. The 

available data were evaluated to determine the original Injury Index and the predicted 

Injury Index If shoulder harnesses anj energy-absorbing seats were used. 12/ 

!_!/ Injury Index: The level or Injury-fatal, serious, minor, and none. 

000032 
APPENDIX D -30-

In cases where shoulder harnesses or el'\ergy-absorbing seats w~re used, the level of 

injury which would have occurred had these devices not been used was determined. For 

example, If a seriously injured occupant would have received fatal injuries if that 

occupant had not worn a shoulder harness, "fatal to serious" WC'uld have been coded. 

For a complete evaluation of the benefits of shoulder harnessP.s and energyabsorbing seats, it is necessary to go beyond the injury index level. Serious injuries range 

from a fractured bone to severe Internal injuries. An occupant's skull fracture and broken 

leg would result in an Injury index of serious. If a shoulder harness would have prevented 

the critical head injury, the occupant still would have a broken lev and the Injury index 

would remain ''serious." Such a circumstance woul':i '>e coded as "serious to serious," thus 

Ignoring the significant head injury improvcmant provided by the shouldel' harness. 

Therefore, a further breakdown of injuries w&o; required. 

Region of injury reduced by shoulder harness and energy-absorbing seat.--Body 

regions of injury were given numerical codings when a significant Injury was documented. 

The Injury then was evaluated to determine whether shoulder harnesses or energyabsorbinz seats would have prevented the injury. The evaluations were done even though 

the overall injury level might not have been reduced. 

Airplane nata 

Fire.--Information about fires was examined to determine whether each fire was 

the result of a crash or was an unrelated fire such as that from a dropped cigarette. 

PUS: path angle.--The (light path angle is the angle of the path of the airplane as 

it dcsce or climbs relative to the horizon. Flight path information data is a direct 

entry item in the Safety Board accident investigation forms. When tt- "3e data were not 

recorded, photographs, drawings, witness statements, and the acciaent report's narrative 

were reviE'wed to determine the flight path angle. 

Terntin angle.--Terrain angle is the angle of the terrain relative to tl~e horizon with 

reference to the direction of airplane travel. When an airplane impacts sloping terrain, 

the terrain is considered to have an "up" angle, if the airplane impacts into rising terrain 

relative to the direction of fli~ht. 

lm~ct angle.--The Impact angle is the difference between the flight path angle and 

the terran angle. A 30-degree impaP.t angle could result from a level flight impact into 

30-deg,·ee rising terrain or from a 30-degree dive into flat terrain. 

lmnct Speed.--lmpact speed is the airplane's speed in knots during the principal 

impact. 1 1 The velocity was estimated based on the aerodynamic properties of the 

alrplane;-such as stall speed and cruise speed, and also was based on airplane 

configurations, such as power setting, flap and gear posltior.s, and aircraft weight. In 

most cases, there was surticient Information to establish whether the airplane was In a 

stall, near stall, or cruise Immediately before impact. It Y''IS more difficult. to estimate 

Impact speed in some cases, in particular high-speed dives, Intermediate speeds between 

stall and cruise, and impacts Involving multiple strikes. 

nrPrrnclp8flmpact occurs when the most severe d~celeratlve forces are experienced 

and the most damage is sustained by the fuselage. The principal Impact may not be 

necessariiy the Initial impact. 

onnn:~3 
-31-

A.PPBNDIX B 

PIVB A.CCIDBNT BXA.MPLI!S 

AND RVA.LUA.TION RBSOLTS 

Five accidents are presented as examples to show the coding procedures that were 

used d~.:ring the course of this study. These accidents ranged in severity from survivable 

to nonsurvivable. 

These analyses show the various considerations involved in a crashworthlness 

evaluation. In each case, occupant movement must be evaluated with respect to the 

existing or desired occupant protection system. Ho'Ulever, the ultimate consideration In 

predicting the benefits provided by crashworthy occupant protection systems rests in the 

definition of survivability, I.e., a livable vo!ume must be maintained and the accelerative 

forces must be survivable. 

