b
P
I
;
Report
No.
.
!
1
!
5.
?eriorning
Crganization
Name
ad
Asdress
i
i0.Wori
Uni:
No.
j
Satiorai
Transportation
Safety
Sward
/
375'D
;
Bureau
of
Accident
Investigation
1
l!.Contrac:
or
Granr
:io.
i
i
Abstract
Cont‘d
The
National
T?a.nsportation
Safety
Board
deternines
:her
:he
p-obable
C~USES
of
the
accident
*ere
a
fir?
of
undetermined
origin.
an
underestinate
of
fire
severity,
and
eo~flie:ht
fire
pmgress
information
provided
to
:he
capair..
i?stitc;e
afi
ezergency descent.
Contributinz
to
the
severity
of
:he awiCeht
;vas
:he
:“,ig’?rc?e.n.’i
2e!ayec?
decision
to
CONTENTS
SYN015Is.
.........................
1
FACTUAL
INFORMATION
...................
2
His?ory
of
the Fiigh:
.....................
2
injuries
to
Persons
......................
a
Damage
:o
Airplene
......................
9
Other
Denage
........................
9
Personnel
Information
......................
9
Airpiane informetion
.....................
5
Tassenger
Cabin
.'Aodification.
t
;ight
end
Cabin
Xaintenance
Logtmok
i'iriteups
is!
Me?eorohgicei
Information.
..................
Ai&
:o
Sevigeiion
:2
......................
12
Cor3miiniestions
.......................
Aerodrome
Information
12
i?
?i:gh:
IZwocders
.......................
10
13
Wreckage
and
Impsct
informtion
i?
zxlerne;
?use:&ge.
......................
ilt
Inierior
F,.w!,ge
Foorwa.-d
of
;he
Aft
La..va:cry
..........
i5
Cargo
mci
A::
.Accessory
Coqartxents
..............
0:
................
2:
;iedicui
Petkoiosiml
kf.x~zs.:iw
..............
2;
Fire
%es?cnFe
........................
';
..u
c
SGrv;ve.l
.+ec:s
.......................
X
.
es:s
kni
?.esex&
......................
.JZ
Fede;x:
Rsrenu
of
I?ves:igerioc
!CBIi
Labo?e:ary
Tests.
......
55
E:lrctricu'
Sys!o-?
Cox?men:s
.................
5.5
r!c.k
.'s!c;ol
i;nc
ii?vLl:3r:.
L'o?:?onen:a.
.............
$5
F!zck
.'+iotor
Ce:,xre
Test.
......
............
3s
.
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Li
-
a.22
He?..:
Tesrs
......................
3s
\i:nliine
Ca'.ii;
Fire
Resee???.
..................
a?he:
info--..;--.
.
.,
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:.".
t.
......................
43.
.Air
C-mCt:
Ope;-etionsi
P.-occ<kre$
.
.
s??oxe Ijc;cZ::or'
47
L.se
of
ii:
Li.*:a:o-y.
$5
~xe3Tlirs:
32
.ai
3t-.er
'IC-?
.4??:mes
..............
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:
-a
<fie
Cc?.!ro!
?roc&crrs
.................
1-
5
:j
DC-?-.32
Liesce-.!
?eerfxz:ence
2;
ANALYSS.
.........................
22
C;ewx:
>3
r
:.e
........
..................
-...
.........
-.
.................
ii
....................
_.,.
................
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3.
AfT
Lave:op
.Area
......................
16
COc:i?i'
coP.mlk
an:
instr;;ier.:s
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.............
3'-
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.......................
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.................
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...........................
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o?Ix3L>mi
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3<x:..:=:
Fhe:n:S
................
34
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lz-f::g:-::
TI"..
?:?;i.ri:I>?.
>C:<-e:icn
68
.&..<i.*
6s
COh'r,LUSIONS.
.......................
$9
t
:-.2::<.<
...........................
69
:,-..
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t?LZC'
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.........................
...............
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........................
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1.
...
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.;.
i
4
.
5
.
RECOMMENDATIONS
.....................
71
APPENDIIB
........................
79
Appendix A
-
Investigetion and Hearing
..............
79
Appendix
B-PersonneI Information
...............
80
Appendix C
-
Airplane Information
................
82
Appendix
D
-
Cockpit
Voice Recorder Transcript
.........
83
Appendix
E
-
1
4
CFR
25
Flame
Resistance Criteria
........
97
Appendix
F-.%ir
Caneda DC
-
9 Emergency Equipment
.......
98
NATIONAL TRANSPORTATION
SAFETY
BOARD
WASEWGTON,
DX. 20594
AIRCRAFT
ACCIDENT
REPORT
-
Adopted:
August
8,1984
-
AIR
CANADA FLIGHT 191
McDONNELL DOUGLAS DC
-
9
-
32, C-FTLU
GREATER CINCINNATI INTERNATIONAL AIRPORT
COVINGTON,
KENTUCKY
JUNE 2,1983
SYNOPSIS
On
June
2,
1983,
Air
Canada Flight
797,
a
McDonneIl Douglas DC
-
9
-
32,
of
Canadian Registry C
-
FTLU, was
a
regilla-ly sthedilled international passenger flight from
Dallas. Texas,
to
Montreal, Quebec, Car!ada,
with
rin
en route stop
at
Toronto, Ontario,
Canada.
The
flight
left Dallas
with
5
crewmembers
zrld
41
passenge-s
on
board.
About 1903, eastern daylight time: while
en
route
at
Eight level 330 (about
attempting
to
extirguish
ihe
hidden fire
and
then contacting air
traffic
control
(XTCI
and
:13,000
feet
m.s.1.1,
the
cabin
crew discovered smoke
in
the left aft lavato
-
y.
After
Seelaring an emergency,
the
crew made
an
emergency descent
and
ATC
vectored
Flight
797
:o
the GreEter Cincimeti int+??nationa!
Air?ort?
Covirqton,
Kentucky.
A?
1920:09,
eastern dayiight tine,
Flighr
79:
ianded on ruawaq-
2?L
8t
the
Greater
Cincir’qati international
Airport
-
As
the
pilot
stopped the airpiane, the airport
fire
department,
which
had been alerted
by
the tower to the fire
on
board
the
ineomiq
pime.
was
i?
place and began fireffghting operarions.
Also,
as
soon
as
the
airplane
stopped. :he fliqht
tittendants
snd
passengers opened the left and right forward doors,
the
ieh foriLiare
overwing
exit: and
the
right forward end aft overwing
esits.
About
SO
to
90
secon6s
after ?he exits were opened,
6
flash
fire engulfed
the
airplane interior. While 18
rhree open overwing exits
to
emcuate tne a$rpia;1e, the captain and
firs?
officer exited
zhrough
:heir respective cockpit
siidi?g
winbows.
HoNever. 23 passengers were
no?
able
:o
get
out
of
:!:e
piane
ad
die5
in
:he
fire. The airplane
was
destroyed.
psesgey
3
Zigbt
ette&n;s
exited
thrsugh
the
forw&
6~~s
mid
slides
and
the
The Sationai Transportation Safety Board determines that the
proaabie
causes
of
:he accident were
a
fire
of
undetermined origin,
an
underestimate
of
fire severity, and
confi.ieting fire
??ogress
informtition provided
to
the captain.
Contributing
?o
t3e severity
of
the
accident
was
the fiightcrc-w‘s delayed
decision
to
ips:i:ilte
AS
emr:.benq descen:.
-2-
1.
FACTUAL WFQRMATION
1.1
History
of
the
Plight
The in-flipht fire
Canadian Registry C
-
FTLU,
was
a
regularly
scheduled international passenger flight from
On
June
2,
1983, Air Canada Flight
797,
a
?dcDonnell Dougla= DC
-
9
-
32,
Of
Dallas,
Texas, to Montreal, Quebec, Canada, with
an
en route stop a: Toronto, Ontario,
Canada.
At
1625
central daylight time, Flight
797
left Dallas with
5
crewmembers and
(approximately
33,000
feet
m.s.1.).
1/
According to the captain, about
30
minutes after
41
passengers
on
board
and climbed to its assigned en route altitude, flight levs!
(FL)
335
depmtslre,
a
30
-
inch
-
long by 9-inc.q-wide louvered panel
at
the bottom
of
the cockpit
dmr
was
kicked accidentally from its mounts and fell to the floor. The panel Wac placed
to
one side and the flight continued. Except for
a
deviaticn
to
the south
oi
their filed
flight
plan route to avoid weather, the flight progressed without incident mtii it entered
the
Irdianapolis Air Route Traffic Control Center's (ARTCC) airspace.
X:
1851:14 eastern deylight time
Z;,
tke three circuit breakers associated with
the
aft lavatory's flush ntotor and located
on
a panel on
the
cockpit wall behind the
captain's seat, tripped in rapid succession. (The motor is
a
three
-
phase alternating
current
(a.c.1 motor; each phase incorporates
a
circuit breaker
io
-
pmtective purposes.)
Aft€.? identifying the circuit breakers, the captain immediately made one attempt to reset
them;
the circuit breakers would
no:
reset. The captain assumed that rhe fiush motor had
probably
seized
and took
no
further action
at
this
time.
About
1859:58,
the captain again
tried unsuccessfully
to
r.:sec the three circuit breakers. According
t.o
the
cockpit voice
recordor
(CVR),
he told
she
first officer that
the
circuit breaker(sj,
"
Pops as
i
push
it.?'
-
a::end&nt
3:
to
identify
e
streripe
odor.
The flight at:endant though: the odor was coimng
About
i900,
a passenger seated
in
the
lasl
row
asked the
NO.
3
flight
from the a?t lavatory. She
took
e
C3.
fire extinguisher
from
the
csbin
;will 8Cd opened
*e
iavatory door
a
few ixehes.
She
saw
that a light
g-ay
smoke
hs<
filled the lavatory
from
the
floor
to
the
ceiling,
but
she
saw
no
flames.
While
she was inspecting the
saw
the
No.
2
f!ight
attendent nearby and asked
her
to
t
the
flight
atrendant
in
charge
lavetory, she
inhaled some smoke end closed the door.
The
So.
7
flight atzendant then
of
the situation. The
Xo.
2
flight attendant restified tnAt she did
not
remember
if
she
had
been
toid there
wes
smoke
sr
fire
in
the lavatory; howea'er,
when
she reached the flight
attendan:
in
charge s5e
'.old
hi-
ther
there
was
a
fire
in
tne
lavatory.
2
Upon being
sdvised
there was a fire, the flight attendaril
in
charge instructed
the
So.
2
fiight atten6snt
to
inform
%?e
captain
and
then
fo
assist the
KO.
3
IXght
attendan:
ir
moving ;he 3assengers forwarc: and
in
opening the eyebrow air vefits over :he
passenger seats
to
direc:
ai7
:o
the rear
of
the cabin.
The
flight errendent
in
cherge then
took
the CO ex:ingJiSh@r
and
dpened the lavatory door
about
three-quarters open. Fie
also
58w
no
?lames,
but
he observed thick
txk
of
Slack
smoke coming
ou?
of
tile
seams
of
the
aft lavatory walts
at
?he top
of
the
wash
basin oehind the vanity and
a:
the ceiling.
-
1;
All
aititudes herein
we
altitude above
rr.ean
se8
!eve!,
unless otherwise :n.licated.
-
2;
Al!
times
hereafter are east=r3
dayiigh?
time
based
on
She
2:-hou?
clock.
3/
There were three
iiigh?
attendmTs
on
lhis
flight
-
-
?he
Gight attendant
in
charge,
a
Tlight
etzendant designated
No.
2,
am
o
flight
attandenr designated
So.
3
(see
section
-3-
)
the
seam
rrom which smoke was seeping and spraying
t4:
door
of
the
trash
bin.
He
then
iie
then proceeded
"
to :xaturate the washroom with
CO
by
Spraying
the PaneKng
and
closer! ?he lavatory door.
At
1902:40,
the
No.
2
flight
attendant reached
the
cockpit end told
the
csptain,
"
Excuse
me,
there's
a
fire
in
the washroon: in
the
back, they're just.
.
.went
back
XG
go
to
pui
it.
out.
"
Upon being notified
cf
the
fire,
the
captain ordered
the
first officer
to
inspect the lavatory. The captain then donned
his
oxygen mask and selected the
1GG-perCent oxygen position on his regulator. The first officer left tine cockpit but did
not take
eitt'er smoke goggles
or
a
portable oxygen bottle with him. (The airplane
was
not
equipped with nor was it required to
be
equipped with self
-
contained breathing equipment
or
a full face smoke mask.) The first officer said that
he
could not get to the aft lavatory
because
tkz
smoke, which had migrated over the
last
three to four rows of seats, was too
opened
?he lavatory
door,
that
he
had discharged the
CC
extinguisher into
the
lavatory,
thick. The
flight
attendant in
charge
told
tbe first
officer
what
he had seen
when
he
end
that.
he
had not been able to
see
the
source
of
the srnzke before closing
the
door.
He
to!d the firs? office:, however,
that
he
did not believz the fire
was
in
the lavatory's trash
container. The first officer told
the
flight attendant
in
charge
that
he
was
goirg
forward
to
ge? smoke goggles.
At
1904:0:,
the
first officer returned
to
the
cockpit and told
the
captain
thet
The snloke had prevented him from entering
the
aft lavatory and that
he
thought
"
we'd
bertei
go
down.
"
He
did not telj
the
captain that the flight attendant in charge had told
him
that the fire was
not
in the trash bin. However, at
1904:16,
before the captain
could
resp~nd,
the flight attendant
in
cnarge came to
the
cockpit and told
the
captain that
tk
passerig-rs had Seen moved fcrward and that
the
captain didn't
"
have to
worry,
I
;?ink its
1
elinost
clear in
the
back.
At
1901:23,
he told the captain,
"
it's
starting to cleai now,
"
and
gowza
:jg
easing up.
"
The
firs:
cfficer looked back into the cabirl. and said that
i:
was
the
iirst
officer's smoke goggles
were
srored in
a
bin
on
the right side of the cockpit and
thet
he
would
go
aft
ag8in
if
thc captain wanted him
to
do
so.
According
to
the
captain,
officer
needed the goggles and since there was
a
hurry,
the
captain gave him
his
goggles
were not
esiiy
accessible
to
the firs'i officer while
he
was
not in his sea:. Sinee
tine
first
and,
8'.
i901:45,
directed him
to
go
aft.
The first officer
akc
testified
That
the captain
an<
he
"
did
not discus the type
of
iire at
ell
"
during the tin;e
he
was
in
the
cockpit before
Tie
went
to
the
!tir~iory
?the
second time.
A?
i30652:
while
thI2
first officer was out of
the
cockpit, the flight attendanz
in
-t!vrge
tc:c'
the ceptain again :hst the
smoke
was
clearing. The captain testified that
he
believer:
the fire
was
in
thf
lavatory trash bin and that he did not decide to descend
at
*-..
:I>
tirne
'se.eeuse.
'*I
expectec:
it
(the
fire)
to be put out.
"
in
rhe
meanwFs,ile?
the first officer proceeded to
the
aft lavatory
2nd
pltr
on
the
smoke
gopgies.
tie
tesrised thaK
he
h6d
intended
to
open
the
door to see
what
the
siruetic-
was
inside,
Sat
when
he
discovered that the lavatory door felt
bot
to
:he
touch,
;;e
.&cider: mt
to
open
it
and ir,strwred
the
cabin
crew
io
leave
it closed.
At
that
xime,
he
noticed
e
!!ish?
attendant signaling him
to
burry
back to the cockpit.
'The
first
officer
:crcrsec:
?cj
the
cwkpi;
end
ggt
into
his
seal, and
a?
:907:11,
ne
told
the
c~tsin,
"I
don':
izs:?
....
WSPI'E
hri?peni;.lg,
i
thilk
we
better
go
down, okay?'?
The
caprain
tesiified
that,
Zr..i-.
~..
.-
.%r-:~~i
.ii..
x..i
<he<
he
kr.d
to
bewend imnediately.
. ..
..
:,A.
...~~
!:?zi
.::!!cc+
voice
i!!r'iection, he knew
that
the first officer believed
the
fire
L~Y_S
6x7
..
.
.
b
.~:>z,3~:
itiz5:35,
shik
the
officer was aft
to
inspect
:he
aft
lavetol-y,
the
r..:.c::s:-2+
::+..::
.zy;:iexed
s
szies
of
ele..i?ical malfunctions.
According
to
:he
cs*:sin,
..
ii
3
T7hs:,:y
z::,:?icz
!:gh:
:::xciEe:e~?
ic~jcatirg
that the eirpbne's
left
e..*.
aZ
d.c.
-4-
electrical systems had lost power. At 1906:12, the captain called Indianapolis Center and
requested the Center to standby because the flight ha3
an
"
electrical problem.
"
About 30
to
45
seconds later, the Louisville high radar sector controller working Flight 797
lost
the
flight's radar beacon
target.
The controller then directed the computer
to
track ail
primary targets. Flight 797% position
was
then depicted
on
the scope by
a
plus
sign
and
associated data block.
About
1307:41,
after
the
first
officer had
returned
to
the
cockpit,
the
master
and d.c.
electrical
buses had lost power. The captain's and first officer's attitude direc-
warning
light illuminated and
the
annunciator
lights
indicated that
the
emergency
4.c.
tional indicators tumbled. The captain ordered the first officer
to
activate
the
emergency power switch, thereby directing battery power to
the
emergency
ax.
and d.c.
buses.
The
attitude directional indicators' gyros began erecting, however, because of
the
loss
of
a.c.
power, the stabilizer trim
was
inoperative and remained
so
during the
rest
of
the flight.
The
descent
At the Air Traffic Control Facilities.
-
At 1908:12, Flight 797 called the radar
high
sector controlfer
at
Indianapolis Center end said,
"
Mayday, Mayday, Mayday.'!
4i
The
Louisville
radar high
sector
controller acknowledged the
call,
and
at
1908:47, theflight
that
it
was
25 nautical miles
(nmi)
from Cincinnati and
asked
"
can you
possibly
make
told
the
controller
that
it had
a
fire and was going down. The controller
told
the
flight
Cincinnati.
"
The flight answered that it could make Cincinnati and then requested
clearance;
it
was
then clea-ed to descend
to
5,000
feet.
At
1909:05, Flight 79'2 reported
that
it
was
leaving FL 330. The flight then told
the
controller that
it
needed to be
vectored toward Cincinnati, that
it
was
declari,?g
an
emergency, and that it had changed
its transponder code
to
7700
-
-
the emergency code. However, the transponder
was
inoperative due
to
the
power loss, and the emergency code was
never
portrayed
on
the
Center's radarscopes. At 1909:29,
the
Louisville radar high sector controller directed
the
flight
to
turr,
to
060°
and toid it that the
Greater
Cincinnati Airport (Cincinnati Airport)
that
FIight 797 had to descenti
"
immediately;': therefore,
he
issued
the
clearance
and
was
at
"
twelve
o'clock
at
twenty miles.
"
The controller said that it
was
cbvioits
to
hin
stated
that
he
was
going to coordinate
the
descent
with
the
other sectors
at
the
center
later.
He
further stated
that
the
060O heading
was
intended
to
place
the
flight
on
course
toward Cincinnati Airport.
He
heard Flight 797 report leaving FL
330;
however,
because
of
the inoperative transponder,
mode
C altitude informetion
was
no
longer being received
and
there
was
no
indication
on
his
radarscope that
the
flight
was
descending.
called the approach eontroller
at
the
Cincinnati Airport's Terminal Radar Conzrol
At
1909:17, Indianapolis Center's Lexington low attitude
D
(LEX
-
D)
controller
(TRACOX) facility to alert him of an impending handoff in
his
southwesi
sector.
Six
seconds leter,
?he
LEY
-
D
controller told the approach controller
at
Cineinanti
he
had
a
"
code
for
you,
"
and
at
1909:25, the
LEX
-
D
controller then toid the Cincinnati approach
approach controller
replied,
'Zero
six six two, thirty
-
five thousand.
"
Zero six six
two
was
controller that he
had
"en
emergency
for you, Air Canada
seven
nine
seven.'?
The
the
code
assigned
to
Continenta:
383,
a
westbound
iiight
at
FL
350.
At
1909:33,
the
LEX
-
0
contro!':r answered,
"
Yeah, thirty
-
three right now, he's twenty
-
five southwest.
"
The &>!roach -ontroller replied,
"
Radar contact, okay.
"
tiowever,
at
1909:38 when the
approach
eoctro&x
accepted
the
han6off of Flight 797, he had mistaken the radar beacon
4;
Tie
icernationai -ediotelephonie distress signal. &'hen repeated three
times,
it
indicates imminent and
grave
danger and that immediate assistance
is
requested.
~
-
I
hendoff, the approach controller had notified the Cincinnati Airport tower
local
controller
target of Continental Flight
383
as that of Flight 797. Shortly after
he
had accepted the
that he intended to
land
an
Air Canada jet with
an
on
bosrd fire on
runway
36.
The
tower's local controller alerted the airport fire station, and crash
-
fire
-
rescue (CFR)
also
been advised
that
the
airplane had electrical problems, that smoke
was
coming from
vehicles were dispatched and positioned for
an
emergency landing. The firefighters had
the
aft lavatory, and
that
there
was
smoke
or
fire in
the
rear of
the
airplane.
At
1919:01,
almost coincident with
the
end of his message
to
the local controller, the LEX
-
D
controller informed the approacn controller
of
Flight 797's assigned
060*
heading.
Although the
approact1 controller repeated the heading, he ststed that he could
not
recall
hearing this message.
%n
emergency, and said
that
it
was
descending. The approach controller acknowledged
At
1910:25,
Flight
797 contacted the
Cincinnati
app-oach controller, declared
and told
the
ilight to plan
for
a
runway
35
instrument landing
system
(ILS)
approach and
requested
the
flight to
turn
right to
090°.
He then realized the
target
he
was
observing
was
not
respoz3ing and attempted unsuccessfully to assign
a
discrete transponder code to
it
in
order to track it bctter. Thereafter,
at
1910:48, Flight 797 reported that it had
a
fire
in
its aft lavatory and that
the
cabin was filling
with
smoke, The controller asked the
flight to
"
say
the
type airplane,
number
of people
on
bosrd, and amount of fuel (on
>o~.rd:."
The
first
officer answered that he would supply this data later because
"
I
don't
have time now.
"
At
i9:2:40,
the
approach controller called the Evansville/Nabb D controller on
;he
landline
to
request assistance. Almost simul?aneous with the call, he also observed
m
eastbound primary
target
and began to monitor it.
At
1912:44,
the
flight requested the
1
:loud ceiling
at
the
airport and
:he
controller responded
that
ths
ceiling
was
"
two
zhousmd five hundred scattered, measure(d) eight thousand
feet
overcast, visibility one
twc
(12)
miles
with
iight rain.
"
The
controller
then
decided
that
the
eastbound target
was
=ontroller said
that,
by
1912:549
he knew that
he
was observing Flight
797's
primary
Flight
797: and
at
1912:51, he
requested
the flight to ':say altitude.
"
The
approwch
target, but that it was not
"
fully
identified.
"
He
also
kt!ew,
based on
the
target's position
--
about
3
nmi east
of
runway
S6's
extended centerline and aboitt
8
nmi
south
of
its
xkreshold
--
and its reported altitutie
of
8,000
feet, that it
was
too
high
m.d
too
fast
to
lad
on
runway
36.
3e
decided to
use
runway 27L for landing, and used the primary
target
TU
xonitor
the
flight
and vector it toward the airport.
At
1913:38, after Flight 797
was
unable
to
tell
him its heading because its
heuding instruments were inoperative, the approach controller asked the flight
to
turn
left.
The controiler said that this was
an
identification turn and that
it
was
also designed
io
pkce
the airplane closer to the airport. At 1914:03, after observing the target
in
a
left
turii.
:he
approach controller said that Flight 797's primary
target
was now rrfully
identified.
"
He
then told
the
flight that this
was
a
"
no
gyro
"
5/
radm approach for
runway
ic:ormeG
it
that
the
surface wind
was
220°
a1
4
knots.
He
informed the tower
of
the
was
1:'
nmi
southeast
of
the Cincimati .Airport, cleared it
to
land
on
runway
2:L,
and
eisnge of !anding runways and the tower directed the fire department
to
positior. its
v-nicjs-s
along runwsy 27L. (See figure
1.)
5,'
gyro
approachhector
-
i
radar approechlvector provided in
case
of
a
-:a!func?ioning
gy-o
compass
or
directional
gyro.
Lnstead of providing
the
pilot
%ith
headipgj
1s
be
flown,
the eontroller observes the radar track
a!<
issues
control
jcs:cuctiox
";urn
righx;teft"
or
"stop
tupn"
as epproyiate.
-.
ir*r~
,
seven left.
.
.'!
and cleared it
to
descend
to
3,500
feet.
H%
then told
:he
flight
that
it
-
b
CRASH/SIRE/RESCUE
UNITX380
FAA
CONTROL
TOWER
a
-7-
)
that
it
w8s
"VFR
[visual flight rules] now.
.
.
.It
The appraach controller vectored the
At
1915:11, Flight
797
reported that
it
was
level
at
2,500 feet, and
at
1915:27,
flight descended
to
2,000
feet,
and
the
controller
continued
to
supply
rnnge
calls.
flight
to
runway 27L, and
at
1915:58, told it that
it
was
12
nmi from
the
airport. The
At
1917:11,
the
controller
told the flight that the crash
-
fire
-
rescue vehicles
were
standing by and again asked the flight
to
prwide
the
number of persons and the
amount
of
fuel
on
board. Flight 797 answered,
We
don't have
time,
its
gztting
worse
here.
"
At 1917:24, the runway and approach lights
were
turned up
to
full intensity.
.:At
1917:35, Flight 797 reported
the
airport
in
sight; the approach controller cleared
it
to
land, and told it
that
the surface wind
was
230°
at
4
krmts.
At
1918:48, the approach
coGtroller told the flight that
it
was
3
nmi from the airport and ther. asked the tower
local
controller
if she !ad the airplane in sight.
The
local
controller said
that
she
&d.
After
tellisg
Plight 797 that
it
was
2
nmi from the airport,
the
approach controller asked the
local
controller
to
tell
him
when Flight 797 had landed. At 1920:0?, the local controller
told
the
approach controller,
"
H
E
'
S
landed.
"
On
the
ai
-
plane.
-
As
the
airplane descended,
the
smoke
front continuously
left
the captain's smoke
goggles
in
the
aft
end of
the
airplane. Therefore, after he
moved forward filling the passenger cabin
an3
enterhg
the cockpit. The first officer had
returned
to
the cockpit,
he
gave
one
of
the two pairs
of
smoke
goggles
stowed
on
the right
cockpit
wall
to
the captain. (See appendix F.) Although there
was
another pair available,
the
first officer chose not
to
use them. The captain donned
the
smoke
goggles
and
wore
them
during
the descent and landing. The captain said that during the descent,
he
wore
his oxygen mask end the
oxygen
regulator
was
set
to
the
100
-
percent position; therefore,
b
he had
no
trouble breathing.
However,
during
the
latter
Sages
of
the approach and
had
to
lean
fcrward
to
do
so.
He
testified that his perspiration
was
causing his smoke
Ieqding, he ked difficulty seeing the
instruments
because
of
thf
smoke in the cockpit and
goggles
to
steam
up and
he
had
to
pull them
away
from his face from time to
time
to
?leer
then!. The firs; officer
ah
wore
his
oxygen mask during
the
descent and
set
his
breithing.
oxygen system regulator to
the
130
-
percent position and encountered
no
trouble
in
"?.fayday'!
call.
The
Lb.ro?t!es were retarded to idie and
the
speed brskes
were
extended.
The
capta:n began
the
emergency descent
almost
simultaneously
with
the
However,
wher
the
s2ted
brakes
were
deployed,
the
spoiler/speed brake handle
%as
moved
inadvertently to
the
f~Al
eft
posltion
and
the
spoiler
paneis
were
deployed
to
the
fuiL-up
or
gro-und
position.
TF,e
captain testified that this
hac
no
effect
O
R
the airspeed
during
*he
descenr but
it
increased
lhe
descent
rate.
The descent
was
flown
at
310
knots indicated
eirspe-d
(K!AS),
end
since
the
needle
on
the instentaneous vertical
speed
indicaror
(IVS;)
was pegged,
the
rate
of
tieseefit exceedzd
6,030
feel per minute (fppm).
Accordkg
to
?he
flighrcrew,
Flight
797
was
ope
-
sting
in
visual
rne:eorolcgIc~:
condi:ions
before
the
emergeney descent. The
cvpiiiin
said
fhat
the ai-piene was
alz-,.
'
totelly in clouds
from
about
FI.
23
to
about
3,009
feet:
however,
it
aid not
encour;e:
either turbulence
or
icisg.
A:
levefcif
at
3,503
feet,
thz
air$ane
was
in
end
otit
of
the
clmd
bases
so
5e
descended
tu
2,000
fee8
to
oStain
WX
flight
condi:ions.
According
to
:he
flightcrew,
except
for
:he
eloclci
cor?di:iuns
at
3,000
feer,
?he
emergemy
descecf
and
kinding were
not
effected
by weather.
that
he
did not remember the door's being open and that he did
not
order it opened.
The cockpit door
was
left open throughout the descent. The ceptak testified
During the initial
stages
of
the descent, the cabin
crew
completed moving tbe
passengers forward of row
13.
They briefed them on the
emergency
evacuation
procedures and passed out
wet
napkins
until
instructed by the first officer
to
sit
down.
They
also
designated passengers
to
open the overwing exits and briefed
them
on
opening
them;
they then prepared them for
the
landing.
After
the initial level off
at
3,003
feet,
the
captain ordered the
first
officer to
although
it
is not required by the emergency procedure
checklist,
he
turned
the
air
depressurize
the
airplane in preparation for landing. The first officer complied, and
conditioning end pressurization packs off.
He
testified that although
he
knew
this
was
not
required by procedure,
he
did
so
"
because the smoke
was
getting bad
at
that point
ana
my
reasoning
was
I
have
to do something.
.
.
.'I
He
said that
he
thought the packs
were
clear
the smoke Prom
the
cockpit,
but
closed
it
almost
immediately
because of the high
feeding
the
fire.
A
few moments afterwaid,
he
opened his sliding window in
an
effort
to
noise level. The first officer opened and closed the window
several
times during
the
final
stage
of
the
flight.
%-hen
the
captain
sighted
the
runway,
he
extended
the
landing
gear.
Since
the
hOFiZGR?al
stabilizer was
inoperative,
the
captairi
extended
the
flaps
and
slats
incrementally
thrcugt!
the
Oo,
j0,
Iso,
2.53
End
40"
positions.
He
allowed
his
indicated
airspeed
to
stabilize
at
each
flap
position
as
he slowed
to
approach speed.
He
flew
the
final
approach
at
143
KIAS
md
completed
?he
landirg. After touchdown,
he
made
a
maximum effort
stop
(using extended spoilers
and
full brakes). Because of the
loss
of the
left and
rlgh?
a.c.
buses, the antiskid system
iues
inoperative
and
the
fow
main wheel
figure
1.)
Ailer
thc
captain
completed the emergency
engine
shutdown checklist,
5o?h he
tiires
blew
out.
The
airplane
was
stopped
just
short
of
the intersection
of
taxiivay
J.
(See
and
the
first officer attexpted
to
go
back
into
the
cabin
an$
assist
in
the
passenger
evec~ation~
but
were driven back
by
the
smoke and
heat.
Thereafter, they exited the
airplaze through their respective cockpit sliding
windows.
After :he
airphx
stopped,
the
left
(5-1)
and right
!X-?)
forward
cabin
doors,
exits
.were
Gpened, and the slides
at
the
L-I
end
R
-
I
doors were deployed and inflated.
the left forward
(L-2)
.,verwing exit, &id
the
right forware
(R-2)
and aft
(E-3)
overwing
The
3
cabin
zitendants
ad
i8
pasengers used
these
5
exits
to
evacuate
the
eirplerre.
After the
18
passengers
aqd
5
crewmembers
>eft
the
sip:ar;e,
the
cabir,
interior
burst
into
flanies.
Twenty
-
three passenge:s perished
in
the
fire.
?;either
thc
passengers,
crew,
imr
wi%esses
outside of
the
airphe
saw
I?&rnes
i~side
'he
cabL? before
ths
survivors lef?
the
plane. The fuselage and passenger cabin
were
g;ltted before airpart
fire personnel
eouid
exringuish
the
fire.
!See
figwe
2.:
I.%
Injuries
to
Persons
Lqjuries
-
Crew
-
Passengers Others
-
Tots!
23
3
-9-
Figure
2.--Airplane after fire burned
'thrc~gh
top
of
fuselege.
-10-
On
September
17,
1979,
the airplane experienced
an
in
-
flight failure
Cf
its
aft
pressure bulkhead shortly after takeoff from Logan International Airport,
Boston,
airplane
had
leveled
off
at
FL
250.
At
the
time
of
the
Logan accident,
the
airplane had
Massachusetts.
6/
The
separation
and
ensuing depressurization occurred shortly
after
the
flown about 28,425
hours
and
had
completed
26,816
landings. The
damage
to
the
aft part
of the airplane was extensive. There
was
disruption of some engine and flight control
components. Except for severed flight data recorder connections, no damage was found
on any electrical components, wires, and cables examined during
the
investigation.
airplane and to facilitate the removal of damaged structure and reinstallation of
However, in effecting repairs, numerous wire bundles were
cut
in order to examine the
replacement structure. Repairs
to
the airplane were made by McDonnell Douglas and
approved company. The
aft
pressure bulkhead and aft accessory compartment were
inspected by Air
Canada
under its authority
as
a
Canadian Ministry
of
Transport
(MOT)
rebuilt at Logan Airport between September
18,
1979,
and November
20,
1979.
