DOT/FAA/AR-99/57

Office of Aviation Research

Washington, D.C. 20591

CAA Paper 99003

Civil Aviation Authority

London, England

Fuselage Burnthrough Protection

for Increased Postcrash Occupant

Survivability: Safety Benefit

Analysis Based on Past Accidents

September 1999

Final Report

This document is available to the U.S. public

through the National Technical Information

Service (NTIS), Springfield, Virginia 22161.

U.S. Department of Transportation Civil Aviation Authority

Federal Aviation Administration London, England

NOTICE
This document is disseminated under the sponsorship of the U.S.

Department of Transportation in the interest of information exchange.

The United States Government assumes no liability for the contents or

use thereof. The United States Government does not endorse products

or manufacturers. Trade or manufacturer's names appear herein solely

because they are considered essential to the objective of this report. This

document does not constitute FAA certification policy. Consult your local

FAA aircraft certification office as to its use.

This report is available at the Federal Aviation Administration William J.

Hughes Technical Center's Full-Text Technical Reports page.

www.tc.faa.gov/its/act141/reportpage.html in Adobe Acrobat portable

document format (PDF).
Technical Report Documentation Page

1. Report No.

DOT/FAA/AR-99/57

2. Government Accession No. 3. Recipient's Catalog No.

 4. Title and Subtitle

FUSELAGE BURNTHROUGH PROTECTION FOR INCREASED POSTCRASH

5. Report Date

September 1999

OCCUPANT SURVIVABILITY: SAFETY BENEFIT ANALYSIS BASED ON

PAST ACCIDENTS

6. Performing Organization Code

7. Author(s)

Ray Cherry and Kevin Warren

8. Performing Organization Report No.

9. Performing Organization Name and Address

R.G.W. Cherry & Associates Limited

20 Bull Plain

10. Work Unit No. (TRAIS)

Hertford

Hertfordshire, SG14 1DT

England

11. Contract or Grant No.

12. Sponsoring Agency Name and Address

U.S. Department of Transportation

Federal Aviation Administration Civil Aviation Authority

13. Type of Report and Period Covered

 Final Report

Office of Aviation Research London, England

Washington, DC 20591

14. Sponsoring Agency Code

 ANM-100

15. Supplementary Notes

The FAA William J. Hughes Technical Center COTR was Richard Hill.

16. Abstract

The objective of this analysis was to assess the potential benefits, in terms of reduction of fatalities and injuries, resulting from

improvements in fuselage burnthrough resistance to ground pool fires. The process employed for assessing benefit is considered

to give reasonably accurate and consistent results within the limitations imposed by the available data. The methodology gives a

reasonable assessment of the tolerance on the predicted levels.

Fire hardening of fuselages will provide benefits in terms of enhanced occupant survival and may be found to be cost beneficial if

low-cost solutions can be found. The maximum number of lives saved per year in worldwide transport aircraft accidents, over the

period covered by the data, was assessed to be 12.5 for the aircraft in its actual configuration and 10.5 for the aircraft configured

to later airworthiness requirements.

17. Key Words

 Postcrash, Burnthrough, Benefit analysis, Fuel fire

18. Distribution Statement

This document is available to the public through the National

Technical Information Service (NTIS) Springfield, Virginia

22161.

19. Security Classif. (of this report)

 Unclassified

20. Security Classif. (of this page)

 Unclassified

21. No. of Pages

 169

22. Price

Form DOT F1700.7 (8-72) Reproduction of completed page authorized
iii

TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY vii

1. INTRODUCTION 1

2. OBJECTIVES 1

3. METHOD 1

3.1 Selection of Accidents 1

3.2 Accident Scenarios 3

3.3 Survivability Chains 4

3.4 Statistical Modelling 6

3.5 Later Requirements 6

3.6 Variation of Benefit With Burnthrough Time 7

3.7 Accident Analysis Methodology 7

4. RESULTS 8

4.1 Benefit Definitions 8

4.2 Benefit Based on the Aircraft Standard at the Time of the Accident 8

4.3 Benefit Based on an Aircraft Standard Applicable to Later Requirements 10

5. ANALYSIS 12

5.1 Number of Burnthrough Accidents 12

5.2 Comparison Between Fatality Rate and Injury Rate 13

5.3 Comparison With Previous Studies 13

5.3.1 Comparison With Cabin Water Sprays 13

5.3.2 Comparison With a Representative Set of Survivable Accidents 14

5.4 Fire Entry Path 14

5.5 Sensitivity 15

5.5.1 Sensitivity to Burnthrough Protection Time 15

5.5.2 Sensitivity to Number of Burnthrough Accidents 15

6. DISCUSSION 16

6.1 Methodology 16

6.2 Results 17

6.3 Cost Benefit 19
iv

7. CONCLUSIONS 19

8. REFERENCES 20

9. DEFINITIONS 20

APPENDICES

AStatistical Modelling

BAccident Rationales 1 to 7

CAccident Rationales 8 to 17
v

LIST OF FIGURES

Figure Page

1 Relation of Selected Data to Whole Database 3

2 Example Survivability Chain 4

3 Example of Survivability Chain Showing Possible Improvements in Survivablity

as a Result of Fuselage Fire Hardening 5

4 Combining Two Independent Assessments 7

5 Variation of Improvement in Fatality Rate With Additional Burnthrough Protection

Time for the Seventeen Aircraft in Actual Configuration 9

6 Variation of Improvement in Injury Rate With Additional Burnthrough Protection

Time for the Seventeen Aircraft in Actual Configuration 10

7 Variation of Improvement in Fatality Rate With Additional Burnthrough Protection

Time for the Seventeen Aircraft Configured to Later Requirements 11

8 Variation of Improvement in Injury Rate With Additional Burnthrough Protection

Time for the Seventeen Aircraft Configured to Later Requirements 12

9 Bar Chart Showing Comparison Between the Results From This Study and That

Derived From the Representative Set 14

10 Reduction in Median Improvement With Highest Contributing Accident Removed 16
vi

LIST OF TABLES

Tables Page

1 List of Burnthrough Accidents Identified 2

2 Fatality Rate Improvement for Aircraft in Actual Configuration 8

3 Potential Life Saving for the Seventeen Aircraft in Actual Configuration 9

4 Fatality Rate Improvement for the Seventeen Aircraft Configured to Later

Requirements 10

5 Potential Life Saving for the Seventeen Aircraft Configured to Later Requirements 11

6 Best Assessment of Median Lives Saved for Varying Improvements in Burnthrough

Protection Time 13

7 Comparison With Representative Set 14

8 Fire Entry Areas 15
vii

EXECUTIVE SUMMARY

The objective of this analysis was to assess the potential benefits, in terms of reduction of

fatalities and injuries in worldwide transport aircraft accidents, resulting from improvements in

fuselage burnthrough resistance to ground pool fires. The process employed for assessing benefit

is considered to give reasonably accurate and consistent results within the limitations imposed by

the available data. The methodology gives a reasonable assessment of the tolerance on the

predicted levels.

The International Cabin Safety Technical Group’s Survivable Accidents Database was used to

identify past worldwide transport aircraft accidents and extract detailed data for those accidents

where fuselage burnthrough was an issue in the survivability of the occupants. Each of these

accidents was analysed in depth to assess the number of lives and injuries that would be saved by

a fire-hardened fuselage.

Seventeen accidents to Transport Category aircraft were identified during the period from 1966

to 1993 where occupant fire injuries were sustained, and fire penetration of the passenger cabin

occurred as a result of ground fires. Each accident was divided into scenarios where it was

assessed that there was a similar level of threat to the occupants. A mathematical technique was

used to model each accident scenario and a Monte Carlo simulation was used to predict a high,

median, and low value for the benefits assessed.