A.~tdent No. l (photographs 1 through 4) 

This accident, which resulted from fuel starvation, was totally survivable. During 

the emergency landing, the right wing struck a 25-foot-illgh tree. Th~ airplane contacted 

the ground 102 feet later and the airplane slid 45 feet. There were three serious injuries 

and one minor injury. Shoulder harnesses were available for the front-seat occupants 

only, but the shoulder harnesses were not used. All seats remained attached to the floor 

structure. 

The measured night path angle was 14 degrees. A pilot statement Indicated that 

the airplane was near a naps-up, power-off stall. ThP. Impact angle was coded as 10 to 

15 degrees, and the impact speed was coded as 45 to 60 knots. 

. , 

, \\' 

Photographs 1 and 2. 

000034 
APPENDIX E -32-

Photographs 3 And -1. 

oooo:~;) 
-33- APPENDIX E 

Occupant 1. --The pilot's head had impacted the ir,o;t;ument par.el, and he sustained 

facial and scalp lacerations, a possible basilar skull f.·ncture, a knee laceratiol", and a 

fractured right thumb. The energy-absorbing seat in which he was seated had stroked 

about 1 inch. Since the cockpit area near the pilot's position was intact, it was assumed 

that the shoulder harness, had it been used, would have prevented the face and head 

injuries. Therefore, the injury data on the pilot was coded as "SerioJs to :\1inor" to reflect 

the sht>ulder harness benefits. The energy-absorbing seat benefit was coded as "Serious to 

Seriou~" since the energy-absorbing scat would not have prevented the head injuries. The 

fact tnat the stroked seAt probably helped to protect the pilot from spinal injuries was 

disregarded. 

Occupant 2.--The right-front seat occupant sustained multiple facial, head, and 

upper body injuries from impacting the instrument panel. These Injuries included facial 

fractures and lacerations, cerebral concussion, fractured left clavicle, chest wall 

contusions, and probable pulmonary contusions. It was estimated that the use of a 

shouh~er harness would have prevented the injuries; therefore, shoulder harness benefits 

were coded as "Serious to Minor." 

Occupant 3.--The right-rear seat occupant sustained a compressed fracture of the 

f,S vertebra. The rear seats were not of an energy-absorbing type, so the energyabsorbing seat benefit was coded as "Serious to :\1inor." The shoulder harness benefit was 

coded as "Seriou~ to Serious" because it could not be determined whether shoulder harness 

use would have prevented the back Injury, even though there was that potential as a result 

of better spinal positioning created by a shoulder harness. 

~ant 4.--This occupant had minor injuries consisting of bruises and tenderness. 

Shoul<Iernarness benefits and energy-absorbing seat benefits were both coded "Minor to 

:\11nor" since these minor Injuries probably would not have been eliminated by a crashworthiness device. 

Accident No. 2 (photographs 5 through 7) 

During a night go-around, the airplane impacted gently rising terrain, damaging the 

propellers. With the loss of power, the airplane then descended down a shallow hill and 

impacted into level terrain. The airplane was flying at slightly above the naps-up stall 

speed and in a right wing-down condition. The speed was estimated at 75 to 90 knots, anJ 

the impact angle, based on ground scar reconstruction, was estimated at 5 to 10 degrees 

down. The decelP.ratlon was more severe than that In accident No. 1 because the soft dirt 

allowed significant gouging. The pilot was injured seriously, although these Injuries were 

considered preventable. 

Occupant 1.--The pilot was not wearing the available shoulder harness, and he 

sustained significant head injuries. The cranial bone above the bridge of the nose was 

driven into the sinus cavities, the right cheekbone was fractured, the nose was fractured, 

the right ankle was fractured, and the left ankle was sprainec1. Back spasms were present 

due to minimal compression of the Tl2 vertebra (no fracture). The hE:ad impacted the 

Instrument panel at the Kollsman knob of the altimeter and at the bug knob of the HSI. 

