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Airplane Accidents and Fires
Thomas Me Murray*
INTRODUCTION
Airplane fires prompt fear and concern for anyone associated with air transport. Those
associated include He passengers and flight and cabin crews, as well as those who must
eventually provide rescue functions and extinguish an airplane fire. Fortunately, the aviation
community experiences few fires while in flight. Furthermore, those fires that do occur on the
ground are typically preceded by another event: a hard landing ruptures a fuel tank; a long
landing prompts a runway overrun; a premature landing causes excessive airplane damage; a
controlled flight into terrain shatters an airplane upon impact; etc.
Due to the frequency of and often repeated- preceding events, Boeing believes that the
most effective safety strategy available today is to PREVENT ACCIDENTS. Many airplane
accidents are preventable using current technology and preferred cockpit procedures. For
instance, controlled-flight-into-terra~n accidents are preventable through technology, the ground
proximity warning systems, and an appropriate response to the warning.
_ . . . . , , _ .
·
From reviewing multiple accident records, Boeing as well as others in the commercial
airplane transportation industry have determined that rarely is an accident the result of only one
event. Rather, most, if not all, accidents occur through a chain of events. For instance, the hard
landing is often preceded by an unstabilized approach; the unstabilized approach may occur due
to air traffic control instructions, weather, or other traffic; or cockpit procedures developed by
the airline may be inadequate for some circumstances. By focusing on these chains of events for
accidents and developing accident prevention strategies applicable to venous links in the chain,
Boeing and members of the commercial airplane transportation industry have found, and
continue to find, multiple opportunities for interrup~ir~g the chain of events leading to an accident
(see Figure I).
Fire certainly fits within the realm of a multiple-cause process. The only place on the
airplane where fire is planned is within the combustion chambers of the engine. Otherwise, any
other fire event on the airplane is unplanned and requires at least one "event or cause" to
precede the fire.
The information in this review of aviation accident data with associated fires is broken
into three parts. First, there is an examination of the commercial jet transport accidents from
1959 through 1993. This information is provided to offer a perspective regarding aviation
accidents from a variety of causes. Then, the second part reviews how fire has influenced the
accident record. This data is presented in a format similar to the overall commercial jet transport
statistics to help individuals compare the frequency of f~re-associated events with the variety of
other causes of accidents. Fire details are also provided to enhance understanding of airplane
fire-related accidents. Finally, the third part examines some specific fire scenarios to illustrate
*Airplane Safety Engineering, Boeing Commercial Airplane Group, Seattle, Washington.
7
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8
Improved Fire- arm Smoke-Resistant Materials
the range of events that occur, since looking at the number of events often fails to illuminate the
many parameters associated with an aspect of aviation accident data, such as fire-related events.
Moreover, these specific fire scenarios will also highlight the mul~ciple-cause process and
examine possible intervention opportunities where the outcome of the event might have changed
considerably through alternative actions. In addition, these specific events have resulted in a
range of outcomes despite some similar scenarios.
Prevent accidents
"Remove the links in the accident chain"
Con ~ ~
Hull loss accidents
Anr~u.J rates,
accidents p r
mililon at
departures
Conclu~lon-The accident rate has not decilned significantly
In the past 20 years
FIGURE 1 Accident chain concept.
Paradigm shift
Former view focused on the single
probable cause of an accident
· Current view:
Examines the entire chain of
events leading to an accident
Promotes multiple intervention
strategies to remove the links
in the accident chain
COMMERCIAL JET TRANSPORT ACCIDENT STATISTICS
Background for Accident Data-CoHection Processes
Boeing has collected accident data since 1959 for commercial jet operations with certified
jet aircraft greater than 60,000 Ib maximum gross weight. This data-collection effort has
included not only Boeing airplane models but also data for a variety of competitor airplanes.
Boeing believes that it must improve airplane safety using all available data sources; therefore,
all catastrophic airplane accidents are reviewed.
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Thomas M. Murrary
9
For the accident information presented in this review, there have been some data
exclusions. First, data for sabotage, military action/operation, and non-operational events are
excluded. Non-operational events include those where the airplane is not in service; the airplane
may be in a hangar for maintenance, on a ramp for overnight storage, etc. Relevant data
includes passenger operations; all-cargo operations; and test, training, demonstration, and ferry
flights. Furthermore, worldwide flight operations are included. However, accident data for
airplane models from the counties of the former Soviet Union are excluded due to the lack of
a complete accident record as well as a different and not well understood airplane certification
process as compared with Federal Aviation Administration (FAA), Civil Aviation Authority, or
loins Aviation Authority certification processes.