The
installation of the aft lavatories and interior furnishings was made
by
Air Canada
at
their
Dorval
Base
in
Montreal. Air Canada
and
McDonnell
Douglas each wrote engineering
reports
on
repairs to
the
airplane.
An
FAA Form
337,
which
was
part
of
the
Air Canada
report
7/,
listed
29
individual repair items.
Item
3
of this list stated,
"
Spliced electrical
wires through aft pressure bulkhead per service sketch
2958.
"
The sketch designated
where
the splices were to be made and the manner
in
which they were
to
be made.
In
additioc, the
Air
Canada report stated
that
the contractual agreement required
"
that
the
specification
for
the sirplane as originally delivered.
"
The
airplane was returned to
repairs
be
carried out to restore the aircraft to condition substantially conforming to
service December
1,
1979.
made during
the
repairs at togan
which
were found and not destroyed were examined.
No
I
evidence
of
arcigg
or
short circuitirg was found.
During
the
investigation of
the
Cincinnati accident, all
of
tine
wire
splices
1.6.1
PWt
and
Cabin
Maintenance
Lq$wk
Writeups
Between June
1,
1982,
and June
2,
1983,
76
writeups were entered in
:he
&k~laiie
Pzgh',
?E
encersing
the
two e?gi%e-driven generators and
the
auxiliary power
unit
(APU)
generetor. One writeup concerned
the
right engine
-
driven generator;
6
writeups concerned
the
left engine
-
driven generator;
34
concerned the
APU
generator;
crosstie relay lockout, only
1
-
on December
30,
1982
-
described
an
accompanying
and
35
concerned crosstie rehy
lockout
malfunctions.
Of
the
35
writeups re1ati.T to the
generator za!function.
The
last
crosstie relay lockout malfunction occurred on
March
18,
1983.
The
seven
?;-riteups
en
the epgi.w-driven generators concerned the generators'
tripping off line.
On
August
1,
1982,
the
right generator tripped End
was
reset
by
the
flightcrew;
OR
August
2,
the
right generator's voltage regulator was replaced. The six left
January
4,
1983, the
left generator control
panel
was removed and
replaced
and
generator
malfunctiois
occurred between Decerriier 28, 1982, and
Jmuary 4,
1983.
On
thereafter
the
generator operated without further problems.
A
shop
check
of the
removed control panel disclosed
e
bad solder connection between
circui?s
or,
the
under
frequency protection printed
circuit
Soard.
-
6/
Natiocal Transportation Safety
Board
kcident Repor:
.AAR-SO-i3.
-
7:
Air
Canada Engineering Report
No.
920-751-3,
Liecernber
20,
1979.
B
-11-
Between May
7,
1983, and Yune
2,
1983,
the
flightcrews logged 38
APLT
generator malfunctions; during this period there were no engine
-
driven generator
malfunctions logged. Thirty
-
four writeups indicated that the APU generator would not
come
on
line;
four
indicated
that
the generator ?.ad tripped from the line. The
examination
of
the flight log showed that corrective action had been
taken
for these
entries. Except in an electrical emergency,
the
APU generator
is
not used in flight.
Flight
797's
flightcrew did not
try
to start
the
APE generator during the flight from
Dallas
to
Cincinnati.
Between
Septenber
1,
1980, and dune
2,
1983,
the
cabin logbook entries
indicated only
mincr deficiencies in
the
toilet pump flushing
system
and routine
flush
pump and
flush
motor
changes;
all were signed off properly with no out-of-the-ordinary
repairs having been made. The
last
flush system component change was made
on
May
4,
1983; the pump assembly
was
replaced and the repair signed off by a mechanic and an
inspector.
On
\lay
2,
1983, during
a
scheduled major maintenance check, an unscheduled
pressure bulkhead in rear cargo (compartment) soaked with toilet detergent liquid,
work
card
--
No.
150
--
contained the following writeup,
"
Insulation at bottom
of
investigate leak.
"
The item was signed off,
as
follows, "Comectors checked and
tightened.
Also,
insulation replaced where needed.
"
1.6.2
Passenger
Win
Modification
b
During
June
1981,
Air
Canada refurbished the airplane's passenger cebir,.
'The
right
eft
lavatory
was
removed and replaced with a clothing stowage area. Overhead
luggage bins
were
installed and
the
cabin
walls
and
ceilings were repIaced.
The
modification was performed using an assembly kit manufactured
by
the Heath Teen6
Corporation,
Kent,
Washington, in accordance with the provision
cf
Suppfemental Type
Certificate
(STC)
No.
i129
issued
5y
the
F.4A
Forthwest Regional Headquarters,
Seattle, Washington,
Oi?
February
2,
1982.
airplanes,
Heath Tecna
had
to apply
for
and
received an
STC.
The materials, drawings,
and
plans contained
in
the assembly kit constituted
6
major overhsul of the eirpIane3
interior. Since
the
DC-9-32 airplmes had been certificated before May
1,
1972,
the
manumzturer had
to
demonstrate that materials met
tie
flammability standards
of
1.4
CFR
25.853
(a)
(b!
as
amended on May
1,
1972,
in order
to
receive an
STC;
these s:enGards
still apply. (See appendix
E.!
The f'.ammabiiity tests were conducted
in
accordance
wit;?
prescribed
FAA
standards, and
all
materials
in
the
kit
met
the flarr,mebility standards.
19
eddition,
all
wiring
us4
in the
kit
met
MIL
kt-81044 specifications
previoirsiy
appro\,&
bv
the
FAA.
Since
t!!p
IIpat.h. Teen6
ase.mb!y
kit
+'as
desim.ed
to
be
esed
or:
QC-S-32
8-
At
the time
of
the accident, the
&ir$hnets
seat
cushion materhl
WGS
polyurethane foam,
the
window panes
were
transparen? acrylic sheet, the interior
cajin
side walls
were
xede
of
acrplonite 9utsdiene styrene
{ABSf
plastic sheet?
the
ceilirg
end
the tabir,
si&wal!s
and Cei'IPg pane! facings
were
decorative vinyl lamin&tc witb
pane3
were
made
a?
CGnpOsite nomex hor,et;comb Core with fiberglass facing materials,
Teak
facirgs.
-12-
showed
a
west
to
east
warm
front
in
central
Kenlucky.
At
2000,
the
analysis showed
a
The
1700
National V;eather Service
(NWS)
surface
analysis
for
June
2,
1983,
warm
front extending
from
southern Ohio through
western
Kentucky with associated rain
and rainshowers.
indicated
weather
echoes containizg rainshowers. These echoes were located south
Weather radar
data
from
the
Cincinnati Airport for 1830 and for 1939
through
west
of Cincinnati Airport and extended out to about
100
nmi. The maximum
echo tops were reported
at
14,000
feet
at
1830;
at
1930,
the
tops were reported
at
13,000
feet. According to
the
NWS,
light rain began
at
the
airport
at
1734 end eaded at
2024.
Between 1900 ana
2000,
a
trace
(less
than
0.01
inch)
of
rain was measured.
the
times indicated:
Surface weather observations for the Cincinnati Airport were
as
follows, for
visibility
-
-
12
rniies, light rain; ternperature
-
63OF;
dewpoint
--
1850
-
2,500
feet scattered, measured ceiling
8,000
feet overcast:
55"
F;
wind
--
190°
at
7
knots; altimeter setting
-
-
30.04 inHg.
-
-
1930
-
2,500
feet
scattered, estimated ceiling
3,000
feet overcast;
visibility
-
-
12
miles, light rain; temperattire
-
-
62"
F;
dewpoint
-
-
55OF;
wind 180°at
5
knots; altimeter setting
-
-
3C.03 inHg.
1.8 Aids
to
Navigation
Not applicable.
1.9
Cornmunicatiox!!
There were no known radio communications difficul?ies.
1-1:2
t%m,zlG
1-
uI€%-mstim
The Greater Cincinnati International Airport, elevation
691
feet,
is
located
9
miles southwest of Cincinnati,
Ohio,
in Covington, Kentucky. The eirpori
is
certificeted
for
commercial operations in accordance with
14
CFR
139,
Subpart
D.
The !anding area consists
of
three runways: 16/36,
9-?
'27L,
and
9L/XR,
Runway
27L
is
7,800
feet
long and 150
feet
wide, snd
has
a grooved corcTete
and
as?hait
medium
inlersity approach light system with runway alignment indicator lights
(MALSR),
r.wtway
27i
has
high intensity
run:%::
edge
ligh?s
(SIRS),
centerline
lights,
e
and visile! approach slope indicator
(YASI-L).
The touchdown zone elevation
is
875
feet.
Runway
27
L
is
served
by
an
ILS
epproach.
7,
^
Standiford
Field,
elevation
437
feet,
is
5
miles
SOU?^
of
Louisvilie, Kentucky.
Sbpa-t
3.
The landing mea consists
of
two runways:
1-i9
8nd
11-29.
Runway
1-1Y
is
The airport
is
cerrificated
for
commereial operation:
in
accordance with
11
CFK
134,
'jghht
system.
Xxmway
11
-
29
is
7,429
feet
long and
150
feet
wide,
end
bas
ar.
aspkeit
7,803
feet
long
end
I50
feet
wide, and has
e
concrete stirface,
EIRL,
and an
apGroach
-13-
l
surface,
HIRL,
and runway end indicator lights (REIL). Runway
29
has an approach light
system;
runway
11
has
a
VASI, but
no
approach lights. Runways
11
and
19
are served by
an
ILS approach;
runway
11
is served by
a
localizer (back course) approach.
1.11
Pwt
Recorders
(DFDR),
serial
No.
127,
and
a
Fairchild
A
-
100
cockpit voice recorder (C'V'R), serial
The airplane
was
equipped with
a
Leigh VDR
-
2 digital flight
data
recorder
No.
1613. Both recorders were removed
from
the airplane
after
the
accident. The CVR
was
brought to
the
Safety Board's Audio Laboratory for processing and readout. Since
the
Safety Boerd's Washington laboratory
is
not equipped to readout the Leigh
DFDR,
the
readout
was
performed at the Flight Research Laboratory, National Research Council
(NEC), Ottawa, Ontari?, Canada, and
was
observee by Safety Board personnel.
however,
the
crash-proof enclosure protected the tape and
the
quality
of
the
recording
Cocicpit Voice Recorder.
-
The
CVR
easing was damaged by fire and smoke;
was excellent.
A
tape was transcribed beginning
at
1848:12
and en6ir.g at
1907:41
when
the
C"R ceased operating. Using the tiine signal recorded on
the
FAA's
Indianapolis
ARTCC's tape
as
a basis for comparison, the CVR tape timing
was
accurate to
the
second.
(See appendix
D.)
The entire CVR tape was examined for sounds of electrical arcing
or
other
events which might be
associsted with
the
accident. About
10
minutes into
the
tape,
Et
1848:I?,
a
sound resembling that of electrical arcing
w&s
recorded. The sound
was
crewmembers
testified
that they did not heer
archg
sounds at
these times.
repeated at
1848:15, 1851:03,
1851:05, 1851:14,
125::42,
185959,
cnd
1900.
The
1
The sprectral
content
of
thr first
two
electrical arcing sounds differed
from
those
which
follo*wed. The
early
wunds were impulse
-
type and contained
a
broad band
of
component with hermocics extending through the frequency range
of
the
recorder.
frequencies resembling radio static.
All
of
the later arcing sounds contained
a
400
Bz
Ai
1905:35? an electrical pulse was recorded simultaneously
on
both the
captsin's
and
ii,st
officer's
radio
channek. The pulse, which :as?ed about
7
milliseconds,
occwred
about the
tiArne
the
ceptain said that the left
a.c.
bus
was lost. Signals from the
radio channels sre taken from the captain's and first officer's audio selector panels.
Flight Data Recorder.
-
The recording medium of
the
Leigh
DFDX
is
a
encompassing
76
airplane performance parameters are recorded.
The recorder, which
was
1/2-inch, continuous
loop,
?-track magnetic tape.
A
total
of
33.5 hours
of
data
~,t
damaged,
whs
opened at the NRC flisht recorder iaSoi-atory; the tape
WEE.
removed
c-.d
then %*ound
on
a szendard comp?er-tape reel. The accident flight was identified borh
by
the recorded
flight
number ard
by
tracing the a!iiPude and heading time histories
from
:?,e takeoff at Dallas. The data showed
thnr
?he recoree: stopped operatirg
I
ho?w
12
I;;inu;es into
the
flight
wh2e
the
airplane
wss
at
FL
50.
The
DFDR
reco*ing cofcair.ed
severai
anornaiie? rhat tuok the
form
of
sign;.:
s3ikes
OF
data
losses
ir;
a number
of
recorded parameter;. These anomalies sere
use^
to
Lwntsin
mierophoae
keying informetion,
it
was
aecessary
to idenrify
event5
th?
were
e&a,h!sh a correkation between the
SVR
end
DFDX
times.
Since
the
DFDR
2id
nor
comnon to both recorders.
The
DFDR anrxaiies were examined
and
cP.z?ted
together
xr;:h
the electrical
signals
which
had
f2en
recorded
o~i
tie
C\-X
chemels. The ?ixe
-14-
incxments between the specific
events,
as recorded on
the
CVK
ard
DFDX,
'#eye
conpared
and a correlation established.
From
this
information,
it
vfas
dstermine.?
lhEt
the
DFDR
also stopped recording
at
1907:41.
1.12
Wreckage
and
Impact
Information
showed
no
evidence of exposure to abnormal heat
oil
fire. There was
no
evidence of
oil
o
Both engines and their associated cowlj*%s were intact, undemagec;,
and
fuel leakage,
and
the
main engine fuel
supply
system did not leak when pressure tested.
The engine fire extinguisher bottles had been discharged.
surrounding
compartnernt were free of
soot
and other fire damage. The
APU
enclosure
The
XPU
was
ir,tact
and was not damaged. The exterior of
the
MU
and
within the aft wcessory compartment was not damaged by fire; however, the enclosure
:vas
coated slightly with
soot.
neither system contributed
to
either the initiation or propagation of the fire. The
Visual inspection and tests of the hydraulic and fuel systems revealed
that
empennage and wings were not damaged by eitlte; fire
or
heat.
The
leadkg edge
skits
and
:railing edge flaps
were
fuily
extended. The nose gear was extended and locked. Except
for
the right axle where
the
splash guard had been cut away in order to tow
the
airplane
from
the runway, the nose gear was r:ot damaged. The nose wheel tires were inthted.
Yo?h
main landing gears were extended and locked. Except
for
;he support
bracket
on
the
Gernaged.
However, all
four
main wheel tires
had blown on
landing.
ieft
tmain
gear,
which
was
bent and twisted
slightly aft,
the
main landi
n-
wear
'%!ss
not
1.1
2.1.
External
Fuselage
The cabin mea of the upper fuselage down to
below
the
lese:
si
tne
tabin
-..;nG~~ws
:.x%
darnaged heavily
by
fire; below that level the fuselage
ivss
relativeiy
iatact.
The
majoritid
of
the cabin windows were either missing
or
had partially melted
out.
(See
figwes
5
and
4.:
Forward
of
the
aft pressure bulkhead,
the
upper
areas
ai
the cabin
t%e
!eft
aft lavatory was
intact,
but
a
rectangular
area
corresponding
closely
to
the
s:qe
vhdows
viere
disco:ored and burned away in several locations. The fuseiage
skin
above
sf
:he
levatory had been discolored to
dark
brown
and
e
!arge
ares
of
saint
had
3een
b;ir?eb
asay.
The rectangular area
begen
above the
engine
pylon
end
extended
to
?he
top
of
the
Paxiage. (See figures
3
and
4.)
:6p
of
the
Puseiage
wes
damaged heavily by heat and had ken burned away
down
to
the
Forward
of
the
aft
lavatory, between fuselage stiltion
(FS!
929
ad
FS
758:
the
!g?
cf
the
cabin windows. Between
FS
756
and
FS
181,
the fuselage upper
skin
was
inrscl
orit
wt;s
buckled
and discolored
by
hea? at the very
Top
between the
li
o'ciock
an3
2
u'?!c&l;
positions (aft looking forwardj. Between
FS
184
forward to
the cabin
ent:y
door
sco:ini,r
arou!ld
the edges
of
the
lef?
and right
forward
caSin
entrencc
doors,
the
fuselage
t.r5
?!I<!!,
the
upper
skin
of
the fuselage had
burned
sway pertiajly.
Except
for
some
?GrwaX
of
fS
200
was
intacr
wiih
no
apparent
heat or fire damage.
I'here
were thick soot deposits
slong
:he
lower
side
of
the
fiisehge
be.y!r.n!ng
ser-ice
pew1
e?
tS
965.
The
~0'051
palzern
trailed rearward
along
the
airpiu;.c's
side,
..
-;
-Lie
..
:-.
.e.,ir~
r
air
outflow!
vaIve at
FS
945
and
from
around
the
scces5
dcn;
in
the
la.vatoq
-
1
5-
Figure 3.
-
Left
side.
of
the
airplane.
Fiyre
.$.--Left
side
of
the
airplane,
rear
view,
depicting rectangular
burn pattern
.md
scot
trail.
-16-
including the tailcone. The cabin air dump
valve,
at
FS
520.
was open, and light
Soot
deposits trailed
aft
from around ihe edges of the valve. (See figwe
5.)
The lavatory service panel is just
aft
of
the cabin autflow valve. The entire
area
inside the service panel access door was covered witt. soot and a black
tarlike
substance. The thickest deposits were
on
the inside surfac.?
of
the panel access door
adjacent to the vent tuoe and
fiushifil! pipe outlets. (See figxe
6.)
An
area
of
heat
-
damaged fuselage skin was founti about
2
feet above
the
lavatory service panel and adjacent to
the
toilet area of
the
aft
lev8.tory.
The d&mage,
blistered paint, which
was
Ciscolored and blackened, and warped skin. The discolored
srea
which appeared
to
have been caused by
hea?
fram
inside
the
fuselage, consisted
of
extended from aboul
10
inches forward of
to
about
28
inches aft of
FS
1,000
and sxtended
downward
from
the
left
engine
pane! for about
5
inches.
1.12.2
Interior
Fuselage
Forward
of
the
Aft
Lavatory
X11
cockpit wicdorvs and windshield
panels
were intact; the pilot's and first
officer's side windows were open. The entire cockpit area
Lncluding the windows and
switch and
circait breaker pane: and to wire bundles
jus?
forwar6
of
the cockpit
door,
the
windshield panels
was
sooted heavily. Excepi
is?
some heat damage
in
the overhead
cockpit
was
not damaged.
back to
the
aft lavatory
was
either consumed
or
damaged
by
fire. The aisie carpet
was
Except for the cabin
floor
and
the aisle carpet, the entire passenger cabin
covered by debris
but
h8d
not
been discolored or damaged
by
heal.
Of
the
100
passenger
seats, only the seat frames and cushions of
Nos.
i2A
and 12B remained in'act. Seat
Sos.
12A
and
123
are
adjacent
to
the left forward overwing emergency exit whieh
had
been
opened during the passenger evacuation and had been used
as
ac.cess
by
fixmen to apply
water to the fire. The remaining seats were either
completely
or
partiail!:
destroyed
Sy
tk.e
fire
(See figures
7
ard
8.)
4
The
aft
lavatory
steel
potable water
tank
at
i:S
990
reminee
%:act
and
attached
to
i;s ceiling mounts forward
of
the aft 2ressure bulkhead. The overheac Gucllng
behind and a5ove the
tank
was intact; however,
forward
of
the
tenk
the ducting
hsd
been
burned away. Above the
water tankc,
the
fuselage insulation
was
partiall:;
in
place:
however, it was wet and soggy. The
eleet;icai wire bund&
which
were routed around the
water tank were burned forward
of
the tank.
1.12.3
Aft
Lavatory
Area
The
aft
ievetory
was
on
the
left
side
of
the caSin, 2nd
bege?l
at
FS
965
and
exten2ed
aft
to
5's
1019,
or
just forward
of
the aft ?rcssure bukhead. The iavotory's
cutboard
wal: conformed essentixily
to
the shspe
of
the airplane's fcsel8ge. There 'was
a
venity
section cor:teining
a
stainless steel
sink
arid
amenities located
along
and
extending
forxard
from
the
tift
wall. The commocie eontzinlng
B
f!ushlng motor
WAS
iwated
along
the Iavetory's outboard wail.
A
trash
chute and container
were
located below and behind
the sink.
and
a
fresh
air
suppiy
outlet
WAS
positioned
below the sink
in
the door
of
the
?here was an
oxygen outlet located
-1
the oxygen mask campartment
in
tb?
a7ien;;ies
vani?!~.
.%so,
%;ow
the trash cmtainer,
an
alumimm sheif
was
installed.
in
addir'w.
section. See
figures
9
and
:C.!
Q
-
1
T
-
Figure
5.-SOOt
trail
deposits
O
E
.!.eft
side
of
filselage.
a:
lavatory
service
panel
and
outflo,.;
valve.
-18-
e
-.
ri:*re
?.-Cabin
Interior viewed
aft
from the forward
galley
ayes.
Figure 8.-Cabin interior viewed 8.ft
from
the
midwing
erca.
-.
.r.
:'ne
gush
fixer
<&as
Found
inree:.
mounted
in
its
norme!
position,
on
the
I..ma:d
krerior ca3iner
wall
>elow
and
ro
the
ieft
of
the
sink.
The timer's
two
ek?CtriCa!
cmnee:;;s
md
tkei-
respective
wiring
haxesses
were
comec:eS
to
the tiEer. The timer
are
comec:ors
shou~ec'
evidence
of
externai heat
end
smoke damtige
only.
The connectors
'ex
x.xo~2ci
end
aii
meting connections *ere ezanhed.
Xo
damage
wes
observed
at
sny
oi
the connec5o.w. The Fine?
was
rexoved
for
fxther
exernization.
Tie
wirir.g
harness
tkat
su?lies
a-phase
?we?
from
the timer
?o
the
hilet
f;;iSh . .
.
:. z.*-rinet.
The
harness
wa5
undamaged between
:he
timer
and
a
point
..
.
_,
eaenirles
portion
of
the
vaniy;.
The
insulation
hsd
meited
aweg
fro.=
?>.
zne
wiring
harness
secfion
berweez
the
midway
point
and
the
lightenins
->
%.le
iii
xk:e
:he
ha,-~.nss
leaves
t,'.e
vanity
~2.d
connects
to
:he
notor.
The exposed
-
in
:!:is
sectior:
'aey
>?it;;e.
-.
.ne
u-i-:.74
L
.
-
ri3er
*.
"
.e
:his!!
3sttm
was
found
?ertialiy
intact.
The
harness
was
undamaged
in
the area
._.
..
ii&iness
;hat
su7p:ies
ax.
power
fro?.
the
ground
service
bcs
to
i:?e
fxr.
3e
:!=e;
ostjoerd
IO
:he
lower anenities
portion
of
the
vanit?.
From
this
point,
cc,-.:inuiw
watboard
and
l~~~ard
through
?he lightening hole
in
the
vanity,
the
wire
Ixuiatioi:
end
zhe
:+.ires were brittle.
The
harness
was
encasec
in
molten
metal
from the
e::
erid
of
:he
-notor
housing.
across
the
wwi5
of
the
housing,
to
the forward
end
of
the
husing.
:be
kaxess
was
no?
identifiab!e
fro?!,
e
point
jst
forward
of
the
motor
housing
to
sii~?T!:;
I
aft
D?
.where :he
harness
leaves
-
ne
ievarory
iorward bulkhead through
m
over'nc.ec
:ic?;tenirg
-0.
hole.
rron
the overhead iighlening
hole,
the
harness
was
routed
ostsoerl
ecd
Co'ari
:o
:he cabin floor. karying degrees
of
htat demage were observed
on
tie
hbrness
ir.
3%
area.
The re%a:nder
of
the harness,
f-0~
a
point
just
below the
cabin
fic~
forw~r-.
dong
?he left side
of
the
airpiale
10
the
eircui?
b.-cakes
on
;he einctrical
?ewer
conrrol
penel,
was
uncarr.qed.
So
wiring
f:om
:his
fiarwss
to :he
fIush
button
J
-
-
..
.
".
CWJ~C: se
iee!nt:::&-
i
The
5Zh:eEing hole between the amenities sec?ion
end
toilet seelion
through
covering
:;?e
>ole's
suriace
wes
not
found;
however,
Gkis
entire area
%as
demr.ged severe:!
;y
;-.et?:
a?d
fire. ihe brac'.et
supporting
the harness'
nyion
cabk
eiaip
was
ptlrtially
,zeiied
ai*;ay
with
on',
:!e
portior.
of
i5e bracket
that
was
riveted
to
The
+?ruet','re
remaining.
,*.p
'Ab.:
:"'L
.
%.!.L
f.
-
'i
..Ls~
I
XO:O~'S
power
hamess
passes
was
exaxined. The
r,y!on
alligator
gron!!ner
-
.an
elec::ica!
contixity
check
was
;i.,ade
of
t?ie
narness
usfxg
e
vol:-ohm
circuits.
ihe
entire harness could not
be
tested. The harness
SHS
cut
61
a
?oint
5
fee;
rne:er.
Secwse :he insulation
had
burned
off
?he wires
in
certain
t?.-eas
musing
short
ajove
:he ca~in
floor,
just
forward
of
the
aft
leveiory
forward
3i;;khetlc.
Continui:y
XES
onserve6
frcm
this
point
to
the circuit
Sreakers.
There
wus
no evleencc
of
line
-
io
-
line
or
..~e-t~-qrosnd
short
circuits.
/:
-
Electrical splices were
iuund
on
the
power
harness
jas:
aft
of
the
fssh
mo:.or
housi-.~.
:ne
spiices a?peared to be intact
and
elcctrica!
continuity
;*.ris
eirabiished
on
fo~r
of
tt~era.
The rexaining s$ices could not
be
tested
bectisse
there
was
not
sufficient
_.
.*:
.r
-
Frritrzdiq
irom
the splices.
B
Douglas
DC
-
9
installation drrwings. These drawings indicate that
the
harness is roirted
The power krness muting
in
this
airplane differed from tie %kDOnnell
from L\e lightening hole
in
the
vanity: across the inboard side of
the
flush
motor housing,
and around the forward side
of
the
housing. The harness is shown seared with support
across
rhe
outboard side
ai
the
motor housing.
No
support clips
or
cable clamps
were
found around the pump well.
It
coulc!
not be determined
whether
or
not
vibiration induced
insli!ation damage occurred at this point.
.lp,
-
md
ceb!e clamps around
the
pump
*+X.
The harness
in
this airplane
was
routed
The wiring harness associated wit:? the aft
attendanr comrnrnications panel
w~s
examined.
i
number
of
e:ectrieal wire splices %ere found
fgst
above the standpipe
feed
-
through located near the inbosrd end
of
the vanity. This harness and the attendant
pane!
?;ere removed
for
further examination.
Electrical components normally located in the lavatory overhead area were
found
ezong the debris recovered
f:om
the
lavatory
floor
eroand the waste tank.
X1!
components were heaviiy damaged
by
fire. The recovered components inchded porlions
of
the
upper
and
;owe? mirror light assen?bly, :he circuit breakers
and
transformer
to
?he
a3
reading lights. the razor convertor,
and
the eontro! transformer
for
the aft mise&-
laneous
Lights.
.%E
t3e overhead wiring from the aft presswe bulkhead forward
to
the cockpit
we5
severeIy damaged
by
fi-e and heat. The
wiring
thet penetrated the
aft
pressure
vi;!kheed
vas
spliced just forward
of
the bulkhead.
All
of
the spiices observed in
h he
area
of
?he eft pressure Su!ithead and
i.n
tie area
of
the aft lavatory were
accomplished
during
xsars
=ace
;c
the airpiane after the Septeabe:
17,
iS79:
aft pressure bolkhend
sepre:!on
at Logan International Airport?
and
the spiices were nede
in
accorcknce
with
s?c.-ting.
Setzerei sezples
of
electrical
wiring.
al!
of
which were spliced: were removed
service sketch
'2058.
None
of
the
wire
splices
in
these
areas
showed evidence
of
ereing
or
fr~m
;he fo:we;d
side
of
the
pressure
buikhead for furthe: esamination.
Xi
of
the Kire
s?!:ces remw-d and examined appeared
to
eshiSit the
same
degree of extreme
heat
damage. The insulation covering was missing
from
a!!
of
the
splices: however,
no
evidence
of
either e!ectrical arcing
or
shorting
was
observed.
1.12.4
Aft
ACWSSOT~
Compartments
and
Cargo
CXJmpartments
..
The interns! fuselage
of
the aft accessory compartment behind
the
sfr
?.-essere
Sukheed was intact with little evidence
of
heat 6a:nage. The insulation
on
the
3::
side
of
the bulkheed
was
intact
but
discolored. Escepi
for
the
buckling
en<
ZLscoioration that
isas
noted
ix
the area above
the
aft lavatory's vanity, the aft pressu:e
o:Akhead
'xac
intact. The systems, lines, and wiring
were
intact except for
some
slight
hetit
dxmage
I=
the wir;ng nearest the lavatory.
The forward cargo compartment was
fully
intact?
and
there was
no
ev!de::ce of
s:?hcr
fire or
heai
damaze. The rear cargo compartment e!so
was
intact. The fire and
heat
damage
in
this compartment
was
concentrated
in
thk area beiow the
aft
iavatory.
The under floor
bianket insulation along
the
aft tunnei area
of
the
peer
cargo
co!npF.r?nen:
was
scorched
from
the
nf?
pressure bulkhead forward to about
FS
915
end
un&r
:bc
n:t
lavatory
3:
the point where the lavatory's aluminum vent tube was routed.
fro3
132
airplane's centerline outboard to the fuselage
skin.
The heaviest scorching was
This
:ube, which verts air overboard from the lavatory. begins near the
commode
and
beneath
the
toile:
shroud
end
ends at
a
venturi
in
the iavatory service
door.
It enters
the
tmnel
just
aft
of
FS
930
and
is
routed forward to
FS
963
and then
'io
the venturi.
-26-
Between
FS
980
anti
FS
965
the tube is rcdted below
the
thee
geserator feeder
cable
bur.;les.
The vent tgbe had meit.;d
away
to within
6
inches of
its
terminus in the lavatory
service panel. The hydraulic, fuel, arid pneltmatic
lines
routed through this
area
were
intact with
EO
evidence of leakage.
The nylon eondeits encasing the
APU
and
the
left and right generator feeder
cables
from
the aft pressure bulihead
(FS
:a191
to
about
FS
965
were
melted away and
between about
2
inches forward to
8
inches
aft
of
FS
980.
The generator feeder cables
the
insulation
on
the exposed cables was scorched. The most intense scorching occurred
ere routed through two Eghteni'ng holes in a
floor
beam located at
FS
980.
The
APU
and
right generator feeder cables pass tnrough
th?
inboard lightening holes; the left
generator's three feeder cables pass through
the
outboard holes.
A
small
notch, typic31
of
the
type
of
damage resulting from electrical arcing,
was
found in the outboard lower edge
of
tn;.
inboard lightenigg hole adjacent to one of
tie
right generator feeder
cables.
The
frame
?f
the outboard lightening hole was burned away
frsm
around the bGiiOm of the
hole The nylon support clamps for
the
feeder cable bundles were xissing
at
both
IipF Lening holes. The clamp screws
fx
the nylon support clamps were attached at the
in'
X-rd hole, but were discolored
by
heat, .4t the outboard hole, the clamp screws were
n:
;sing
and
the area where they artached was damaged
by
heat
and
par?ially
ba-ned
away.
At
FS
965,
the nylon support clamps for the
APT'
feeder eabies were intact
while
those for the right generator feeder cables
were
only partially intact. The support
clamp for
the left generator
feeder
caSles was missirg: however, the clamp screw
was
on
either lightening hole
at
FS
965. The support clamps were intact and the generator
attached
at
the lig3tening hole. There was some heat dainage,
but
no
evidence
of
arcing
feeder cables were supported properly
at
the remaining lightening holes observed.
Q
generators showed
?hat
each
had been damaged by intense heat in the area between
FS
The examination
of
the feeder cables
of
the two engine
-
driven and
the
APU
965
and
?S
996.
The feeder cables
of
the
right generator showed evidence
of
arcing
near
structures. During the investigation, the support clamps in the lightening holes at
FS
980
FS
990.
The nyion conduits containing :he generator feeder cables are semi
-
rigid, pipelike
were removed from
a
sister DC-9-32. The conduits remained in place and did not contact
the surfaces
of
either lightening hole.
The
feecier cables
of
the engine
-
driven
snd
?he
APU
generators were
disconnected
ai
the generator relays and at the engine and
XPU
firewall connectors.
%hen
testec,
each
line showed continuity and
no
line-to-1ir.e
or
line-to-ground short
circuits were observed.
Eight
-
foot
-
long sections
of
the three generator feeder cable assemblies were
cui
out and removed for closer examination.
Each
feeder cabie assembly exhibited
an
area about
2.5
feet long wherein its nylon conduit had melted away and the insulation
within this melted area was brittle and charred heavily.