The knees impacted Into the subpanel, and the seat pan was torn from downloading. 

ooooar. 
APPENDIX E 

Photogrnphs :i Anrl n. 
APPENDIX E 

. Photof{t'aph 'i. · 

· Slr,N! sh<>Ulder h&l'twss usc would l'ln (!Xp(:cted to have proventod the hend irijuries 1 · 

·.the shoulder har'n(;•~s bcrwfit wf!f: (!odcd as "Serious· to Minoi'.il ·. Hn<l on energy--absorbit1(f 

sNit tHwn nvrti1nble, the rnin:H' bn(•l< injtH•ies possibly could huvc been nvoided. The 

· · m1ergy'·nhs()rtliflt! f>(•;,t btmefit .vns coded as "Scl'ious to Set'ioits'1 since tiH~ seat nlono woulrl 

not hnve Pl'eventHd tho sel'ious hcwl ii'IJHt·IPs. · · ·· · · 

ACc.iiiont No, :~ (pll<)lnf{t·nph:i 8 through 11) 

,." Y··--~~l~s ~~~::~tknt N!C!mred on a gusty d~y, nnd tl)o pilot lost control of tile nirplilnc on 

.npproach .to landing. 'l'he akpluoc mnrle n lmrd rigl1t turn1 ci[(~I)J'C<l some tt•ees, and then ·.· 

lnHde. a stiJop, ri!l,'ht dc~iiqending · turt1• into the t{1'0ttnd. Ground scilr recotlsthtctlon · · 

indjcnted that the itnpn(~t. un!* wn$ tienl' 35 ~legrees ntid tM t'ol\ nn!rle was near. 90 .. 

dogrc<Js, (See rigme 10.) The flaps Wtll'(~ llJ), nne! ~he imp~;ct speed was tclStiii1Ht(}(\ at GO to 

· 75 I<nots: Since. tho riKllt wing wns down ilt impll.ct, thoiwc was sqhstnntiar cilbin · ... /II) fol'IO(tfi(m in. (he upper rit~hl front <51' t h~:.cockpit. The left cockpit l:ll'~ll hod on)y minor. 

def Col' Illation. T!JCI'OV•I!lS QlV~.fiJtality nndtwo BBI'ioUfl injUt'iC;S. . . . . .. . . . . . . . . 

. ·. Q%!-tffi.\!.n.~ l.: ~ ... ~'~'h~~ l:lrt-front seat oeeup~rHSustttln()dfatn! injurl<~sby itn[)!\Ctlng .the · . . .. . :radro (>tll(lk. 1'hese HIJIP'Jos I!Ofl:-llstl'!d of multtple blunt trmllnrt to tl1e head and m.ulttplG! 

' > frachirM or tiH~ slwll .resulting in lnceratloi1 ond h<~tnQI'l'l1nge. uf tl)e britin. Su(l<)n(')nry. 

··. ·. · Injur•ies inclurle<l diffli:iocl pulmonm•y lJemurrhnge. · NearlY il U M thcsn in)uries> oo\titi.l)fi\/.t;; .· 

. .. J)l1QIJ prcivt,lnted had the; 1.\VHil!M·o i!hi)Uldt)l' hal'J1CSS. been U?Od' : It 113 poRslble tha rserioUs .• . 

injuries still might !'lltVi:uJ<.l(Hwl;t'ld 6N!.Hus¢ of the 11ft movcfn ciil (if t11c f1oorbJ>&rds ut1d the) · ·. •. · 

irV:ltrum(:nf pnncl; howe\let' 1 it is ~tl\c)f'(i pt•iJl)flble ttwt the inj\H'y·l(~Vf:l}would haye been .·· 

··redUci9<'J. tO mi11M hy. the shoulder · hnl·rt(ls~. Thet'()for·a, the shoulder hiir'i1ol5s tH>.r)(lJ'It wns · ·~o'd~d 11l1nta 1 to \1irH~:w. tJ · · · • · · · ··•· .·· · · · · · · / · · · · · • · · · ·· · • · .. · .....•.. 