To determine the flight time and cycles, data is collected by both the aircraft
manufacturers and the engine companies. This data is gathered from operators' aircraft and
engine logs.
Accident data are obtained, when available, from government accident reports. In
addition, information is solicited from operators, manufacturers (both for the completed airplane
product as well as for various systems and components), and various government ant} private
information services. The accident selection criteria essentially corresponds to the U.S. National
Transportation Safety Board's accident definition. However, events are excluded that involve
nonfatal injuries resulting from maneuvering, atmospheric turbulence, loose objects, boarding
or disembarking, or airplane servicing activities.
To fully understand the accident data that Boeing collects, it is important that the
following definitions be relayed:
Aircraft accident means an occurrence associated with the operation of an aircraft
that takes place between the time any person boards the aircraft with the intention
of flight until such time as all such persons have disembarked, in which any person
suffers death or serious injury as a result of being in or upon the aircraft or by direct
contact with the aircraft or anything attached thereto, or the aircraft receives
substantial damage.
Serious injury means any injury that (~) requires hospitalization for more than 48
hours, commencing within 7 days from the date of the injury received; (2) results
in a fracture of any bone (except simple fracture of fingers, toes, or nose); (3)
involves lacerations that cause severe hemorrhages or nerve, muscle, or tendon
damage; (4) involves injury to any internal organ; or (5) involves second- or third-
degree burns affecting more than 5 percent of the body surface.
Fatal injury is defined as an injury that results in death within 30 clays of the
accident.
· A hull-Ioss means damage due to an accident that is too extensive to repair, or that,
for economic reasons, was not repaired, so that the aircraft was not returned to
service.
A survivable accident is one in which the fuselage remains relatively intact, the crash
forces do not exceed the limits of human tolerance, there are adequate occupant
restraints, and there are sufficient escape provisions.
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Improved Fire- arm Smoke-Resistant Materials
Boeing has accident data for 9 airplane manufacturers, which include data on 28 different
mode} types. As of the end of 1993, there were ~ 1,433 aircraft in service; 6,465 of these aircraft
were Boeing models. From 1959 through 1993, the commercial jet transport industry had
accumulated 406 million flight hours (237 million on Boeing aircraft) and 270 million departures
(149 million on Boeing aircraft). Figure 2 provides visual information for both the number of
airplanes in service and the annual departures since 1964.
Aviation Accident Data for HuN Losses and Fatalities
Hull-Loss Data
The aviation accident record, as measured by the number of hull losses each year,
suggests that the aviation industry possesses an enviable safely record compared with other
transportation modes. Overall, the worldwide commercial jet fleet has a hull-Ioss accident rate
of approximately two accidents per million departures. Figure 3 displays the worldwide
commercial jet fleet hull-Ioss accident rate per million departures for all airplane models. The
to~ number of hull losses from 1959 through 1993 was 512. From 1984 through 1993, 171 hull
losses occurred. Further specifics regarding the hull losses can be seen in Table I.
1 2,000
1 0,000
Aircraft
8,000
6,000
4,000
2,000
14
12
10
Annual
departures 8
(Millions) 6
A
1 1 ,433
-
-
-
o
65 67 69 71 73 Is 77 79 81 83 85 87 89 91 93
13.86
:
65 67 69 71 73 75
FIGURE 2 Jet aircraft in service and annual departures.
77 79 81 83 85 87 89
91 93
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Thomas M. Murray
50
40
30
Annual rates
accidents
per million
departures
20
10
o
\
59 61 63 65 67 69 71 73 75 77
Year
FIGURE 3 Hull-loss accidents (excludes sabotage and military action).
TABLE 1 Hull-Loss Accidents
11
79 81 83
85 87
89 91 93
1959-1993
1984-1993
512 hull losses
U.S. operators
· 97 during passenger operations
· 27 during all cargo operations
· 16 during test, training,
demonstration, or ferry
Non-U.S. operators
· 295 during passenger operations
· 43 during all cargo operations
· 34 during test, training,
demonstration, or ferry
171 hull losses
U.S. operators
· 23 during passenger operations
· 8 during all Argo operations
· 3 during test, training,
demonstration, or ferry
Non-U.S. operators
· 103 during passenger operations
· 24 during all-cargo operations
· 10 during test, training,
demonstration, or ferry
.