Examination
of
the left generator cable showed that the
B
-
and
C
-
phase lines
had areas wherein the insulation had chafed.
A
metal
globule
was
foiind
on
t'nr
exposed
wire
strands
in ?his area. Another chafed aiea
was
in
the C
-
phase line about
112
inch aft
of
the
mete!
globule. There was some melting
of
the wire strands
in
this area; however,
no evidence of arcing was found.
5
-27-
generator feeder cable bundle.
A
metal
globule, similar to
that
noted on
the
left
A
small
area
of chafed insularion was found on the phase
€3
line
of
the right
generator lines, was found
on
the exposed wires.
The areas where
the
metsl globules were found
on
the left and right generzior
lines correspond to where
the
lines appeared to have contacted the
floor
beam structure
)under tne aft lavetory at
FS
980.
The
APU
feeder lines showed
no
evidence of chafed
insulation
or
electrical arcing.
The examination
of
the airplane's electric81 wiring included the components
in
the
electrical and electronics compartment located below the cockpit. This compartment
and the electronic components used for communications, cavigation, and flight control.
inciudes
the
components used for a.c. and d.c. bus power distribution and fault protection,
There
was
light
to
moderate heat, water, and firefighting foam damage observed in the
Compartment; however, the wiring
hamesses showed little heat damage.
All
components
had been disconnected by the firemen, were
in;act. The following were removed
for
were
intact and were mounted properly in their respective racks. The batteries, which
further
testi.ng: the static
inver?er;
tht;
voKage regulators
of
the
three generators; the
lei: and right
geaerator control panels; and
the
ex.
bus
control pane!.
1.12.5
CNckpit
Controls
and
3nstruments
-
The reedings of
the
cockpit instru."nents, the positioning
of
t'le cockpit
ccntrols,
and
the positioning
of
the
switches
in
the cockpit were
also
dccurnented during
a1r siviteh was
off,
the right air Conditioning supply switch was
off,
an2 the left air
the investigation.
Kith
regard to the &ir conditioning and pressurization packs. the rem
conditi0ni.y;
supply
switch was in the
HP
(high pressure) bleed position. The left air
conditioning supply switch was reported originally to have been
in
The
off
position, and
investigators could not determine if the switch had been moved.
1.13
Medical
and
Pathologicactl
Information
Elcod samples were taken
from
the
16
surviving and 23 deceased passengers
and were
enaiyzed
by
the
FAA's
Civil Aeromedical Institute, Oklahoma City, Oklahoma,
indicated that the deceased had elevated carbon monoxide levels ranging from
20
to
63
for
carbon monoxide, cyenide, fluorides, and ethyi alcohol. The results
of
the analyses
percent saturetion; the threshold for carbon monoxide
in
the blood at which incapacitation
occurs is between
:0
and
50
percent saturation. The cyanide levels found in the blood
samples
of
the deceased ranged from a l.%v
3f
0.6
to
a
high of
5.12
mierogrvins/'ml; the
toxic level
fc8r
cyanide
in
the blood at wbich incapacitation occurs
is
between 0.5 and
9.7
microgramsiinl. The fluoride levels ranged
from
410
micrograms/lUO ml
to
63
rnicrograms:100
m!;
however, the significance
of
these fluoride levels is unknown.
Alcohol
levels on three
oi
the deceased were in excess
of
0.10
percent concentration.
Slood
sanples wete taken
from
the survivors about
'2
to 3 hours after
the
accident. The concentrations
Of
carbon monoxide and cyanide
foiind
in
the survivors'
blood
sanrpies were below
0.10
perecnt concentration and
.06
micrograii?siml,
respectively. Fourteen
of
the
IS
survivors'
Dl&
samples tested negative for alcohoi;
the
other
4
samples
tested
beiow 0.10 percent concentration. Kith regard to the blood
alcohol levels, since
i3e blood samples were taken
2
to
3
hours after the accident, these
values may
be
low.
Uiood alcoho: levels dccrease
tlt
about 0.015 percent per hour after
alcohol intake has
ceased.
-28-
County Coroner, and
an
additional
five
under contrsct for Air Canada.
No
evidence of
Autopsies were performed on five bodies
under t5e direction of the Boone
antemortem impact injuries
was
discovered during these examinations.
1.14
Fire
Response
Q
cabin until after the flight had landed and tine survivors had
iett
the airplene. The last
Although the fire on board Flight
797
began in flight: no
one
saw
flames in tine
passengers to depart the airplane through the
left
and right overwing emergency exits
scene
commander stated that some of
his
men went
to
assist the passengers down from
stated that they
saw
flames Immediately after stepping onto the wing. The firefighter on
the
wing and that, at that time, he saw flames in
the
cabin.
797
landed and followed behind
the
flight until the airplane was stopped. According to ?he
The crash
-
fire
-
rescue vehicles entered
runww?
27L
at its approach after Flight
fuel
gauge readings noted during the cockpit documentation, the center
wing
tank
was
ernpty and there were
6,200
pounds and
6,050
pounds
of
jet
-
A fuel
In
the
left and right
wing
main
tanks, respectively. The airplane's fuef
tanks
did not ruptcre and the jet4
fuel
was
not
involved in the fire.
Flight
797
came to a stop about
1920,
and
7
airport cresh-fire-rescue vehicles
containing
13
airport firefighters were
positioneS
st
the airplane. (See table
1.)
Upon
arriving
et
the
aLLp:ane,
the
firemen
saw
heavy
smoke
roXiw
out
of
the
overwing exIis
'
.
and front doors. About
i921,
as
suxiuing passengers and crewmembers were departing
the airplane,
the
firefighters initiated
an
exterior attack
on
the fire. Foa~ was
discharged
fro!n
the turrets on the firetrucks onto the top
c:
the
airplane's fuselage and
on
the ground beneath
it
in order to cool the interior
of
the airplane and to povide e
foam
blanket in case of
a
fuel spi!!. Other firefighters assisted pasenzers at the escape s!ides
Q
an2 helped passengers
off
the
wing to the ground.
%-hen the
on
scene commander ordered an interior attack
on
the fire tc be
airplane through
the
left
forward cabin
door
and overwing window exits.
The
first interior
made for rescue purposes and
to
extir!guish the fire, passenge-s were still letlving
the
etteck
was
made through the left aft window
for
several reasons. According
to
the
on
scene commander who executed the order, he believed that most peopie would try
io
esir
the airplane through the !eft forward
door;
therefore,
he
did
not want
to
Dlock that exit
with a !adder and hose.
ALSO,
with the escape chute deployed. it
would
have been difficult
for
the
firefighters to enter
at
that door with their protective equipment and hoses. The
on
scene c.>mmander t.estified that it would have been
possible,
"
but
it
would have s!o*ed
us
down.''
Tte
on
scene command
-
r
also
testified that
he
wanted
to
enter the
airplene
through the overwing windo~w exits,
"
because we wanted to get
in
between the passengers
and
the
fire
to
make their chances
(to
escape) bettcr."
Within minutes of arriving at the eirplane and
aftar
the passengers were
off
of
?he left wing, two firefighters
momted
the
left
wing
carrying
a
1.5-inch handline, opened
the left
eft
overwing emergency exit, and applied foam into the cabin.
The
firefii;-!?ters
were
wetiring proximity
suits
wilt,
sc1f-conta;ned brcathing apparatus; however. they were
not
wearing the proxi!nity suits' protective hoods bccause the hoods did
not
fit
over their
brcuthing eppnratus.
.Af:er
spp1:jing
the
foam into the cabin,
they
attexpted
to
enter it
throw$ the overwing exit but were drivel? back
by
the intensc smoke
and
ktit.
According
to
one
of
the firefighters;. he did not
see
any flames during this a.ttc:np? to enter the
-29-
Table 1.
-
-
Responding
Airport
Crash Fire Rescue Equipment
Agent Discharge
Vehicles! Capacity Rate
Unit
No.
(gallons)
Crah truck
Unit
907
3,000*
500
AFFF**
750*
Unit
913
3,000
+
750
500
protein
Quick
Reaction
Vehicles
Unit
967
100
AFFF
450
pounds
Purple
K.
***
Engine Companies
Unit
951
1,000* 1,000
Ladder Companies
Unit
960
300*
Ambulances
Unit
964
n!'e
RescQe
Squads
Enit
980
n:a
Quantities
Used
kallons)
3,000
-
3,000
+
0
0
1,000
n;a
n;a
*
Iriaier
**Aqueous
film
forming foam
**+Dry
chemical extinguishing agent
+
Indicates
more
than
the
cited amount
was
used.
-30-
cabin. About
2
to
3
minutes
after
the attempt to
enter
the cabin from
the
wing failed,
the
tailcone
was
jettisoned, and these
two
firefighters, !!sing
a
ladder, entered the
aft
fuselage with
a
1.5
-
inch handline. Thc
rear
pressure
bulkhead door
was
opened;
however,
the firefighters
were
driven back by
the
intense
heat.
The firefighters atteapted to
reenter
the
left
overwing exit and then the forward left cabin door; both attempts were
unsuccessful.
At
1925,
the
on
scene
commander called for firefighting and ambulance
mutual aid assistance.
Altnough the
call
went out
as
"
ambulance only,
"
two firetrucks
arrived on the scene about the
same
time
as
the ambulances. Before the fire
was
extinguished,
12
pieces of firefighting equipment and
53
firefighters had responded in
mutual aid from neighboring towns.
under control.
."
when
water
and extinguishing agent additive were almost exhausted.
According to
the
on
scene commander,
the
firemen
"
had
the
firs pretty well
According
to
the commander, supplies began
ta
run
out zbout
10
minutes after
firefighting efforts were begun, and
at
1952,
the on scene crash
-
fire
-
rescue units depleted
their water supplies. The units
were
replenished :hrough supply lines laid by airport and
mutual aid personnel to a hydrant located abou:
800
feet from the airplene.
At
20i7,
56
minutes after the firefighting
began,
the
fire
was extinguished.
The amount and
t-ype
of
firefighting equipment required at
an
airport is
described in
14
CFR
139.49
arid is based
on
of the iongest airplane having five
or
more
Caify scheduled departures from
the
airport.
At
the tine
of
the
accident,
the
Greater
Cincinneti International Airport was classified as
an
Index C airport. (Index C: airplanes
more than
126
feet
and not more than
160
feet long.) Therefore, the airport fire
depa
-
tment
was
required
to
have one lightweight vehicle providing at least
500
pounds of
1
dry chemical extinguishing agents, or
450
pounds of
dry
chemicals and
50
gallons
of
water
for aqueous fiim forming foam, and two additional self
-
propelled
fire
extinguishing
vehicles.
The total quantity
or'
water
for
foam production required
for
Index
C
is
3,000
gallans.
At
the time
of
the accident, the firefighting equipment at
the
airport exceeded
Standiford Field, Louisville, Kentucky,
is
also classified
as
an
Index C airport.
Index
C
requirements and met those of Index
E
(airplanes more than
200
feet long).
1.15
Survival
Aspects
emergency situations
are
set forth
in
Air Canada Publication
356.
Flight attendants are
The procedures to be followed by Air Canada flight attendants during
directed to
"
secure the nearest appropriate tyDe hand fire extinguisher and immediately
attack
the
fire,
"
and simultaneously to Cali
or
signal another flight attendant to notify the
captain immediately.
..%
flight attendant must maintain continuous communication with
the
captain. The procedures ais0 relate the need to
"
use
the axe to obtain access if
necessary. Rapid access to the
fire
may require local des?ruction
of
various panels.
"
The flight attendant
in
charge testified
that
he had been taught how to use the
fire
axe
during initial training;
howwer,
he
was
not
taught which lavatory panels could be
removed
or
destroyed without endangering critical airplane components. The flight
attendant
irl
charge also testified that
it
was obvious that the fire
was
contained behind
have had to
dzstroy the whole area
of
pa.leling
in
the lavatory
to
"
get to
it.
"
Although the
the lavatory paneling, but that
he
did not consider using the
crash axe because
he
would
procedures
do
not
indicate that :he
use
of
the fire axe
must
be authorized
by
the captain,
the flight attendant in charge testified that since the axe is stowed
in
the cockpit
behind
the
captain's seat,
:here
would be
no
waj
to get the axe without the captain's knowledge.
-31-
Air Canada Publication
356
contains both pictures and descriptions of the
fire
extinguishers used
on
their airp!anes; it also depicts
where
each fire extinguisher is
how
each
fire extinguisher operates and what type extinguishe: should be used to fight
located
on
each airplane operated
by
the company. Publication
356
explains
ana
depicts
different types of fires. With regard
to
a
lavatory fire, Publieation
356
states,
in
part,
chemic81 extinguisher.
"
The publication also contains directims for
the
most gffective
"
Execute
flame
knockdown by repetitive discharges of
a
carbon dioxide
(CO
Or
dry
use
of each type
of
extinguisher. According to the manual,
the
user
of
a
CO
extirguisher
should,
"
AIM
the
gas
at &\e outside edge (of the fire) and
then
in
a
ciking fashion
towards
the
center.
"
All Air Canada flight attendants receive
"
hands on'' training in the
use
of
all
fire extinguishers during initial and recurrent training.
In
addition, during initial
training
they are required to exthguish an actual fire.
presmt in
the
cabin,
the
flight attendants should
"
relocate passengers away from
the
area
Publication
356
also states,
in
part,
that
if excessive smoke md fumes
are
of
severe smoke and
fumes
if possible.
"
The passengers had been moved forward in the
cabin, and
no
passenger was seated farther aft
than
row
12.
The two passengers
in
seats
Nas.
12D
and
12E
refused to .move forward because their
seats
xere
next
to the right
forward overwing exit window. (See figure
12.)
directed aft,
the
smoke appeared to lessen, but shortly thereafter
the
smoke began
to
Once the passengers had been repositioned and the cabin air vents opened
and
increase rapidly. Several passengers stated that
tine
cessation of airflow
from
the
vents
coincided with the increase in the smoke. Other passengers stated
that
it occurred
at
the
beginning
of
the descent or sometime
shortly
after
the
ai.rp:me bezan descending.
B
Air Canada emergency procedures state that the oxygen
inasks
should not he
deployed below
10,000
feet
as
a means of avoiding smoke inhalation. Below
19,000
feet
design
of
the
mask
and
the low altitude,
the
user
is merely breathing ambient cabin
ai?.
less
than
1
liter per minute
is
being supplied through the mask. and therefore, due to
the
The company procedures also state,
"
When fire conditions exist, drcpping the
masks
and
pressurizing
the
oxygen manifold
may
contribute
to
combustion.
"
The procedures further
remove them as soon as practical once the cabin pressure altitude drops below
13,000
note,
':If
!oss
of cabin presswe has caused the masks
to
drop.
. .
.'l
the passengers should
feet.
exit windows after
the
airplane landed and stopped.
None of those designated could recall
The flight attendants designated several
male
passengers to open the overwing
vjhether the attendant had given them specific directions as to how the esits
were
to be
opened. However, nearby passengers recalled hearing a flight
attendapt describing the
operation of the overwing emergency exit
.n.indows. Tinree of
the
four
emergency
operating
and removing
the
window
exits.
overwing
exit windows
were opened by passengers, and none encountered difficulties
in
During descent. the cabin filled
with
black, acrid smoke
froa
tne ceilins down
to about knee
level.
Passenger and flight attendant testimonj and statements indlcated
that all of
the
surviving passengers had covered their faces with either
wet
towels
6istributed
by
the flight attendants
or
urticles
of
clothing. They all attempted to breath
as shallowly
as
possible. and all reported that the smoke hurt their noses, thyoats,
and
chests and caused their eyes to water.
By
the time the ai:'plane landed, they could not
see
?
-ZE-
-33-
1
their hands in front of their faces
while
seated
or
standing. Some of the passengers
said
that
they leaned forward in their seats and
put
their heads down and the:
this
seemed to
relieve
so!ne of the distress they were experiencing. One passenger
was
experiencing
severe distress trying to breathe. He was brought forward and seated on
the
forward
flight attendant
jump
seat, and the flight attendant
in
charge administered oxygen to
him
from the portable bottle.
The
Air
Canada Land Emergency Procedures require the
flight
atterrdant
in
charge to make numerous announcements advising
the
passengers of what they are
rcquired to do during a forthcomirg emergency landing and airplane evacuation. The
announcements include,
in
part,
a description of the brace positions,
the
location of the
doors and exits, instruction to passengers to
remai?
in
their seats until the flight
attendants direct them to move toward the doors and exits, instruction
on
which
exits to
use during the evacuation, information
on
how to get off the airplane
wing
after using
m
exit window, and what to do after leaving the airplane. According
to
company
p-oeedilres, the public address
(PA)
system should be
used
for all announcements before
the airplane
has
been stopped and before the doors and exits have Seen opened,
X
megaphone, which was stowed
in
the right overhead luggage rack above row
b,e
used inside the airplane
if
the PA system
is
not working, and outside the airplane to
2,
was not
put
to use.
Air
Canada emergency procedures state that the
"
megaphone
is
to
give imtructions after the evacuation,
"
and the flight attendant in charge
is
responsible
flight
attendant training, the megaphone
is
not to be used to issue evacuation commands
for removing the megaphone. According Publication
355
and the
Air
Canada director of
orice the ai.>lane
doors
&id
exit windows have beer! opened.
b
charge testified that he tried to
use
the aft
PA
microphone
"
after the smoke subsided and
At
the Safety Board's pubEc hearing into the accident, the flight attendant
in
it
didn't work.
"
He also testified
that
he
had thought of using the megaphone; however,
by
that time the airplane was
in
a steep descent, the smoke
was
advancing rapidly, artd
he
thought
it
wouid have been
"
unwise to waste valuable time.
.
."
to try and go back and get
the megaphone.
The
Air
Canada
DC
-
9
emergency evacustion procedures call for three flight
attendents
on
the airplane.
A
flight attendant in charge is positioned on
the
forward
jump
seat, and he
or
she
is
to open both forward doors and inflate
the
escape slides. The
No.
2
attendant's position
is
in
seet
No.
13C, and he or she
is
responsible for supervising the
remoral of the overwing exit windows and the evacuation through
the
overwing exits. The
directing the passengers to move forward
or
to open the alternate tailcone exit should the
No.
3
attendant's position
is
the aft jumpseat, and he
or
she
is
responsible for either
attendant
is
unable
to
occupy the aft jumpseat, seat
13B
will be used if it
is
available.
other exits be blocked. However, the procedures also state that
if
the
No.
3 flight
Seat
13E
is
the aisle seat
of
the two seats adjacent
to
tbe left eft overwing exit window.
down. When the command was given, the flight attendant
in
charge was seated
in
the
Sometime before landing, the first officer told
the
flight attendants to sit
forward jumpseat aiding a sick passenger, and he stayed
in
that seat. The
No.
2
and
No.
3
flight attendants were distributing wet towels. The
No.
2
flight attendant moved aft and
sat in
an
aisle seat at approximately
row
8;
the
Nc.
3
attendant
sat
in seat
3C.
While
seated
in
3C,
she briefed a passenger in row
2
to restrain the passengers from moving
toward the airplane forward doors until they had
been
opened
end
until he had received
imtructions to move toward and out
of
these doors. Shortly thereafter, she got
up
and
moved aft checking passenger
seatbelts When she reached the vicinity
of
row
9,
she
was
D
-34-
joined by
the
No.
2
attendant, and they
both
moved forward rechecking
seatbeits
and
comforting passengers. When they
reached
the
forward cabin
area,
the
No.
2
flight
attendant
sat
down in row
3C
and remained
there
until
the
airplane landed.
The
No.
3
flight attendant moved aft again. She
sat
down in an
aisle
seat
in rows
7,
8,
01'
9
and
remained in that
seat
until
the airplane landed. While seated, she shouted '*brace"
instructions
'to
the passe~gers before
the
airplane landed. Several passengers said
that
they
heard
these
instructions.
the
ieft forwazd cabin
door,
inflated
the
slide, and sent
a
passenger
seated
on
the
jump
After the airplane landed and stopped,
the
flight attendant in charge opened
seat
down
the
slide.
He then positioned himself in
the
doorway
and
shouted for
the
passengers
to,
"
come
this
way.
"
One
of
the
passengers
recalled
hearing
that
order.
doubtful
if
anyone could draw sufficient
breath
to
shout loud enough to be
heard
at
any
Another passenger testified
that
by
this
time, given
the
conditions in
the
cabin,
it
was
distance.
Warning,
"
Publication
356
states,
"
Flight attendants should do all possible to evacuate
With
regard
to
the
flight attendant's duties during
a
"Land Evacuation
With
everyone, but
&re
not obliged
to
risk
their own lives.
"
The flight attendant in
charge
testified
that
he
stayed in
the
left cabin entrance doorway until no
more
passengers were
corning.
At
that
time,
the
heat
was
becoming
too
intense
to
remain,
and
he
exited
?he
airplane.
The
No.
2
flight attendant went forward after
the
airplane stopped.
She
saw
the attendant
in
charge open the forward door and deploy the slide. She saw
a
male
passenger exit through
the
door, and
she
followed
him
out of
?he
airplane. Thereafter,
she
helped
and
supervised
other
passengers
as
they
left
Lhe
airplene. The
Eo.
3
flight
attendant got
to
her
feet
after
the
airplane stopped. The
smoke
was
so
thick
that
she
could not
see.
She testified
that
she
"
did not think
to
go
back to
the
overwing exits,
so
she
felt
her
way forward.
"
She went
to
the
right forward c&bir! entrance door, opened the
door, and infiated
the
slide. She
stood
in
the
doorway, yelled,
"
Come
this
wey," waited
3
at
the bottom of the
slide and when no
one
came,
she ran around
to
the
left side of the
to
4
seconds, and then
exited
the
airplane down
the
slide.
She
waited
a
couple
of
seconds
airplane
snd began to assist the other crewmembers
in
rendering aid
to
the
survivors.
forward cabin entrance door and
slide;
one
flight
attendant exited through
the
right
Seven passengers
and
two
flight
attendents exited
the
airplam through
the
:eft
forward
door
and slide; four passengers exited through the right forward overwing
exi:
window;
and
six
passengers exited
through
the
left
forward
overwing
emergency
exit
emergency exit window; one passenger exited through
the
right
aft
overwing emergency
smoke
in
the
cabin
was
reportedly
so
thick
that
most
of
the
passengers had to
get
to
the
window. The three
overwing
exit windows
were
opened by designated passengers. The
exits by using
the
scatbacks
to
feel
their way along
the
aisle.
None
of
the
passengers
noticed
if
the
emergency
lights
were
illuminated. Several passengers
said
that,
when they
either bent forward
or
got
on
their
hands and knees, they were
able
to breath and
see
a
little
better,
but
it
was
not
much
of an improvement. One
of
the
passengers who used
an
overwing emergency window exit said
that
she
was
able
to
locate
it
when
she
saw
a
very
dim
glow
of
light
coming through
the
aperture. Another
stated
that
she
was
able
to
locate the overwing emergency exit window
when
she
felt
a
slight draft on
the
back
of
her
knees.
Ddring
the
evacuation, passengers
in
the
seats
2-8,
2
-
E,
3-4
3
-
C,
3
-
E,
5
-
C,
and
8
-
C
exited through the
left
forward cabin door; passengers
in
seats
9
-
E,
10
-
A.
10-B,
II-A,
11-B,
and 113 exited through
the
left
forward overwing window exit; passengers in
-35-
)
and
the
passenger
in
seat
9
-
C
exited through the right aft overwing window exit.
Seats
10
-
E,
11-C,
12
-
D,
and
12
-
E
exited through the right forward overwing window
exit;
Except for two fatalities found in the aisle at rows
14
and
16,
the majority of
the fatalities were found either
in
the aisle
or
seated
in
?ows
2
through
9.
(See figure
12.)
The fatalities at rows
14
and
16
had been seated in seats
8
-
B
and
9
-
B,
respectively.
1.16
Tests
and
Research
1.16.1
Federal
wlreau
of
Investigation
(FBI)
Labwetory
Tests
FBI
laboratory
for analysis: samples
of waste tank water; fiberglass
insulstior. from the
The following items from
the aft lavatory of Flight
797
were delivered to the
aft lavatory; a plastic vial and tag recovered from the lavatory
floor;
an
aluminum shelf;
fiberglass flooring; and soot deposits from the inside of the lavatory service panel access
door.
The results
of
the examination were as follows:
So
flarnnable accele-ants
were identified
on
the items listed above.
The
source of the
qots
on
the fijerglass
flooring could not be determined. The soot deposits conTaineC residues which were
characteristic of a phenolic residue, resulting from
:he
burning
of
phenolic resips such
es
those contained
in
the cabin
and
lavatory walls
and
other materiels.
1.16.2
Electrical
System
Components
The
electrical system components removed
from
:he
f3rwe-d
eiec::onic
compartment beneath the cockpit were tested under Safer?
BoarZ
supe:v:sion
&:
?he
'
Westinghouse Electric Corporation,
Lima,
Ohio.
generator control panels of the
APU
ana the
leh
and right engine
-
driven generators
Functional testing of ?he
8.c.
bus
control panel,
and
:he
voirage
regd1a:o:s
and
showed that these
units
were operational.
printed circuit board had corroded and that the electronic components
on
one
of
the
Inspection
of
the
APU
generator
control
panel r2vealed
thsl
connecxors
on
the
that this
was
damage incurred after landing as a result of the firefighzing activities.
printed circuit boards had been damaged
by
water and foam. The Safety Bozd concluded
differential control
circuitries
in
each of
the panels had detected
fadlts
OF
their
Tests
of
the two engine
-
driven
generator control panels
showed
that
&e
respective a.c. buses, displayed the faults
on
the control panels,
and
then tripped each
generator
off
its
respective
bus.
The differential current circuitry
of
a generator control
panel
is
designed
so
as to trip the associated generator
froin
the line
within
13.1
second
after detecting a
20
-
to 40
-
ampere
fault
current. During the test of the generator
control
par'els, the protective trip occurred
within
the prescribed limits.
The static inverter used
to
provide emergency 8.c. power was tested
functionally
by
the Safety Bard at Air Canada's Maintenance Base, Dorval, Quebec,
was
torn
down for detailed examination and testing. Two
of
the eight power transistors
Canada. The
28
-
volt
d.c. power terminals were found to be short circuited, and
the
unit
were
folrnd
to
be short circuited. When the shorted transistors were replaced, the
short circuits.
inverter
fmctioned normally. Tie Safety Board could not determine the cause cf the
-36-
1.16.3
Flush
Motor
and
Lavatory
Components
components removed from the airplane were taken to Transport Canada% Safety
The flush motor,
flush
motor components, and various oiner electrical
Engineering Laboratory
in
Ottawa,
or
to
Air
Canada's Maintensilce Base, Dorva!
performzd under
the
supervision of Safety Board personnel.
International Airport, Quebec, and examined and tested. The tests and (examinations were
The
X-mys
revealed
no
evidence
of
intexal melting
or
shorting of motor components.
X
-
rays
of
the aft lavatory flush motor were taken before
it
was disassembled.
Solidified melted
metal
was observed which appeared
to
be rnelted motor housing.
Solidified melted metal deposits were removed from inside the motor, below the rotor.
The motor shaft appeared to be encased
in
solidified melted meta!; however,
it
could be
rotated very slightly.
A
wire was
still
attached to a ground
stud
imide the motor. When
electrical arcing observed on
the ground
wire
or
the stud.
the stud
was
removed,
the
wire broke due
to
brittleness. There was no evidence
of
A
portion of the wlidified melted metal which partially encased the stator was
removed,
and
the stator was rotated about
i80".
The fiberglass insulating material aromd
the stator windings and the silicone
glass
was intact but scorched. The stator assembly
was intact and showed
no
visible signs
of
electrical arcing.
When the remainder
of
the solidified melted meta! depo6.t which partially
encased
the stator was removed, two wire segments were found which hhd been encased
so!irce
of
the metal deposit apparentkg was a portion of the motor housing which had
partiall] within it. One additional wire segment was loose under the metal deposit. The
melted, flowed downward, and entrapped the wires between the motor
mountirz flange.
When the metal deposit was removed from the mounting flange,
180°
of
the wire's
circumference was visible.
The fiberglass insulation
on
the visible portion
of
the wire
segments was intact,
but
showed evidence
of
scorching. Wire splices were found
in
the
two wire segments
exased
in
the molten metal as well as
in
the loose wire segment. The
splices were located
just
outside the solidified melted metal deposit.
Xo
evidence
of
electric&] arcing
was
observed
on
the exposed wire segments
or
on
the splices.
X
-
rays
were taken
of
the solidified melted metal deposit and wire segments; the x
-
rays revealed
no
evidence
of
electrical arcing.
4
motor mount and the mounting flange was brittie and scorched. The rem8.ining solidified
The motor
was
removed front
its
mounting flange. The gasket between the
shaft and formed a deposit around the motor mount.
The
mating face
of
the motor mount
melted metal from the motor housing appeared to have flowed down around the rotor
was intact and showed
no
evidence of melting.
The motor's
stator
assembly was removed and inspected. Tne cable clamp
that
routes the power leads from the timer harness to the motor stator was still intact around
attachment point at the
motor
housing could not be found;
it
apparently had melted away.
four
wires. The mounting hardware was still attached to the clamp; however, the
The four power leads
still
were routed to the stator windings. X
-
rays
of
the stator
assembly revealed
no
evidence
of
electrical arcing
or
internal melting.
The
stator
windings, where the power leads were connected, was partially disassembled. The enamel
insulation around the wire used in the stator
wineings had been melted away, and bare
copper wires were exposed.
No
evidence of arcing was observed at the power lead stator
connections
or
in
the stator windings.
-
3
?-
b
sump
we2
next
io
the
motor
mount.
Four
of
the
segments
had
splices
in
them;
the
other
Six
segments
of
wire from the
flrtsh
motor
timer
harness
were
found
i?
the
i.,
L*%o
wires
had
no
splices. The
TWO
wire segments
th&t
had not been spliced were
considerably shorter
than
the
four
segmmts
with
splices. The insulation sleeving
around
the splices appeared to
have
been melted away; however,
the
mechanical connecticins
of
th-
splices were intact. The splices showed
nc
evidence of electrical arcing
or
shorting.
However: three
of
the
wtre
segments showed
signs
of electrical arcing
-
the wire ends
xere melted into the shape
of
a
globule. The metallic globules, which were located
on
the
wire segments
at
the point where :he wires traversed the lightening hole in
the
pa-rition
betTween the toilet and amenities section, were exemined using
e
scannir-x electron
microscope
(SEX!!.
The X
-
ray energy dispersive ana!ysis indicated
tnat
t3ey were copper.
The
ilush
motor
wiring harness
was
examined closely
for
eny
evidence
of
electrical arcing
6amage from
intense
neat.
Except
for
a
small
tear
25
inches
from
the connector,
the
or
shor:ing. The connecto:
ai
:he
flush
timer end of tne harness
showed evidence of
s!eeving
whk>
surrounded the wires was found intact from
the
connector to
a
point
35
inches away. The teflon insulation on the individuai wires within
the
harness was found
intact
from
the connector
to
a
point
38
inches away.
From
tiat point to the end
of
:he
harness, the sieeving snd teflon insulation had melted
away
progressively,
and
toward the
end
of
:he
harness,
Sere wires were exposed.
90
indication of electrical arcing or
shorting
was
observed
on
any
01
the wires.
were removed
from
the cockpit
end
were X
-
rayed, revealing
no
interne! damage. Duriilg
The 5
-
ampere phase--$, phase-B?
and
phase
-
C
flush
moior
circuit breakers
E
Fmctiofia! test, ali three
cir-ui:
breakers tripped
when
the electrical
load
exceeded the
5-empere rating. The circuit breakers were connected to
a
power source and load and
subjected
tc
a 100
-
percent lG-ar,:pere current overload. Only the phase-.$ circuit breaker
esceefed
?he
time
iimit
designased
in
the ;peciiic;itions before
ii
tripped. The Safety
ijoesd
could
no;
Getermine
:he
reason
for
tne failure of the phase-A circuit breaxer to
..lee:
i:s
specifications; however,
all
three circuit brelkers showed evidence
of
aaxage
due
to
ET:
external
heat
source.
B
The
flush
motor
timer
was
exannined.
A
continuity check of
the
timer's
:i.i
.e
-
phsse power
relay
contacts showed that they were open
--
the normal
position
of
~:e
rei?+
when
the
flush
button
is
not engaged.
.>
connect@;
at the timer
to
just
9,iltside and forward
of
the lightening hole
i,;
:he
vanity
A
3
-
foot. 5
-
inch
portion
of
the
flush
timer's
wiring
harness,
from
the
slructure, was removed and examined
for
any evidence of electrical arcing
md
shorting.
T!x
first
2
fee;
of
the sample was relstively intact.
From
a point
2
feet
6
imhes
to
e.
?oint
3
feet
5
inches
from
the connector, the outer insulation
layer
of
the indiviouai wires
hed
Seen yradueliy melted away; however, the fiberglass inner insuiation remained intact.
The wires were
bplre
of
insulation over the iast
5
inches
of
the harness.
end
when
the
ha!.nc.ss
was
removed, the wires broke ciue to
jrittieness.
Xo
evidence
of
arcing or short
circuiting
was
observed
en
any of the wires.
Tne
following electrical components were removed
from
the lavatory
and
examined
for
electrical arcing
and
short circuiting: the lower mirror light assembly, the
upper mirror light
aid
dimming switch assembly,
the
aft
reading
light transformer and
circuit breakers, the razor
outlet converter, the
aft
atteqdant panel, and the
aft
miscellaneous lights control transformer.