A range of burnthrough protection times was used, and results are presented for protection times

from 30 seconds up to 8 minutes. Eight minutes was chosen to encompass the highest level of

protection thought to be practical. The reduction in the structural strength of the fuselage as a

result of a pool fire appears to have a limited effect on occupant survival. If this is confirmed it

is likely to result in a greater opportunity to find cost beneficial solutions to hardening aircraft

against pool fires.

The analysis was carried out for the aircraft standards at the time of the accident and assessed for

the aircraft if it were configured to the latest airworthiness requirements.

Fire hardening of fuselages will provide benefits in terms of enhanced occupant survival and may

be found to be cost beneficial if low-cost solutions can be found. The maximum number of lives

saved per year, over the period covered by the data, was assessed to be 12.5 for the aircraft in its

actual configuration and 10.5 for the aircraft configured to later airworthiness requirements.

The variation of benefit with degree of burnthrough protection is approximately an exponential

curve with a horizontal asymptote suggesting limited improvement beyond the four to eight

minutes additional protection points.

The assessed benefit derived from this study is similar in magnitude to that determined from

using a representative set of survivable accidents, giving confidence in the results. Costs have

not been assessed to ascertain the cost per life saved for possible methods of enhancing the fire

penetration of aircraft. However, the relationship between benefit and additional burnthrough

protection, derived from this study, will assist in carrying out such an analysis.
viii

The prime fire penetration route is via the fuselage skin and no evidence could be found to

suggest that alternative routes contribute significantly to occupant survival.

Aircraft configured to the latest cabin safety requirements are likely to exhibit limited enhanced

protection against large external pool fires since major penetration of the fuselage skin is likely to

result in the rapid progression of fire throughout the passenger cabin.

It is not considered likely that the rate of fatalities and injuries per year caused by fuselage

burnthrough will change markedly for the near future.
1

1. INTRODUCTION.

This report contains the method and results of a benefit analysis carried out on fuselage

hardening for burnthrough protection against large ground pool fires.

A number of past accidents have been identified which are considered to have involved fire

penetration of the passenger cabin with a consequential threat to occupant survival. For each of

the accidents identified, the assessed benefit in terms of the reduction in number of fatalities and

injuries has been derived assuming improvements to the fire hardening properties of the aircraft

fuselage. Section 9 of this report contains the definition of terms used in this study.

2. OBJECTIVES.

The objective of this study was to assess the potential benefits, in terms of reduction of fatalities

and injuries, resulting from improvements in fuselage burnthrough resistance to pool fires by:

• Using the International Cabin Safety Research Technical Group’s Survivable Accidents

Database to identify and extract detailed data for those aircraft accidents where fuselage

burnthrough was an issue in the survivability of the occupants.

• Analysing each accident in depth to assess the number of lives and injuries that might be

saved by a fire-hardened fuselage.

• Assessing the benefits in the context of all survivable aircraft accidents.

3. METHOD.

3.1 SELECTION OF ACCIDENTS.

Survivable or potentially survivable accidents on scheduled or nonscheduled passenger carrying

transport aircraft were selected for inclusion in the analysis based on the following definition of a

burnthrough accident:

“An aircraft accident where the fuselage skin was penetrated by an external fire while live

occupants were on board.”

This definition would exclude instances where the fuselage was consumed by fire after the

evacuation period was complete and those accidents where the fuselage burnt through from the

inside.

For the purposes of this analysis, the definition of a survivable accident is:

“An aircraft accident where there were one or more survivors or there was potential for

survival.”
2

Only survivable or potentially survivable accidents, in which there were fire injuries, were

selected for analysis. Accidents in which there were no fire related injuries were not analysed

since there could be no benefit to be gained from a fire-hardened fuselage.

The accidents were selected using the Survivable Accidents Database of the International Cabin

Safety Research Technical Group and from information contained in reference 1.

Where accident information did not explicitly state that burnthrough had occurred, it was

necessary to make the assumption that a pool fire existing outside an intact portion of fuselage

would burnthrough, given the nature of the intensity of the fire.

Seventeen accidents were identified as listed in table 1. The relationship between this subset and

all fatal accidents on the database is shown in figure 1.

TABLE 1. LIST OF BURNTHROUGH ACCIDENTS IDENTIFIED

Date Location Aircraft

14-Sep-1993 Warsaw A320

01-Feb-1991 Los Angeles B737

31-Aug-1988 Dallas B727

26-Jun-1988 Habsheim A320

22-Aug-1985 Manchester B737

30-Aug-1984 Douala B737

07-Dec-1983 Madrid B727

13-Sep-1982 Malaga DC10

07-Oct-1979 Athens DC8

17-Dec-1978 Hyderabad B737

15-Mar-1974 Teheran Caravelle

30-Jan-1974 Pago Pago B707

22-Jan-1973 Kano B707

20-Dec-1972 Chicago DC9

18-Apr-1972 Addis Ababa SVC10

08-Apr-1968 Heathrow B707

16-Feb-1967 Menado L188
3

Note: This does not represent all survivable accidents over the time period considered.

FIGURE 1. RELATION OF SELECTED DATA TO WHOLE DATABASE

3.2 ACCIDENT SCENARIOS.

The severity of hazard in an accident can vary markedly throughout the aircraft. Experience has

shown that considering occupant injuries on a “whole” aircraft basis can be misleading when

assessing the effects of survivability factors. It is therefore necessary to divide the aircraft into

“scenarios.”

A scenario is defined as:

“That volume of the aircraft in which the occupants are subjected to a similar level of threat.”

A similar level of threat need not necessarily result in the same level of injury to occupants. The

extent of injury sustained can vary with numerous factors including age, gender, adoption of the

brace position etc. Furthermore, the threat to occupants can vary over relatively small distances.

For example, a passenger may receive fatal injuries because of being impacted by flying debris,

and a person in an adjacent seat may survive uninjured. Dividing accidents into scenarios

provides a more meaningful basis on which to analyse accidents than considering the whole

aircraft due to the marked variation in survival potential with occupant location.

The flight deck and flight attendant areas are generally considered as separate scenarios. The

flight deck often has the potential for greater impact damage, and crewmembers usually have full

harness restraints. Furthermore, sliding cockpit windows in the area provide a nearby method of

egress. The flight attendant areas are normally considered as a separate scenario from the

566 (*See Note) SURVIVABLE ACCIDENTS

ON THE DATABASE *

356 ACCIDENTS WITH FATALITIES

(25001 OCCUPANTS)

17 ACCIDENTS INVOLVING

BURNTHROUGH

(2201 OCCUPANTS) 1966 - 1993 (28 YEARS)

140 FIRE RELATED FATAL

ACCIDENTS

(11975 OCCUPANTS)
4

passenger cabin due to the significant differences in seating, restraint systems, and exit

availability.

For these reasons all analytical work carried out during this study has been based on carrying out

assessments for each scenario.

3.3 SURVIVABILITY CHAINS.

A mathematical model, known as a Survivability Chain, has been developed such that the overall

effect on survivability may be determined from improvements made to survivability factors,

taking into account injuries that may be sustained by occupants. A Survivability Chain is derived

for each scenario in each accident.

A scenario where injuries are sustained due to impact and subsequent fire has been modelled

using two levels in the Survivability Chain.

An example of the model and the effects of improvement in injuries and fatalities resulting from

changes to fuselage fire hardening are shown in figure 2.

FIGURE 2. EXAMPLE SURVIVABILITY CHAIN

There are therefore:

• 45 uninjured survivors.