From the hullL-Ioss accidents chart (Figure 3), it appears that the commercial airplane
transportation industry has significantly reduced the accident rate from its initially high level to
a relatively low rate. However, despite the low accident rate, THE COMMERCIAL AIRPLANE
TRANSPORTATION INDUSTRY MUST CONTINUE TO IMPROVE. Indeed, the Boeing
goal, and now FAA-industry goal, is zero accidents. Consequently, Boeing has promoted the
concept of "preventing accidents" as noted in the introduction.
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Improved Fire- arm Smoke-Resistant Materials
Figure 4 shows why the current hull-Ioss accident rate is unacceptable. If the aircraft fleet
continues to expand (and there are a number of reasons for expansion to continue: increased
traffic in Asia, South America, arid counties of the former Soviet Union; increased global
business processes; increased leisure travel; etc.), then it is possible that the aviation industry
could experience a hull-Ioss every week by the year 2010. Clearly, this possibility is
unacceptable for the aviation industry.
40
35
30
25
Annual
hull 20
losses
15
10
5
o
2526
-
121 1
22
~1
1 1515
14
20,
l
1 990
21
,? .. ~ ~ .. a ~ ~ In. w~.~, ~.
~ Projected hulilosses per year
1 995
Year
1 985
2000 200s 2010
FIGURE 4 Projected hull-loss accidents based on accident rates for past 10 years and expected fleet growth.
Furthermore, some recent trends, as shown by a 5-year moving average of the hull-loss
accident rate, suggest that those in the aviation industry must remain vigilant in the pursuit of
zero accidents due to an apparent increasing hull-loss accident trend. (See Figure 5.)
From Figure 6, it appears that most of the newer-generation commercial jet transports
are contributing favorably to the lower hull-loss accident rate. However, the overall accident rate
is still I.9 hull-loss accidents per million departures. This airplane generation assessment is
further detailed by Figure 7. In this figure the hull-loss rates for various airplane generations,
except for those airplanes from the first generation of commercial jet transports, are noted.
The aviation industry is not without guides or direction as to the types of accidents that
occur and possible remedies. As Figure ~ shows, there are specific phases of flight where the
majority of accidents occur. For instance, final approach and landing phases of flight account
for more than 40 percent of the hull-loss accidents. On the other hand, these two flight phases
represent only 4 percent of the total flight time. Due to this data and other indicators used by
the airlines, many airlines have instituted specific final approach criteria. For instance, Boeing
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Thomas M. Murray
4
3.5
3
2.5
Annual rates,
accidents
per million 2-
departures
1.5
1
0.5
~L
~5 ear movie avera e:
a/1 1 T K'' ~ .
J
_ _
85
/
T
83
7:T 7: ! 7g 81
o
76 78 80 82 84
8 7 8 3 91 93
86 88 90 92
YEAR
13
FIGURE 5 Five-year moving average of hull-loss accident rates (excludes sabotage, military action, and former
Soviet Union airplane models).
Airplane Tvpe ~9.631
707D72O8 ~9.55
8801990 = 5.96
Tvic7e21n70 ~ 3.87 1 i_3.31 1 55.00
BAC 111 _ .1.18 _2,37
737-100/200 ~ 3|82
747-100/200/300 i= 1.11 1,
MD80 =~0.98
767 oo.29
BAG 146 _0.6 0.95
737 300/400F500 1.17
A320/A321 2 50
7474008 ~1~86
MA0~o 0 00
A330 0.00
Overall Rate 1.90
0 1 2 3
4 5 6 7 8 9 10
Accidents per million departures
FIGURE 6 Hull-loss accident rates per generation of aircraft (excludes sabotage and military action).
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14
Improved Fire- arm Smoke-Resistant Materials
20
15
Annual rates,
accidents 1 0
per million
departures
o
Second Generation
.~ .
Second
generation
..........