A11
Of
these components
and
their associated
evidence
of
electrical
arcing was observed
on
any
of
the
wires.
wiring were
damaged
by heat,
and
portixs
of
some
of
?hem
were missing; however,
no
examina:ion from
the
forward side
of
the
eft
pressure bulkhead.
Al!
of
these semples
!n
addition,
several samples
of
qliced
eieet-ice1 wiring were
reaoved
for
exhibited evidence
of
exposure
to
extre-ely
high
tenperatures. The insuiation eoverirg
was
missing from
a!!
of the
splices; however: no evidence of elccrricsi
arckg
?:
shortirg
was
observed.
1.16.4
Flu*
Motor
Sei-
Test
At
Air Canada's Dorval Ne%tenance
sese,
the Sefeq Board siir.s!af.ed the
conditions produced
by
a
seized
or
:rozen flush sotor assembly driire shaft.
A
Western
Gar
Motor,
;!ode1 353JC2, identicnl
ta
that
on
Flight
797:
was
connected
to
a
tcst
fixture which 2-ovided 115-vcit 8.c. th:ee-phase power through 5
-
ampere circuir breeiiers
anl
the internal motor temperature and motor case temperature were meastired.
connected to the motor power leads. Th,5 rotor shaft was
locked?
the
motor
was
operated.
The
inzernal motor temperature began
to
;ise
9s
soon
as
power
was
e>pliied.
.a:
I
minute
30
seconds
after
power
was
ap?Iied,
smcke
was
visi!;y
emaxting
from
eround
the
~O~OF
cover piate.
At
this
time,
the
motor
temperature
was
331°F.
At
5
minutes
15
seconds
afte-
power
xes
applied, maxiram
rotor
temperalure
or
517'F
iw35
reached.
.-1
few
seconds later, two
phases
of the motor stetor windings epened.
At
7
minutes after power application. maximum
motor
case temperaturel
405*
F,
was
reached.
at
which
time
both
rotor
and
case temperature
I
began
to
decrease.
Bozh
temperatures
continued
to
decrease
until
the test was terminated.
it
27
ininures
16
seconds
afze:
power eppiication,
the
reiliaining motor
stator
windip!
opened. Since no further curent
-o:or
temperaiure observed
at
this point
was
546'F
and
the
case
temperature
WES
374"F.
2o;v
'was observed in
any
of
the
three
-
phase motor leads, the test
w6s
terminated. The
The
S-empere cixul: breekers
did
not :rip during
the
test. The maximum current
flow
recorded during the tes:
was
1.85 entpe-es per ;?base.
After the inntor assembly cooled. it was examined. Examination revealed
the;
the
rotor
%'as
heavily darkcned around
the
circumference
of
the rotor
area
which &!igns
the stator. The rotor
was
intact and appeared undamaged. The stator eshibited
t?
heavily darkened area around its circumference where
it
aligned with the
roior.
S-~eys
of
:he
staior
did
no?
reveal
any
in;ernei electrical arcing
or
melting.
guring
tke
investiga-aiion. the Safety Board conducted flemn>a5i!ity tests on
the
xaterials
contained
in
the
Heath Tecna
cabin
interior assembly kit.
in
addition, tests
com20nen:sl Eush
motor
pump
components. wiring bundies, wire insulation. and
waste
A.,.
eoncwtcd
to determine the effecs
of
fire
and.!or
heat
flus
on
DC
-
9
-
32 lavatory
Jersey.
zx:erials. These tests were ccnducted at
:he
F.4A
Technical Center. Pomona.
Sew
.
'p'e
Cs3-n
Siateriais
Burn
Tests.
-
-
The mate-ials contained
in
?he Heath Teem Kit
(See
sppendis
F.)
X1
of
the materials tested met prescribed
si;anda.-ds.
were
subjectel
to the cuxent standard Runsen Burner tests
as
set
inrth
in
11
CFR
25.853.
A
piece
of
poiyurethene seat cushion,
similar
both
in
time
of
service
find
ir:
cornomition
io
:he
seat cushions
on
Flight
797,
was
subjected
to
vertical and
h0rizon:r.i
Sunsen
Burner
tes?s.
The materia! fai!ed the ver:ical test Stit passed the
horizonftk!
test.
-39-
t
-.
:.qe
FAA
project
manage;
in
cherge of fuli-scale fire
testing
a%
:he
TecPaical Ceczer
was
asked
why
~e materia!
had
failed
the :est ar':er
only
18
mon:hs
in
service. He speculated
becaxse
of
the effects
of
wear
and
body
mckstxe
on
t$e ouxe? surfece.
He
Testified
81
128:
:he
partieuier
piece
of
foan
res:ed hac
10s:
some
.~f
its
:^ire-reiardant
capkdities
the
80.~rd3
public hearing
that
Center
technicians
had
encountered
sim!laar
failures
whet
testirtg older seat
cushion
materials ana
*ha7
he
did
not
3elieve
~hal
L5e depraded
eape3i:iry
of
the
seat
cushion
would
have
cont;ibu:el
to
the
propagation
of
:3e Ire
OR
-.
Eight
737.
line
similar to
the
ope that
had
melted
thrmgh
on
Flight
79;
'ha
evskared.
.X
sample
Cold
Air
Su~~iy
Line Tesrs.--'Ths susce$ibiii:y
io
heat
of
a
cold
aii
sup?Iy
co!d
ak
sspp!y
line
was
piaces
near
m
ekcct-icgliy poxered
;heat
elerner,r capble
of
pr0.?3cing
a
radiant hea:
2u.u
of
about
7
l5TL':ft--sec. The amount
of
heat
fP~x
wes
conrmlled
by
Fiacirg
tine subject line
at
predeternined dis:en.ces
from
%e heat socrce.
The
cold
air
suppi;:
line
was
ctlpped
at
one end.
and
as
the line >ea:edt
e
conslen?
internal
ahminun
cold
air
supply
Erie
was
held stationary
for
about
15
minztes
unt!i
there
wes
no
pTesure
of
1
psi
was
maintained
by
a:snuaLy
opening
a
reiief valve.
3tirkng
each test, the
no?iceab!e increase
ef
pressure
witfin
the
!;ne.
..
Tpzee
tests
x$re conduc;ed.
Ths
heel
fluxes
in
the
eole
air suppiy line were
abcui
2.
5, and
7
3TU.lEt-sec.
There
WES
20
eitiiience
of
heat
&.=age
io
the
iir,e
and
;hardness
test resui% showeS
:ha:
the
line
remeined within
its
spsciiied
to?er&nces.
paper
towels
were
cmnpled
by
hand
and
ignited
by
a
.ne<ch. end
t3e,
hear
flus
was
The
i3Tt"s
generaled
from
oumixg
paper Iowek were
also
evaluated. Three
measured.
The
zaximurx
r.ersured hear
flux
w?s
abcu:
1
BTC:ft--sec.
and
the
1
te-nperatxe
was
about
1.2000~.
The
heat
generated
Dy
wrnirg
toweis
with
and
without
airflow
was
also evaituetea: the
nasimxm
he.at
flus
rerna!.ned
e;
4
I3Tc.:rt"-sec.
,-
).
9
constructed
with
actus!
airoitine
hardviare.
Tests
were conducted
io
esD!ore
:he
effects
CC-9-32
Lavatory
Mwbp
%sts.--A
partial
DC
-
9
-
32
'kvatory
was
of
3dian:
heat from
a
toilet
fhsh
nlotcr
on
adjscenr
!av~:ory
components. en6
the
et
various
iocetions
wiihin
the
~OCPJ~
to
nozitx
temperatures.
So
air
flow
wes
used
for
effects
ef
fire
impinging
on
the
f!ush
sFstcm
power ,iar!less. Thermocoupies
were
placed
these.
tests.
first
tcs.
!n
order
X.
si=u!zte
an
ow-hexted
motor
cmditior,, the
rotor
shaft
was
A
Viesterr, Gear
Fish
Motor.
iicdei
353:Cl.
Serial
Yo.
2384.
wes
used
in
the
cast
eiam:num
mounting
flange
and
instaikd
in
the
waste
tunk.
Exeep?
for
the
restriction
mechanicaUy
restricted. The motor
was
then
mounted
on
II
pur:?
asse-bly
utilizing
a
of
the
rotor
shait
ro1e:icn.
these
concitions
sj:nulsted
~xBc:!~
Ihc
assezbl>-
of
the
acciden?
airpiene.
Three-;rhase
ll5-volt
kc..
303
!iz
power
ifas
supp:i?d
<a
the
!nolo:
through
B
power
supp1y
end
of
i?e
harries
was
protected
by
the
use
of
rhree
5-axpcre
ci.:cuiil
wiring
harness
0:'
the
same
length
and
type
er
that
ins:aXed
in
:he
accident
sirptane.
The
breakers.
The
wiring
harnezs
in
?he
!ev81ory
mocku?
as
rcu:ed
sinilariy
:o
the
jrls:aflaiion
in
the accident tiirpianc.
t:
fiush
ti3ner
WYS
not
u.sed
fo:
this
test;
however.
the
power
harness
was
route6
io
the
!oca:inn.
in
the
vani:y,
where
the
tir-er
was
installed.
The
power
harness
was
meted
to
:he
flush
mctor
:hrough
fiw
use
of
H
jumction
box
a3d
noxnaily
used connectors.
-4F-
the
?IO:O:
had
failed open. Light smoke
was
oSserved coming
from
the toilet
Sow!
about
5
Three-?hase power was applied to *&e
motor
until
el!
th?ee
stator
windings
of
niirttes
<j
seconds into
the
Zest.
Subsequently. the
phase--k,
-
B,
enl
-C
stator
windings
fsiied open
at
6
minutes
4C
seconds,
17
minutes
45
seconds, and
11
minutes
25
seconds,
Pes9ec:ively. The xevimum notor case ternperature
--
431°F
-
-
was
reached
at
9
a!nxes
45
seconds
after
power was
&?plied.
The
rnexirnurr.
tespe:a:ure
on
en
aijacent
lavatory cozponent
(toilet
shroudj
of
15'Z°F
was
reacheo
12
minutes
55
seconds after
potve?
was
a;plie& Twenty
-
five minutes
of
data
was
recorded
at
which rime the
test
was
vanity
or
wese
tmk
components
was
observed.
*
-
-
.c:
;nine:&.
So
evidence
of
any deformsrion. discoloration,
or
overheating
of
any
or'
the
resid
-
e
.xes
found
jelovi the motor cese on the mounting flange. When the
cop
cover $ere
The
flush
rnotor
'&as
removed
fro=
tAe lavatory
mockup
and exaFined.
Oiiy
of
:he
zotor
xas
reno.$&, evidence
of
over5eathg of the ccver gesket, rotor,
end
stator
assexSiies
was
apparent. The
lotor
eppeared locked when
hand
ro'arion wrs attempted;
cii:
:%her:
adfitiocal
torque
was applied
to
the
shaft,
the
rotor
turned freely. Tie
rotor
asse:nSIy
was
removed
end
evidence of arciq
at
numerous
FoinZs
along
its
?OD
outboa:-d
fees
i
observed. The
stator
assernbiy
was
removed
fro=
the
motor
cese
and
exsmined.
oSsexeC.
.I?.
e!ectrical
continuity check
was
mede
of
the
stator
~indings;
no
continuity
lze
!o;ver
gasitex under
the
stator
assembly
was
intaci.;
however. oily
residue
xas
'xes
c3serviid
$xse-:c-phase
or
each phase-?o-neutrei. However? there was high
resistance
ccnanu!ty
Serxeen the phase
-
5 winding
to
?he
stator
assembiy case,
and
the
25se-C
wirdini;
LO
the csse. lhese resistance reedings were greater than
2
megohms
ana
i.3
xeg:oh;;.s. respectiveiy. The wire harness
which
provides power
to
the
stator
assernbiy
snowed
no
sIgn
af
damage.
.~-
-.
..
,..
I?
?he seccnd test.
e
flush
motor housing
containing
a
coctroZeSle electric
-.-t::iq
??e:?efit
v;es
piaced
in
the waste tank
in
the
levatory
mockup. The voltage
to
the
.?eating
eier.en:
wes
then
increased
until
?he
texperi:tsre
on
the
outside
the
mo;or
case
:efickeG
e
~!fi.ximum
or'
siighrly
above
800°F.
This ternpert!ture excaeds
Sy
netlriv
100
2ercen:
the highest te.x?eralure tht
has
been
reporred
on
:his type
of
ino~or.
The
?:&nun
iempera:;ire
of
893°F
wes
?erc,'led
42
n:ix?es
into
',?e
test.
.C,X::;-:OLLT
m:inales
inro
?he test,
the
maxiz~u-
ter+we:ure
on
2x1
edjaceait
i~a?~;:;
?orr.:.;onent
--
:he
roiIet
shraud
--
had
reached
255'F.
Pocxcr
was
re.rovei:
f?oz>
the
herrifig
eIe!ne?:.
area
ir.
the:
u't
otitooa-d
corner
of
:he
Ici!et
shroud
di:ee:ly
aoo':e
ttx
f!ush
motor.
This
The
on;:<
oo.se-v:?3le
chsnge
?o
any
:ttva:ory
eor;:poneni
KES
In
a
5-inch-sqcere
rea
'ms
,xf;r:ce:
qwrd
!o
a
he@t
2
IT4
inches
above
the
shrew3
support
Sracke:
on
Gefor?:a:;on
0:'
ti:e
shroud:
ho.sever.
some
adhesive
!?a:eriel.
used
to
bond
8
double:
to
.;,e
forwr-6
face
0:'
the
vk1ni:y.
There
xes
no
di:,~o!ord:lon.
meiting,
or
an!:
other
the
mdersice
0:'
:he
s3:o-d
smxd
?he
:oile:
ho~l
ci1toijt,
<!owed
from
the
bond
!ine
end
dri;pec
onto
the
iiusi
!not~r
ccse.
Tne
udhcsive
also
gripped
onte
'.he
elfisTorneric
hose
rmcing
:703;
the
:':us:;
?dm:,
ntcurting
f!ange
to
the
toilet
bowl.
$,.
The
.?KJ:o~
cese
rezioined
inzact:
however. obvious signs
of
overheating
were
?resent.
The
naz:c
piate
on
the
!OD
cover
was
con?p!ete!y
biackeried.
snd
the
:?side
of
:he
cover
was
brown
sr~uw!
the
outer
edge,
becomipz lighter
toward
the
cente;.
?Ixsh
'40t0r
Poive:
iiarness
Fire
Test.--.*
test
fixture
was
construcLed using
a
pic:e
oi
0.033-inch sheet
clczinux
21
;;'2
inckcs
>y
6
inches.
1
i
2
-
inch
dirnleter
iigi,tr?r!hg ho!e
was cut
in
the fixture,
NT;
ulligetor
grommet
was
i?sh;!?G around
the
-41-
lightening hole, end
E
nylon cable clamp
'-.as
installed above
the
hole.
A
flush
system
power harness
end
e
flush motor harness supported by the cable clamp
were
routed
through the lightening hole perpendicular
to
the
test
fixture.
This
configuration simulated
outboard forward vanity
area
of
the
accident airplane.
the lavatory vanity structure, lightening hole,
and
flush
syste-
wire routing in the
lower
The flush system primary power
harness
used
for
this
test
consisted
of
eight
conductors of
.?IIL-W-5086
type wire bundled in heat shrink tubing. One end
of
the
ground. The harness
was
protected through
the
use
of
three
5
-
ampere circuit breskers
harness
was
connected
to
a
115
-
volt 8.c.: 3-phase,
400
-
Hz
electrical power source and
to
connected at the power supply end
of
the circuit. The other end
of
the
harness
was
not
connected
so
9s
to
simulate
power being supplied to
a
flush timer that
was
not wtivated
iiiush
jiitton not pushed).
Tie
test
fixture was electrically grounded
io
the
same
point
as
:'?e
namess.
A
portable p?opane torch
was
used
as
the heat
source.
The torch
was
produce
a
9roeder flame pattern. The torch was adjusted
so
Chat
the
flame's vzrtica:
?ositioned mder the fixture aqd
the
nozzle
was
removed from
the
torch
in
order
to
heig?.t covered
the
entire height
of
the
test
fixture
End
the
width
of
:he
flame
was
sufficient to cover the diameter
of
the lightening hoie e:id adjacent structure.
Three
-
phase
8.1.
power
xas
applied to
the
tesi fixture, and the
test
began
when
the
2,ropsne
:orch
bas
placed under
the
test fixture. After
28
seconds, the nylon
caole clamp began to melt and drip. After
40
seconds, the wire bundles
fen
and rested
on
the
5ot:orn
of
the lightening hole. At
4
minrrtes
7
seconds into
the
test, zudible arcing
WP.S
hem3
and
e!ec:rical arcing
WPS
visibie where the xire bundles contacted the boxtom
oi
the
li@teEing hole.
Less
thsn
a
second later,
all
three circuit breakers tripped
in
rapid
successio;?.
The flame irnpinging on the power harness
and
flush
motor
harness
se'if-extinpished.
The
heat
generated
by
the
torch
was
measured using
e.
csiorimeter
ar.d
thermoi;oup!e. The heat
flux
from the flame
aree
that
impinbdd
on
the
wires
was
4.4
STC!Ft--sec
ar
a
temperature
of
1,650°io
1,700°F.
.I
continuity check
was
rnade
of
the
power harness before it
was
removed
from
the
test
iixrux.
Phase B
-
to
-
ground measured
175
ohm.,
and phase C
-
to
-
ground
zecisured
YO
ohms.
30th wiring harnesses were removet
from
the
test fixture
and
examined. The
actually burned wes
1
318
inches. The area
of
the harness
that
had burned through was
?owe:
hainess
was
discolored
for
about
2
114
inches. The iength
of
harness that
was
examined
unckr
high msgr.ification.
At
least one conductor clearly showed evidence
of
electricai
ercizg
-
-
A
copper bail codid
be
seen
on
the wire. The
fhsh
motor
harness
was
Ciseolored
for
2
inches and
was
actualiy Surned for about
3/4
inch.
Chace Tests
of
the
Flush
Motor P,Jwer Harness.
--
The Safety
Board
conducted
exemplar
power harness
from
sn
Air
Canada
DC
-
9.
In
order to
simukte
a
flush timer
in
chafe tests
of
the
flush
motor
wiring
harness
at
:he
FAX
Technical Center
using
an
its
normal state
with
8
deacrivated
flush
tztton,
the
harness
was
powered; however,
no
lmt
was connected. The
harnc::
was
routed through the lightening hoie between
the
arnenities
and
toilet sections
and
then
pullc.6
back and forth vigorously through the hole
by
t'ao persons. During
the
pulling, which encompassed
a
aistance
of
2
inches,
a
heavy
I
doivnward
force was exerted
again:'
the s'.ructure
of
the lightening hole.
-12-
The first chafe
test
was
conducted with the
nylon
alligator
grommet around
cover of the harness was penetrated. The outer nylon insulation
of
two
of
the eight wires
the
surface
cf
the lightening hole.
After
1,:
nintites of rubbing,
the
outer heat
shrirk
in the harness had been chafed slightly; however,
the
insulation had not been penetrated.
The
same
test
was
conducted with the alligator gronnet removed. After
2
outer insulation of one wire
was
chafed. After
3
minutes,
the
insulation of one wire
was
minutes of rubbing.,
the
heat shrink outer covering had been penetrated and
the
nylon
penetrated exposing bare conductors; however, no electrical activity was observed. After
4
minutes, the exposed
wire
broke.
After
about
8
minutes, electrical arcing occurred
between another wire in the harness and the structure
of
the lightening hole. but none of
the
circuit breakers tripped. The
test
was resumed, and
2
seconds later,
the
exposed wire
severed a?
the
point
of
contact with
the
lightening hole. The phase
-
B circuit
breaker
tripped simultaneously
wi.th
the severing
of
the
wire.
The
rnethcd used to expose the
wires
in
tre
harness
auriTg
the
two tests
was
not intended
to
duplicate what xould
occur
during actual operatip3 conditions had either
light
weigat
of
the
harries,
even
had the support and
thc
grommet Seen
nissing,
the
the
hamess
support feiied,
or
had
the
alligalcir
grommet
beec missing,
or
both.
Given
the
hamess wou!d not trave
oem
subjected to the abuse during ectual operating conditio'm
tia: it was subjected to during the tests. The
tests
were conducted to deterxine
what
would
occur
!I
:he
wires
!n
the harness 'were exposed
ar.d
to determine the effo:: required
to
abrade
the
i.lsu!arion
and
chefe
the
wires.
."
1.16.6
Airplane
Cabin
Pipe
Research
dynamic
range
of
condirions present in
actual
cabin
fires.
Consequer!tly. about
1978,
tie
Small
scale individual fire tests of cabin materials
do
not
replicate
the
FAA
instituted a research program
at
its Technical Center involving fuii scale cabin fire
tesis. The
tests
are conducted
in
i!
full
scsle,
wide
-
body test platform, constructed from
e
surplus McDonnell Douglas
C
-
133
airplane. The purpose
of
the tests
has
been
to
understand
ana
demonstrate the behavior
of
cabin materials
in
a ?OStCreSh fire. The
results
of
these
tests
*ere described at the Safety Board's public hearins
by
the FAA
project
rnafiager in charge
of
fitil-seale fire testing and are
also
contained
in
the
Advisory
Group
for
Aerospece Research and Development
(.%GARD)
Report
LS-123,
".4ircraft Fire
Safety.
"
Of
particular relevance
to
this accident we those data relsting
to
flashover,
fleshfire,
seet-5Iockiw. and cabin hezevds crested
by
burning interior materials.
The
FAA
p:ojec:
manager testified that two
main
phenomena
occur
when
:arge
fires
are expanding; one
is
?he
C!ashover,
the
other
is
flashtire, and mosi often. they
occur
in
combinatioil. Flashover
in
a.n
airplane cabin environment occurs w>en enough
heat
cas
buiit
up
along the ceiling
so
that the radiant
flux
down to the materials below the
heat
layer
reaches
a
level thzt
is
high enough to cause an almost instantaneous igni:ion
of
the zaterial.
F.4A
resesrch
has
indicated
thar
fleshover produces nonsurvivable
conditions throughout the cabin within
a
mutter
of
seconds.
Flashfire
is
the burning
of
combustible gases. According to the
FAA
project
mmager,
it
"
is really
a
mild explosion.
"
Flashfire occurs
when
materials
in
a
iocalized
area burn and emit combustible gases. The combiistible gases,
a
result
of
incomplete
combustion, accumulate
until
they reach
a
flamm3bie limit and
wit;,
if
there
is
a
source
cf
ignition, ignite. The
resultant fire
will
propagate
rapidly,
usually
fit
the
ceiling
where
;he
comblustible
gases
have collected. With regard to
the
ignition so'drcet
the
FA.\
project
-43-
conditions inside rhe cabin
will jecome
nonsurviveble within
a
metier
of
seconds.
Since
manager testified
that
the
fire itself
usually provided the
source
of
ignition.
Again,
flashr^ire
is
dependent
on
the concentration
05
heat and combustible
gases
in
the upper
levels
of
a
cabin, airflow through the cabin would redlrce the buildu? levels
-iy
dispersing
and
venting sone
of
the products overboard. The
FA.%
project manager testifiee
that
airflow
through
a
cabin would have
a
"
vast influence
on
delaying
"
a
flashfire.
above
flmr
levei
on
survivability. The model tekes into consideration the effects
of
heat.
The
AGXRC
Report presents
a
survival model relating ?ne effect
of
height
carbon
dioxidel carbon monoxide, hydrogen cyanide,
and
irritent Reid gases
such
es
hydrogen fluoride and hydrogen chloride. The report states that the survival model
is
hypoZhetical and its main purpose
is
to provide
a
means
of
predic?ing the
time*;^-
incapacitalion within
a
fire enclosure based
on
measures
of
elevated temperaxre and
toxic gas concentration which change, in some
cases
substantially.
with
time. Thus? it
is
a
cogent parameter:
time
-
to
-
incapacitation,
or
the hypothetical time at which
an
average
tooi
for reducing
a
fairly large number
of
somewhat abstract meas.i:ements into
a
single,
individual
can
no
longer escape unassisted.
Hoiv
well the model relates to escape
potential
under actual fire Conditions is unknown and, realistically, cannot be determined.
It has been
long
recxnized that a zone
of
safzty exists near the
floor
insi,?e an enclcsufe
hazards
at three eleva:ions
and
cakulating the survival time at each elevation. The
in
which there
is
a
fire. The validity
of
this belief was examined
by
meexring the major
at
5
feet
6
inches were
202
;econds,
193
seconds,
end
is9
seconds, respectively.
l:!
calculated
data
shou;ed that the survival times at
1
fee:
6
inches, at
3
fee:
6
inches,
and
-
Air Canada flightcrew's normal, abnorma!: and emergency operational
procedures are contained
in
its
DC
-
9
Airplane Operating Manual
(-403.1).
In
addi?ion to
?he flightcrew's normal, abnormal,
and
emergency procedures, the
AOM
conta'u
descriptions
of,
and procedures
for,
cperating the airplane's systems and components.
Unless otherwise noted,
ali procedures cite@
or
excerpted herein are from the
XOX.
electrical po"er
Cor
?he airp!ene.
A
t>id
ax.
genera:or,
driven
by
the
APL',
serves
as
a
Electrical System.
-
-
Two
X.C.
generators, one
on
each engine. provide
standby
A.C.
electrical power source when the airplane
is
in
flight. Four iransformer
rectifier
(TK)
units transform
and
rectify ?he ax. power output
of
the generators to
provide
a
supp!y for all d.c. operated services
and
units. Autonaiic protective ciwuits
ennmciator penel lights located
on
the annunciator panel
will
indicate these conditions
to
will
isolate
ttne
affecte5
pert
of
the kc. system
if
certain faults occur and advisory
The flightcrew.
of
the d.c. distriSu?ion systems
under
ceruin abnormal conditions
and
the batteries
art
T;po
nickel cadmium [Xicad) batteries are instal:ed
ic
supply
a
limited
portion
maintained in
a
charged
condition
by
a
battery charger unit.
in the
event
a11
H.C.
generating capability
is
lost, the flightcrew cen piace the
emergency power switch to
"
on
"
and route battery power
to
the
emergency
d.c.
bus and
emergency inverter.
The
emergency inverter,
in
iUrn.
pov;ers
the emergency 8.c. bus and
provides
8.c. power
to
essential airp!ane components
anlong
which
are
the
oirpiane's
rrtitude and heading
indiaxting
instr.'
,merits.
-
11:
?.GARD
Report
LS-1;?3,
page
5-18,
Figures Y(a)
md
9(3).
when
tripiped, cannot
be
electrically reset until cooled. Those
,mi'
,
requiring threeThese
Individual units are protected
Sy
individual trip-fzee circuit breakers. These,
supply
wiir
have individual breakers in
ech
phase.
of
circuit Sreaker
t~ipis)
are contained
in
the
abnormal operation section
of
the
+ION.
Ekctrical System Abnorinalities.-The procedures to
be
followed
in
the event
reset
rt~y
tripped circuit breaker. The procedure notes that it
may
be
necessary
T
O
aliow
Uniess directed otherwise
in
e
specific
abnorma!
operation, the pilots
may
ailezpt
to
about
3
xinutes cooling
time
before
a
circuit breaker
will
reset.
I?
also states,
"If
the
breaker
will
not
!etch
or
trips immediately efter reset, leave the
breaker
open (oGt>.'T
Tne
xocedure
also
contains the io!lowing note,
"
Ail
circuit breakers protectirg
a
singie
pbse
ere
trip
free.
;Ianu.aily
holding in
a
breaker which
will
not
latch.
will
not
comp1e:e
a
circuit.-
The
Air Ceneda ?,!anager
of
Fly!%
Operations testified that
if
a
circuir
breaker cannot be reset, flightcrews are instructed
to
wait
for
!'an
appropriate
cm?ing
period
"
&?d
ihen
I-;
lo
rese:
it.
If
the reset
fails?
the circuit breaker
is
:efr
OUL
He
Xestified that
"
no
nore investigation is required because
the
eleccrica; ?oiver
to
ihe
inalfim.ct:oni.ng
circuir has
been
cut
off
and
you
don?
want
to
do
anything
th6?
might
restore
ir:'
*
<e'*.c';
ihe
emergency procedures sectior.
of
the
manus!
contains
2
checkiist
for
~~-~.nc
the source
0:'
electricai
smoke
or
fire.
The
4-p~ge
checkiis: essen?';a!ly requi-es
the
pi!o:s
to
skt
down each
of
the
eirplane's
eiecrrical
system.
assess the
quantity
of
smoke, and then
turn
on each
wmponent
of
the
system
one
ai
a
tine
in order
?P
izscertain
a-hich co.npor.ent
is
the
source
of
the
smoke.
Smoke P,emova: Procedures.--The fol!ou;ing
aonormal
procedures
concern
the
remove!
of
smoke
from
either the cocQit
or
:he passenger
cebin
of
the ei-piane:
The procedure
used
9;
Air
Canada
for
removing
smoke
from
the
passenger
developed
by
?dcDonnel!
Douglas.
its
!IC-9
cabin
smoke
remove! test flights
sh3wed
tha:
.cabin
by
opening
the
right
forward
ga!!ey
door
and
eft
??essure
Sa!khead
630:
:*?as
when
the
risht
forward
galley
service
door
md
the
aft
?resure bulkhead door werz
unseated.
smoke
introduced
intrr
the
?aDin
by
smoke generators was forced
forward
end
airfl0.w
ou3,de
the
two
doors.
The
higher
loce!
airflow
outside the
galiey
service door
out
of
the
@!ey
service door. Tiis
flow
patter:, was
:ie
resulz
of
the differenrial
in
arnbient pressure
inside
the tagcone
at
the
aft
presswe bulkhead
door,
thus forcing the
prcduccd
a
lower outside ambient pressure
ai
the
galley service
door
rel&tive
:o
the
smoke
forward
end
out
:he
ga:ley
service door. The procedure
was
presented
LC
the
FSL
for
approval
as
an
emergency procedure
end
was
rejected.
.According to the
F.4.4
DC-Y
project manager
test
piiot,
FAA
disapproval
was
not
based
on
the efficecy
of
the smoke
removal capabiiity,
but
on
the
fac:
that
it
required
B
flight
crewmember
io
leave
the
cockpit
lo
operate
the
doors during
a
period wherein it believed
his
presence
was
recjui:ed
in
the
cockpit. According to the
??st
pilot,
the
FAA
fligh:
test personnel weze
not
euthorized
to
judge
&tether
or
no!
the
door
operation
co~ld
be
performed
by Eight
attendants: therefore,
based
on
the foregoing, the procedure
was
disappyoved.
iiowever.
operators as a nanufrcturer's rt:co!nmended proce&re. McDonneI!
:)ouglas
provided
the
the
regufations
did
not
prec:ude
the
manufacturer
from
providing the
procedure
to
DC-9
procedure
to
its
DC-9
operators, and
Air
Canada,
with
tile approval
of
Transport
CantIda.
incorporated the procedure
in
its
,404:.
During the public hearing, a fire protection engineer who had participated in
the
on~cene investigation as a member of
the
Safety Board's structures group testified
tha?
in
his
opinion,
if
these doors had been opened as envisioned
in
the abnormal
procedure,
"
there's a very strong potential that (the forward airf!ow) would have pulled
the
fire out
of
the
lavatory into tne cabin and certainly would have moved the smoke
forward and faster over the passengers heads.
"
He stated that it would have endangered
the passengers and also the safety of the airplane.
?he company
did
not
advocate using the cabin smoke removal procedure unless
the
fire
According
to the captain,
and
;he
.4ir Canada manager
of
flight operstions,
was
out. The captain ah9 testified that the procedure required the first officer to leave
:he cock?il
in
order
to
either supervise the opening of the doors or
to
open them.
In
the
circumstances of
the
accident flight, given the airplane's electrical and mechanical
2robiems, he Selieved the firs1 officer was needed
in
the cockpit. Therefore, the captain
did not consider ordering the crew to
use
the cabin smoke removal procedure.
Exergency Descent Procedures
B
EMERGENCY
DESCENT
If
muclu~~!
;n!aOrih
!I
cn
doubt.
limit
-d
as
much
as
*
IGN
Selector
OVERRIOE
*
CABINSIGkS
.......................
ON
*
KJTOP!iDT
......................
OFF
wsaqe
and
BVOIG
nioh
maPewarin0
13ear
.......................
THRO~~LES
......................
C
L
O
S
E
*
SPEEDBRAXES
.... .........
....
CXTENC
8
Inir~arsihscrn!
...........
0
76
H.'320-3?0
KIAS
*
Dons!
rel-m
horizonla:
sabiimi
Do
no!
*ic*ec
10'
DIfCll
eown
Cabtraltiiudebeiow
!O.3oofl,
.........
CREW
OXYGEN
MASKS
STOW
PA
Announcement
....................
AS
REOUlRE3
conditioning is
provided
by
the ieft and right
air conditioning and pressurization packs
Air
Conditioning
and
Pressurizstion System
-
-
Airplane pressurization and air
(packs; which are supplied bleed air from their respective engines. Normally,
?he right
system supplies the air requirements of
the
cabin and the left system suppiies the air
requirements
of
cockpit.