. . . - ~ .• 
\PI'E:\Ill'\ ·· ~ ·.I r 

fltloto;;rftphs x Hnrl 9. 

i}l)ill':~:~ 
, .. ' • 

I 

I •, 

• j 
APPENDIX B -38-

00' 

f-6'--i 

64 48' 42' 36' 3:l' 18' 12' 

163' 149' I 141. 22'9" 

~ -

RH Wing Tip Timber 

Plgure 10.-Reconstructlon of 'lllpaot angle and attltudt using 

groundscar Information. 

6' 0' 

000041 
-39- APPENDIX E 

Oeeupant 2.--The right-front seat occupant sustained serious injuries. The injuries 

were more widespread than the left-front seat occupant beeause of the closer proximity 

to the focal point of the Impact. This occupant sustained a mid-faeial bone fracture, 

closed-head injury, multiple lacerated wounds of the face, cervical sprain, contusion of 

the chest, fracture of the transverse process of the 1.5 vertebra, feet fraetures, and a 

hand fraeture. 

Although there was aft dis(Jlaeement of the instrument panel, the upper body 

Injuries would have been less severe had the available shoulder harness been worn. The 

seat also came loose. Had it stayed in place and been of an energy-absorbing type, the 

baek injuries would have been less serious, and possibly lesser loads would t.ave been 

imposed on the feet. Therefore, the shoulder harness benefits and energy-absorbing 

benefits were coded "Serious to Minor." 

Oecupant 3.--This occupant's lapbelt separated at the buckle when the adjustine ~am cut through the webbing. Other areas of the belt also showed evidence of high loads. 

This occupant was ejected from the airplane and sustained serious injuries. His injuries 

were a perforated small bowel, a fractured clavicle and scapula, a fractured arm and leg, 

a head laeeration, ftnd a general concussion. Had he worn a shoulder harness, the lal"belt 

loads would have been better distributed, resulting In a lesser load to the lower abdomen. 

A shoulder harness also would have reduced the likelihood of the lapbelt separation and 

subsequent ejection. The shoulder harness would have resulted In a lesser Injury level and, 

therefore, the shoulder harness benefit was coded "Serious to :\Unor." 

Accident No.4 (photographs 12 through 15) 

This accident was relatively severe for a survivable accident. The airplane 

cartwheeled and susequently stopped inverted. The pilot was killed, and the two 

passengers suffered significant head injuries. The attitude at principal Impact was 28 t::> 

30 degrees nose down with a 90-degree roll. The speed \\as estimated at slightly above 

stall or between 45 to 60 knots. 

Oecupant 1.--This occupant, the pilot of the airplane, sustained fatal injuries. The 

Injuries consisted of fractures of the sternum extending Into the chest cavity with severe 

hemorrhaging, fractures of the second, third, fourth and fifth lef' anterior ribs, and 

multiple brain contusions. These Injuries resulted from Impact lnt'J the control column 

and instrument panel. The Instrument panel on the pilot's side moveo aft far enough to hit 

the door post, reducing the livable volume. It Is believed however, that the fatal injuries 

could have been prevented with the use of a shoulder harness even though the oecupant 

still would ha•1e sustained serious upper body Injuries. Therefore, the shoulder harness 

benefit was coded "Fatal to Serious." The stroked energy-absorbing seat probably 

prevented severe back injuries. The energy-absorbing seat benefit was coded "Fatal to 

Fatal" since such a seat would not have prevented the fatality. 