• 25 injuries, 10 as a result of the impact, 10 as a result of the fire, and 5 seriously injured

as a result of the impact and fire.

45 UNINJURED

SURVIVORS

10 FIRE

INJURIES

60 IMPACT

SURVIVORS

20 IMPACT

INJURIES

IMPACT

FIRE

 100 OCCUPANTS

FIRE

20 IMPACT

FATALITIES

5 FIRE

FATALITIES

10 IMPACT

INJURIES

5 IMPACT/FIRE

INJURIES

5 IMPACT/FIRE

FATALITIES
5

• 30 fatalities, 20 as a result of the impact and 10 as a result of the fire (5 of whom

sustained nonfatal injuries from the impact).

If improvements were made to fuselage fire hardening, such that it was assessed there were now

only 2 fatalities and 6 seriously injured of the 20 impact injured occupants and only 2 fatalities

and 7 seriously injured of the 60 impact survivors, then the survivability chain becomes as shown

in figure 3.

FIGURE 3. EXAMPLE OF SURVIVABILITY CHAIN SHOWING POSSIBLE

IMPROVEMENTS IN SURVIVABLITY AS A RESULT OF FUSELAGE

 FIRE HARDENING

Hence the improvement to the fuselage fire hardening results in:

• 51 uninjured survivors.

• 25 serious injuries, 12 as a result of the impact, 7 as a result of the fire, and 6 as a result

of the impact and fire.

• 24 fatalities, 20 as a result of the impact, and 4 as a result of the fire (2 of whom sustained

nonfatal injuries from the impact).

The overall situation is summarised as follows:

Survivors Injuries Fatalities

Prior to Improvement: 45 25 30

Post Improvement: 51 25 24

51 UNINJURED

SURVIVORS

7 FIRE

INJURIES

60 IMPACT

SURVIVORS

20 IMPACT

INJURIES

IMPACT

FIRE

 100 OCCUPANTS

FIRE

20 IMPACT

FATALITIES

2 FIRE

FATALITIES

12 IMPACT

INJURIES

6 IMPACT/FIRE

INJURIES

2 IMPACT/FIRE

FATALITIES
6

3.4 STATISTICAL MODELLING.

Software has been developed to use this model in a mathematical representation of an accident

using Monte Carlo Simulations. This simulation enables an assessment to be made of the change

in numbers of survivors, injuries, and fatalities resulting from predictions of the range of

improvements that may be possible from changes to a survivability factor.

For each scenario, a numerical assessment is made of the effect on the number of fatalities and

injuries because of changes to fire hardening of the fuselage. The assessment results in a

prediction of the highest, median, and lowest number of fatalities and injuries that could

reasonably be expected from the change.

From the example described in section 3.3, the best (or median) assessments were made of the

improvement in the number of fatalities and injuries resulting from enhanced fuselage

burnthrough protection. When making this determination an assessment would also be made of

the maximum and minimum number of fatalities and injuries that are likely to result from a

change in the fuselage fire hardening.

It is then assumed that there can be 100% confidence that the fatalities and injuries will lie in the

range from the maximum to the minimum. The software makes random selections over the

range 0% to 100% to arrive at a particular number of fatalities and injuries.

From this, a re-evaluation of the number of survivors may be made using the Survivability Chain

generated for the accident scenario. This is then compared with the actual number of survivors

of the accident. The iterations are then carried out many times to generate a distribution. From

this distribution the 21⁄2, 50, and 971⁄2 percentile values are selected to represent a range of the

likely improvement in fatality rate for fire-hardened fuselages.

This simulation process is described in detail in appendix A.

It is recognised that the models are not perfect representations of an accident nor are the

statistical assessments totally accurate. However, they will provide a better assessment of the

likely impact of improvements to fuselage fire hardening than would otherwise be derived from a

simple estimate of the resultant change in number of survivors.

3.5 LATER REQUIREMENTS.

Assessments of the improvements in fatality rate were carried out for the accidents based on the

aircraft standard, and operating requirements, at the time of the accident. Each accident was then

reanalysed taking into account the improvements that might have been made to numbers of

fatalities and injuries if the aircraft had been configured to the latest requirements.

The benefit information, relating to aircraft configured to the latest requirements, was entered

onto a separate computer database and the statistical analysis described in section 3.4 repeated.
7

The later requirements used to reassess the accidents were:

• Floor proximity lighting/marking

• Seat blocking layers

• Fire hardening of cabin interior materials

• Improved access to type III exits

3.6 VARIATION OF BENEFIT WITH BURNTHROUGH TIME.

The benefits of a fire-hardened fuselage will depend on the extension to burnthrough times

provided. Since this study does not make any assumptions about how the burnthrough protection

is achieved, it was necessary to employ a range of burnthrough times and repeat the analysis for a

number of different values.

It was difficult to assess from the accident rationales exactly when the burnthrough penetration

occurred; therefore the assessments were based on incremental burnthrough improvement times.

The process of assessing high, median, and low values for fatalities and injuries was repeated

using the following increases in fuselage burnthrough times; 30, 120, 240, and 480 seconds.

The statistical model was run for each of the protection times and for both the actual aircraft

configuration and the aircraft configured to later certification and operating requirements.

3.7 ACCIDENT ANALYSIS METHODOLOGY.

The assessments were carried out by two analysts. Each of the accidents was analysed by analyst

1. After the assessment was complete, there was a discussion between the analysts on each

accident. Analyst 1 then made a revised assessment and analyst 2 made another, independent

assessment. The results from these assessments were combined by using the largest extremes of

the predicted number of fatal injuries and taking the average of the medians as shown in figure 4.

This technique was used to reduce the effect of any bias either analyst might have had in making

his assessment.

FIGURE 4. COMBINING TWO INDEPENDENT ASSESSMENTS

Extreme of "highs"

Extreme of "lows"

Average of "medians"

Analyst 1 assessment

Analyst 2 assessment
8

4. RESULTS.

All of the results contained in this section of the report are based on the assumption that the 17

accidents identified are the only fatal burnthrough accidents that have occurred over the period.

Subsequent sections of this report discuss the validity of this assumption and the most likely

benefit to be achieved from enhancements to fuselage burnthrough protection.

4.1 BENEFIT DEFINITIONS.

The following definitions are used for the benefits assessed by this analysis.

An improvement in fatality rate is defined as:

“The reduction in the number of fatalities divided by the total number of occupants aboard.”

An improvement in injury rate is defined as:

“The reduction in the number of serious and fatal injuries divided by the total number of

occupants aboard.”

In order to derive the total number of lives saved in all survivable accidents in which there were

fatalities, the fatality rate must be multiplied by the total number of occupants, i.e., 25001.

(Refer also to figure 1.) In order to derive the number of lives saved per year, the total number of

lives saved must be divided by the number of years the data encompassed, i.e., 28. A similar

process is adopted for deriving the total number of injuries from injury rate.

4.2 BENEFIT BASED ON THE AIRCRAFT STANDARD AT THE TIME OF THE

ACCIDENT.

The high, median, and low prediction of effect on fatality rate was based on 9999 iterations of all

burnthrough-related accidents identified on the database using the method described in section 3.

These predictions were based on the aircraft configured to the standard at the time of the accident

and took no account of the improvements offered by the introduction of later requirements.

The values shown in table 2 represent the incremental change in fatality and injury rate predicted

for all survivable accidents in which there were fatalities (25001 occupants, refer to figure 1).