727
Trident
VC-10
BAC 111
DC-9
737-1 00/200
F28
DC-10
L-1 011
A300
, W
i ~
/,
Ah/
59 61 63 65 67 69 71 73 75 77 79 81 83 85
Year
,
Wide body New
(early) types
747-1 00/200/300 &1D80
MD1 1
737-300/400/500
747-400
757
767
A310
A320/A321
A330
A340
BAe 146
F100
\ ~
. New Types
_____
j\ ~l ~
87 89 91 93
FIGURE 7 Hull-loss accident rates by generic group of aircraft (excludes sabotage and military action).
Exposure percentage based on an average flight duration of 1.6 hours
Percentage of accidents
Load, | Takeoff
taxi | 14.3%
unload
2.0%
"" 1
54.5%
~. ~
Initial
climb
1 0.5°
Cruise
4.5°/O
Climb Cruise Descent Initial Final | Landing
7.0% 4.5% 7.2% approach approach 18.4%
11 .5% 24.6%1
/ Flaps retracted n \
~ /, = . _ ~ \~
Nav Outer
fix marker
1% 1 1% 1 13% 1 60% 1 10% 1 11% 1 3%1 1%
Exposure, percentage of flight time
FIGURE 8 Hull-loss accident rates for specific phases of flight (excludes sabotage and military action).
recommends that a stabilized approach be achieved by 1,000 feet. Most airlines require a
stabilized approach by at least 500 feet. If the airplane is not stabilized by 500 feet, most airlines
that require the airplane to circle for another approach go-around. One airline that uses the
~ ,000-feet stabilized approach guideline as a requirement has never had an approach accident.
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Thomas M. Murray
15
Take-off and initial climb also represent an opportunity for improvement. Some 25
percent of the hull-Ioss accidents occur during this phase of flight. Some actions that have
occurred include reinforcement of appropriate procedures for refused take-off decisions. For
instance, Boeing airplanes purposely disallow some messages from getting to the flight deck
during the take-off phase to prevent the pilots from being distracted by airplane functions that
do not affect the flying capability of the airplane.
As shown in Figure 9, the non-U.S. operators still have a higher accident rate than the
U.S. operators.
30
20
Annual rates,
accidents
per million
departures
10
o
T:~
'at
'at
Non-U.S
operators
L
. ,,,
, ,.
81 83 85 87 89 91 93
U.S.
operators
~ . ,,# ,,
_ _
_ _
59 61 63 65 67 69 71 73
75 77 79
Year
FIGURE 9 Hull-loss accident rates, U.S. and non-U.S. (excludes sabotage and military action).
Fatality Data
Hull-Ioss data is not the only measure of airplane safety processes. Another measure used
by Boeing and many airlines is the number of fad accidents that occur. This measure is useful,
since many hull-Ioss accidents do not result in fatalities. Table 2 shows a breakdown of the 398
fad accidents that occurred from 1959 through 1993.
Figure 10 shows that the fatality rate has declined from its initial high rate. However,
the number of fatuities per year does not show a similar decline.
As shown in Figure ~ I, there are particular events that have prompted the most fatalities.
Controlled flight into terrain (CFIT) remains a dominant cause of fatuities despite the
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16
TABLE 2 Brealcdown of Fatal Accidents
Improved Fire- aru] Smoke-Resistant Materials
1959-1993
1984-1993
398 fatal accidents
Passenger operation
· 319 fatal accidents
· 18,956 fatalities*
All~argo operation
· 44 fatal accidents
· 174 fatalities*
Test, training, demonstration,
and positioning
· 35 fatal accidents
· 168 fatalities*
120 fatal accidents
Passenger operation
· 96 fatal accidents
· 5,397 fatalities*
All cargo operations
· 18 fatal accidents
· 76 fatalities*
Test, training, demonstration,
and positioning
· 6 fatal accidents
· 53 fatalities*
*Onboard fatalities only.
introduction of Ground Proximity Warning Systems, improved crew procedures, and continuous
· ~
training.
Despite the low accident rates, any fatalities are unacceptable to all aviation participants.
The aviation industry must continue to find ways of interrupting the accident chain to PREVENT
ACCIDENTS.