The
AOM
states,
"
The distribution
of
conditioned air
to
the flight
cornpartmen:
is
designed as a continuous smoke removal system.
"
With
?he packs
operating, conditioned air enters the cabin through ceiling outlets. The air is esheusted
through
perfarated panels
at
th?
cabin
floor line
and
through the left and right tunnels in
:he cargo Says
to
the outflow valve. The outflow valve controls the exhaust rate
to
the
atmosphere. The airflow
in
the cockpit
is
similar to :hat
of
the cabin. Opening tne
m:fluw
valve, either man!lally
or
electrically, causes the airplane to depressurize.
Engine bleed air is furnished to the
phcks
from
the
engine's
8th stage (low
pressure)
or
13th
stage (high pressure) bleed air manifolds, depcnding upon engine power
settings and the demands on
the
pneumatic supply.
If
the pack supply switch is in the
-46-
"
auto
"
position and the low pressure bleed air decreases
to
about
18.5
psi
or
less,
the
systemk augmentation -Jalve opens
and
high pressure bleed air
is
introduced into the
c
syitem to maintain
18.5
psi.
When
bleed air
pressure
returns to
18.5
psi, the
augmentation valve will close. (The augmentation valves
are powered
by
the left and
right
d.c. buses and will fail closed if electric power is lost. The other two valves in the
system
-
-
the
flow control and ppessure regulation valves
-
-
are powered by the
d.c.
emergency bus and
wilI
fail open if electric power
is
lost.) During
a
descent, if the.
engines are at flight idle
thrxst, high pressure bleed air
is
required
to
maintain the
minimum system pressure.
At
level flight thrust settings, at any altitude, the low
pressure bleed air will
maintail the pneumatic pressure
at
or
above
18.5
psi.
cockpit and cabin
air volume (4,391 cubic feet)
is
exchanged every
2.2
minutes. During
At
33,000 feet, in level flight and
with the
pack switches in "au:o,"
the
entire
descent
to
3,000
feet with the engines at flight idle thrust,
the
time required to exchange
completeiy the cabin and cockpit air varies from 2.3
to
2.7
minutes. In level flight at
3,000 feet. the exchange would be completed
within
2.2
minutes.
could not
be
deterrnicer!
from
their positions after landing. Regardless of the position
of
The positions of the flow control and pressure regulation valves durisg flight
their
.-espectiVe pack supply switches.
ivith
no pneumatic pressure in the systems and
with
ali
ekciric power off the aiplane, these valves would have returned to the open position.
(There
:?r.s
ro
evidence tha; smoke entered the cabin thmugh
:h?
air
conditioning systen.)
I$;+
the louvored door
a&
from the overhead duct. it is vented out of the lavatory through
.
x&
regard
To
the aft lavatory, the air supply enters the aft lavatory through
:he
floor
and
the aiuminum vent Tube within the toilet shroud. In addition, the flow of air
in
the amenities section
of
the vanity
flows
forward into the toilet area below the shroud
and is also vented out of the airplane through the vent tube. Given this flow pattern, the
FAA
project manager was asked what effect opening the lavatory door and then chopping
away the lavatory waii panels would have had
on
the fire. He testified that since
he
did
not know the exact location of the fire
or
its intensity? it would be difficult to determine
what effect cpening the door would
have
had on :he fire.
"
However, because there
is
a
vzst arnoun?
of
ai?
supplied through the vents
in
tile lavatory,
"
he did not believe that
opening the door would have provided
a
large
amour,?
of
addirional air to the fire.
Conseqwntly, opening the door might have allowed some sndie and some flames,
if
there
were Flames
in
the
area, to escape
for
a
shor:
period
of
time while the door was open.
closed container; there
is
already airflow in
the
area behind the sideiv3:l.s. He suspected
With
regard
to
removing
the
lavato~y paneline,
he
testified
that
the
lavetory area
is
not a
that opening the
are by removing the paneling
"
would not sufficiently intensify (the fire).
It
may initially get it burning
a
little bit,
but
anything that you could do
to
gct
at
the fire
to fight
it,
if
you had the means
of
doing
so,
and you could do it, should be done.:'
1.11.2
LJse
of
Aft
Lavatory
Passenger interviews indicated
tht
the left aft lavatory was
used
several
times
during the flight. The last known pssenger to use the lavatory stated that she had
operated the toilet while she
was
in
the lavatory
and
that it had operated normally, cnd
she heard no unusual noises while the toilet was operating. She observed nothing
unusual
while
she
was in the lavatory and when she exited there was
P.
male passenger wailing
to
enter. The male passenger
could
not
be
identified.
According to the passenger. about
25
minutes after she kit the kvatory, she
"
heard
a
cominolion
in
the back
of
the airplane.'' The passenger
also
stated that she does
not smoke.
-47-
b
1.17.3
Smoke
Detectors
The lavatories on board Flight
797
were not equipped with smoke detectors
nor
were they required to be
so
equipped by either Canadian
or
United States regulations.
With regard
to
the
capability
of
a
smoke
detector to detect the fire on board Flight
797
dwing its early stages, the
FAA
project manager testified
that
it would
have
depended
seat, it might have detected
a
fire in that
area
very
early after ignition. However,
if
a
upon the location of the detector.
Had a smoke
detector been placed under the lavatory
fire
was in the lavatory itself, a detector under the seat might not have detected
it
early.
He
testified that, if the fire had
been
behind
the
walls of
the
lavatory,
a
detector
installed below
the
lavatory seat might not have
detected
the
fire
because
the
airflow
in
the
area might have been very small and flowing down the sidewall out of
the
lavatory and
away from the detector rather than toward it.
The evidence developed
by
the Safety Board during tke investigation showed
airpiane lavatories
are
available, unresolved problems curtail their acceptability. Among
that while technology has reached a point where smoke detectors that could
be
used
in
the problems noted
by
air carrier operators were locating the detectors, the sensitivity
of
the detectors, and the redwtion
of
the false alarm rate to one that would be acceptable
to
&?
operator.
installed smoke detectors in the lavatories
of
their airplanes. To date, these carriers have
However, since the pdblic hearing, two
C'S.
air carriers have voluntarily
indicated that they have not experienced false alarm problems with the installations.
One
of these carriers, Pan American World Airways, installed residential type, battery
operated ionization detectors on the ceilings of the lavatories
of
all
the airplanes in their
flee;. Since January
1,
1084,
they ttave had
35
to
40
smoke detector alarms. Two
of
cigarette ignition of waste
paper in
the bin.
In
these two incidents
the smoke detector
these alarms were caused
oy actual
lavatory
trash bin fires. The
lires were caused by
ectivated before the automatic Halon suppression system in the trash container activated.
The majority of the other incidents were the
resrilt of passengers smoking
in
the
levatories
&qa
air contarnination of the cabin environment from some external source
sdci
as the airplane engines.
1.17.4
Examinetion
of
Other
DC
-
9
Airplanes
surroundins a report of heavy smoke which originated in the aft lavatory on board
a
Du:ing the investigation, the Safety Board examined
the
circumstances
chartered DC
-
9. The examination disciosed that the aft lavatory flush motor had
overheated and had emitted smoke; however, there was no fire. During the examination
of the vanity area, which was identical
to
that in the Air Cansds DC
-
9, paper debris and
a
bottle top were found beneath the trash container and to one side of
the
tresh container.
Toilet paper was found on the lower shelf
of
the amenities section and
the
lightening hole
containing tne
flush
motor
power harness was stuffed with wadded toilet gaper.
1.17.5
Air
Traffic
Control
Procedur-
-
s
The indianapolis ARTCC and Cincinnati TRACON controllers provided ATC
assistance to Flight
797
Ltt
the onset
of
the cmergency, during the emergency descent, and
during the
subseqient landing. Indianapciis Center was equipped with
a
National Alspace
System Stage
A (NAS
Stage
-
A) computer; the Cincinnati TRACON was equipped with
an
wn
track,
display,
and attach a data block
to
a
nonbeacon
or
primary target;
the data
Automated
Kadar
Terminal System
111
(.&KTS
111)
computer.
The
NAS
Slage-.4
computer
-48-
block displays the airplane's call sign, ground speed, and last assigned altitude. The
ARTS
III
computer in service at
the
Cincinnati TRACON could not track, display,
or
attach
a
daia block
to
a primary target; however,
the
airport surveillance radar
was
capable of
displaying an airplane's primary target. Since Flight
797's
transponder
was
inoperative,
an
automated handoff of
the
flight from Indianapolis Center
to
the Cincinnati TRACON
was
nut
possible. Therefore, the controllers used the interfacility landline to hand off the
flight manually.
FAA Order
7110.65C,
"
Air Traffic Control,'! January
21,
1983,
contains
the
controller
to
another
or
from one facility
to
another. Controllers are required to be
recommended procedures
for
transferring radar identification of
an
airplane from one
exercise their best
judgment
if
they encounter situations that
are
not covered by it (the
"
familiar with the provisions that pertain to their operational responsibilities and to
Order).':
the receiving controller that
he
has
a
"
handoff.
"
Thereafter, he shag provide the
The procedures require the controller initiating a manual handoff
to
convey to
receiving controller with the position
of
tine
tar@
relative to
a
fix,
a ma:, symbol,
or
a
known radar target which
is
displayed on
the
screens
of
both the Peceiving controlle? and
airplane identification, its assigned altitude, any
restrietioq and if applicable, whether
zhe
transferring controller. The controller initiating the handoff should provide the
the airplane
is
climbipg
or
descending.
He
should also advise the receiving controller
of
peTtinent information not contained in
the
data bltick
or
flight progress strip. Pertinent
information includes assigned heading, airspeed and aititude restrictions, observed
track,
and beacon code if different
from
that norrrally used
or
previously coordinated. The
receiving eontroller shall, in turn, insure
thEt the target's position corresponds with that
given by the transferring controller
or
that there is
en
appropriate association between
an
automa?ed data
block
and
ths
target being irsnsferred before accepting a handoff.
(
Paragraph 651b
of
the Order states,
"
If
identification
is
questionable
for
any
reason, take immediate action
lo
reidentify the aircraft
or
terminate radar service.
"
Wilh regard
to
identifying a primer? target, parsgraph
254
states, in pazt, that
a
primary
target
CBR
be
identified
by
'~bserving a target make!ingl an ideniifying turn
or
turns
of
30
degrees
or
more, provided.
.
.only one aircraf:
is
observed making these turns.
"
Three methods
of
identifying beacon +argets are provided
in
paragraph
655.
The controller can either request the airplane to activate the identification (ident)
airpfane to change to a specific discrete
or
nondiscrete transponder code and then observe
function of the transponder and then observe the identification display; request the
the
display change;
or
request the airplane to change its transponder to :'standby" and
observe the loss
of
the
beacon target, then request :he airplane to return the transponder
:o
normal, and
observe
the reappearance
of
the beacon target.
Cincinnati TRACON was a
"
team effort,
"
between him and the
LEX
-
D
controller. The
The Louisville high controller said tnat the handoff
of
Flight
797
to the
LEX
-
D
controller's positicn, which was located across the ai:;ie from the Louisville high
controller's position,
is
a
nonradar position
and
is responsible
for
coordination betsveen
sectors, flight pian updating, and computer inputs. The
LEX
-
D
controller, who
WHS
however,
he
had overheard
him
discuss the emergency
with
Flight
797.
The LEX
-
D
radar
-
rated, had not been in direct communicatior, with the Louisville
high
control!er;
controller
did
not cross the aisle either to observe the Louisvilie high controller's
-49-
b
D
i.
radarscope
or
to
talk
with him. He said that he tried to configure the radarscope next to
his
position to obtain a transponder code and data block
on
Flight
797,
but his initial
attempts failed. He
knew
the
flight was being vectored to land
at
Cincinnati; therefare,
at
1909:17,
he called the Cincinnati TRACON on the landline to alert
the
Cincinnati
approach controller
of
an
impending handoff in his southwest sector. He also asked his
display Flight
797's
data block
so
that he could
get its
transponder code for
the
handoff.
radar controller seated at the
radarscope next
to his
position to program the computer
to
The
LEX
-
D
controller stated that he
also
had overheard Flight
797
receive
clearance to descend to
5,000
feet and to turn to
060".
He
knew
the airplane had
an
standard operating procedures, Flight
797
should have been handed from Louisville High
onbcard fire, but he was not aware of
its
electrical problems. According to th.e Center's
Radar Sector to the
EvamvilldNabb
Low
Radar Sector and then to Cincinnati approach
control. The LEX
-
D controller said that he independently made
the
decision to effect a
direct handoff of Flight
797
from the Louisville high controller to the Cincinnati xpproach
corYaller.
The
LEX
-
D
contrcLler
said
that, when the approach controller accepted the
handoff, he did not hear the approach controller say the
0662
transponder code; he only
heard
him
say
the altitude. He said that, at that mo'ment,
he
was talking directly to
his
radar controller seated beside him and he believed that
the
"
yeah
"
in his response was
directed to
his
radar controller.
He
was not aware thet
he
had also trsnsmitted the word
"
yeah'! to the Cincinnati approach contrciler when he called later to correct
the
altitude.
symboi and data block were being displayed
on
the adjacent radarscope. However,
he
did
-According to the
LEX-0
controller, by
190995,
Flight
797's
primary target
not tell
the approach controller that Flight
797's
transponder was inoperative because
he
was not sure
that
it was, in factt inoperztive. He stated
that
a
beacon can b? missed for
computer
wili
display a p:imary target symbol on the radarscope.
several sweeps
of
the
radar antenne, and
in
the
interim, until it is reacquired, the
797
diiring the handoff. He believed that he hed pointed out the correct target and
that.
The
LEX
-
D
controller stated that there were
no
beacon targets near Flight
the Cincinnati approach controller had accepted the target he had
poir.'?d out.
Thereafter, at
1910:01,
the
LEX
-
D
controller called
the
approach controlier on the
lendline and told
him
that Fiight
797
had been assigned a
060°
headhg and that the
epproech controller repeated
the
heading and signed
off
with
his
operating initials. At
1910:03,
the
LEX
-
D
controller told the approach controller that tie flight was descending
to
5,000
feet.
he saw a westbound beacon target in the southwest sector
of his radarscope. The target
\$hen the Cincinaati approach controller was alerted to the impending 3andoffl
was above the 12,000
-
ioot upper altitude filter limit
of
his scope and
was
displayed
as
an
asterisk with no dote block.
As
a result
of
the
1909:23
and
1909:25
transmissions
froin
the
LEX
-
D
controller. he knew he was accepting
an
emergency
but
he
elso
expected to
receive a
transponder coaed handoff.
He
used
his
compdter trackball
12/
siewed to the
target he had observed earlier, entered the position into
his
computer,
and
re2eived
a
partial data block containing
a
0652
transponder code and the airplane's sitirude
-
-
three sweeps
of
the redar antenna.)
Xe
advised the
L.2-9
controller
of
the code. the
Fi
350.
(Under t:.ese conditions, the partial. data block would
only
be displayed
for
about
altitude he had observed, and when
LEX
-
D
answered
"Yep.ht
thirty-rhrce now.
tie's
twenty
-
five southwest.''
it
confirmed
his
belief :!?ut he
had
i5enrificd and wce??ed Flight
797.
-
-50-
The approach emtroller said that there were
no
other beacon
targets
or
prlcnary targets
near
the
0662
code. He said he
was
aware
of
the
altitude difference, but
h?
also was aware
that
Flight
797
had declared
nil
emergency and
was
probably
uescending. Therefore, the mode C altitude data might be lagging.
At
the
time of the
handoff, he had not been told the flight's assigned heading. Believing he had identified
%e
correct airplane, he assigned a radio frequency and waited
for
Flight
797
to cor,tact him.
I
saw
no
response from
the
target he had been obscving,
he
observed a partial data. block
The approach controller stated that after
he
had requested the
090'
turn and
containing an
Air
Canada
797
identification tag in the vicinity of
the
secondary target he
had
initially identified as Flight
797;
the
TRACON supervisor also stated that
he
had seen
this data
block.
Pbout
1911,
the
Evansville/Nabb
D
controller
had
"
forced
"
an amended
flight
pla?
for
Flight
797
into
the Cincinnati ARTS
III
equipment. The flight plan,
as
amended, contained Flight
797's
assigned transponde: code, changed its destinstion to
Cincinnati, and stated
that
the flight
was
Gescendi~g
to
10,000
feet.
Had Flight
797's
transponder been operating,
the
"
force
"
would have configdred the Cincinnati
AriTS
III
computer
to
accept
an
automated handoff at the geographic point where the computer
was programmed to accept handoffs from the
EvansvUelNabb sector. However, since
Flight
797's
tramponder was inoperative,
the
ARTS
111
computer could not loeaze
a
beacon
target
to
associate with the :'forced"
data
block and the .'force" merely placed the data
block
on
the approach controller's radarscope. The data block, because
it
did not match a
properly
mded
beacon
target, was displayed only
for
about three radar sweeps.
The approach controller was asked, based on his emergency
arccedures
training, how far
from
the threshold
of
runway 36 he would have had to have p:aeed Flight
797
in order
for
it land
on
that runway. He testified that it would depend on the weather.
If
the
descent :vas conducted
in
visual flight conditions, he thought that "the pilot might
be
able
to
descend from five
or
six thousand feet from
a
point ten miles swath
of
the
airport at a
slowe? speed and complete a landing.
If
it were
an
IFR (instrument flzht
rules) approach, he'd want to be level at twenty
-
five hundred feet
or
three thousand fe,et
maybe seven or eight
or
ten
miles
from the airport.
In
this
situation, it
was
difficult for
me to judge how quickly
the aircraft could descend (and) how tightly he could turn.
"
The
controller testified that
he
wanted to avoid vectoring Flight
797
to runway 36, have
it
arrive too high anl too close to the runway threshold
to
complete
the
landing, and ?hen
have to
circle
the airport
in
order to
lard
on
another runway.
either the indicated airspeeds
or
?he dcscent rate capabilities of a DC
-
9
-
30 airplane
The controller was not familiar
with
nor was he required to
be
familiar
with
diiring an emergency desctn:. He also said that even
if
he had identified Flight
797's
primary target earlier he would not have turned
the
Fight
away from the airport
and
towat-d the
soath
in
order
to
space it to !and
on
runway 36. He would have
"
kept
him
goiq for the airport at all times.
"
1.17.6
ATC
Radar
Data
Data .4nalysis Reduction Tool
(DART)
radar data information was obtained
from the Indianapolis
ARTCC.
The data included airplane position informtion
and
available mode C altitude information
for
Flight
797
and for Continental Airlines
Flight
383,
which was transmitting
on
eode
0662.
The Safety Board's laboratory reconstructed
the ground radar tracks of both Flights
797
and
383.
Runways
9K-2;L
and
-
12/
A
movable position identification device available to the controilm
to
identify radar
terz-pts
on
his
radarscope.
.
-51-
D
18
-
36
of
the Greater Cincinnati Airport were digitized and plotted with
the
gromd
tracks.
ground track. The
last
radar
fix
retrieved from the DART'S data occurred
at
1914:15, and
Times of key transmissions and selected
key events were included along Flight
797's
radar
the
last
transponder information from Flight
797
was
received
at
1906:12. (See figure
13.)
1.17.7
DC-4-32
Descent
Performance
According to
the
manufacturer, assuming a descent at flight idle
thrust,
landing gear retracted, flapsislats retracted, speed brakes extended,
at
a
temperature
descent weight at 3,000 feet of
61,600
pounds, and
at
airspeeds of
.76
Mach and 310
KIAS,
3OC warmer than international standard atmosphere temperature
(ISA
+3'C),
a
final
Flight
797
was capable of achieving the following descent
rates:
at 30,000 feet
at
20,000
feet
7,800 fpm
at
5,000 feet
5,700 fpm
5,100
fpm
The time required to descend from 33,000 feet
to
3,000
feet was
5
minutes
11
seconds and
the still air distance
was
34 nmi.
Since
the
touchdown zone elevation of runway
27L
at
the Greater Cincinnati
descent from 3,000 feet, decelerate from descent speed, configure
the
airplane for
International Airport was
875
feet, additional time would be required to complete ;he
landing, and fly
the
final approach. The Safety Board constrticted
a
descent model
containing the time required to complete these phases
of
the descent and landing. The
model
is
based
on
the following assumptions:
9L
I
Phase
of
Flight
Time
1.
Descend from
3,000
feet to
decelerate from 310 KIAS to
2,000
feet at
500
fpnl
and
200
KIAS.
2.
Extend the landing gear, and
extend the flaps incrementally;
stabilize the airspeed
at
each
flap increment.
3. Final approach
-
descend from
2,000
feet to
675
feet at
7ZQ
fpnl.
2
minutes
1
minute
1
minute 30 seconds
Based
o~r
the times contained in
this
model and the manufacturer's performance data,
the
total time required
to
descend from 33,000 feet
and
land
on
runway
27L
was
9
minutes
41
seconds.
The field elevation at Standiford Field, Louisville,
Kentucky,
is
497
feet. The
Safety
Board estimated :hat
10
minutes
11
seconds would
have
been required to descend
from 33.000 feet
and
land at Standiford Field.
NORTH
RANGE
IN
N.M.
wx
Om
CI
D
U
W
U
-53-
b
As
stated earlier, the captain had inadvertently extendec:
the
speed brakes
to
the ground position. According to the manufacturer, during the emergency descent at
.78
Xach and then at
310
KIAS, the airflow over
the
wings would blow the speed brake panels
down
:o
the
position they would
have
assumed had
he
extended them
tc
the position
prescribed in the flight manual.
Thus,
despite the mispositioning
of
the speed brake
conlrol
lever, the airplane's descent rates during the emergency descent would have been
essentially the
same
as
tiiose
cited above.
A?
1909:05,
Flight
797
reported
that
it
was leaving
FL
330.
Therebfter, it
reported it
was
at
8,000
feet at
1912:59;
at
2.500
feet et
1915:il;
and, at
2,000
feet
at
the emergency descent were as follows: between 1909:05 and 1912:59,
6,410
feet per
19?6:07.
Based
on
these altitude csllouts, tine average rates of descent obtained during
minute
(fpm); between
191259
and
1915:ll:
2,500 fpm;
and
between
1915:ll
and
1916:07,
536
ipm.
2.
ANALYSlS
2.1
Cieneral
The airglane
was
certificated, equipped, and maintained
in
accoraance with
Transport Canede and
US.
FAA
regulations and company policies and procedures. The
flightcrew
ws
quaiified and certificated properly and the flight attendants were qualified
for
tf&
flight. Each flight and cabin crewmember had received
the
training ma off-duty
tine prescribed
Sy
Canadian regulations. There was
no
evidence of
any
p-existing
medical
or
psychological conditions that might h&ve affected the performance of the
:light
and
cabin crews. involved air traffic controllers were certificated properly, and
each
controiier had received the training and off
-
dutp time prescribed by
FA.1
regulerions.
Accordinglyt the Safety
Board
directed its investigation to the ignition and
propgation
of
the fire; to
ATC
procedures; to the performanee of the pilots and flight
iittendsnts
after
the fire
was
discovered; and to factors
which
affected the survivability
of
the
passengers
ar;d
crewmembers.
b
2.2
Fire
-
dete?:ed
3y
:he flight attendants, there
was
a fire located within the vanity and/or
the
fgnition.-The evidence substantiates a conclusion that when
:he
smoke was
toilet
shrocd
in
:he aft lavatory. Therefore,
the
Safety Board tried
to
identify all possible
discovered. the Safety Board identified five possible ignition sources: an incendiary
or
Ignition swxces
in
this area. Given the location of
the
fire at the time
the
smoke was
explosive
device; deliberate ignition; a burning cigarette; the toilet flrsh motor:
or
the
flush
motor
electrical harness.
In
addition to these five, the arcing damage found
on
the
ieedcr
cables
of
the left and right a.c. gmerators and the maintenance history of the
of ignition
-
the generator feeder caSles which
were
routed beneath the floor of the aft
tlirplane
a.c.
geneyealing system led the Safety Board
to
investigate a sixth possible source
lavatory.
liased
on
the examination of the physical evidence and the results
of
the
F"DI
laboratory
ttnaiysis.
the Safety Board concluded that neither
an
explosive
nor
incendiary
device
was
involved.
Also.
there was
no
evidence that the fire
was
deliberately set.
-51-
the fire resistance criteria contained
in
14
CFR
25,
it would have been virtually
Since the tests of tine materials used in
the
aft lavatory showed that they
met
irnpossibile
for
either a lighted cigarette or sparks produced by electrical arcing to ignite
the materials used in the construction
of
the lavatory.
L?
order to ignite
the
lavatory
partitions and walls, some combustible
ma?eriai capable
of
sustaining high temperature
combustion for
the
amount lime necessary to ignite the lavatory walls had to have burned.
Therefore,
in
investigating
the
possibility that the fire
was
ignited
by
a burning cigarette,
the Safety
soar6 focused on two areas below
the
vanity which could have co,nt&.ned
combustible materials and into which a cigarette might have fallen
-
the
sink
area
containing the trash chute and receptacle and the adjoining amenities section. Since
the
and since a Ywniig cigarette could fall down the trash chute into
the receptacle, the
iavatory
tmsh receptacle was
?he most
logical
piace for
combustible material to collect
damage in this area was evaluated. Had
a
cigarette started a fire in the receptacle,
+he
o?ly
propagation path out
of
the receptacle would have been the
trasfi
chute.
LQ
order
for
the fire to reach and short circuit
the
wires in
the
flush motor harness,
it
would have had
to
have burned from the
?op
of
the trash chute to the lightening hole containing the
harness.
T>e lightening hole where the
flush
motor harness wires had short circuited was
several
feet
outboard and
well
Selow the top
of
the
chute and
the
fire damage was not
conticuous from the top the trash chute to the a-ea of the lightening hole. Xoreover,
away where it
attached to
ths
sink
shroud, down to the
flush
motor harness, shorted
the
it was unlikely
that a fire could have
sp-ead from the top
of
the chute, which
F.ad
burned
wires, and then remained undetected for
11
minutes.
trash
chute and the receptacle, the automatic Haion fiye extinguisher had discharged only
Although there was some evidence
of
flame damage both
in
the area of the
into
the chute. The evidence showed that as the trash receptacle was being !leated by
the
fire, warm
air
within the Yeceptacle rose into the trash
chute,
and was trapped
in
the area
where
the
heat
-
activated discharge nozzle was locatid. Based on the earnage
in
this
area, the Safety Board concludes that the air reached the melting point
of
the nozzle
before the temperature below tne sink could
attain
that level
and
the en:ire Halon
suppiy
was discharged into the trash chi;t.e.
In
addition, since there was no evidence
of
a
eontimous flame path from the top of the trash chute down to the
areti
of intense fire
damage under the vanity, the Safety Board further concludes
that
:he
fire
did
not
originaie within the
trash chute.
Also
the presence of urrburnea trash within the trash
receptacle further corroborates this conclusion.
1
The amenities section of
the
vanity was almost completely destroyed
by
fire.
The
flame patterns showed that the area of most intense burning
wcs
in the lower sit
outboard corner
of
the void space located in the lowest level
of
the amenities section and
almost directly below
the failed cold air supply
line.
The fire was
so
intense that it
remained intact. Since the cold air supply line outlet was closed,
ihere was no airflow
melted a part of the aluminum bottom sheif in this area, while the rfmainder of the shelf
suppliec; air to the fire and caused it
to
intensify. The coid air supply line break coincided
through
this
pipe initially. However, once the line melted throogh, airflow began which
almost exactly with she most intensely burned area on the aft bulkhead. Given Chis
evidence
of
fire damage aad given
the
fact that the amenities section adjoins the
sink
area containing the trash chute
“nd
receptecle, the Safety Board etternpted to determine
whether
ti
lighted cigarette could
have
penetrated the void spncc
of
the ameiiities section.
An
Rluminum
partition seperaled the
sink
section containing the trash chute
above the
floor
there
is
a
4
-
inch
-
square hole
in
the partitior. through which
loose
material
and receptacle from the
opn
space below the amenities section. However, about
4
inches
can pass into tine open space beneath
the
amenities section from the area beneath the
sink.
Thus,
if
the
fit between
the
trash
chute
and waste disposal door
or
between
the
chute and trash receptacle had not been secure, it is possible
that
a
lighted cigarette
placed
in
the chute partition could have fallen from the chute and thereafter rolled
or
maSe
its
way
through the hole into the open
area
below the
amenities
section.
The
fact
Lhat debris can enter this area
was
illustrated
by
the discovery of the vial and
m8.intenance tag below Flight
797's
vanity, w,d the waste materials found
in
this
area
on
another
air
carrier's
DC
-
9.
The Safety Board concludes that
the
possihility
thet
this
occurred cannot be
p:iled out.
To investigate
the
possibility
that
the
fire
was
ignited
as
a
result
Of
a?
overheated
flush
motor, the Safety Board conducted two tests. The highest temperature
achieved during the
tests
was
803OF,
which was not high enough to ignite isvatory
components
in
the
vicinity of
the
flush motor.
k
addition,
the
izotors used in
the
tests
were damaged internally by heat. The flush motor involved in
the
accident did not show
any
evidence of internal
heat
damage
or
internal failure.
In
order
for
the
flush
motor to overheat in service, three ma!functions
must
take place: the motor
must
seize;
the
flush button
must
be held in
or
fail
in
the
depressed,
or
power
on,
position;
ard
finally, the timer
must
either be defective
or
fail.
(A
properly functioning timer will limit the
flash
motor to
a
LO
-
second
cycle
even if
the
flush button
is
held in the depressed position. Once the timer cycles the
motor
off,
the
flush button
must
be released and then depressed again to restart tne motor.) The
recovered components
of
the timer circuitry were
tested
functionally after
the
accident
and were found to
be
operationel.
The
last
known person to use the lavatory did
so
about
35
to
40
minutes before
the fire
was
detected. She stated that the flush
motor
worked properly
at
that time. She
also stated that another passenger was waiting
to
enter
the
lavatory when she
left;
therefore, the Safety Board conciudes that the flush motor
was
operating normally within
demonstrated that an overheated flush motor would not produce temperstures high
enocgh
35
to
40
minutes
before
the
fire
was
Ciscovered. Given
the
facts that
(1)
the
test
failed internally and
was
not
damaged internally
by
heat:
(3)
there
was
no evidence to
to ignite edjacen: lavatory materials;
(2)
evidence showed that the
flush
motor had
not
operating normally before
the
fire was discovered, the Safety Board cor,c!udes it uniiely
indicate that tke flush motor timer had failed; and
(4)
the
flush
motor was most probably
that the
flush
motor was the source
of
ignition of the fire.
discovered
was
the flush motor wiring harness. The tripping
of
the three circuit breakers
Another possible source
of
ignition Fear the area
where
the fire
was
accompanied
by
the arcing sounds recorded by
the
CVR
occurred at
1851:14.
The
three
circuit breakers tripped almost simultaneously indicating that the circuitry
of
all
three
phases shorted at
the
same time. The only evidence of wiring damage
was
found
where
the
amenities section
and
the toilet
section of the lavatory. The damage noted in the
the
flush
motor wiring
harness
passed through
the lightening
hole in
the partition between
wiring harnes
et
this location
could
only
have
been
the
result
of
fire and heat, and
the
Safety Board concludes :hat the damage
?o
the wiring which caused the three &ash motor
circllit breakers
to
Pip was caused
by
heat md fire.
numerous arcing
sounl;s
were recorded
on
the
CVR.
The.:e sounds were accompanied by
Beginning
3
minutes
2
seconds before the
'hree
circuit breakers tripped,
voltage
fluctuetions and
the electrical components
whic!. showed these fluctuations,
as
well
as
the
flush
motor,
were ell powered
by
the right
LC.
bus.
Because
of
the
extensive
-56-
fire damage
in
the area, it could not
be
determined whether
the
flush motor electrical
harness had been properlv suspended
in
the
lightening hole,
or
whether the protective
grommet had been installed around
the
rim
of
the li!htening
hole.
Based
on
the available
evidence,
a
hypothesis
that
the grommet was mlsing and that the wires were not
suspended properly before the fire cannot be supported readily by tangible evidewe.
However, assuming that this may have xcurred, tests
were
conducted after the accident
conductors,
the harnes
could
chafe
agaiEt the
exposed edge
of
the lightening
hole. The
which showed
that,
although
considerable force
and effort were required to expose the
tests
showed
that
the
chafed wire could arc egainst the edge
of
the hole without causing
the circuit breaker to trip. Such an
occurrence
could accodnt
for
the unexplained arcing
signals noted on
the
CVR.
A
trash fire ignited
by
this initial arcing cou:d explain how an
external
hea?. source
was
generatee which melted through the insuiation
of
the remaining
simultaneous tripping
05
the
three circuit breakers after a 4
-
minute
exposure
Of
the
wires and caused the circuit breakers
to trip
simultaneousiy.
Also,
tests
demonstrated the
harness
to
a
4.4-BTL;/ft see exrernal
flame.
Since the flammable source which fueled
the fire initially could not be identified, the flame used in
the
test might not have been
representative
of
the heat level of the initial fire aboard Flight
797.
Although the Safety
Board
cannot eliminate the
flush
motor electrical harness as a possijle ignition sourcet
given tne facts that
(1)
the tests demonstrated that a great amount of effort end force
was required
to
chafe away the
fksh
motor harness
a!!d
?he insulation
of
the wires in the
harness;
and
(2)
the
fsct that thc '.arness would not
have
been subjected to the abuse
duri-s.y- actual operating conditions that it was subjected to during the tests, the Safety
holes
was the source
of
ignition
for
a fire
in
the
amenities section of the aft
lavatory.