TABLE 2. FATALITY RATE IMPROVEMENT FOR THE SEVENTEEN AIRCRAFT IN

ACTUAL CONFIGURATION

Additional Burnthrough

Protection Time

Median Improvement in

Fatality Rate

Median Improvement in

Injury Rate*

30 seconds 0.00279 0.00315

2 minutes 0.00568 0.00484

4 minutes 0.00751 0.00841

8 minutes 0.00764 0.00952

*Note that injury rate includes fatal and serious injuries.
9

These results are summarised in table 3 for the best estimate (median) of number of lives saved

over the period 1966 to 1993 and the average per year. They are also displayed graphically in

figures 5 and 6.

TABLE 3. POTENTIAL LIFE SAVING FOR THE SEVENTEEN AIRCRAFT IN ACTUAL

CONFIGURATION

Additional Burnthrough

Protection Time Median Lives Saved

Median Lives Saved

Per Year

30 seconds 69.6 2.5

2 minutes 142.1 5.1

4 minutes 187.7 6.7

8 minutes 191.0 6.8

Aircraft in actual configuration

0

0.002

0.004

0.006

0.008

0.01

0 100 200 300 400 500 600

Additional Burnthrough protection time (secs)

Improvement in fatality rate

High

Median

Low

Curve fit

FIGURE 5. VARIATION OF IMPROVEMENT IN FATALITY RATE WITH ADDITIONAL

BURNTHROUGH PROTECTION TIME FOR THE SEVENTEEN AIRCRAFT IN ACTUAL

CONFIGURATION

The graph is shown overlaid with a least squares exponential curve fit for the median line having

the formula 0.0077(1-e(-0.013t)) where t is the additional burnthrough protection time in seconds.

It should be noted that the coefficient 0.0077 is the horizontal asymptote and represents the

maximum assessed improvement in fatality rate with a perfectly fire-hardened fuselage.
10

Aircraft in actual configuration

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0 100 200 300 400 500 600

Additional Burnthrough protection time (secs)

Improvement in injury rate

High

Median

Low

Curve fit

FIGURE 6. VARIATION OF IMPROVEMENT IN INJURY RATE WITH ADDITIONAL

BURNTHROUGH PROTECTION TIME FOR THE SEVENTEEN AIRCRAFT IN ACTUAL

CONFIGURATION

The graph is shown overlaid with a least squares exponential curve fit for the median line having

the formula 0.0102(1-e(-0.0063)) where t is the additional burnthrough protection time in seconds.

It should be noted that the coefficient 0.0102 is the horizontal asymptote and represents the

maximum assessed improvement in injury rate with a perfectly fire-hardened fuselage.

4.3 BENEFIT BASED ON AN AIRCRAFT STANDARD APPLICABLE TO LATER

REQUIREMENTS.

The high, median, and low prediction of impact on fatality rate was based on 9999 iterations of

all accidents on the database using the method described in section 3 assuming that the aircraft

were configured to the later requirements standard.

The values shown in table 4 represent the incremental change in fatality and injury rate predicted

for all survivable accidents in which there were fatalities (25001 occupants, refer to figure 1).

TABLE 4. FATALITY RATE IMPROVEMENT FOR THE SEVENTEEN AIRCRAFT

CONFIGURED TO LATER REQUIREMENTS

Additional Burnthrough

Protection Time

Median Improvement in

Fatality Rate

Median Improvement in

Injury Rate*

30 seconds 0.00266 0.00250

2 minutes 0.00457 0.00466

4 minutes 0.00618 0.00782

8 minutes 0.00636 0.00852

*Note that injury rate includes fatal and serious injuries.
11

These results are summarised in table 5 for the best estimate (median) of number of lives saved

over the period 1966 to 1993 and the average per year. They are also displayed graphically in

figures 7 and 8.

TABLE 5. POTENTIAL LIFE SAVING FOR THE SEVENTEEN AIRCRAFT CONFIGURED

TO LATER REQUIREMENTS

Additional Burnthrough

Protection Time

Median Lives

Saved

Median Lives

Saved Per Year

30 seconds 66.5 2.4

2 minutes 114.2 4.1

4 minutes 154.6 5.5

8 minutes 159.1 5.7

Aircraft configured to later requirements

0.000

0.002

0.004

0.006

0.008

0.010

0 100 200 300 400 500 600

Additional Burnthrough protection time (secs)

Improvement in fatality rate

High

Median

Low

Curve fit

FIGURE 7. VARIATION OF IMPROVEMENT IN FATALITY RATE WITH ADDITIONAL

BURNTHROUGH PROTECTION TIME FOR THE SEVENTEEN AIRCRAFT CONFIGURED

TO LATER REQUIREMENTS

The graph is shown overlaid with a least squares exponential curve fit for the median line having

the formula 0.0063(1-e(-0.014t)) where t is the burnthrough protection time in seconds.

It should be noted that the coefficient 0.0063 is the horizontal asymptote and represents the

maximum assessed improvement in fatality rate with a perfectly fire-hardened fuselage.
12

Aircraft configured to later requirements

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0 100 200 300 400 500 600

Additional Burnthrough protection time (secs)

Improvement in injury rate

High

Median

Low

Curve fit

FIGURE 8. VARIATION OF IMPROVEMENT IN INJURY RATE WITH ADDITIONAL

BURNTHROUGH PROTECTION TIME FOR THE SEVENTEEN AIRCRAFT CONFIGURED

TO LATER REQUIREMENTS

The graph is shown overlaid with a least squares exponential curve fit for the median line having

the formula 0.0088(1-e(-0.0076t)) where t is the burnthrough protection time in seconds.

It should be noted that the coefficient 0.0088 is the horizontal asymptote and represents the

maximum assessed improvement in injury rate with a perfectly fire-hardened fuselage.

5. ANALYSIS.

5.1 NUMBER OF BURNTHROUGH ACCIDENTS.

Seventeen accidents were identified as matching the selection criteria in section 3.1 and were

considered appropriate to use for the benefit analysis.

It was considered likely that there are other accidents where burnthrough was an issue but

because there is little or no data available, they cannot currently be identified. If other

burnthrough accidents have occurred, then the derived benefit would increase. This is because

the incremental change in fatality rate and injury rate is derived from the total number of

occupants in survivable accidents - which is a constant for the period considered. Therefore, the

results contained within section 4 can be considered as the minimum level of benefit achievable.

From a study carried out of the Survivable Accidents Database, it is assessed that of the

worldwide fire related fatal accidents (currently 140 on the Database) only 54% have sufficient

data to assess whether burnthrough occurred. If the accidents not having available accident data

have a similar benefit potential to those that do, then it is likely that the levels actually realised

will be approximately 1.84 times (1/0.54) those contained in section 4 of this report.
13

Application of this factor to the benefit derived from the accidents studied results in the assessed

median lives saved shown in table 6.

TABLE 6. BEST ASSESSMENT OF MEDIAN LIVES SAVED FOR VARYING

IMPROVEMENTS IN BURNTHROUGH PROTECTION TIME

Additional Burnthrough

Protection Time

Median Lives Saved

per Year

30 seconds 4.4

2 minutes 7.6

4 minutes 10.1

8 minutes 10.5

The factor of 1.84 may be applied to all of the benefit assessments based on the 17 accidents in

order to obtain an assessment applicable to all accidents.

5.2 COMPARISON BETWEEN FATALITY RATE AND INJURY RATE.

Examination of the results in tables 2 and 4 shows that the potential improvements to injury rate

can be less than the improvement in fatality rate. Injury rate includes serious and fatal injuries

and might be expected to improve at a greater rate than fatality rate alone.