COMMERCIAL JET TRANSPORT DRE STATISTICS
Recall that Figure 3 shows the worldwide hull-Ioss accident rate. Similar information for
fire-related hull-Ioss accidents follows. The fire-related hull-Ioss accidents were divided into two
categories: those hull-Ioss events where the fire was the primary cause of the hull-Ioss and those
events where some other event preceded the fire, thus fire was a secondary event. "Primary f~re-
related hull-Ioss events" include cargo compartment fires, lavatory fires, fuel tank fires, engine
fires, engine burst, etc. For primary fire events, the events were screened with the following
criteria: "If the fire had not occurred, would a hull-Ioss not have resulted?" If the answer to this
question was yes, then fire was the primary cause. (Engine burst was included in the primary
category despite the screening criteria, since flight crews have minimal control of the engine
burst phenomenon.) "Secondary fires" include such events as a hard landing where the landing
gear subsequently punctures the fuel tank, CFIT with resulting fire, refused take-off events
where the wings are sheared after the airplane goes off the end of the runway, etc. Secondary
events include all the events not placed into the primary category.
Given these two categories, the f~re-initiated hull-Ioss accident rate is 0. ~ per million
departures. The non-fire-initiated hull-Ioss accident with fire rate is 0.7 per million departures.
Figure 12 displays this data along with the overall accident rate. The f~re-caused hull-Ioss
accident rate, or primary category, is plotted in Figure 13 for 1959 through 1993.
OCR for page 17
Thomas M. Murray
20
Annual
rates
Accidents 1 0
per million
departures
o
15
Annual 1 0
fatalities,**
hundreds 5
o
17
_ __
~ ~ ~:
. _
L/ \/\
. ~ _ ___Wi
_/ ~ ~ ~
l
1
** Onboard fatalities only
_ _ 1 , ~
T
59 61 63 65 67 69 71 73 75 77 79 81
Year
83 85 87 89 91 93
FIGURE 10 Fatal accidents, annual rates, and annual fatalities (excludes sabotage and military actions).
2,000
1 ,500
Fatalities
1 ,000
500
o
Number of fatal
accidents (76 total) 28
r 1 88:`
,~
~306
3,513 total fatalities
1 993
~ ~4
357 ,57
278
157
~ 43 15
Loss of Loss of Airframe Mid-Air Ice/snow Fuel Loss of Runway Other
control Control collision exhaustion control incursion
(airplane (crew) (weather)
caused)
10 14 4 1 4
FIGURE 11 Worldwide airline fatalities (excludes sabotage and military action).
2 3 5
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18
FIGURE 12 Overall hull-loss accident rates and fire.
4.5
3.5
3
Annual rates, accidents 2 5
per mililon departures 2
1.5
1
0.5
o
FIGURE 13 Fire caused hull-loss accident rates.
Improved Fire- arm Smoke-Resistant Materials
Overall Hull Loss Accident Rate
1.9 Accidents per million departures
... - .~..?. '.. - . .~._
~ · Fire Initiated Hull Loss Accident Rate
per million departures
· Non-Fire Initiated Hull Loss with Fire
R ~, - , i# ~-
. ~Accident Rate
, ....................................................... ;
H.ar.d...l~a.ndiri~
it: : ................ . . ~. ~
. ~
'.. Staiiii~g.s of Control ~
................................................................................... ~
.................. .............. . ..
a : CoII.iSton
. ~
............................................. ..... .
hi' ~ _ E ~ ~
.7 per million departures
-
/ -
/1 1 1 ~ I i 1 t 1~ 1 1 ~1 1 ~ I I I I I I I I I
~ Q _ CatA" ~ A ~ Al ~ O - Cod Cal) ~ if) ~0 1~ a) Ch O - N All ~ ~ `0 ~ ~ 0~ 0 - Call CO
try ~ ~
0% 0~0% 0~ 0~ ~ ~ 0~ 0~ 0~ ~ Cat ~ ~ 0~ ~ ~ Ch
_ __ ___ ___________ _________ ______ ___
Year
Of all of the hull-loss accidents with fire, only ~ ~ percent of these events were initiated
by fire or in the "primary" category. Indeed, the remaining 89 percent of these hull-loss
accidents with fire were preceded by some other significant event, as shown in Figure 14 with
details on the contributors to both the fire-initiated and non-fire-initiated hull-loss accidents.
OCR for page 19
03 ~
~-
- ~
~- .
CD. 00 IS
- ~
~- .
- ~
~- ~
1
c]
of
CD
A
A
93
o
~-
.