Boarc concludes
it
unlikely that the chafing of
the harness wires against the lightening
The sixth possibility
of
an ignition source
-
a high resistance short circuit on a
genera:or feeder cable where it passed through ihe lightening hole in the floor beam
4
below the !evutory
floor
at
FS
980
-
was considered prinarily because of clear
indications
of
arcing between
the
left and right engine generator feeder cables and the
chafed areas
on
both engine generator feeder
cables
which
exposed
the bare conductors at
floor
beam.
Thew indicetions cossi,sted
of
a notch
burned into the
floor
beam ai
FS
980,
FS
980: and the physical indications
of
short circuiting on the exposed conductors
of
both
feeder cables. Further, this
potenxial ignition source was in proximity to
the
floor
of
the
af? lavatory.
In
addition, this ignition source
was
gven consideration due to repeated
electrical problems with this aircraft
2rior
to
the fire and the
"
electrical arcing
"
sounds
recorded on
the
CVR.
This arcing was recorded
3
minutes prior
to
the ?ripping
of
the
three circuit breakers on the lavatory flush motor.
A
decreasc in the right a.c.
bus
voltage occurred simultaneously as recorded
OR
the DFDR.
aluminum
frame
at
FS
980. This would asscxe that tire conduit was either missing andior
For ignition
from
this soerce to occur, the cable must have contacted
the
jroken, thr'. the cables were not supported properly at
FS
980,
and that
the
differential
designed to trip the generators. Given these conditions, it appears possible that sufficient
current
fwlt
would have been
of
a low order which would elude tae protective circuits
electrical energy could be transferred
from
the cab!e to heat
and
eventually
ignite the
nylon conduit and propagate
a
fire
to
other combustible materials, probably the epoxy
behind the aft and side walls
of
the lavatory.
vicinity of
FS
980
precluded a determination
of
whether the generator feeder cables weTe
The damage and destruction which occurred beneath the lavatory
floor
in the
properly suspended within the lightening holes at that locatisr,; however, the evidence
of
chafing
in
the Pibergiass insulation
of
the generaror feeder cables where they passed
through the lightening hole at
FS
980
indicates that the cables may
not
have been properly
supported, and that
they
could have sagged and chafed against the
floor
beam. Further,
although
the
fault
protection circuitry had actuated aad
had
tripped the generators
off
circuit breakers
of
tine
flush
rnotor
harness
to trip. Sinoe the protective circuit??
Only
the Line,
this
occurred about
14
and
15
minutes after fire damage had caused
the
three
operates when the current differential between the generator and the bus
exceeds
about
cable insulation could have provided sufficient heat
to
have ignited the nylon conduit.
20
to
40
amperes, it appears that
a
transfer
of
up
to
40
amperes through the abraded
In
an effort to examine the possibility of the generator feeder cables
as
an
ignition source, the electrical system discrepancy reports
were
reviewed
to
determine
whether any might have indicated
an
intermittent electrical short circuit in
the
generator
feeder cables. The
analysis failed to disclose a problem
that
could
bi-
related to such
a
condition in the feeder cables, even though the electrical problems continued up to
the
time
of
the
accident flight.
Because of
the
extensive damage at
FS
980,
it
xas
not
possible to determine if
the electrical wiring
was
properly secured and protected, nor
was
it possible to positively
establish a fire patzern which would permit
a
conclusive determination that the fire
started
as
a
result
of
a
generator feeder cable fau::. However,
tinis
possibility could not
be dismissed.
ProDa~ation.--R~ardless
of
the ignition source, the physical evtdence showed
section of the amenities section, and
i: also showed
that
the fire propagated forward from
that there was an area
of
intense burning in the lower aft outboard corner of
the
:.owest
that point.
As
the
fire moved forward from the amenities section, it also burned rhrough
the 'lavaTory
walls
allowing the smoke, hot gases, an6
Fdmes
to rise
in
tihe
air space
between the lavetory shell and the airplane's outer skin and
Setween the
cft
pressure
bulkhead and
tF.e lavatory's liner walk The seams connecting the lavatory side wak and
ceiling
walls are not sealed: thus as the smoke rose,
it
began to enter the lavrtorg through
the
sidewall and ceiling seams, while the fire remained concealed behind
the
amenities
section and below the toilet
shro;ld.
of
the waste tank,
the
hot gases, sxoke,
and
zeited plastic were still being vented
As
the fire moved forward into the area between the toilet shroud and the
top
overboard through the lavatory vent
line.
The vent line exits the lavatory
and
enters the
generator feeder cable
bunzjles to
8
point just forward of
FS
965
where it exits
the
tunnel
in
?he aft cargo compartment aft of
FS
980.
It
is
then routed forward below
the
airpiane through a venturi
in
the lavatory access panel. The hot gases caused
the
aluninum vent tube
io
melt away,
thus
permitting the entry
oC
superho? gases in?o the
cable bundles where they passed through the
iighteninc holes
in
the floor beam located
at
floor
beam area below the lavatory
floor
and ?heir impingement
on
the generator feeder
cables,
and
hetween
1905:35
and
190?:11,
the
protective circuits :?@ped them
off
tiie
FS
980.
As
a result
of
the heat, faults developed
on
the
left and right generetor feeder
Line.
valve assembly was located close to the inlet of the lavatory
vent
line.
When
the flexible
The
flexible connection for th.e waste tank
flush
and fill pipe and its check
connection and the plastic
ball
in the check valve failed, this stainless steel
flush
and fill
pipe also became
an
overboard vent. The denosits
of
s?ot
and tar
on
the access
door
to
the
hvatory service panel and
the
melted rivc-ts
in
the pi;e connectsr at
the
service panel
confirm that the pipe aid
become
an
overboerd
vcr!t.
-53-
Except
for
the damaged area below
the
lavatory floor, the fire damage noted
on
the
The path of almost
sll
fires is upward and in
the
direction
@f
the
airflow.
airplane was above
the
airplane3
floor
line. The lowest and aftmost point of
fire
damage
Was
within the amenities section
at
the
outboard part
of
the lavatory and
tine
forward wall
of
the
aft
pressure bulkhead, respectively.
From
this location, based
on
the
dwnage
pattern,
the
path of
the
fire
was
upward and forward. The direction
of
airflow within the
amenities section and
the
toilet shroud
was
aiso forward.
The damage below the lavatory was
in
ihc
tunnel below its floor. While there
damage, and
the
;avatory floor had not burned through. The most severe damage in this
was
some evidence
of
fire damage,
the
damage
in
this
area was
for
the most part
heat
area
was located above
the
failed lavatory vent
tube
between
PS
965
and
FS
980.
Ln
this
area,
the
SisGension and insulation
of
the generator feeder cables
had
melted away and
arcing
had occurred. Given the proximily of the failed lavatory vent
Zube
to
these cables
and
the
type damage noted
on
the cables and structure in
this
area, the weight of the
evidence
indicates that the damage
in
Llis
area was caused by the
hc-:
gases
from
an
existing fire
in
the
lavatory being vented through the tube. This evidence tends
to
further
corroborate
the
hypothesis that
tk
arcing of
the
generator cables was the result
of
the
fire
and
no: the source of its ignition.
The momentary smoke abatement
note2
by
the
firs?
officer and Sight
attendant in charge between
1904:16
and
1904:23
was probebly attrihtab!e
Po
the dilution
effect of opening the lavatory door
ar,d discharging the
CO2
itlto the aren. reclosing the
lavatory door, and the
al9ost sirnulraneoils failure
of
:he 'lavatory vent line and the flush
and
fill
pipe eonnections
and
check valve, ell
of
which increased the ven?iletiun rate
beneath
the
toilet shroud and accelerated the flow
of
smoke and gases to the area below
the
lavatory
floor
and overboard.
4
The rectangular scorched area on the airplane's outer skin above :he ief:
engine and coinciding with the aft lavatory's frarne channels snowed th?:
e:
the
fire
consumed the
lavaxory structure
it
used the airspace between the lavatory cutboard
wail
and
the
airplane's outer skin as a flue. The superheated gases progressec!
L!:
these
channels
and
forward along the space between ceiliq liner and the airplane's outerskin,
and Segan to preheat the ceiling panels. Smoke and
fume?.
generated
by
the fire Segan
to
collect in the ceiling space. The smoke, fumes, and hot gases then entered
:he
cabin
through the ceiling
and
sidewall liners end Segan
to
collect
in
?he upper porTions
of
:he
cabin.
After the captain stopped Flight
797
on the runway. both forward exit doors
and three overwing emergency exit windows were opened
and
en
unlimited supply
of
fresh
oxygen became available to
the fire. With this availability
of
oxygen. the preheating of
the
ceiling panels, and the large quantities
of
unburned
gcses
in
the upper cabin,
a
back
draft and flashfire occurred, and the
fire
progressed rapidly through the entire caSin. Tne
evidence showed that
the
carpets, the lower portions
of
the sidewall pnnels, and
con.Llustible portions
of
the lower sear- structure, including wmrests,
did
not
ignite and
burn, whereas almost all combustible
nateria:: above the windowline were destroyed
or
heavily damaged by fire including large portions
of
the airplane structure
and
skin.
'The
physical evidence indicated that the
fire
in
the
cabin ignited initially
ncx
:he ceiling and
thereafter
the
seat surfaces were ignited by the heat radiatcd from the fire
ai
the ceiling
and
luggage rack level. Therefore, the Safety 3oard
concludes
:hat flashfire. rather than
flashover
occurrcd.
Q
-59-
b
Based
on
estimates
by
firemen
and
passengers,
the
fleshfire
probebly
cecumd
within
60
to
SO
seconds after the
doors
and overwing exits were opened.
The
upper
cookg
rifecis
of
the airflow
of
flight ended, failed rapidly. The absence
of
significa!t
fuselkge
skin,
after the cabin ceiling's insulation blanicet was consumed
by
Pie
and the
smoke stains
O
R
the outside
of
the
open exits supports
this
view, since following
the
doors
and
oat
the
ruptured fuselage
skin
at the top
of
the airpiane.
failure
of
the upper fuselage skint the airflow wouid reverse
and
go
in
the windows and
point of originaticn of the fire, the evidence indicates that
the
fire propagated through
In
summery, although
no
positive conclusion
can
be
drem
as
to
the
precise
the
lower part of
the
amenities section of the Is-atory vmity. Because
of
:he
direction
of
the airflow from
the
areas below the vanity
and
above the toilet waste tank,
the
smoke,
fumes,
and
hot gases were vented overboard
ani;
pulled
away
from
the
passenger
cebin
ma
the
open area of the lavatory, allowing
the
fire
io
burn undetected
for
almost
1.5
minutes. The first noticeable evidence
of
smoke within the open area of
the
hvatory
was
observed after the fire penetrated the iavatory liner and
'began
to
rise behind and
outboard
of
the liner. Smoke then began to penetrate the sidewail and ceiiin;
seams
of
the lavatory Lining as described
by
the
two flight attendanrs.
2.3
The cap&in and first officer testified that they did
not
hear the arcing
sounds
vshge exedxions
on
the right
a.c.
bus. The airplane's wiring diagrars showed that the
recorded
by
the
CVR.
The DFDK showed
that
the arcing sounds were accompanied
by
analysis
of
Zhe arcing sounds showed
that
they contained harmonics that were obove the
DFDR
and
Ci'l?
wiring
was
routed near the generator cable feeder bundles. Spectxm
frequency range that would
normaliy
be detected by the picrophone
and
preamplifier in
the
cockpit
3rea
microphone (CAAI) channel. Given the proximi:!:
cf
the
C?'S
wiring to
the generator cable bundles, the Safety Board concludes that
th2
arcing
signal
was
eiectrornagnetiw11y induced
into
the
CAM's
circcitry
and,
therefore,
20t
audibie
to
the
:':igh:crew. Since the ercing sounds which were recorded
by
the CVR were
not
heard
by
the flightcrew. :he
trip?ing
of
the
flush
motor's three circuit breakers
at
1851:i4
was
the
57s:
abnormal occurrence
they
noted.
b
AI
?851:27.
:he captain tried unsuceessi'i2lly
10
reset
rhe
circuit breakers.
A:
i859:58,
he agais tr:ed unsuccessfully
to
reset the three circuit breakers. Air Csneda
flightcrews are taught to meke one attempt to reset
a
c.pped
circuit breaker. They e?e
tau$t
;ha;
it may Se necessary to allow
a
3
-
minute cocling time before
e
circuit bresker
therefore,
a
circuit cannot
be
completed
by
holding
in
an
unlatched single
-
phase circuil
.aiil
accept
R
reset
and
that circuit breakers 2rotecting
a
single phasc
are
trip
free:
circuit
p;.??:c.cied
Sy
the
circuit
breaker
is
no
longer powered. The flightcrew and other
b?ceker.
Most
important, they are taught that
a
tripped circuit breaker oeno?es that the
uncommon
occL!rrcnce,
and
the procedure coniuined in Air Cenadtl's DC-S/AON ailows
,\ir
Canada
::igi?t
personnel
stated
:hat
circuit
hreukcr trips
&ring
flight are pot
&I?
personnci
to
cupe
adequtitely
with
such occurrences.
breakers
twice; the
firs?
aitempt occurred
cilmost
immediately after they had tripped and
In
this
cmc. the captain sttempted
to
reset ea-h
of
the tripped circuit
was unsuccessful. lie testified that
he
"thought
?.t
the time that the unit
(flush
n:otor)
might be overheated
so
I
just
continued the routine
of
the flight..
.
and
sfte?
a
certain
time
had
psssed.
.
.
1
ttttcmpted to rcsct the circuit
breakers
agair,
io
make sure.
.
.
.
The
circuit breakers
~~ouid
not
move."
Although the captain was unablc to detect any
movement
of
the ci;c;lit
breakers,
the
Cb'R
showed that arcing sounds. which were
not
b
-60-
audible to either the captain
or
first officer, accompanied each
attezqt
to reset each
circuit breaker indicating
that
the circuit breaker had moved aiid momentary electrical
conract had been made. However, once the contact was made, the protective circuitry
caused the breaker to trip again. Since the fire was already well
estabzished, the
attempts to reset the circuit
breakem
had
no effect on
the
sequence of events. About
breakers,
the
No.
2
flight
attendant informed the flightcrew
that there
was
e
'!fire.
"
1302:40,
11
minutes
26
seconds after the inirial trip of
the three
flush
motor circuit
Khen the circuit breakers tripped, there was no resson. based
on
their
training, for either pilot to surmise that
&n
emergency ccpable
of
compro,nising the
safety
of
the airp!ane existed. Aithough
in
this instance
the
failed
component could
be
checked visually, the abnormal procedures checklist made
no
distinction between faiied
components which
are
visllaliy
accessible to crewmembers and those which are
sat.
The
pilots
are
required only to
allow
the circuit time to
cool,
and thereafter, li.nit themseiws
component is
shut
down and,
if
required, perform the action
set forth
in
an applicable
to one reset
attexpt.
If
the circuit breaker cannot be reset,
they can
ass'dme
that the
checklist. While
it
can be argued that the captain, from the stendpoinz
of
passenger
comf3rt, should have requested
a
fiight attendent to inspect the lavatory and ascertain
:he reason, if possibie, for the failure
of
the flush motor circuit, it
was
a
matter of
Judgment on
his
part
as
to whether he should require this to be doze.
In
retrospect, his
decision not
to
do
so
may have forestalled
an
early opportunizy to discover the fire.
Initial
ac?ions taken by the cabin crew when the sxoke
was
discovered weie
ir.zclequete to
assess
quickly the origin and scope of the fire.
'ishen
the flight attendent
in
ckrrge opened the lavatory door, he
was
able
to
see into the
Lavatory
and
observe ?hat The
sxoke
;vas
emerging through the seams
of
the aft wall of the lavatory. Ever. :haugh
he
spate6 that he knew the fire
:vas
not
in the trash container, he never did open the door
of
Q
the
GO,,
into
:he
lavatory had little or no effect on
+he
fire.
In
order
for
t5e
the
si%k
compartment
to
inspect visualiy the
trash
chute and container.
The
dispersal
of
ex?inp!sh:ng agent
to
be effective, it
must
be applied to the base
of
the flames.
.(r
.
According to Air Canada procedures, the fire
axe
s>ouid
Se
used,
"if
necessary,!' to remove paneling
to
obtain e,ccess
io
the fire. After assessing ?he sit!>ation
in
:he lavatory,
the
flight attendant
in
charge did not request that the
exe
be
brougi-it
to
him
from
the cockpit because he did not believe he could use it. He te-t!?c<
&at
he
d:d
rhe aircraft
to
get to
it.
"
The fIight attendant
in
charge's testimony
also
show&
:he:2
not
consider usiag the axe
to
remove
the
paneling
because,
"
I
would have to
destroy
ha:?
while
he
knew the company procedure, since he had nst been shown which paneling cou:6
be removed
with
the fire axe without endangering critical airplane components, he
was
reluctant
to
use the axe. Xoreover,
he
was afraid that this action
rnigh:
provide
a
dmft
to the fire and accelerate combustion.
whether removing
the
lavatory panelirg would have enebleC the flight attendant
in
charge
Based
OR
the conditions
in
the lavatory,
the
Sufety Board cannot detwzine
to expose
and
attack the fire successfully
or
whether the remove:
of
the paneling would
have acceicrateci the propagation
of
the fire. Further, given the situation inside the
lavatory, even
had the
fire
axe been hought to the lavatory, the Safety Uoerd is
no:
convinced that the flight attendant in charge could
have
carried
out
the
firefightkg
activities contaiined
in
the
Air
Canada mandal effectiveiy without
A
full
face smoke
Inask
with self
-
contained breathing apparatus.
-61-
b
the
flight attendant in charge briefed
the
&st
officer on what
he
had done.
Also,
he
told
After
he
had dispersed
the
CO
into
the
lavatory and ciosed the lavatory door,
the
first officer that
he
did not believe the fire
was
in
the trash contniner
but
was
1WateG
elsewhere. Neither
he
nor
the
first
officer told the captair.
that
they had
not
seen
the
fire and
that
they
did
?ot
know exactly
where
it
was
or
how intensely it
was
bJrnhng.
On
the
other hand, the captain did not question either
man
aboilt
the
Iocation
or
severity
of
the fire.
The only crewmembers to observe the conditions in
the
lavatory
were
two
retreated the first time because he did not have smoke goggles with him: the second time,
flight
attendants. The first officer made two trips aft, but did not enter the lavatory.
He
bssed
on
the
heat
he
felt
on
the lavatory door, he decided that
it
was
not
adviseMe
to
open
the
door. Since
the
flight
attendant
in
charge and
the
first officer were not &le
to
determine
the
location
of
the
fire, they were not able to
assess
the severity
of
thn
Lrs.
Consecpentlj',
based
merely on their assessment of the c(;urse of
the
smoke drifting into
the
lavatory though the seams of
the
lavatory walls, they provided the captain with
ei:
inadequate assessment
of
the fire's severity.
officer
to
go aft and assess
the
situation. About
1904:07,
the first officer returned to the
The fire
was
reported to the captsin at
1902:10
and he directed the first
cockpit and
he
told the captain,
"
I
think
we
had
Setter go down;
"
however,
he
Mer
simultaneously, the captain received a series of optimistic reports from both
the
fiight
testified that at that time he was not thinking of an emergency descent.
Almos:
area, and at
1904:46,
the captain directed the first officer to go aft a second time to
attendant in charge
md rhe first officer concerning
the
smoke conditions in
the
aft
cabin
elapsed between
the
time that the
No.
2
flight attendant told
the
captain there
was
e
fire
reassess
the
conditions in the aft cabin area.
As
a
result, about
5
minutes
30
secoxds
in the aft iavatory and
his
decision to begin the emergency descent. While an actual in
-
flight lire
is
an extremely rare occurrence, ail reports
of
smoke
in
the cabin
must
5e
an
overheated fllisning motor
sr
waste ignited by a discarded cigarette in
a
trash
regarded
?s
potentially serious. Howeger,
such
reports often turn
out
to be smoke
from
receptecle designzd to contain a .!ire, conditions which are normally identified and
corrected
by
flight attendants without further consequences. Therefore, the Safety Board
realizes that there
is
a need to evaluate the situation before deciding on
the
emergency
action required. However,
in
this case, the time to make the decision appears excessive
given
the
circumstances.
Most
significantiy, neither the flight attendant
in
charge
nor
the
first officer was able to
fix
precisely the source of the fire
or
to assure the captain
that it had
ken extinguished. The Safety Board believes that a precautionary emergency
descent
shwld have been initiated
9s
soon
as it became evident that the fire had not been
visually located and
coulti be attacked directly with extinguishant. This became known at
IPOA:07
when
the
first officer came forward from his first inspection of the aft cabin
area, about
3
minutes Sefore
the
decision to
begin
an emergency descent.
b
A:
1904:07,
after the first officer returned from
his
first trip aft, Flight
797
was
about
14
nmi
northeast of Standiford Field, Louisville. Kentucky,
at
FL
330.
Had the
ern?rgef;cy been declared
at
this time
and
the descent started, performance data indicate
that
FXJht
737
,auld
have
landed
at
Standiford about
19;4:i8,
or about
5
minutes
51
seconds earlier than it landed
at
Cincinnati. However, given the actual conditions
in
the
airplane Juring the descent, it
is
not
realistic to expect the capiein to have duplicated the
times
and
optimum rates contEined in the descent performance profile. For example, the
evidence showed that during the actual descent, the
total
time require6
to
descend from
33,000
feet to
2,000
feet was about
i
minute longer than that required
in
the descent
profile. The Safety Board believes thet ?he evidence indicates that it would
be
reasonable
-62-
to
85Sume
that,
given
the
conditions in
the
cockpit,
the
descent and ianding wouid require
i
70
2
minutes
longer
than
the
elapsed time shown in
rhe
descent profile. Therefore, the
Safety Board believes that, had Flighr
79: landed
at
Standjford Field,
the
flight
most
probably would have landed about
3
to
5
minutes earlier than
it
did
et
Cincinnati.
While the
research
data does not permit
:?.e
Safety Board
to
conc!ude whether
doubt
that
the decreased exposure time of the passengers
to
the toxic environment in
:he
the
shortened
flight
time would have delayed
or
prevented the flashfire, there can be
no
cabin
would
have enhanced their physica!
and
psychological capability to escape after
?he
cabir.
doors
and overwing exit windows were opened. Consequently,
the
Sefety Board
conciudes
that
the
delayed decision
to
descend contributed
to
the severity
of
:he
accident.
At 1908::2, when the captah did declare en emergency, Flight 797
was
closer
to
Cincinnati thsn Louisville;
therefore,
the
Louisville
high
controlle? veciored it
to-ward
the
Greeter Cincinnati Airport and cleared it
to
descend. At 1909:05, the flight deparred
.ATC
handoff
,which
occurred
at
1909:38.
FL
330
and it landed
at
Cincinnati
at
1920:09.
in
the
process, howeve-, there
"as
3
fsulty
misidentification of Flight 79: resulted from the attempt
on
the
part
of
:he
controllers
at
The Safety
Board
conclucies
that
the
faulty interfacility handoff leading
to
the
in-f3-q
the Ir.dia?apolis Center
to
expedite
the
handlirg
of
an aircraft experiencing
a
dangerous
,l,ht
emergency.
The
Safety Board believes
that
the
LEX
-
D controller's
decision
to
hand off Flight 797 directly
tc
Cincinnati approach
control
wes
2
valid exercise
of
the
controiler's discretionary authority and if handled properly wouid have eliminated
additional radio frequency
changes
and
decreased flightererv and cont:.oller
workloads.
The
Safety Board
also
concludes
that
by beginzing
tine
handoff without direct communica-
iwluding
hi2
directly
in
the handoff
procedure,
the
timely transfer
of
vital information
lion with
the
Louisville
high
sector
controller
who was handling Flight
797
end by
not
between :he
two
facililics was either compromised
or
never accomplished. The
most
importcnt omission was the LEX
-
D controller's failure
to
tell
the Cincimati apr,roach
controller
thai
he
was
being handed off
an
airplane w'th
an
inoperative transpcnder.
to
the
faulty handoff. Instead
of
waiting for the initiating controUer
to
apprise him
of
:he
The Cincinnati approach controller
also
contributed, tinough
to
a
lesser
degree,
identification, transponder
code,
heading, and altitude
of
the
target
to
be
transferred.
he
received from Indianapolis Center
at
1909:l'i. Thus
at
1909:23, when
:he
LEX
-
D
trackballed
out
to
the target he assumed
was
the subject
of
the alerting
cell
he
hed
controller
told
him,
:'I
got
a
code for you,
"
instead
of
waiting for
the
remainder
of
the
information,
he
supplied the transponder code
to
the
initiating controller and thereby
ccntributed
to
the ensuing communications breakdlown. Th.: primery question presented
by
the
faulty handoff
was
whether
it
delayed the landing of
Flight
797.
At 1909:05,
wt,c?
Fliight
797
began the emergency descent, the DARTS
dots
showed
that
it
was
about
27
nmi southwest
of,
and turning toward, the Greater Cincinnati Airport. According
to
the
optimum performance data, it would require
34
nmi
to
descend
from
33,000
feet
to
3,000
feet.
In
addition, the winds aloft data show,ed
that
the winds during
the
fiight's
descent
were
from
the
west
at
spepds ranging
from,
about
85
kno:s
at
FL 330
to
about
8
knot;;
a:
3,000
feet; thus it WOUid require
more
than
33
nini
lo
descend
to
3,000
feet. The
evidmce
was
conclusive that regardless
of
which runw?y the controller elected
to
USC
for
landing,
he
would have
to
vector Flight 797 through some type
of
traffic pattern in order
to
lar-d
it
at
Greater Cixinnati Airport.
In
this
case,
he
elected
to
vector
it
to
'.and
on
runwa.;
27L.
-53-
b
According to optimum descent perfordance
data,
it would require
9
minutes
41
secocds
to
descend and lend
at
the
Greater Cincinnati Airport. Since
tix
descent
begsn at
1909:05,
the earliest possible landing time
was
1918:46,
or
1
minute
23
se-onds
earlier than
the
flight had actually landed. Bowever, since it
is
un-ealistic
to
expect
the
captain
to
have duplicated the optimum descent
data
during
tifie
approach, and
given
the
Safety
8om5
concludes
that
the faulty handof!
not
delay
the landing
of
Flight
797
small diffei-ence between
the
calculated
iandirg
time and the actue! landing time,
the
appreciably. Since the descenl and hdkg at Greater Cincinnati Airport
was
accom
-
plished expeditiously and
since
ATC
prweddres did
not
delay
+;ne
landing,
the
Safety
Board concludes that the only factor which
sipificant?y
delayed
Flight
7973
landing
was
the fligh?crewrs delayed decision to descend.
Duririg
the
descent. the
smoke
in
:he
passenger cabin continued
?o
eceunulafe;
it
was heaviest at the
&Ling
and became ircreasingly thick
from
the
ceiling down to
the
floor.
As
the
airplane descended,
the
smoke moved fo~wa-d in
the
cabin.
In
addition,
eked,
erd
high
pressure bleed air
was not available.
Therefare,
when
the
engines
wee
with
tile
loss
of
electrical pcwer,
the
dgmentation
valve
in
the
pressurimtio?. system
retarded to flight
id!e
for
the descent, little
or
no
fresh
ai?
was
-bei!lg
!.ntroduced
inta
:he
cabin.
Some
of
tie passengers noiec! that
air
stopped flowing
.out
of
the
eyebrow
vents
during
the
descent, confirming that
tr.e
augmentation valves had closed. However.
when
air would have been restored, provided
the:
the air conditioning
end
prescrizetion pwks
the airplare
was
leveled off after the descent and engine t;?r!lst appliee,
2-e
eschmge
Gf
had
not
Seen turned
off.
The
captain's difficulties during. the descent were com?our.ded
by
the
condition
of his flight instruments.
About
8,000
fee: during the descent.
?he
emergency
;r,ve:lc.
was
!os?..
The Sefety
Soerd
could not determine the
cause
0:
:he failure:
howe?.er.
with
situation indicators, and radio magnetic indicators became hoperhtive. an6
the
only
the
loss
of
the inverter. :he emergency
%e.
bus
was lost. The airplane's
ADPs,
iorizon:al
attitude indicating instrument available
was
the
smaE
e[Eergency standby
A31.
The
standby
AD!
and
his
airspeed indicator.
L?
addition,
wirh
srnnuite enterkg the cockpitl
he
captain
new
the latter
part
of
the descent,
tne
treffic
pettern.
anc
ihe
landing
using
the
had difficulty seeing the
icstrgments.
1
eock?it. The
cep?ain
hzd
not ordered the door
io
be
left
open
end
as,
in
fact,
not aw%-e
The daxaged cockpit door
was
not closed sfter
the
.'.?st officer reentered the
that
it
was
o?en.
The first officer
had
decided
to
lave the door open bpcause it
facilitated communication with the cabin crew.
As
a
resutt. the smoke entered
unimpeded
iittg
the cockpit. Since the louver panel
ives
missing from the cockpit
door,
closing
the
door would not
hRve
blocked totally the entry
of
the smoke. However,
even
with the panei rniqsing, a closed door
would
have delayed
the
accumulation of smoke
wilhin
:he cockpit.
however, the flightcrew
did
not
i-y
to
use the cabin smoke elimination procedure
-
-
The smoke
in
the cabin increased rspidly
during
!he
emergency
descent:
depressurize
the
airplane after it descended below
10,000
feet.
open the
sf:
pressure
btdikhead
door,
end
open slightly the righ!
forwad
cabin door. The
captzin
testified
that
he
did not order the prxedure
to
be
used
bccauw
the
fire
was
not
ost
and
because
he
needed the first officer'.; assistance
in
the
cockpit
in
order
to
fiy
the airpiene *?feiy.
Had
this procedure been tried, the airflow thyodg-h the cabin wouid
have
been biri'cted
fwwa;d
and nut the right forward cabin
door.
Though
ideally
the
procedme
would
be
use2.
when
Y
fire has been extinguished, eceording to the airplane manufacturer, the ??ocedure
can
Se
used
when
Y
fire
is
stiii
bcrning.
According
io
the
manufacturer.
the
flighierew
must
-64-
judge
whe:her
survival depends on the elimination
of
the
entrapped smoke
regardless
of
the effect that
a
draft
of
air
might have
on
the
fire. However,
the
fire
protection
Q
engkeer
who
investigated
the
airplane fire damage believed
that
opening the
doors
wou!d
have
created
!'a
very strong potential
"
that
the
fire
:VOL.!~
have been
&awn
from
:he
!ax:a?ory
into
the
cabin; that
the
smoke would have been moved forward faster;
and
that
a'rphne. The evidence concerning
what
would
have happened had the procedure been
the
use
of
the
p?eceaure
would
have endangered the
passengers
ard
the safety
of
the
used
was
highly
conflicting,
and
therefore,
the
Safety
3oa-d
\vi11
not spewla?e
as
to
what
rnigh:
have
occurred
had
the
procedux been used.
After
2escerking
through
3,900
feel,
ihe captain
o?dered
the
first
office?
lo
a'.rendan?s
a??
passengers
woilid
be
able
to
open
the
doors
a;id
overruing
exits.
Tie first
de2:essuriz.e
the
airplme
in
order to prepare
it
for
lending
and
to
insure
that
the
flight
officer
depressuriz.ed
the
airplane en3 then,
a1:hodgh
the
procedures
do
not feci?i;.e
this
to
operating
becaiise
they
are
powered
5y
the
emergency
d.c.
bus.
The evidence
showed
that
be
done, turned
the
air conditioning
pack
swtches
off
which
sii!I
sou!d
have
been
?he
zepain
did
no:
order
;he
first officer
io
shc:
of:
the
air
conditioning packs, nor
did
he
know
that
they
were
shci
sff.
The
firs:
officer
?esTified
that
after
the
airpiare
hfid
been
depressunized
he
decided
lo
WT
rbe
pcks
off
because
the
smoke
was
gettlng
bad;
he
dmught
he
had
to
do
se.metininp,
and
he
ihought
zhaz
"
those
pecks,
t.hey
are
jus:
feeding
???e
fi;e:'
-.
-
:he
sle?emex
md
resiirnony
concerning
*he?
the
air
conditioning
pecks
were
Sku?
off
is
sliehtly
.,
conf2icrir.g.
However,
the
CG~S~~SUS
of
all
?he
resrir?ony
ar.d
statements
inc:zated
tinet
?hey
ae?e
almost
certainly
turned off
by
the
rime The airplane
reached
2,00:!
ieer.
ihe
ATC
transcripts
showed
that Flight
79:
xyorted
"
at
two
-mxar!d
fiw
hndred
an<
'!,xe're
VF&
now,"~?
1915:11
anb
1515:27~
respectiveiy.
The
Xg>t
Ian6ed
at
1520:051,
3ased
on
the
fiightcrew's
testimony
and
statements and
the
times
ir:
the
ATC
transcript:
the
Safety
Board concludes :'.at
the
air
conditioning
packs
'cere
txned
ciff
st
!east
1
micutes
before
?he airplane landed
in
whic!;
airnost
two
comp'ete
zhanges
of
Cabin
and
ccczpit
air otherwise would
have
occurrea.
r.