This apparent anomaly is because the general reduction in injury severity allows for fatally

injured occupants to move into the seriously injured category and potentially increase their

numbers if insufficient seriously injured move into the minor or no injury category. By way of

example, consider the fire hazard presented to the 60 impact survivors shown in figure 2. If the

five fire fatalities were reduced to two by the introduction of some enhanced cabin safety feature,

then there would be an obvious reduction in the fatality rate. However, if this resulted in the

number of seriously injured occupants increasing to 13 (those previously sustaining fatal injuries

now being seriously injured), the total number of serious and fatal injuries would remain at 15.

There would therefore be no change in injury rate.

5.3 COMPARISON WITH PREVIOUS STUDIES.

5.3.1 Comparison With Cabin Water Sprays.

The benefit analysis that was carried out on cabin water sprays (reference 1) in 1991 concluded

that

“... today cabin water sprays would save on average 14 lives per year world-wide.”

This benefit should be compared with the assessed 10.5 lives saved per year for enhanced

burnthrough protection times of eight minutes derived in this study.
14

5.3.2 Comparison With a Representative Set of Survivable Accidents.

As part of a separate study (see reference 2) a representative set of survivable accidents has been

derived. This set of 55 accidents has been selected such that it has similar attributes to the entire

population of survivable accidents. Within this set, there are four burnthrough accidents. From

this study it is assessed that these four accidents have the potential for 62 median lives to be

saved from 1967-1995 an additional eight minutes of protection time for an aircraft configured to

the latest requirements. Over the twenty-eight-year period involving a total of 356 survivable

accidents this equates to (356/55) x (62/28) = 14 lives per year.

TABLE 7. COMPARISON WITH REPRESENTATIVE SET

Assessment of Lives Saved

per Year From This Study

Assessment of Lives Saved per Year Based

on the Representative Set of 55 Accidents

10.5 14

COMPARISON WITH 

REPRESENTATIVE SET

0

5

10

15

Assessment of lives

saved per year from

this study

Assessment of lives

saved per year

based on the

representative set of

55 accidents

FIGURE 9. BAR CHART SHOWING COMPARISON BETWEEN THE RESULTS FROM

THIS STUDY AND THAT DERIVED FROM THE REPRESENTATIVE SET

The similarity of the two values suggests that the prediction of benefit, taking into account the

accidents for which data are not available, is reasonably accurate.

5.4 FIRE ENTRY PATH.

During the accident analysis, the fire entry path was identified, where possible, in order to gain

an understanding of the susceptible areas of the fuselage.

A summary of fire burnthrough areas is presented in table 8. The median number of lives saved

were included so that an assessment may be made of the contribution of each fire entry area to

the overall life saving capability.
15

TABLE 8. FIRE ENTRY AREAS

Date Location

Fuselage

Skin Doors Windows Cargo Hold U/C Bay

Equipment

Bay

Median

Lives

Saved*

14-Sep-93 Warsaw Y ? ? ? ? ? 1

01-Feb-91 Los Angeles Y N N ? ? ? 0

31-Aug-88 Dallas Y N N N ? ? 1

26-Jun-88 Habsheim Y N N ? ? ? 3

22-Aug-85 Manchester Y N Y N N N 40

30-Aug-84 Douala Y ? ? ? ? ? 0

07-Dec-83 Madrid Y ? ? ? ? ? 0

13-Sep-82 Malaga Y N N ? ? ? 22

07-Oct-79 Athens Y N N ? ? ? 6

17-Dec-78 Hyderabad Y ? ? ? ? ? 0

15-Mar-74 Teheran Y N N ? ? ? 13

30-Jan-74 Pago Pago Y N ? ? ? ? 9

22-Jan-73 Kano Y N ? N ? ? 52

20-Dec-72 Chicago Y ? ? ? ? ? 7

18-Apr-72 Addis Ababa Y N N ? ? ? 7

08-Apr-68 Heathrow Y ? ? ? ? ? 3

16-Feb-67 Menado Y ? N ? ? ? 11

* = For 8 minutes additional protection with aircraft configured to later requirements

Y = Conclusive that burnthrough occurred

N = Conclusive that burnthrough did not occur

? = Insufficient information to determine whether or not burnthrough occurred

While conclusive data pertaining to each of the possible burnthrough routes is not available in

most cases, it is evident from table 8 that the fuselage skin is the prime entry route for pool fires.

5.5 SENSITIVITY.

5.5.1 Sensitivity to Burnthrough Protection Time.

The improvement in fatality rate has been shown to vary with burnthrough protection time in an

exponential manner. It can be seen that the assessed benefit can increase significantly with

burnthrough protection time. An additional burnthrough protection time of 2 minutes

approximately doubles the improvement in fatality rate compared with an additional 30 seconds

of burnthrough protection time.

5.5.2 Sensitivity to Number of Burnthrough Accidents.

An assessment has been made of the sensitivity of the number of lives saved per year to the

contribution made by any one accident.

The accident, which contributed the highest number of lives saved by burnthrough protection at 8

minutes (the longest time assessed), was in Kano on 22 January 1973. This accident contributed

a median saving of 52 lives. If this accident is removed from the analysis the median number of

lives saved per year reduces by 1.9, i.e., 5.7 reduces to 3.8. While this is a significant reduction,
16

the value still is just on the edge of the range assessed by this analysis prior to applying the

correction factor of 1.84 as discussed in section 5.1 of this report. If information were available

for all burnthrough accidents then the deletion of one accident would have less of an effect.

Aircraft configured to later requirements

0.000

0.002

0.004

0.006

0.008

0.010

0 100 200 300 400 500 600

Burnthrough protection time (secs)

Improvement in fatality rate

High

Median

Low

Median Less Kano

FIGURE 10. REDUCTION IN MEDIAN IMPROVEMENT WITH HIGHEST

CONTRIBUTING ACCIDENT REMOVED

6. DISCUSSION.

6.1 METHODOLOGY.

The mathematical and statistical models developed from previous studies for the analysis of

accidents is considered an extremely useful tool, especially when analysing accidents with

limited data. The technique of assessing a range of improvements as well as a best estimate

provides a prediction of both the most likely benefit to be gained and its potential range.

A precise time for burnthrough could not be determined for any of the accidents. Hence, rather

than using absolute values for burnthrough time, assessments were made for the potential benefit

of increasing burnthrough time, by 30 seconds 2, 4, and 8 minutes. From studying the accidents,

it became apparent that improvements in burnthrough time greater than 8 minutes would have no

further life saving potential. However, this comparatively high value was chosen in order to get

an indication of the maximum achievable benefit providing the technology was available to

produce this degree of fire hardening.

Consideration was given to using a standard value for assessing the likely number of lives to be

saved for each second in improvement of burnthrough protection time. However, when

considering each accident it became apparent that it would be incorrect to adopt this

methodology. For example, consider an accident where the pool fire develops to the extent that

at some time during the evacuation an exit is rendered unusable due to being engulfed in fire. In

this instance, there would be a step change in the egress rate at the time of loss of the exit. The
17

analyses were therefore carried out by making unique assessments for each accident scenario and

the number of occupants that might escape for discrete improvements in burnthrough penetration

times.

6.2 RESULTS.

The potential benefit in terms of reduction in fatality rate and reduction in injury rate was

assessed for each of the accidents listed in table 1. As can be seen from figure 1, of the 140 firerelated fatal accidents occurring during the period covered by this study, only 17 were identified

as involving burnthrough. It has been assessed that the benefit derived from the accidents

studied should be multiplied by a factor of approximately 1.84 in order to obtain the

corresponding figure for all accidents. If this factor is applied to the assessed benefit for an

additional 8 minutes of burnthrough protection time, then the benefit becomes 10.5 lives saved

per year.