CD
=e ~ .
3 3
o
~ ~ o
'A
~ i
o P)
lo.
=. ~ ~ ~
~ L~.e
B.
m
~ it ~ ~
~ ~-· 5" ~
· ~ g o
(D
to
~ I-' ~
{D ~ (p
=`
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20
Annual Fatatlies, 3
hundreds
2
FIGURE 16 Annual fire-smoke~aused fatalities.
Improved Fire- arm Smoke-Resistant Materials
~ T
5
4
^L~ ~IVI I IV'I I I lVIVi l\ ldlL
-
5; ~ ~ ~ $ ,; ~ :8 7; $ $ ° ~ '~ ~ ~ )Q i~ ~ ~ ~ ~ a' '~ ~ ~ ~' ~ ~ 0 8; ~ ~ ~ 8:
~ ~ ~ ~ on on ~ on on on ~ on ~ ~ on
__________ __________________
Year
SELECTED lilRE SCENARIOS
Although the statistics provide very detailed information regarding fire events, some
sample scenarios also reveal the diverse nature of the fire event. Therefore, summaries of four
different hull-Ioss accidents where fire occurred are provided. Event sequences are provided for
each accident to help readers focus on the chain of events preceding the accident.
The key message from these example accidents is that most, if not all, airplane accidents
are a chain of events. Therefore, these chains contain multiple opportunities to interrupt the
accident scenario.
Example: 727, Salt Lake City
The airplane had originally departed New York and landed in Denver (see Figure 17~.
The captain had flown that segment. The first officer was flying the Denver to Sail Lake City
segment. The airplane arrived within the Salt Intake approach area south of Provo, Utah.
Although it was dark, it was typical Utah weather: VFR (visual flight rules) to Il,000 feet
Normally, the captain preferred to descend prior to Provo, but that night the descent was delayed
momentarily. Eventually, the first officer started the descent. To meet the threshold
appropriately, the descent was motivated such that the airplane showed descent rates greater than
2,000 feet/minute. Company policy was to descend at 600 to 800 feet/minute. Prior to the
threshold, the first officer moved his hand to the throttles to arrest the descent. The captain
restrained the first officer. The flight engineer reported later that he, too, felt that the descent
needed to be arrested. The descent continued. The airplane landed 335 feet short of the runway
with a descent rate of 2,300 feet/minute. Despite the hard impact, the airplane remained
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Thomas M. Murray
21
relatively intact. Although He impact injuries were not excessive, many individuals were killed
by fire-related agents: smoke, fire, and lack of oxygen.
Again, there were multiple opportunities for altering the chain of events. First, the air
traffic control center needed greater understanding of the preferred airplane descent profiles.
Although airplanes can lose altitude very quickly, accelerated descents not only affect safety but
also affect airplane engine life. Next, the cockpit communications environment needed to utilize
the capability and recognize the concerns of all the flight crew members. One the outcomes of
this accident was to develop and promote the concept of cockpit resource management: all flight
crew members offer input while still allowing the captain to maintain his or her role as final
decision maker.
Accident profile
· November ~ 1, 1965
· 727 mode}
· Salt Lake City
Chain of events
1 . .
· Fatalities: 43
· 85 passengers
· 6 crew
First officer
flying
1 - -- ---- - - 1-- -----
Captain holds
throttle
· 1
Departs Arrive for Airplane
Denver SLC approach lands short
· Change
~ Procedures training for flighicrews
FIGURE 17 Lessons learned, 727 Salt Bake City accident. NOTE: Timelmes not to scale.
Example: DC-9, Cincinnati
The airplane had departed Dallas and was enroute to Toronto (see Figure 181. At 1851
the lavatory breakers popped on the flight deck. The flight crew cried multiple times to reset the
breakers. There was no communication between the flight crew and the cabin crew. At 1900,
there was a strong odor noticed in the cabin by both the passengers and the cabin crew. Within
a minute or so, the cabin crew recognized that there was a fire in the aft lavatory on the left side
of the airplane. Multiple CO2 fire extinguishers were deployed to arrest the fire in the lavatory.