{
yesscrizstion
pcks
had
failed
io
the
close3
position;
therefore,
the
smoke
in
the
cabin
3uring
the
descent,
t3e
augmentalio;.
vaives
in
the
air
condi?i~ni~% and
sad
cockpit
was
not being purged overboard
BS
xpidiy
8s
it
would
have Deen
had
these
cabin
end
cock;!?
increased
which
may
have
led
to
the
first
officer's
belief
that
the
..ir
va!ves
remeined operational. Consequently:
the
rate
at
which
the
smoke
was
fiilizg
ttv
cosdtionirg
and
pressuriza?ion
~acks
'were
suppiying
sir
flow
to
the
fire. Given
<he
ccn6i:ions
that
existed
in
rhe
cat-in
daring
the descent,
ttre
first
officer's sctio? was
understandab
-;
?,GWCVP.P,
when
the
packs
were
shu:
off,
the
best
avaifebie
;neans
of
i?iinir.ati.T
smoke
from
bot:.
!be
cockpit
end
the
cabin
was
inoperative Since
the
ram
air
vai*>e never
was
opened and
the
pressurimtlon system hac Seen
shut
off,
there
vias
virtually
no
fresh
eir
suppi?
to
the
cockpit
and
cabin.
Witit
no
exchonge
si
ai?
ir,
the
aircraft,
smokt:
and
heat
continued
to
accumuia:e
at
the
ceiling and
to
build down
tow3rG
?he
floor
and
the
toxicity of
the
air
in
rhe
cabin begen increasing
a:
an
accelerated
r2t.e.
,Lloreover,
with
no
airflow
availab:~
to
reCuce
the
b~li!dup
of
heat
knd
combustib!e
gascs
at
t3e
upper
iaeis
of
the
cabin,
the
onse?
of
iactcrs
conducive
:o
i!r.shover
or
flashfix
was
accelerated.
in
conclusion, once
tiif
decision
tc
descend
was
made
the
flightcrew executed
ccscendir:s
2a1Yic
pattern
to
the
landing runway using
cn!y
rudimentery airplane
an
c;..ergency descent
2nd
then,
in caorr3nation
with
the
approach controller, fiew
a
-65-
1
of
engine and flight instruments,
and
a?
1noperxtL:e horizontal stabilizer trim system
was
instrumentation. The captain, though
corfr;
-tee
with
a
hostile cockpit environment,
loss
Rble to maintain
his
concentration,
end
with t:e assistance
of
his first officer, configwe
unfamilar longitudinal control fwces resulting from the inoperative horizontal stabilizer,
the
sirplane
for
landing, slow
it
to
the debired indicated airspeeds,
and
despite the
the descent and landing,
.-.:<
Safety
Board
concludes that the captain exhibited
iend
the airplane safely.
Cc
idering
the
conditions which confronted the captain during
oulstanding airmanship
without
~hich
the
airplme and everyone on board would certainly
heve berkhed.
Evacu6tim
of
the
Airphe
because sone of the survivability factors were violated.
By
definition,
a
mrvivable
Aithough
fataiities ctcurredt this accident must be considered survivable
eccidert is one
in
which
the forces transmitted
to
the occupants
do
not exceed the limits
of
human tolerance
io
abrupt acceleration, either positive
or
negative, and
in
which
the
srrdcture in the occupant3 immediate envircnment remains str?lcturel;y intact
to
the
e:c?eni that
an
occupiabie voiuxe
is
Drovided
for
:he occupants throughollr the crash
sequence.
13;
in
:his
accident, the Edselage integrity was
no:
“i-eached during the lsnding
and nme
of
the occupsnis Were espcsed
to
decelerative forces beyond the limits
of
humar,
tolerances.
-
According
to
the passengers and
flight
attendants. when the airpiene landed
cabin floor.
In
addit]
n?
durir.g the descent
and
landing, the passengers and mew were
the
visibility
in
the
ca’
‘n
was
virtually
nonexistent at heights higher than
1
foot
above the
exposed
to
constantly increasing quantities
of
smoke and toxic
gas2s,
and these
factors
combine?
-:
make the evacuation procedures moie difficuit to execute
and
compiers.
The flight attendmts: efforts
to
move the passengers
forwar,
2;
row
12
2nd
away from the source
of
the smoke
and
heat (except for
two
passsnsers
in
seats
120
ani
12E
who
hai
refused
to
xove because their seats were next to the right forward
emergency exit
window>
and
their selection an5 briefing of able-bcdiei male pssengers
ro
open the
four
overwin.. exit windows, apparently were successfdi sirce
tkree
of
these
four
exits
had
been opened anci were
used
5y
surviving passenge
-
s. Additionally, the Tiight
attendants attempted
to
brief passengers
on
how
io
assune the brace
pasition
and
other
gases
in
the cabin, they
had
gyeat difficulty communicating,
s.?d
in
so%e csses, passengers
items relevant
:G
the emergency siruarion. 3owever. because
of
the
smoke
an6
toxic
did
not
hear
all
these instructions.
Virtually
ail the survivors
state@
tha:
they
haci
covered
514
flight attendants. iiet
towels
&E
filter
out
smoke
psrtic:es?
eci6
gkscs
such
es
rheir
mo~ths
and
noses
with
toweis: sriicles
oi
clothing,
or
c-her
iike
items,
as
instrxte?
hydrogen
chloride
and hydrogen fluoride, and hydrogen cyanide.
iihile
bret1:hir.g
zhrough
items
of
clothing
wii!
elso
filter
out
smoke
particies.
the
clorhing
wouid
probebly
5e
less
reduce the
carion
monoxide concentration.
Therefore,
e!??o~gh
This
prccecicre
WES
not
effective in
GItering
out
:he
acid
gases
ani
hydrcgen cyanide.
Seithe:
iIiter
systex
wii!
d$:rib:.te
3yeI
towek and
inst?xt
xhe pessmgers
to
bresrkz
:hrc.u.-h
the
tocwei;
or
o:i‘e?
conta!
ed
in
the
cornpen::
.;:anaai,
the
in:liztive on
:he
pert
of
:he
f:i@t
z?rerder;zs
70
i;enx
c.
clothing
may
heve
3:oec
:he
surviw!
of
the
g3ss;nge~s.
13
Z’
..
1
-66-
of the passengers. Tne flight attendants
at
the forward doors were not
abk
to make
in
spite
of
these efforts, several factors limited the success
of
rhe
evacuation
confirm that those who succumbed either made no
atternpt to move toward
ari
exit
o?
themselves heard inside the cabin. The location of the fatalities in the cabin tends to
started too late
md were ovexome as
they
attempted
to
move toward
an
exk St!ii;es
indicate
that
in the absence
of
ccmmands,
some
passengers will remain seated and awair
?rders,
e
phenomenon known as "behavioria: inaction.
"
14/
It
is
ais0
possisle
that some
of
?he
passengers were incapacitrted because of exposure7o toxic gases and smoke during
the descent and landing.
tine overwing exit windows indicated
thx the visibility in this area
of
the
cabin was
The statements
and
testimony of the survivors who exited
tine
airplane through
probably worse than that
in
the forward cabin. The survivors who had moved aft to reach
their seats and the exits and thereafter counted the rows by feeling tine seatbacks as .;ley
?he
overwing exits found
them
because they had memorized i'ne number
of
rows between
moved aft; because they 'were able
to
see a dim glow
of
light when they reached the exit
area;
or
as
in
one case, the survivor felt
a
slight breeze across the back
of
her
legs
when
she reached
the
art
a
of
21,
open exit,
doors and overwing exit windows were opened. Although
all
of
the passengers ha2 Seen
The evidence
s5cw:ed that the cabin environment deteriorated ra?idly after the
seated forward
of
row
13
when the airplane stopped, two
of
the fatalities were
loud
in
the
cabin aisle at
rows
14
and
16.
It
is
likely that these passengers hac ne& their
way
aft trying to locate the overwing exits; however, the visibility had deteriorated
so
badly
that they were not abie
to
locate them. Based
on
this evidence and the difficulties
experienced
by
the survivors who were able to locate the overwing exit windows,
the
Safety Board believes rhet had floor levei,
or
new
floor level, emergency
?igktting
denoted
the
location of the overwing emergency exit windows, not only might these two
e
passengers have been able to find thea, the task
of
the other survivors would have been
made easier.
Xany
of
the survivors stated that they were able to see better either by
bending forward
or
by crawling. The survivors? experiences appeared to follow closely
the
resul?s
of
reseerch contained in the
AGARD
report concerning the stratification
of
toxic
gas concentrations
within
a
cabin and its effect
on
survival times. Based on the results
of
the
FAA's
cabin environment research studies, the Safety Board concludes that the cabin
environment became
nonsurvi%raSle within
20
to
30
seconds eftnr the flashfire.
'The evidence also
indieaced that there were instances
in
which the flight
attendants had not complied completely with the Air Canada evacuation procedures.
In
the event
of
failure
of
the PA systen, Air Canada procedures direct the use
of
a mega
-
phone
to
make required announcements before
the
airplane door and exit windows are
opened. Even though the flight attendant
in
charge knew that the airplane
PA
system was
inoperative,
he
did not remove ?he megaphone to make the announcements prescribed
in
could heve required one
of
the other attendants either
to
take care
of
the passen,
the company briefing format. Although he was
busy
attending
to
a sick passenger
-
, :?e
take the
megaphone and make the announcements to augment the inr'ividual briefings
Der
or
to
given to the passengers
by
'the
Nos.
2
and
3
flight attendants. The Safcty Board concludes
that had this been done, the emergency briefings probably would have been heard, by
more, if not all, of the passengers, and
in
any
event
in
greater detail. However, eve11
had
al! the passengers heard the bTiefings, the Safety Board cannot conc:ude that this would
have aitered appreciably the
sequence of events which occurred after the doors and
exit
windows were opened. One
of
the required announcements contained
in
the briefing
Aircraft Accident,
"
Safety Journal,
1972,
First Quarter.
14:
Daniel Johnson,
"
Behavioral inaction
Under
Stress Conditions Similw to $he Survivable
-
-67-
)
format would have directed the passengers to remain seated while
the
flight attendants
completed opening the doors and exit windows
end until thne attendants directed
them
to
get
up
and move toward the doors and exits. The evidence showed that
a
passenger seated
in row
2
had, in fact, been briefed to restrain the other passengers from moving toward
ekeye. This procedure is
designed
to prevent congestion
at
the
doc.rs
and exits
so
that
the forward doors until
he
received
the evacuation command from the flight
attendant
in
:he attendants can operate
then:
without interference.
h
a smoke
-
free environment this
is
en excellent procedure; however,
on
Flight
797
the procedure
wodd
have operated to
the detriment of the passengers. The poor visibility made it impossible for the passengers
to see either
the
opened doors, the opened exit windows, or
the
flight attendants.
Givien
these conditions and give3 the contents of
the
briefing announcement, the Safety Board
believes it highly unlikely that
the
use of the megaphone during
the
descent would have
provided
a
better briefing to the passengers who did not move after the airplane stopped
End
the doors and exits
were
opeced.
Since neither the
No.
2
or
No.
3
flight
attendant
was
able to reach and occupy
her designated emergency landing position,
no
direct supervision of
the
emergency
evacuation through the overwing exit windows
was
provided
by
a flight attendant.
Botin
of
these
attendants were
in
the cabin aisle either briefing
or
attending passengers when they
the aisle checking seatbeits
an;
briefing
and
comforting qassengers. Since
the conditions
were
61 ected to sit
down
by
the
first officer. Despite
that,
they continued to move along
in
the cabir? made it impossible for them to look outsrde and estimate how
soon
the
airplane would land, it was incumbent upon
the flight attendants to seat themselves as
soon
as
possible after receiving the first officer's command. The
No.
2
pnrl
KO.
3
flight
attendants
were
seated
in
seat
3C
and
in
an aisle seat in
rows
7
e.
L-
3,
respectively,
when the airplane stopped.
Neither flight attendant tried to reach
he?
designated supervisory position at
the overwing exit windows. In order
to
do
so,
the
No.
2
attendant wouid have
had
to
have
moved
aft against the flow of passengers moving toward the forward doors. The
No.
3
f'iight attendant was closer to the overwing area. However, had she tried to go aft, it is
doubtful if her presence would have altered the evacuation sequence at these exits. She
probably
cou!d not have reached the exits before ti
-
e passengers seated at rows
10
through
12
reached them, opened them, and left the airplane. The survivors who exited the
eir?lane through the overwing exit vindows stated that they barely had the strength and
presence
of
mind
to negotiate the exits
and
that they were
3
to
5
rows closer
to
the exit
than the flight attendant. Ever: assuming that the
No.
3
flight attendant had reached the
area
of
the exils, her ability
?o
exercise supervisory functions
at
the four exit windows
would have been
dininished severely,
if
not totally.
In summary, the evidence showed that two flight attendants had opened :he
commands
and
directions to the passengers. They remained
at
tf:ir
posts at those doors
two forward
doors,
deployed and inflated the slides, md attempted
to
call aut re.quired
passengers wore :Roving towaro tl~e doors. They had briefed passengers on
the
location
unti: they were either driven out
by
the heat or until
they
Jelieved that
no
more
and operation
!
the overwing emergency exit windows. Though
not
Fequired by company
procedures, they had, until directed
by
the
firs?
cfficer to
"
sit down,
"
passed
out
wet
towels and directed the recipients to breathe through them
and
otherwise attended
to
the
passengers.
Tne
Air
Canada proczdures require their flight xttrndants to
"
do all possible
to
evacuate everyone, but they ?re
not
obliged
to
risk
their
ONR
iiveb." Given the location
of
the flight atlendants when
%e
sirplane Stopped on the runwa:; and
giv-:
the conditions
within the cabin
at
the1 time, :he Safety
Board
can
cr.1)'
conc!ude that
any
a:tempi
by
the
-68-
flight attendants
to
move farther aft into the cabin and
to
remain
within
the
cabin for
any
appreciable lengt? of time could not have been made without placing their survival in dire
Q
jeopardy and that it is doubtful
that
additional lives would
have
been saved thereby.
firefighters to extinguish
the
fire
on
board Flight
797
were consistent with those used
10
The response of the crash
-
fire
-
rescue units
and
the methods
used
by the
fight typical airplane fires, primarily fuel
spiils and interior fires. The tactics
used
by
crash
-
fire
-
rescue units in response to
these
types of fires are designed
to
prote3t the
passengers leaving
the
airplane and to assist them in moving
from
the endangered =ea.
Thereafter, rhe attempt can be directed to
save
the
airplane. The effcrts of the
passengers and crewmembers were
on
board and
they
did not know how
mxh
fuel
was
on
board. Xowever, they did know that smoke had been reported coming from :he airplane's
aft lavatory and
that
there
was
smoke
or
fire in the rear of the airplane.
2."
Likefighters in
this
case were complicated
by
the fact
that
they did not know how
many
In
evaluating the atternpa
to
attack
or
contain
the
fire, the question arises as
to
whether
ai?
entry at the left forward door with a handline would have been possible and
passengers possibly rescued from the interior. When the firefighters arrived
at
the
more logical.
From
this location, the fire might
have
been pushed back and several
airplane and began applying foam
on
the top of the fuselage and
on
the runway directiy
after the
last
survivor had left the airplane. The
on
scene commander testified
that
:vhen
underneath
the
airplane, flames were not visible. The fire did not become visible
untii
his personnel began the attack, passengers were still exiting through the left forward
door, and he believed that
an
attenpt to enter the airplane at that door at that moment
would have impeded passenger egress. He also believed that the deployed escape chute
would have impeded and slowed
the
entry of his personnel into the airplane.
In
addition,
the
firefighters did not know
the
seat location
of
the passengers. Therefore, the first
interior attack
was
mounted at tine left overwing exit and was designed not only to assist
the
passengers in this area, but also to insert firefighters between the fire and the
remainder of the passengers
stilI
on
board. The decision
to
mount the initial interior
commander, and
was
based upon his assessment
of
the sitation. Based
upon
the evidence,
attack through
the
left overwing exit was an operational decision made by the
on
scene
coiiid not have been averted
by
other tactics.
the Safety Board concludes that
his
decision
wcs
reasonable and that the ensuing flashfire
The evidence also showed that the firefighters involved
in
the Three interior
attacks were
not
abie
to
don their protective hoods
over
their self
-
contained brzathing
apparatus. The lack of protective hoods impeder:
G.=.
interior attacks. Testimony of the
FAA's airport safety specialist indicated
that
the
r
-.!.llrernents for protective equipment
for
airport firefighters are ambiguws
or
nonexiste.:t,
cn15
tnat the p'ovisions of
14
CFX
139
do not specify the need
fc:
training
in
interior firefighting tactics. The deficiencies
of
14
?FR
139
in hddrcssing crash
-
fire
-
rescue training and protective zquipment have
been addressed in some detail
in
the National Transportat;on Safety Board's recent
Airport Safety Study.
-
15/
2.5
In-flight
Fire
Prevention/Detection
During
this
investigation, the Safety Board identifizd the continued presence
of
causa! factc-7 similar to those identified
in
previous Safety Board investigations
of
__
15i
Safety Study:
"
Airport Certifications and Operations.
"
(NTSB/SS-84/2).
-69-
D
airplane lavatory and cabin fires.
As
a result
of
these earlier investigations, the Safety
Board had made recommendations
to
the FAA designed eithe; io preckde ?he recurfence
of similar occurrences
or
to minimize their severity should they recur. Had conprehen-
sive action been taken in response
to
some
of
these recommendations,
the
Safety Board
believes that the severity of this accident would
have
been lessened.
On
September
5,
1973,
the Safety E3oard
issued
the following Szfety Recommendations to
the
FAA:
Require
a
means
€or
early detectim
of
lavatory fires on all turbine-
powered, transport-category aircraft operated under Part
121
of
the
orocedilres
for
the frequent inspections
of
lavatories
by
cabin
Federal Aviation Regulations, such
%s
smoke detectors
or
operating
attendants. (Safety Recommendation
A
-
73
-
61)
Require emergency oxygen bottles
with
fill face masks for each cabin
attendant
on
txbine-powered transport aiicraft in order to permit the
attendants
to
combat lavatory and cabin fires. (Safety Recornmendation
A
-
73
-
68)
Mile
the
FAX
has required more frequent inspections
by
fiight attendants, neither smoke
detectors nor full
-
face smoke masks are required
by
regdetion to be placed on board
transcort category aircraft. Given the conditions inside tise lavrtory on Flight
797
when
the flight zttexdants first opened
the
door, the Safety Bo?rd b-iieves that
an
operable
snoke detector would have alerted tine crew to the existence
of
the
smoke before it
was
actually discovered.
The flight attendant in charge was able to see tine aft wall and that smoke
was
emerging from the seams in the lavatory walls when he entered the lavatory. The Safety
Board believes that had an oxygen bottle with a full
-
face smoke mask been available and
aggressive actions to locate the source of the smoke and to fight the fire,
as
set forth in
used,
i?
:eight
have encouraged and enabled the first attendmt to take immediate and
the company manual. The Safety Board believes that had either the smoke detector
or
ccnsequences would have been less severe. There can be littie doubt that, at the very
the
fill!
-face smoke mask,
or
both,
been
available and sed
on
Flight
737,
the
ieest, earlier detection
of
the smoke would have produced
a
mxe
prompt
assessment
of
the severity
of
the conditions
in
the lavatory, and consequen2y an earlier decision
to
descend and land.
3.
CONCLUSIONS
3.
I
Findings
1.
The airplane was registered, equipped, acd maintained
in
accordance
with
Canadian regulations, and
it
was operated within the United States
in accordance with applicable Federal Aviation Regulations.
2.
The flightcrew and the cabin crew were qualified and trained in
accordence with Canadian regulations and
Air
Canada requirements.
Each crewmember
had
received the off
-
duty times prescribed by
Canadian regulations.
3.
A
fire propagated through the amenities section
of
the aft iavetory and
ha3
burned undetected for almost
15
minutes before the smoke was first
noticed.
-70-
The fire
was
not set delioerately nor was it
*.e
resu!?
of
an explosive
or
incendiary device.
The Safety Board could
not
identify the origin of
the
fire.
The first
malfdnction to evidence
itself
to ?he flightcrew
was
the
simultaneous tripping
of
the three flush motor circuit breakers, about
11
minutes before the smoke was discovered. Tne flightcrew did not
consider this to
be
a
serious problem..
The smoke in
the
aft
lavatory
was
discovered by
e
iiight attendant. The
smoke
was
reported to
the
captain as
a
fire.
The source
of
the smoke was never identified either
by
the flight
attendants
or
the
first officer. The ca2tain
was
never told nor did he
inquire as
to
the precise location and extent of the
"
fire,
"
which had
been reported to him. Thereafter,
he
misconstrued reports tnat the fire
was
abating and he deIayed his decision
to
declare an emergency
and
descend.
Because
of
the delayed decision to descend, the airplane
lost
the
opportunity to be landed
at
Louisville. Had the airplane been landed at
LouisviIle, it could have been landed
3
to
5
minutes earlier than it
actually aid land at Cincinnati. The delayed decision to descend and
lend
contributed
to
the severity of the accident.
A
fauity ATC handoff did not delay significantly Flight
7973
landing at
Greater Cincinnati Airport.
The fire consumed the lavatory walk, propagated into
rhe
ceiling, and
then
began
to
move forward. Smoke, toxic fumes,
and
heated gases
began to enter the cabin, spread forward, and
co!lect along the ceiliqg
of
the cabin.
The
flight attendants'
passi'g
out
wet
towels
to
the pessengers and
instructing them to breathe through
the towels
or
through articlzs
of
clothing aided in the survival
of
some of the passengers.
The
first
officer turned off the air conditioni?g and pressurization packs
circu!ation accelerated the accumulation
of
smoke, heat, and toxic geses
in the
belief
that the airflow was feeding the fire. The resulting
loss
of
in
the eabin and
likely
decresst the time available
for
evacuation.
Three
of
the four overwing exit windows were opened
by
designated
passengers who
had
been sel.ected and briefed to opon them
by
the flight
attendants.
When
the
airplane stopped, smoke had filled the cah,in and visibility
floor.
within the cabin was almost nonexistent
2
to
3
feet above the cabin
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
1-
13.
-
7
i-
3.2
16.
A
flashfire occurred within
the
cabin within
60
to
90
seconds after
the
doors and overwing window exits
were
opened. Flames from this fire
were
not evident untii
after
the
survivors
had
left
the airplane. Flames
from
the
original fire
never
were evident within the airplme
or
to
persons on
the
groimd.
1:.
This
was
a
survivable accident.
Probable
&use
of
the accident were a
fire
of undetermined origin,
an
underestimate
of
fire
sevlr..;,
and
The National Transportation Safety Board determines that the probable
'tauses
conflicting fire
progress
information provided to
the
captain.
Contributing
to
the
severity of the accident was the flightcrew's delayed
decision to institute
an
emergency descent.
4.
RECOMNIENDATIONS
Varig Airlines, Boeing
707
accident near Paris, France, in which
124
persons died after
a
On July
11,
1973,
the
Safety Board participated in the investigation of
the
September
5,
1973,
issued the following Safety Recommendations to the Federal Aviation
fire erupted in
the
rear lavatory.
As
a result
oi
that accident, the Safety Board, on
Administration
(FAX):
turbine-powered, transport-caregory aircraft operated mder Pa2
Require
a
means for early detection of lavatory fires on
all
121
of the Federal Aviation Kegiilations,
such
as
smok?
detectors
or
operating procedures for the frequent inspections
of
lavatories
by
cabin attendants. (Safety Recornmendation
X
-
73
-
67)
Require emergency oxygen bottles with full
-
face smoke
masks
for
each
cabin attenriant
on
turbine
-
powered transport aircraft in
order
to
permit the attendants to combat lavatory
and
cabin fires.
(Safety Recommendation
A
-
73
-
68)
Organize a government/industry task force on aircraft fire preven-
:ioc to review design criteria
and
formulate specific modifications
for
improvements with respect to the fire potential of
such
enclosed areas as lavatories in turbine
-
powered aircraft operatizg
under
the
provisions
of
Part
121
of
the Federai .4viation
Regulations. !Safety Recornmendation
A
-
73
-
70)
Follovring the investigation of
the
Pan American
World
Airways,
Inc.,
Boeing
land
at
Boston, Massachusetts, after tne detection of a fire
in
the cargo compartment,
the
707
accident That occurred
on
November
3,
1973,
while the flightcrew
was
attempting
to
Safety
BoaTd
issued these additional Safety Recommendations to the
FAX:
Provide operators of
the
subject aircr&ft with da?s to enable
flightcrews to identify smoke sources,
and
require operators
LO
evscuate smoke effectively &wing
the
specific flight
ye-:..
establish procedures in their operating manuals to control and
-~es.
(Safety Recommendation
A
-
73
-
121
issued January
10,
1974)
4B
of
the
Civil
Air
Regulations prior to
the
effective date of
Requfre tha: transport category airp!anes certificated under Part
amendment
45-8
compIy with Far?
25.1439
of
the Federal Aviation
Regulations. (Safety
Recommendatioi:
A
-
74
-
5,
issued February
6,
1974)
Reqiiire that a one
-
time irspection
be
made
of
all smoke goggles
provided
for
thne flightcrex of all transport cawgory airplanes
to
assuie that these goggles conform
to
the provisions of Part
25.1439
of the Federa! Aviation Reguletions. (Sefety Recomxendation
A
-
74
-
6,
issued FebLv-uPry
6,
1974)
rl
July
17,
1971,
and :he other aboard a Boeing
72:
airplane
011
August
9.
1971,
the Sai'ety
As
a
result
oE
two other lavato-y fires, one aboard a Boeing
747
airplane on
Board recommended that the
F.%A:
Reqdire that automatic-discharge fire extinguishers be installed in
lavatory waste paper containers on
a31 transport aircraft. (Safety
Recommendation
A
-
74
-
98,
issued December
5,
19741
In
response to Sefety Xecommendation
A
-
73
-
67,
the
FAA
issued
en
Ai?
Carrier operations Builetin
(No.
I-76-?7,
"
In
Flight Lavatory Fires
"
) instructing Principal
to
institute routine flight attendant inspections of lavatories before takeoff and periodic
-
Operations Inspectors to encourage air carriers to prohibit smoking
in
the lavatories and
ally during flight. This sciion was followed by an Airworthiness Directive which required
the
insta1:ation
of
"So
Smoking
"
and
"
No
Cigarette Disposal
"
signs
in
the iavatories
of
transport category airplanes.
the installation
of
smoke detectors
such
as
those
using
ionization and photo
-
electric
Although
these
mtions fe2 short
of
the
Safety
Board's intention to promote
technology to trigger an alarm signal, the Safety Board,
in
May
1379,
closed Safety
Recommendation
A
-
73
-
67
and assessed th6 FAA's action as acceptable. Whiie the Safety
Board at that time was sympathetic
to
the industry's position
tirat
the leek of
smoke detectors would
degrade their effectiveness, it
now
is
convinced that the
demonstrated reliability
and the potential
for
false alarm
problems
associated with such
technology exists to provide an effective and reliable early warning fire detection system
in the lavatories
of
transport category airplanes. Further, the Safely Board notes that the
FAA
report
"
Feasibility and Tradeoffs of a Transport Fuselage Fire Management System,
"
(FAA
RD
76
-
54,
dated June
2376)
concludes that such systems ere feasible with current
technology.
standards and requirements
for
protective breathing equipment
to
provide Pzghtcrew
Safety Recommendatio'ls
A
-
73
-
68
and
A
-
74
-
5
both
addressed the need for
members with a supply of oxygen and
a
mask
of
eye protection
so
that they could continue
to
perform necessary airplene control functions and cabin duties,
GS
well
as
firefighting
functions
in
the event
of
an in
-
flight fire.
In
response
to
Safety Recommendatiori
A
-
73
-
68,
the
FAA
issued
a
revision to
the
Federal Aviation Regulations effective Fehruary
1,
1977:
which required the installa
-
tion
of
protective breathing equipmer.t in each isolated separate compartment of
the
airplane
in
which crewmember occupancy
is
permitted during flight. This revision
was
not
responsive to the recommendation since it did not provide
for
portable protective
breathing
equipmen:
For
use
in passenger compartments.
Also,
the
FA?,
issued an
NPRM
-73-
and eye coverings. However, the proposal was later withdrawn
with
the reasoning that
in
1975
proposing to amend
14
CFR
25.1439
to include new standards for oxygen mWkS
fu7ther
testicg
was
needed to establish the standards, The FAA's response regarding
Safety Recommendation A
-
73
-
68
and
A
-
74
-
5,
in
August
1981,
advised
the
Safety
Board
standards
for
emergency equipment to provide flightdeck and cabin crewmembers with
that
an
updated Technicai Standard Order
(SO)
would be prepeyed
to
prescribe minimum
eye and respiratory protection from toxic atmospheres during in
-
flight emergencies. The
FAA has stated that it intends to issue
an
Advisory Circular after it adopts
the
TSo
to
recommend that operators upgrade
the
protective breathing equipment aboard their
airplanes to
meet
the
new
TSO
standards. The FAA
has
stated that the Advisory Circular
wouid also recommend that operators provide eqltipment beyond regslatory requirements
for cabin attendants. The Safety
Board
assumes that
the
issuence of
"39,
"
Protective Breathing Equipment,': on june
27,
1983, completed the first phase of
FAA's
intended action. An FAA witness
from
the
Civil
Aeromedical Institute testified at the
Safety Board's public hearing in the Air Canada case that much of the equipment in
current
use
fails
to comply with
the
newly establkhed minimum standards.
He
descriiied
serious shortcomings particularly in the effectiveness and
fit
of
sh:oke goggles. Another
FAA witness from Aviation Standards Office
of
Airworthiness
slated
that he
was
not
aware
of
any FAA plans for regulatory action to require that the protective breaching
provisions
of
14
CFR
22
;439 and
14
CFR i21.337 meet
the
minimum
standards prescribed
equipmefit
currently
installed on transport category airplanes in accordance with the
in
TSO-C99. Furthermore,
the
FAA has not indicated that it intends to requlre by
regulation the installation of portable breathing equipment which would be
avsilable
immediately
in
passenger 2ompartments for use by cabin attendants in combating cabin
contemplated
Advisory Circular recommending voluntary
action
by
operators is not
fires. The
Safety Board believes that regulatory action is required and that the
1
adequate
to
asure passenger safety.
the Safety Board acknowledged that the establishment
of
the
Special Aviation Fire &nd
In
evaiuating the FAA's aciions regarding Safety Recommendation 8
-
73
-
70,
Explasion Reduction (SAFER) Advisory Cc-mmittee in
&?\lay
1978 would
be
responsive
to
the
and
industry
representatives, went beyond
the
specific scope
of
the
Safety Recommenda-
recommendation. The mandate of this committee, which
was
composed
of
government
postcrash scenario
-
?he
SAFER
committee's short
-
term recommendations
were
di-ected
tion
and considered the broader aspect
of
the airplane fire problem
by
addressing
the
primarily toward actions
to
inhibit the ignition
and
rapid propagation of a postcrash
fuel
-
fed fire.
?he
committee determined that there was
a
need
for
continued resa.r?h in
regarding
the
flammability, smoke, and toxic emission characteristic of cabin materials.
interior cabin materials before new testing procedures and standards could be established
Although the
FAA's
action to convene the
S.4FER
committee was viewed as
responsive
to
Safety Reeornmendation A
-
73
-
70, the Safety BoaFd maintained the recom
-
mendation ir! an open status pending further progress toward the mandating
of
safety
enhancing improvements
to
airplane cabin interiors.
?he
Safety Board
has
received no
further response
from
!he FA8 regarding this recommendation since March
14,
1979.
Zowever, the Safety
Board
has followed
end
has encouraged the continuing research being
conducted at the
FAA's
Technical Center
at
Atlantic City,
New
Jersey. The Safety Board
believes
that
this
research
has
ident:fied several potential
cabin
improvements which
intention
to
issue
two
Notices
of Proposed
RLilemakiilg
(NPRX)
proposing
new
could be
implemented now.
'The
Administrator
announced
on
October
11,
1983,
FAA's
performance standards
for
the use
of
fire
-
blocking materials
OR
passenger seats
to
inhibit
the
propagation
of
cabin fires
end
new
standerds
for
emergency lighting thst would
be
more effective for passengers evacuating smoke
-
filled cabins. One
of
the parties to the
Air Canada accident
invesrigation has recommended that,
in
addition to relocating :he
-74-
cabin emergency lights, tectiie aisle markers
like
those on
the
overhead stowage
bhs
on
many airplanes
be
installEd near to tbe
floor
to guide persons to emergency exxs
in
the
smoke-filled environment. The Safety Board agrees with this recommendation.
Further,
in addition
to
the pmpojed improvements already announeed by the Administrator,
the
equipment. These
tests
have demonstrated vividly that
the
performance
of
hard
fire
FA.:
tests conducted
at
the Technicai Center
have
identified other needed upgrading
of
performence
of
the carSon dioxide, dry chemical,
or
water
-
type hand extinguishers and
extinguishers with the Halon extinguishing agent is significantly superior to
the
that safety will be enhanced
by
rephcirg
the
latter types of extinguishers with
the
Halon
type. The Safety Board strongly encourages
the
FAA to expedite the rulemaking actions
exit indicators,
and
hand fire extinguishers usirig advanced technology extinguishing
to make
fire-blocking seat materials, improved emergency lignting, tactile emergency
agents
mandatory in the transport airplane Ceet
as
early
as
practicable.