Injury rate and fatality rate are defined in section 9. It should be noted that in this context,

injuries include fatalities and serious injuries. From table 2, a comparison of the injury rates with

fatality rate shows that the potential improvement in injury rate is not greatly different from the

improvement in fatality rate. Whilst improvements in burnthrough time are likely to reduce the

number of fatal injuries, the serious injuries may for some accidents actually increase. This is

because the occupants that would be saved from fatal injuries may still sustain serious injuries.

Hence, for some accidents there may be no improvement in injury rate (fatal plus serious) but an

improvement in fatality rate.

The assessment of fatality rate and injury rate was carried out for varying increases in

burnthrough time for each accident. A similar benefit assessment was carried out as if the

aircraft had been configured to the standards required by the latest cabin safety requirements.

The results of these assessments are presented graphically in figures 5 through 8 for varying

increases in burnthrough time. Also shown in these figures is the assessed 95-percentile range in

benefit using the methodology previously described. For each of these assessments, a curve of

best fit has been derived for the median, or best estimate, of the improvement in fatality rate or

injury rate. This curve of best-fit tends to take the form of an exponential relationship between

improvement in burnthrough time and improvement in fatality/injury rate

improvement in fatality/injury rate = A (1-e -Bt ).

Where A = the asymptote of the equation representing the maximum possible improvement in

fatality/injury rate attainable, and B = a constant that represents the magnitude of the change in

improvement in fatality/injury rate with improvement in burnthrough time.

If the factor of 1.84 is applied to the derived values contained in section 4.2, then for an increase

in burnthrough protection time of 8 minutes the assessed number of lives saved per year is 12.5

based on aircraft configured to the standard at the time of the accident. The equivalent reduction

in number of injuries is 15.6 per year.
18

For the assessment based on aircraft configured to the latest requirements the derived values for

an additional 8 minutes of burnthrough protection time is 10.5 lives saved per year. The

equivalent reduction in number of injuries is 14.0 per year.

The assessed change in benefit, both in terms of reduction in number of fatalities and injuries,

between the actual aircraft configuration and what is predicted for an aircraft configured to later

requirements is not as pronounced as might be expected. This may be because, major penetration

of the aircraft skin is likely to result in rapid progression of fire throughout the passenger cabin.

In this respect, the later requirements result in less benefit in protecting from large external pool

fires than they do for smaller external fires or for internal cabin fires.

By way of comparison, the assessment carried out for cabin water sprays (see reference 1)

suggested that water sprays would save in the region of 14 lives per year worldwide. Hence,

enhanced burnthrough protection has the potential to save in the region of (10.5/14)

approximately 75% of what was assessed for cabin water sprays. However it is likely that

techniques for improving the fire penetration resistance of fuselages would impose less costly

changes to the aircraft than would cabin water spray systems.

A comparison has also been made between the predictions of benefit from this analysis and those

derived from a study of a representative set of survivable accidents as described in section 5.3.2.

The results compare reasonably well as shown in figure 9.

An inspection of the data relating to median lives saved for an additional 8 minutes protection

time shows that certain accidents make a significant contribution to the overall benefit

assessment. For example, the Kano accident contributed a saving of 52 lives. In order to assess

the significance of accidents with these high levels of potential benefit, the improvements in

fatality rate were assessed for all of the accidents excluding Kano. The subsequent derived rate,

whilst significantly reduced, approximated to the lower band of the prediction for improvement

in fatality rate. On this basis, it is considered that the results of this study are realistic and

reasonable.

The structural strength of the aircraft exposed to a pool fire did not appear to have a significant

effect on occupant survival. Although there were limited data available, only two accidents (Los

Angeles and Manchester) were positively identified as involving structural collapse. Structural

failure occurred at 18 minutes for Los Angeles and hence was not a factor in occupant survival.

As previously discussed, it is assessed that there is limited benefit to be gained beyond 8 minutes.

There is insufficient data available to ascertain the time that structural collapse occurred for the

Manchester accident. Confirmation that structural strength is not a factor in burnthrough

accidents is important. If confirmed, changes intended to fire harden the fuselage do not need to

take into account the residual structural strength.

Whilst for almost all accidents the data available on the fire penetration route is extremely

limited, it is evident that the fuselage skin is by far the most significant path, as might be

expected. This is illustrated by the data contained in table 8. Whilst other areas of the fuselage

(windows, doors, etc.) may have been penetrated by the fire, it is considered unlikely that they

contributed significantly to occupant survival.
19

There is insufficient data to determine whether the frequency of occurrence of burnthrough

accidents has changed significantly during the period covered by this study. However, if there

has been any change in rate of occurrence, it is unlikely to be significant when compared to the

benefit that may be derived from improving the fire hardening of the aircraft. This is not

surprising since the factors contributing to the probability of occurrence of a pool fire have

probably not changed significantly. Furthermore, the fire resistance of fuselage skins would be

much the same in the current world fleet as it was 30 years ago. On this basis, it is likely that

burnthrough accidents will occur at a similar annual rate (per number of flights) for the

immediate future.

6.3 COST BENEFIT.

The cost benefit will, of course, relate to the solution adopted for protection of the cabin from

external pool fires. Since the benefit has been derived in terms of fire penetration time, an

assessment of the cost of each potential solution may be readily calculated. Since it is unlikely

that changes in the fuselage skin material will be cost beneficial, then other solutions must be

sought. Some work has been carried out by the Federal Aviation Administration and by

Faverdale Technology showing the difference between various thermal acoustic insulation

materials. If it can be confirmed that structural strength is not a significant factor then solutions

such as this are likely to show great potential for being cost-effective. It may be argued that

additional benefit may be gained by enhanced flammability standards for cabin floors. However,

any enhancement in flammability standards of cabin floors to improve the survivability of

occupants in pool fires would require a further study of its effectiveness and feasibility.

7. CONCLUSIONS.

• Fire hardening of fuselages will provide benefits in terms of enhanced occupant survival.

• The assessed reduction in fatalities and injuries from enhanced aircraft fire penetration

resistance is shown in the following table:

Reduction in Fatalities

Per Year

Reduction in Injuries

Per Year*

Based on Aircraft Standard at

Time of Accident 12.5 15.6

Based on Aircraft Configured

to the Latest Requirements 10.5 14

*Injuries include fatal and serious injuries

• The rate of improvement in benefit appears to vary exponentially with minimal

improvement beyond the 4 to 8 minute additional protection point.
20

• The assessed benefit derived from this study is similar in magnitude to that determined

from a study of a representative set of survivable accidents, thus providing some

confidence in the results.

• The prime fire penetration route is via the fuselage skin and no evidence could be found

to suggest that alternate burnthrough routes contribute significantly to occupant survival.

• Aircraft configured to the latest cabin safety requirements are likely to exhibit enhanced,

but relatively limited, protection against large external pool fires.

• It is not considered likely that the rate of fatalities and injuries per year caused by fuselage

burnthrough will change markedly for the near future.

• The reduction in the structural strength of the fuselage as a result of a pool fire appears to

have a limited effect on occupant survival. If this is confirmed, it will result in a greater

opportunity to find cost beneficial solutions to hardening aircraft against pool fires.

• Costs have not been assessed to ascertain the cost per life saved for possible methods of

enhancing burnthrough protection of aircraft. However, the relationship between benefit

and additional burnthrough protection, derived from this study, will assist in carrying out

such an analysis.

8. REFERENCES.

1. Civil Aviation Authority Paper 93010, Cabin Water Sprays for Fire Suppression. Design

Considerations and Safety Benefit Analysis Based on Past Accidents, August 1993.

2. “Cabin Safety Research Prioritisation,” R.G.W. Cherry & Associates Limited,

Hertfordshire, England.

9. DEFINITIONS.

Accident Scenario

“That volume of the aircraft in which the occupants are subjected to a similar level of threat.”