At 1902, the first officer attempted to view the aft lavatory, but was stopped by smoke midway
through the airplane. By 1904:07, the first officer returned to the flight deck and informed the
captain of the situation. Within seconds, the cabin appeared clear. By 1905, the captain asked
the first officer to return to the aft lavatory using the captain's smoke goggles to get a first-hand
appraisal of the situation. Within 30 seconds, the airplane electrical system showed anomalies
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22
Imp roved Fire- arut Smoke-Resistant Materials
to the captain. The first officer returned to the cockpit where the captain was attempting to
diagnose the electrical system problems. By 1907:41, the master warning light illuminated. At
1908: 12, the captain declared an emergency descent and asked for the nearest airport.
During the venous attempts by the flight crew to understand the extent of the fire in the
aft lavatory, the airplane had passed Standiford Field where the airplane could have landed. The
airplane arrived on the ground at 1920:09 at Cincinnati International Airport. After this event,
at least two specific changes and procedure reinforcements were made to respond to airplane fire
events. First, all lavatories have smoke detection systems to alert crews of problems. Second,
for any event where fire is suspected, flight and cabin crews must communicate immediately,
and the flight crews will seek the nearest airport.
· Accident profile
· June 2, 1983
· DC-9
· Cincinnati International Airport
· Chain of events
Strong odor
in cabin
Fatalities: 23
· 41 passengers
~ 5 crew
Electrical Master
Flightcrew system warning
informed abnormalities light
1 1 11 . I I I 1 1
1 rid 11 1 1 1 7 1
Lavatory Flight attendants Cabin Electrical Descent
breakers pop recognize fire appears problem declared
clear diagnosis
· Changes
· Smoke and fire detection system
· New fire procedures
FIGURE 18 Lessons learned, DC-9 Cincinnati event. NOTE: Timelines not to scale.
Example: 737-200, Calgary and Manchester
The Calgary and Manchester events involving 737-200s were very similar; however, their
outcomes were remarkably different (see Figure 19~. In both events, the engine experienced an
unconfined engine burst phenomenon. The wing fuel tanks were impacted. Fuel then spilled
from the wing and ignited. The pilots, in both cases, were unaware of the extent of the fire.
After becoming aware of the fire, the pilots chose to continue the taxi to exit the runway.
Emergency evacuation was then initiated. However, the difference between the two accidents
was the direction of the wind as related to the final stop for the airplane. For the Calgary case,
the airplane was almost lined up with the wind. Thus, the fire did not penetrate the fuselage as
quickly as in the Manchester case.
Some of the industry responses to these events included engine improvements (blade
changes because of the Calgary accident and burner can improvements because of the
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Thomas M. Murray
23
Manchester accident); fuel door improvements; reinforcement of known procedures for
communications between the flight and cabin crews and for information flow from the tower to
the flight crew; arid reinforcement of current procedures by flight crews for fire events. One of
the procedures that pilots were reminded of was the need to stop the airplane immediately. This
action prompts airplane occupants to leave the airplane faster, promotes fuel runoff away from
the airplane when fuel spills occur, and favors the wind direction.
· Accident profiles
· March 22, 1984
· 737-200
· Calgary, Alberta
· Fatalities: None
· ~ 14 passengers
· 5 crew
· Chain of events
Calgary~
Takeoff Loud
initiated bang
Manchester
· August 22, 1985
· 737-200
· Manchester International Airport
· Fatalities: 55
· 131 passengers
· 6 crew
Left engine
parameters
Tower confirms Emergency evacuation
fire, 62 sec initiated, 1 min 55 sec
Flight attendant
identifies fire, 45 sec
Left engine
fire warning
Taxi Passengers
continues escape
Airplane Emergency
taxis evacuation
Takeoff Thud
initiated
Tower confirms Airplane parked Multiple
fire in crosswind fatalities
FIGURE 19 Lessons learned, 737 Calgary and Manchester events. NOTE: Timelines not to scale.
SUMMARY
Airplane fires, whether in-flight or on the ground, prompt not only apprehension in the
flying public but also can cause major devastation, both to life and property. However, despite
the enormity of the event, the commercial jet transport industry experiences such events very
infrequency. Furthermore, most fire-related events are preceded by events where intervention
at multiple points might prevent the accident.
Therefore, the commercial jet transport industry must retain its vigilance for preventing
airplane accidents by examining accident event chains, understanding the various links in the
chain, and then attacking multiple links to prevent the accidents.
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Representative terms from entire chapter:
million departures