The
FAA
acted promptly
in
response to Safety Recommendation A
-
73
-
121 to
result
of
the
FAA's assessment
and
tests,
the
relevant section of the airplane's Flight
assess
the adequacy of the smoke removal procedures
on
the
Boeing
707
airplane.
As
a
Mar~ual was revised to include improved
:xd
clearer saoke removal procedures. Both the
recommendation and the FAA's actions were specifically directed
to
the Boeing
707
airplane.
On
that basis, Safety Recommendation
A
-
73
-
121
was close"
an?
FAA's
response
was deemed acceptable. However, the circumstances of the Air Canada accident indicate
McDonnell Douglas
OC-9
airplane. The Safety Boerd questions
the
applicability
of the
that
the
flightcrew
encountered difficult? in
controlling smoke in
the
cockpit
of
the
prescribed procedures when a cabin fire continues to generate smoke and toxic gases.
Further, testimony at
t3e public hearing disclosed uncertainties among
both
fightcrew
and expert witnesses regardicg optimal smoke control procedures,
such
as
the best
use
of
cabin air conditioning systems. The Safety Board, consequently, believes that smoke
removal procedures
in
all
types
of
air
carrier airplanes should
be
reassessed.
The
?AA
dia
cot
concur in
the
SafeLy Board's recommendation
to
require that
automatiedischarge fire estinguuishers be instailed
in
lavatory waste receptacles
on
all
transport airplanes (Safety Kecommmdation
A
-
74
-
98).
The FAA reasoned that the
combined actions
of
installL~g
fully
sealed waste receptacles to assure fire contsinment
and extinguishment, as required by Airwo-ihiness Directives for transport category
airplanes, and
the
prohibition
of
smoking in airplane lavstories eliminated the
need
for
discharge fire extinguishers have been installed
in
the lavatory waste
receptacies
of
some
mandatory
instailation
of
automatic
-
discharge
fire extinguishers.
A!though
actcmatic-
airplanes, including the Air Canada
DC-'3,
they i;ave not been required
and
are not
generalip installed. The Safety Board closed Safety
Reconkmendation
74
-
98
after
assessin:
FAA's
action as unacceptable.
Moreover,
the
Safety Board is concerned that the FAA's actions to assure a
sealed
Ciesign of the lavatory waste receptacle have
not
been adeqwte.
On
June
25,
19S3,
a flight attendant aboard
en
Eastern Air
Lines
Mc1)onneil Douglas
DC
-
9
airplane noticed
smoke coming from the right rear lavatory as the airplane
was
being
taxied
lo
the gate
after
landinz.
It
was determined that the
fire
had started within
the
lavatory waste
receptscle and propagated behind
the
vanity
io
the
lavatory aft wall before
ir
wss
extinguished
by
the airport iiie department. The inspection
of
the undamaged left
rear
lavatory in
tile
airplane revealed that the upper area of
the
waste
chute
behind the
disposal door was not sealed to contain a fire,
6c.d there
was
no fire extinguisher in
the
receptacle. Further, it was evident that waste could accumulate
in
the
enclosed area of
the vanity adjacent
to
the waste receptacle. Following this incident, the Safety Board's
-75-
Safety 3owd
on
July
1, 1983,
issued the following Safety Recommendation:
personnel have observed similar discrepancies aboard other airplanes.
As
a result,
the
Issue a Telert maintenance bulletin to all principal airworthiness
inspectors to inspect immediately
all
lavatory paper
ad
linen
waste receptacle enclosure access doors and disposal doors
on
the
appscable aircraft
for
proper operation, fit, sealing, and latching
for
the
containment of possible trash fires,
in
accordance with
the
recyirements
of
AD
74
-
08
-
09.
(Safety Recommendation
A
-
83
-
46)
telegraphic General Notice
(GENOT),
So.
8320.283,
describipg discrepancies
in
airplane
On
the same
day
that the recommenda.ion was issued, the
FAA
issued
a
lavatories observed by
FA.4
inspectors aad emphasizirg the need for
%?
aircraft lavatory
maintenance and inspection program designed to
zorrect these discrepancies. Tne Safety
Eoard believes that this immediate action was appropriate; however, it appears
that
the
continued fire containment integrity of lavatory waste receptacles cannot be assured even
with periodic inspection. Thus,
the
Safety Board
wYd
continue to advocate
that
more
positive protection against
fires
in and adjacent
to
waste receptacles be provided by an
au?ometic-discharge fire extinguisher.
Cntii recently, Safety rioerd recommendations
and
related
FAA
actions to
minimize the
lawtory fire hazard have focused on the waste receptacle
as
the
most
common
fire
origin. However, since the Air Canada accident, the Safety Board
has
examined ;he potential hazard of overheated electrice.1 components associated with
the
iavatoFy
flush
pump motor circuits. Concern regarding
&his
safety hazard was expressed
after
the
Safety Board's investigation
of
an incident which occurred
on
July
12,
1983,
in
Safety Recommendations
X-S3-4'1
through
X
-
83
-
49
which were :?sued
on
July
19, 1983,
involving
an
American Internstional .\irways
DC
-
9
on
the ground
st
Charlctte, Xorth
Caroiina,
in
which smoke
wes
observed coming from
the
airplane's rigt.t rear lavatory
while
it
was being serviced. Shortly thereafter, maintenance personnel observed that
several circuit breakers
had
tripped, including the 5
-
ampere breakers for the 3
-
phase
electric flushing motor. Examination
of
the components disclosed
that
the flushing motor
hai overheated, that a phase
-
to
-
phase short had taken place
in
the motor, and that the
recommended
on
July
19,
i9S3,
that the
FAA:
flushing circuit timer had
been
Gamaged
by
overvoltage.
As
a
result, the Safety Board
inspection
of the
tavatory flushing
pump motor and
the assxiated
Issue
m
Airworthiness Directive
(1)
to require
an immediate
wiring harnesses between the timing components and
the
motor
in
the lsvatorics of transport category airplanes
for
evidence
of
moisture
-
induced corrosion deteriorated insulation and to
exhibit
such
conditions be replaced, and
(2)
to establish a3propriate
require that flushing pump motors
or
wiring harnesses which
periodic intervals for repetition
of
these inspections. (Safety
Recommendation
A
-
83
-
17)
airframe
manlfacturers,
a
procedure
which
airline
maintenance
Establish,
in
con;unction
with the
flush
pump motor, timer,
an6
personnr:
could employ
to
verify
that
the electrical circuitry of
lavatory flushing pump motors has
not
been damaged
by
corrosion
or
other
cnuxs
so
as to produce excessive heat during motor
operation. (Safely Recommendation
A
-
83
-
48)
-76-
ance Inspectors
to
assure
that airlines
have
an
acceptable program
Issue
a Maintenance Aiert Bulletin to require Principal Xainten-
(1)
for
the freqitent removal
of
waste from all areas
of
the lavatory
with particular attention to those enclose5 areas in
and
around ate
susceptible to the accumuiatior,
of
fluids
in
the vicinity
of
wire
wate
receptacles, and
(2)
which gives sufficient emphasis
to
areas
harnesses and other electrical components which can cause corro
-
sion.
(Safety Recommendatioq
443-49)
Safety Recommendations, issued Notices
of
Proposed Rule Making (NPRM):
N?RM
83
-
24,
The Safety Board notes that the
FAA
has, in response to several
of
the
33crd's
NPRM
83
-
15,
and
SPRM
84-5.
NPRM's
83
-
14
and
83
-
15
were issued on October
i:?
1983.
The proposed
rules
contained in NPRX
83
-
14
establish more stringent flammability
requirements for type certification
of
transport category airplanes and would require that
previously certified airplanes conform to the more stringent criteria within
3
years
from
the date the proposed rules are made effective.
NPR;M
83
-
15
would establish the requirement to provide
floor
Froximity
emergency escape path markings in transport category airplanes. The proposed
rule
requires
#at
the
floor
proximity emergency escape path provide visda! guidance to
passengers
when
all sources
of
illumination more
?han
4
feet above the caSin aisle
floor
are
obscured
by
dense
smoke.
Previously certified airplanes would have
ta
CGZI~~~
with
the
new
standard within
2
years from the date
the
proposed rule jecomes effective.
The
2roposed rules
would require
the
insthilation
of
automatic fire extinguishers
for
each
On
&fay
17,
'
984,
NPR%
84
-
5,
which contains three proposed rules, was issued.
lavatory disposal receptacle for towels, paper, and waste. The rules would
also
require
i
the installation of smoke detector systems
in
the
gaIIegs
end
lavato~es
of
air transport
category airplanes and increase the number of hand fire extinguishers
to
be
located
in
passenger compartments. Because
the
chemical agent Halon
1211
has
demonstrated
superior performance
and
effectiveness in combating fires, the proposed mle would
require that at leas: two Halon
12li
hand fire extinguishers be installed
in
the airplane
cabins.
All
air carriers would have to comply with these provic:o!!s within
1
year after the
rules become
effeliive.
following additional recorninendations to the Federal Aviation Administration:
Upon
its
consideration of this accident report, the Safety Board issued the
Require that
Air
Cerrier Principal Opxations Inspectors review
the
that
they
be
amended
to
emphasize requirements:
training programs
of
their respective carriers and if necessary speciry
-
for flightcrews to take immediate and aggressive action to deter-
begin
an
emergency descent for landing
or
ditching if the source
mine the source and severity
of
any
reported cabin fire and to
end
severity
of
the fire are not positiveiy
and
quickly determined
or
if immediate extinction is not assured.
-
for flight attendants to recognize the urgency
of
informing flight
-
crews of the location, sortrce, and severity of
>my
fire
or
smoke
within the cabin.
B
-77-
-
for both flightcrews and flight attendants to
be
knowledgable
Of
the proper mthcds
of
aggressively attacking
a
cabin fire by
including hands
-
on
-
training in the donning
of
prctective breathing
equipment,
the
use of
the
fire ax to gain access to the source of
the fire through interior panels which can be penetrated without
risk
to
essential aircraft components, and the discharge of
an
appropriate hand fire extinguisher on
ai?
actual fire. (Cless
11,
Priority Action) (A
-
84
-
76)
Require
that
Airplane Flight Xanuals, Air Carrier Flight Operations
Nanuals, and Flight Attendant Manuals be amended to include cornpre-
hensive discussions and ilhstrations showing
the
proper use
of
a
fire
ax
and
the
locations
in
each modei
of
aircraft opexted where a fire ax
can
be used safely to gain access
to
e
fire
or
smoke emission source.
(Class
11,
Priority Action)
(X
-
84
-
73
Require that those interior cabin panels of transport category airplanes,
including panels
of
the lavatories and galleys. which can
be
safely
penetrated with a
fire
ax be identified
by
an
acceptable and standardized
means.
(Cilss
11,
Priority Action) (A
-
84
-
33)
The Safety
Board
believes that its recommendarions when implemented will reduce
or
eliminate possible sources of ignition, provide earlier detection af cabin fires, and
provide improved
procedures
and eqiipment
for
fligh:crew and cabin crew personnel to
combat and control cabin fires. Since these recommendations address
every
possible fire
1
Board also believes
that
its actions
will
either prevent
or
reduce
the
possibility of a
source and every possible area where cabin fires most logically could originate,
the Safety
recurrence
of
a fire similar to thet encountered on board Flight
797.
BY
THE
KATIONAL TRANSPORT.4TiON SAFETY
BC.ARD
/sf
JIX
BURNETT
Chairman
lsj
PATRICIA
A.
GOLDMAN
Vice Chairman
/sf
G.H.
PATRICK
BURSLEY
Member
!si
VERNON
L.
GROSE
Member
August
5,
1984
-79-
5.
APPENDIXES
APPENDIX A
INVESTIGATION AND
PUBLIC
HEARING
1.
investigation
The National Transportation Safety Board was notified
of
the accident about
from
its
Wasnirgton,
D.C.
headquarters. Investigative groups were formed
for
operations
1930,
on
June
2,
1983, and immediately dispatched an investigative team to
the
scene
and witnesses, air traffic control, meteorology, human factors, structures,
powerplants,
systems, flight data recorder, maintenance records and cockpit voice recorder.
Parties to the investigation were the Federal Aviation Administration,
Air
Canada, lilcDonnel1 Douglas Corporation, L'nited Technologies Corporation, and
the
Greater Cincinnati International Airport. Transport Canada appointed an accredited
representative to assist the Safety
hard
during
the
investigation. The accredited repre-
and
Canadiar Air Lines Flight Attendants Associarion. Transgort Canada also
made
sentative was assisted
by
advisors from Air Canada, Canadian Air Line Pilots Association,
available
its
laboratories
and laboratory personnel.
2.
Public Hearing
1
August
16,
1983. Parties represented
at
the hearing were
the
Federe! Aviation
A
4-day
public hearing
was
held in
Fort
Mitchell, Xentucky, beginning
Administration,
Air
Canada, McDomell Couglas Corporation, Heath Tecna Corporation,
Transport Canada appointed
an
accredited representative
to
assist the Safety Board
Canadian Air
Line
Pilots Association, and
the
Greater Cincinnati International Airport.
during the public hearing.
-80-
APPENDIX
B
PERSONNEL
iNPORMATION
Cep'ain Cameron
Captain Donald
S.
Cameron, 51:
was
employed by
Air
Canada
on
March
28,
1956.
He
holds Canadian Airline Tramport Certificate
No.
YZA
000964
with
airplane
sh$e
and muitiengine
le?&
ratings. The captain
is
type rated
in
Grumrnan 673: Vickers
CaGCein's
last
class
-
1,
group-l
Canadim Medical Certificate was issued February 17,
VC-9, Lockkkeed
7,-49,
and
:,::3onnell Douglas DC
-
3,
-4,
-
8,
and
-
9
airplanes. The
1983,
End
contained
the
foliowirg limitation,
"
Valid only when required
glasses
are
available.':
passed
his
last
proficiency
check
on
February 14, 1983;
his
last
line
check
on July
16,
CapTajn
Cameror!
quaiifid
as
ceptein in
the
DC
-
9 during November i974.
He
1982;
and
completed
his
last
recurrent training on
Janusry
24, 1983. The captain had
flcwn about 13,000
hours,
4,939
of
which
were
in the DC
-
9.
3L;ing
the
fast
90 days, 30
days, and
24
hours
before
the accident, he had flown
ill
hours, 39 hours, and 9 hours,
respectively. The captain had
been
off duty sboux
If
hours
55
minutes before re?orting
for
this
flight.
At
the
time
of
the accident, he
had
Seen on duty about
7
hours 35 minutes,
5
hours
10
ninutes
of
which
was
flight
time.
First
Officer Ouimet
Fht
Officer Cleude OuImet,
34,
was
enployed
by
Air
Canada on
November
25,
1973.
tie
holds Canadian Senior Ccnmereial Pilot Certificate
No.
ULS
(
102366
with
2
Class
1.
Group
I
Instrumen? Rating valid
to
February
1,
1984;
ratings
for
all
types
of
Class
7
airplanes
of
i2,500
pounds or
:e%,
and for
the
DC
-
9. The license is
net
valid
for pilot-in-eommand
in
"airplanes
of
more then i2,500 pounds engaged
in
commercial
air
service and passengers carried.
"
His
last
class
-
I, group-1 .Tar,adian
Sledice1 Certificate was issued April
21,
1983, with no iimitations.
First Officer Ouimet qualified
as
first
officer in
the
DC
-
9 during February
19;U.
He
passed
hi?
lest proficiency check on July
14,
1982: his
last
line
check on
Xay
26,
1985; and completed his last recurrent training on January
12,
1983. The first officer had
flown about
5.659
hours, 2,499 of
which
were in
the
DC
-
9. Durirg the
last
90
days,
30
days,
and 24 hcurs before t>e accident, he
had
flown
144
hours,
75
hours,
and
9
hou-s,
respectively. The first officer
had
been
off
duty about
11
hours
55 minutes before
reporting
for
this
flight.
At
the
time
of
:he
accident,
he
had
been
on duty about
T
hours
35
minutes,
5
hours
10
minutes
of
wnich
was
fligh:
time.
11
CFR
129.15 states:
current certificate or
license issued or validated by the
country
in
90
person
may
art
as
a
flight crew
-
member unless he holds
a
which
that aircraft
is
registered showing his ability to
Gerforrn
his
duties connected
with
that aircraft.
Since both the captain and first officer possessed Canadian certificates with DC
-
9
type
ratings,
they
were qualified to opcrutc DC
-
9 type airplanes
within
the
United States.
-81- APPEXDIX
B
b
Flight Attendant Benetti
Flight Attendant Sergio Benetti, 37,
was
employed by Air Canada Jarwary 2,
1972. The
Elignt attendant completed
his
initial training Jenuary 3, 1972, and
his
last
recurrent
trainky
on
August
11,
1982. The fiht attendant had been off duty for
11
hours
55
rninctes
before reporting
for
this flight.
At
the
time
of the accident, he had been on
duty about
7
hours
35
minutes, 5 hours 10
minutes
of
which was
flight
tine.
Flight Attendant Kayama
Flight Attmdant Laura Kayama,
28,
was
employed by Air Canada in
?iky
1975.
The flight attendant completed
her
initial training in June 1976; and her
latest
recurrent
training
on
February 16, 1983. Her duty and
off
duty
times
were
identical
with
those
of
Flight ;Ittendant Benetti.
Flight Attendan? Davidson
Flight Attendant Judith
L.
Davidson, 33, was ep.p!oged by Air Canada
on
July
9,
1973. She had completed her initial
training
on
September
7,
1973, and her
latest
recurrent training on
June
17,
1982.
Her
dutv
ana
off duty times
were
identical
with
those
of
Flight Attendant Benetti.
Gregory L.
Ka-ar,!
B
TRACOX.
The approach controller was employed
by
the
FAA
on
January
9:
1374, and
is
a
Gregory
L.
Karam,
36,
was
the approach controller at the Cincinnati
full
performance
level
controller.
His
last
second
-
class medica: certificate
was
issued
November 5,
1982, and
the
.pontroller
was
required
to
ifpossess
glasses
for
'ear and distant
vision.
"
On
June
2,
1983* the controller reported for duty
at
1500 and assumed his
approach
contro! station
at
1557.
James
L.
Ferguson
James
L.
Ferguson, 49,
was
the
Louisville high altitude radar controller.
He
controller and
is
also an area supervisor
at
the Indianapolis XRTCC. The controller's
last
was
employed by
the
FAA
on
December
12,
1956.
He
is
a
full performance
level
second
class
medical certificate was
issued
February
16,
19S3 and contained no waivers
or
limitations.
On
June
2,
1983, the contro'ler reported
for
duty at
1245
and assumed
the
Louisville high altitude radar controller dkties
at
1744.
Jack
B.
Xartin
December
2,
1957, and is
e
full
performance level contrdler. His
last
second
-
class
Jack
?ilartin,
S9,
was
the
LEX
-
D controller.
He
was employed by the FAA
on
medical
certificate
was
issued
February
24,
1983, and contained
no
waivers
or
limitations.
On
June
2,
1983,
the
controller reported
for
duty at 1200 and assumed
the
LEX
-
D
position
at
1745.
-82-
APPENDIX
C
AIRPLANE
INFORMAEON
~
~
McDonneli Douglas DC
-
9
-
32,
C
-
FTLU
April
7,
1968, and had been opersted by
the
airline continuousli; since
that
time.
A
review
The
airplane manufacturer's
serial
No.
47196 was delivered
to
Air
Tanada on
of
the
airpiane's
flight
logs
and maintenance records showed
that
ali
applicable
Airworthiness Directives had
been
complied with, and that
all
checks and inspections were
completed within
their
specified time !hits.
The
records review showed that the airplane
had Seen
maintsined in a-cordance with nompany procedures and Canadien rules
end
performance
of
the airplane and any
of
its
components.
i
i
regulations
znd
disclosed
no
discrepancies
that
could have affected adversely the
The
airplane was powered
by
Pratt
and Whicney
JT8Dl-:R
engines
rated
at
?1,000
pounds
of
static
thrust
for
ttlkeoff
at
sea
level
at
84O
F.
The
following
is pertinent
statistical
data:
Airplane
Total Airplane Time
-
36,825 hours
Total
Airplene Landings
-
34:987
Powerplants
Engine
~
No.
1
-
X%
2
Serial Number P657758D P657360D
Total Time
Total Cycles
20,942 hours 28,990
hours
29,598
21,459
-33-
APPENDIX
D
'T2,5-SCili?T
DF
A\
AIR
CA'<ADA
COCKPIT
VOICE
RECORDER,
S/N
1613
RE?iOYED
FRO+!
.<
D2XL.G
DC
-
9
WiiICH
X.=
INYCLVED
IS
A'i
ACCXDES?
AT
CXNCiKKAX,
OHIO,
OS
JUhY
2,
19S3
LEGESD
Cockpit
ares
microphone voice
or
sand
smxe
Rsdio
transmission from accident aircraft
.,
voice idenzified
as
Captain
Voice identified
as
First
Officer
mice
identified
as
male
Flight Attendant
..
ya
:
-
ident'r'ied
as
female flight Attendmt
t-sice
i6m:liied a;
a
male passenger
Indiz?zx::5
Cezrer
i'arou5
aircraft
Unintelligible word
Sonpextinent
word
(&testionable text
Editorial insertion
Pause
X1
times are expressed in
centrai
standard
time.
INTW-COCKPIT
T
I
ME
e
SOURCE
CAM
18~18:12
CAM
1848:lS
CMI
1851
:O3
CMI-1
1851:04
CAM
CAM
-
2
CAM
-
I
1851
:09
CAM
-
2
1851:14
CAM
CPM-2
CAh-
1
1851
:
19
CAM
-
2
CAM-
1
CAM
-
1
rAM-2
-
-
.
-
-
COWW
-__
((Sound similar
to
arcing))
((Sound similar
to
arcing))
((Two
sound!: similar
tu
arcing))
How
is
your
sea
food,
nice?
((Sounds similar
to
arcinq
and
snapping))
It’s
good
steak
nice?
Ciffercnt,
a
little
bit
dry
hut
okay
((%unds
similar
to
arcing
and
snapping))
(What
was
that?)
II
It’s
right there,
I
see
it
Yeah
nc
bus
Which
one
is
that.?
-.
CONTENT
C
h
1
r;
0
b..
ip
3
1
2
it
Y
r;
b..
n
T
I
M
E
e
SOURCE
CAM
-
1
CAM
-
2
1852:26
CAM
-
1
1853:16
CAM
-
1
1853:21
CAM
-
1
1853:25
CAM
-
2
CAM
-
1
CAM
-
2
1853:30
CAM
-
I
INTRA
-
COCKPIT
CONTENT
*
put
it
in
the book,
there
Log
it
Now
I
want
to
log
it,
eh
Somebody
must
hove
pushed
a
rag
down
the
old
toilet
or
something, ch?
Jammed
it,
and
it
overheated
Is
it
flushing you
pushed?
It's
flushing, yeah
(Motor)
*
Toilet flushing, three hrcakers
banged
AIR
-
GROUND
COKMLINICATIONS
TIME
4
SOlJRCE
_
-
-
CONTENT
W
m
1853:SS
CTK
Air
Canadn
seven
ninety
seven,
contact
Indianapolis
on
one thrcc
three
point
zero
five
WO-
2
1fi53:40
Air
Canada
seven
nine SCVcn,
So
long
1853:41
C'l'l<
so
long
0
n
a
-
4
0
U
a
rt
rt
*rt
*-
0
d
x-
3
8
m
x
U
a
z.
m
1
*
m
1-
d
R
(P
x
R
3.
1
(P
m
0
-.
a
5
*
0
m
-5
Ip
m
0
(Y
A
a
m
3
.
rt
5
m
"
(Y
3
-
x)-
om
Ov,
IW
v,
w
d
..
3
INTRA
-
COCKPIT
TIME
6
SQURCB
CORmeNT
CAM
-
1
(Well
it's)
1858:16
CAM4
That (one)
is
lettered
D.G.
*
CAM
-
1
Oh
I
see,
oh
yeah, yeah
*
1858:27
CAM
-
1 A1 ternate, ah,
must
be
dur
a1 ternate
here
CAM
-
1
Ah who
gives
a
#
1850:43
CAM
-
1 Nothing
to
do with us
CAM
((Sound similar
to
cockpit door))
CAM
-
3 Yeah thank you
sir
1859:02
CfrM-7
uw
x
CAM
-
1
1859:30
Twenty
nine
U,
W,
and
X
twenty nine, those
are the grid references
1859:3?
CAH-2
Twenty ninep yeah
1859:4z
CAM
-
1 Twenty ninu
UNX
three
---
the left toilet
flushing
CAI*!-
2
Left
AIR-tiROUND
CWICATIONS
TIME
4
SOIJRCE CONTENT
W
I
m
I
A
TIME
8
SOURCe
1859:47
CAM
-
1
1859:5%
CAM
1859:59
CAM
1900:
00
CAM
NOTE
:
CAF1-
1
CAM
-
2
CAM
-
1
1900: 51
CAM
1901 :12
"-2
1901
:
33
CAM
-
1
CM
1901 :42
-I_
CONTeNT
Yeah
aft
left toilet flush, and they
wouldn't accept a reset
sound
similar
to
arcing))
((Sound
of
f!rst
attempt to reset and
sound
siniilar to
arcing))
((Sound
of
second
attempt to reset' and
sound similar to arcing))
((Sound
of
third attempt
to
reset and
copilot said they did not hear the sound
((When questioned later, the captain and
of arcing noted on the
CVR
CAM
channe:.
just one time each))
They said they attempted to reset breakers
Pops as
I
push
it
Yeah, right
Yeah
((Sound of cough))
Zero two seven set for ya Don
Better
---
have dinner here
((Sound
of
chime))
AIR
-
GROUND
COMJNICATIONS
TIME
6
SOURCE
CONTENT
I
m
I
u)
L..
c
m
rt
In
0
rz
E
a
3
rn
'5
ID
e+
0
U
C
7:
0
-4
J
01
f
a
-
06
-
8.
INTRA
-
COCKPIT
TIME
8
SOURCE
CAM
-
2
CAM
-
2
1902:40
CAM
-
4
CAM
-
1
CAM4
CAM
-
2
CAM
-
1
1902
:
50
CAM
-
2
CAM
-
1
CAM
-
4
CAM
-
5
CAM-
7
190
3
:06
CAM
-
5
CAM
-
?
CAM
-
5
1903
:;I?
CAM
-
.,
CONTENT
((Sound
of
whistling))
Louisville
---
Rosewood, zkay
at the back, they're
just
oh went hack
Excuse me, there's a fire
in
the washroom
to
go to put
it
out
Oh
yeah
They're
still,
well they're
just
gonna
go
back now
Want me to
go
there
Yeah
go
*
the brakers
W
up
Leave
my,
leave
my,
leave
my
dinner
in
the
thing
there for a minutc
Okay
(Can
1
buy you a drink cause there's
something going on,
drink
or
a shot)
Ah,
I
wouldn't say that
Yeah okay
Still there huh?
Yeah
Got the, ah, breakers pulled
AJR
-
GROUND
COWJNICATIONS
TIME
4
SOURCE CONTENT
_I_
_.__
-
INTRA
-
COCKPIT
TIME
0
SOIJRCE
CAM
-
1
CAM
-
2
CAM
-
I
1913:21
CAM
-
4
1903
:
31
CAM
-
4
CONTENT
It's
the
motor
Pardon me
You
got
all
the
breakers pulled
out?
The
breakers are
all
pulled, yeah
(*
*
make
'em
all
seat?)
Captain
is
it
okai:r
LO
move everybody
up
as
far forward as possible
1904:07
CAM
-
2
Okay
I
eh,
you don't have to do
it
now,
I
can't
go
back now,
it's
too
heavy,
I
think we'd hetter
go
down
AIR
-
GROUND COMMUNICATIONS
'i'lMfi
fi
SOURCE CONTENT
p_I-__---
I--
CTR
Republic
two
eighty eight Indianapolis,
Memphis
one
thtec
three
point eight five
three
three eight. five, goodbye
77
L
seven srven lima (Knoxsville)
*
two none
zero
--
I
iD
N
CTR
Seven seven lima (Knoxsville) roger
I
CTR
1903:51
Delta
sixteen
twenty
six
continue
desccnt to flight level
two
four
zero,
Indianapolis
(X4
1904
:
00
Center one
two
eight five live on
two
four
zero
at
twenty cjl:ht
fifty
five,
so
long
RIXl-'?
(CJearcd)
ah
okay
I!
a
c.
-
3
Q
-
is
-
...
'a
2.
1
n
5;
2
-
f
i)
Y
U
W
0,
B
c1
r
m
INTRA
-
COCKPIT
TIME
fi
SOURCE
comrrr
CAM
-
1
CAM
-
3
1906342
CAM
-
3
CAM
-
1
1906:
50
1906:52
CMI-
3
1906:54
CAM
-
1
CMI-
3
190G:SS
CAM
CAM
-
2
(Coming along okay)
Getting
much
better, okay
inside the
washroom
wen
though
I
could
1
was able
to
discharge half of the
CO2
not see the
source
bot
its
definitely
inside
the
lavatory.
Yeah,
it's
From
the toilet,
it's
from
the toilet
COZ
it
was
almost half a bottle and
it
now almost cleared
Okay, tktank
you
Okay, good 10cX
((:Sound
similar to cockpit
door))
Okay,
you
got
it
*
AIR-GROWD
COFMIJNICATIOI4S
TIME
6
SOURCE
CONTENT
.,..-
-_.
1906
:
03
CIR
Canada
scven ninety seven Indianapolis
Center, go
ahcad
1906:lZ
RliO-l
Ywh,
we've got
nn
electrical problem
here, we
may
he
off
communication shdrtIy
ah
stand
hy
TIME
6
SOIlRCI!
CAM-
1
CAM
-
I.
1907:ll
cm-2
CAM
-
1
1907:
14
CAM
-
2
I
don't
like
what's
happening,
I
thini;
we
hettcr
go
down,
okay?
Okay
Okay,
I'll
he
back
t,here
in
a
minute
1907:41
((Recorder
goes
off))
AIR
-
GROUND
-_
COMMUNICATIONS
TIME
&
SOIIIKE CONTENT
-
-
__.I-
1907
:
28
Q362
Hello
Centcr,
I'iedmont
three
sixty
I
two,
wetre
level
at
flight
lcvcl
threes
threc
zero
I
CTR
I907
:
32
Zlrcc
sixty
two
Indianq~l
is
Ccotct-
roger
1907:3§
1'362
We'll
take
direct
Ilolston
Mountnin
if
you
can
do
thot
APPENDIX
E
14
CFR
25
FLAME
RESISTANCE
CRITERIA
14
CFR
25.853.
Section
11
CFR
25.853(a) states in part:
Flame resistance criteria for airplane compartment materials are contained in
Interior ceiling panels, interior wall panels, partitions: galley structure,
large cabinet walls, structural
flooring snd materials
used
in
the
construction of stowage compartments (other than underseat stowage
compartments for stowing small items such as magazines ana maps)
must
be self
-
extinguishing when tested vertically in accordance with
the
applicable portions of appedix
F
of
this
part,
or
other approved
equivalent methods. The average
burn
length
may
not exceed
6
inches
and the average flame time after removal
of
tine
flame
source
may
not
exceed
15
seconds. Drjppings from
the
test
specimen may not continue
to flame
for
more than an average
of
3 seconds after falling.
Section
14
CFR
25.853C~)
states, in part:
Flax covering textiles (including draperies and uphoisterg) seat cushions,
paddinz. decorative and nondecorative coated fabrics, leather trays and
galley furnishings, electrical conduit, thermal and acoustical
insillation
:nd
insu!ation covering air ducting, joint and edge covering, cargo
compartment liners, insulation blankets,
. . .
must be self
-
extinguishing
appendix
P
of this part,
or
other approved equivalent methods. The
when tested
verticaliy
in
accordance with the applicable portions of
average burn length may not exceed
8
inches and the average flame time
after the removal of the flame source
may
not exceed
15
seconds.
Drippings from the test specimen may not continue to flame
for
more
than an average
of
5
seconds after falling.
demonstrate compliance with
i.4
CFR
25.853
are contained
in appendix
F
of
14
CFR
25.
The acceptable test procedures, fiame
heat,
and apparatus required to
Kith
regard to vertical and horizontal flame testing,
and
the
appendix states, in part:
(e)
Vertical test.
.
.
.
For
materials covered
by
section 25.853(a), the
flame must
be
applied
for
60
seconds ar?G then removed. Flame time,
burn length, and flaming
+ime
or
drippings, if any, must be recr-:
4
The burn length determined in accc,;:
Tdt
-+th
pa.
...z
raph
(h)
of this
eppendix must be measured to the nearest one
-
tenth inch.
(e)
Horizontal test.
.
.
.
The fiame must be spplied for
15
seconds and
then removed. Minimum of
10
inches
of
the s?ecimen
must
be used
for
burning f;ont reaches the
'
ning zone, and the average burn rate
must
be
timing purposes, approximately
1
ii2
inches must burn before the
recorded.
(h)
Exn
length.
Surn
length is the distance from
the
original edge to the
farthest evidence of damage
to
the test specimen dae to flame
impingement, including
arecs
of
partial
or
complete consumption,
charring,
or
embrittlement,
but
not including areas
sootr-3,
stained,
warped,
or
discolored. nor areas where material has
shrunk
or
melted
away from the heat source.
..
-86-