Burnthrough Accident

“An aircraft accident where the fuselage skin was penetrated by an external fire while live

occupants were on board.”

Fatal Injury (Source. ICAO)

“An injury resulting in death within thirty days of the date of the accident.”

Fatality Rate

“The total number of fatalities divided by the total number of occupants aboard.”
21/22

Improvement in Fatality Rate

“The reduction in the number of fatalities divided by the total number of occupants aboard.”

Improvement in Injury Rate

“The reduction in the number of serious and fatal injuries divided by the total number of

occupants aboard.”

Injury Rate

“The total number of serious and fatal injuries divided by the total number of occupants

aboard.”

Serious Injury (Source. ICAO Annex 13, Eighth Edition, July 1994)

“An injury which is sustained by a person in an accident and which:

(a) requires hospitalisation for more than 48 hours, commencing within seven days from the

date the injury was received; or

(b) results in a fracture of any bone (except simple fractures of fingers, toes, or nose);or

(c) involves lacerations which cause severe haemorrhage, nerve, muscle or tendon damage;

or

(d) involves injury to any internal organ; or

(e) involves second or third degree burns, or any burns affecting more than 5 percent of the

body surface; or

(f) involves verified exposure to infectious substances or injurious radiation.”

Survivable Accident

“An aircraft accident where there were one or more survivors or there was potential for

survival.”
A-1

APPENDIX ASTATISTICAL MODELLING

Software has been developed to represent a mathematical simulation of an accident using Monte

Carlo Simulations. This enables assessments to be made of the likely range in numbers of

survivors resulting from improvements in survivability factors.

Stage 1 of this process is shown diagrammatically in figure A-1. The in-depth analysis of

accident details results in the generation of a survivability chain, or series of parallel survivability

chains for accidents with several accident scenarios. In this study an assessment has been made

of the effect on number of fatalities as a result of improvements to cabin burnthrough times. The

assessment results in a prediction of the highest, mean, and lowest number of fatalities that could

reasonably be expected from the improvements.

Stages 2 and 3 of the process are shown in figures A-2 and A-3.

Figure A-2 illustrates the principle for assessing the effect on survivability of variations in the

effectivity of improvements to survivability factors. From the rationales, the best (or median)

assessment is made of the number of fatalities and injuries that would result in improvements to

cabin burnthrough time. However, when making these determinations the analysts will also

determine a maximum and minimum number of fatalities and injuries that are likely to result

from the improvements.

It is then assumed that there can be 100% confidence that the fatalities will lie in the range from

minimum to maximum according to the distribution shown in figure A-2. The software has been

developed so that random selections may be made over the range 0% to 100% to arrive at a

particular number of fatalities and injuries.

From each random selection a re-evaluation of the number of survivors may be made using the

survivability chain generated for the accident scenario as shown in figure A-3. This is then

compared with the actual number of survivors of the accident. Thus improvements in

survivability, and hence survivability rate may be generated. The formula employed is

T

S S S B

F

− =

Where SF = the assessment of the increase in survivability rate

S = the reassessed number of survivors due to the improvements for all accident

scenarios

SB = the actual number of survivors for all accident scenarios

T = the total of all occupants for all accident scenarios.

Stages 2 and 3 are repeated a number of times, typically 10,000, which builds up a statistical

distribution of values for the improvement in injury rate. Refer to figure A-4.
A-2

Stage 4 of the process is simply to determine the 21⁄2, 50, and 971⁄2 percentiles from the resulting

distributions to ascertain a mean and likely range for the prediction.

Whilst it is recognised that the models are not perfect representations of an accident nor are the

statistical assessments totally accurate, they will provide a better assessment of the likely impact

of improvements to survivability factors than would otherwise be derived from a simple estimate

of the resultant change in number of survivors.

IMPACT

FIRE FIRE

Figure A-1. Statistical Modelling Process, Stage 1

For each

scenario, assess

the highest (H),

best estimate

mean (M), and

lowest (L)

number of

fatalities and

serious injuries

with improved

fire hardening

H

M

L

H

M

L

H

M

L

H

M

L

Occupants

Impact

Fatalities Impact

Survivors Impact

Injuries
A-3

Figure A-2. Statistical Modelling Process, Stage 2

Low

Median

High

0% 50% 100%

Range

No. of

Fatalities/Injuries

RANDOM SELECTION

READ OFF VALUE FOR

NUMBER OF

FATALITIES/INJURIES

Repeat stages 2 and

3 many times

(e.g., 10,000

iterations)
A-4

IMPACT

FIRE FIRE

Figure A-3. Statistical Modelling Process, Stage 3

Reassess number

of uninjured

survivors

S

Evaluate injury rate improvement using:

T

S S S B

F

− =

Where:

SF = the assessment of the decrease in injury rate

S = the reassessed number of uninjured survivors for all accident

scenarios

SB = the actual number of uninjured survivors for all accident

scenarios

T = Total number of all occupants for all accident scenarios

A similar technique is used for fatality rate improvement.
A-5/A-6

Figure A-4. Statistical Modelling Process, Stage 4

From statistical

distribution, read

off 97.5, 50, and

2.5 percentiles.

97.5%

50%

2.5%

Values from circa

10,000 iterations
B-1

APPENDIX BACCIDENT RATIONALES 1 TO 7

The rationale for each accident that was analysed appears in this appendix. Each accident is

presented with the following sections:

• Description of the accident reproduced from the Survivable Accidents Database.

• A description of the fire penetration mechanism using relevant extracts from the database

together with any assessments and assumptions made.

• A diagram showing the location of occupants and scenario boundaries.

• Survivability chains for each scenario.

• Effect of later requirements.

• Effect of a fire-hardened fuselage.

The accidents are presented in reverse chronological order.

Key to injury location diagrams:

Exit

Exit used

for

evacuation
B-2

AIRCRAFT: L188 DATE OF ACCIDENT: 16th February ‘67

REGISTRATION: PK-GLB LOCATION OF ACCIDENT: MENADO

INDONESIA

1. Description of Accident

RESUME

On 16-Feb-67 Lockheed Electra L-188C registered as PK-GLB was on approach to Mapanget

Airport, Menado, Indonesia.

The pilot-in-command adopted an awkward approach technique and the aircraft landed heavily 3

ft short of the runway manoeuvring area and some 156 ft short of the runway threshold. The

undercarriage collapsed, the aircraft skidded, caught fire and came to rest on the runway.

The aircraft was destroyed by fire.

There were 8 crew and 84 passengers aboard. 22 passengers suffered fatal injuries. 12

passengers suffered serious injuries. 8 crew and 50 passengers escaped with minor or no

injuries.

IMPACT

Examination at the site of the accident revealed that the aircraft first struck the ground with its

right main landing gear which collapsed rearward and inboard. Marks on the manoeuvring area

indicated that the propellers struck the ground in the order 4-3-2-1 and were all torn off from

their respective engines. Impact of the left main landing gear was quite severe and the left wing

failed, spilling fuel. The aircraft skidded on its belly along the runway and came to stop on the

runway.

FIRE

As the aircraft skidded along the runway, fuel spilling from the left wing caught fire and when

the aircraft came to a stop it was ablaze. The heat of the engine and also the heat produced by

the friction between the aircraft body and the ground, could all have ignited the fuel.

Due to the inadequacy of the fire fighting equipment the aircraft was burnt out.

EVACUATION

The crew consisted of a pilot-in-command, co-pilot, flight engineer, flight radio operator, 3 air

hostesses and a steward.