Occu~~mt 2.--This occupant was In the right-front seat near the crush line on the 

airplane an sustained serious Injuries. Typically, the crush line can be regarded as the 

grouoo line, and If t.he crush line moves near the seat area, the occupant usually sustains 

very serious or fatal Injuries. However, she did receive significant protection from the 

stroked energy-absorbing seat. Her Injuries Included a fractured sacrum, fractured hand, 

and facial laceration. The facial lacerations were not classltled !lS serious, but they did 

present a danger since she was hanging upside down. A local far "Tier had to clear her 

mouth and throat of blood to prevent suffocation. The shoulder harne:s benefit was coded 

0000~2 
APPENDIX E -40-

... : ...... ..........._ 

PMtographs 12 and 13. 
-- --

'· 

~)~ I 

I 

I 

. ,. ~ . ., 

.· . ~... - I . 

I 

Phc~to~mphs 1·1 nnd 15. 

.\PPI:NDIX E 
APPENDIX E -42-

"Serious to Minor." The energy-absorbing seat probably prevented very serious !njuries 

but would not have prevented all of the serious injuries. The injury level woulc'l have been 

serious with or without an energy-absorbing seat. The energy-absorbing seat benefit was 

coded "Serious to Serious," but it was flagged so that the protection orrered by the seat 

could be accounted for in this study. 

Occupant 3.--The right-rear seat occupant also had serious Injuries. She sustained a 

burst-type fracture and dislocation or the J,2 vertebra. No neurological effects were 

noted. A shoulder harness could have benefited this occupant only by providing a better 

sitting position at impact and thus giving the back better protection. Since this is not a 

function or shoulder harnesses and only would orrer limited injury protection, the shoulder 

harness benefit was coded "Serious to Serious." An energy-absorbing seat could have 

orrered a great deal or protection. The energy-absorbing henefit was coded "Serious to 

Minor." 

Accident No.5 (photographs 16 through 18) 

This accident wss considered nonsurvivable even though the cabin remained 

relatively Intact and two or the four occupants survived for several hours. The Impact 

attitude or the airplane was the prime reason that the decelerative loads and secondary 

Impact loads preclud,~ survival. 

The alrpla~a contacted trees causing a wing to separate and the fuselc.ge to yaw. 

The airplane decended to the ground along a 39-degree flight path. The fuselage hit 

sideways with a nose-down attitude or about 25 degrees and a roll attitude of about 

30 degrees. (See figure 11.) Since the predominant impact force would have driven the 

occ•.pants to the left, neither shoulder harnesses nor enerl7)'-absorblng seats would have 

pro•1ided the lateral protection that was reQuired for survival. All occupants were coded 

"Fatal to Fatal" (01" both shoulder harness and en~rgy-absorbing seat benefits. 

Oc~1pant 1.-The pilot was very near the crush line and sustained more severe 

injurle3 thb'l the other three passengers. He had a depressed fracture of the skull with 

profuse hem 'lrrhage, complete cervical fracture, multiple pelvic fractures, ruptured 

aortic arch, Md a ruptured bluod vessel In the chest cavity. No head contact area could 

be identified in the airplane, but evidence or body contact could be seen on the sidewall 

next to the pilot': position. It was assumed therefore that the head contacted the ground 

through the pilot's $ide window during the impact. 

Occu~ant 2.-The copilot also had severe upper body injury, but he did not receive 

extenslveower body Injuries. lie had 8 frActured cervical spine, with incomplete 

transection or the spinal cord, severe brain hemorrhage, fractured sternum and ribs 

<nailed cnest), and 8 fractured leg. Again, no evidence or occupant contact was round on 

the Instrument panel. Occupant movement was lateral (to the left) which precluded 

shoulder harness errectiveness. 

Occupants 3 and 4.--The left-rear seat occupant had severe bleeding due to 

significant facial fractures and a flailed chest. The right-rear seat occupant survived 

brlefiy but died or a severe brain hemorrhage. 

0000t1fl 
APPENDIX E 

Photographs 16 and 17. 

0 (} 001 f) 
APPENDIX E -44-

Ph()!O<;:r 11 ph I:<. 

.2 - 1.67 ft. Crush 

Figure 1 I .--HC'l'Onstrw•tion •>f irnpud •tnhh· 11nd Httit11~l1•. 

0000·1 (