According to the crew, just after the aircraft came to a full stop the co-pilot instructed the flight

engineer and the cabin attendants to open the forward main entrance door but unfortunately they

did not succeed in opening this door from the inside. Meanwhile smoke and fumes began to

penetrate the first class cabin (aft). The cabin attendants advised all passengers to proceed

forward in order to escape from the right hand forward emergency exit and cockpit sliding

windows. One of the cabin attendants tried to open the overwing emergency exits but was

advised by another crew member not to open them because of fire outside the window. During
B-3

that same time the flight crew attempted to open the forward main entrance door from the

outside; however, they did not succeed either. Survivors evacuated from the aircraft through the

right forward emergency exit and cockpit sliding windows.

Passengers who tried to escape from the rear service door, but were unable to open it quickly

were trapped in the burning wreckage.

AIRCRAFT FACTORS

The aircraft was a Lockheed Electra L-188C registered as PK-GLB. The aircraft was airworthy

and maintained in accordance with the approved maintenance specifications. There was no

evidence of failure or malfunctioning of the aircraft or its components prior to touchdown that

could have led to the accident.

The type of fuel used was not stated in the accident report.

The cabin was fitted with a main entry door at the front on the port side with a service door

opposite. There was an overwing exit above each wing. At the rear there was an entry door on

the port side with a service door opposite.

ENVIRONMENTAL CONDITIONS

The accident occurred at 05:21 hours GMT in daylight. The prevailing weather conditions

before and at the time of the accident were reported to be overcast with light showers over the

airfield. The 05:00 hours weather report was: wind southerly and about 2 kt, visibility 2 to 3 km,

cloud 3/8 at 900 ft and 4/8 at 2000 ft.

INJURIES TO OCCUPANTS

There were 8 crew and 84 passengers aboard. 22 passengers suffered fatal injuries. 12

passengers suffered serious injuries. 8 crew and 50 passengers escaped with minor or no

injuries.

Casualties were primarily caused by fire and not impact. All those passengers who apparently

tried to escape from the rear service door, but were unable to open it quickly were trapped in the

burning wreckage.

2. Fire Penetration Mechanism

As the aircraft skidded along the runway, fuel spilling from the left wing caught fire, and when

the aircraft came to a stop it was ablaze. Further, it was reported that smoke and fumes began to

penetrate the cabin from the aft end first.

It is therefore concluded that the ignited, spilt fuel lay predominantly under the rear of the

fuselage and burnt through the lower skin in that area. Once burnt through, smoke and then

flames would have penetrated the passenger cabin through the floor at the aft end of the fuselage.

Based on the above it is assessed that the prime burnthrough route was through the rear lower

fuselage skin. However there was insufficient information to be conclusive about detailed

burnthrough areas.
B-4

3. Location of Injuries and Scenarios

Due to the lack of detailed information on the location of occupants during the accident, it has

been necessary to consider this accident as one scenario containing the whole aircraft.

4. Accident Scenarios and Survivability Chains

This accident is considered as one scenario.

Scenario 1 contains the whole fuselage. Fire entered at the rear and propagated forward. The

scenario contains the 4 flight crew, 4 cabin crew and 84 passengers.

5. Effect of Later Requirements

For Scenario 1, it is assessed that later requirements would have improved flammability

standards such that the occupants would have had additional time to escape. It is assessed that

11 fatalities would have escaped with non-fatal injuries and further that 11 seriously injured

would have escaped with minor or no injuries.

The survivability chain for Scenario 1 therefore becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with more time to make their way to the forward exits.

58 12

FIRE

92

22

SCENARIO 1

69 12

FIRE

92

11

SCENARIO 1
B-5

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 60 12 20

M 63 15 14

L 73 12 7

For 2 minutes protection:

S I F

H 62 12 18

M 70 14 8

L 80 12 0

For 4 minutes protection:

S I F

H 64 12 16

M 83 9 0

L 92 0 0

For 8 minutes protection:

S I F

H 64 12 16

M 84 8 0

L 92 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 69 13 10

M 75 12 5

L 87 5 0

For 2 minutes protection:

S I F

H 69 15 8

M 80 11 1

L 92 0 0

For 4 minutes protection:
B-6

S I F

H 69 16 7

M 86 6 0

L 92 0 0

For 8 minutes protection:

S I F

H 70 19 3

M 88 4 0

L 92 0 0

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 8 6

2 minutes 14 10

4 minutes 22 11

8 minutes 22 11
B-7

AIRCRAFT: B707 DATE OF ACCIDENT: 8th April ‘68

REGISTRATION: G-ARWE LOCATION OF ACCIDENT: HEATHROW

1. Description of Accident

RESUME

On 8-Apr-1968 BOAC B707 registered as G-ARWE was taking off from London (Heathrow)

airport.

Approximately one minute after take-off the No. 2 engine failed and a few seconds later caught

fire. The fire did not go out and the aircraft was manoeuvred for the quickest possible return.

During the approach, the No. 2 engine fell away from the aircraft. The aircraft made a successful

landing but fuel released on the port side caught fire.

An emergency evacuation was initiated using exits on the starboard side as the fire and smoke

spread from the rear forwards. The assist means did not perform well and as a result the crew

lost valuable time during the evacuation.

Of the 11 crew and 116 passengers aboard, 1 crew member and 4 passengers suffered fatal

injuries. 38 passengers suffered serious injuries. 10 crew and 74 passengers escaped with minor

or no injuries.

IMPACT

The aircraft made a smooth touchdown and the Captain brought the aircraft to halt normally.

There was no impact.

FIRE

When the aircraft came to a stop, the fire, which had continued to burn near the No. 2 engine

position, increased in intensity and the fuel tanks in the port wing exploded. The accident

investigation established that the fire continued to burn because of an omission to close the fuel

shutoff valve after the engine caught fire. After the aircraft came to rest, the captain ordered a

fire drill on the remaining engines. Before this could be carried out, there was an explosion from

the port wing which increased the intensity of the fire and blew fragments of the wing to the

starboard side of the aircraft. The captain then ordered immediate evacuation of the flight deck.

The engine fire shutoff handles were not pulled and the fuel booster pumps and main electrical

supply were not switched off. There were more explosions and fuel, which was released from

the port tanks, spread underneath the aircraft and greatly enlarged the area of the fire.

EVACUATION

There were 5 flight crew and 6 cabin crew and 116 passengers aboard.

The cabin crew opened the emergency exits as the aircraft came to a stop and started rigging the

escape chutes (this involved positioning a bar behind clips on the cabin floor). The passengers

commenced evacuation from the two starboard overwing exits, and shortly. afterwards, when
B-8

the escape chutes had been inflated, from the rear starboard galley door and then the forward

starboard galley door.

However, because of the spread of the fire under the rear of the fuselage, the escape chute at the

rear galley door soon burst and following the first explosion, the overwing escape route also

became unusable.

The starboard overwing exits were the first utilised: 18 passengers escaped by these exits under

the direction of the Chief Steward before he stopped their further use because of the smoke and

flames which enveloped the starboard wing area following the main explosion.

Nobody left the aircraft by the forward port overwing exit.

The starboard rear galley door's chute was rigged, inflated, and found to be misaligned. One of

the stewards climbed down to straighten it. Only 5 passengers and 1 steward escaped down this

chute before the sparks and flames spreading from the port side burst it. 5 passengers jumped

through this doorway after the chute became unserviceable.

The starboard forward galley door's escape chute was delayed in being put into operation, due to

difficulty getting the chute retaining bar into its clips. After this initial delay, the main body of

passengers evacuated the aircraft rapidly by this route. The evacuation tended to slow down as

passengers, both injured and otherwise, began to collect round the bottom of the chute and in

front of the starboard wing. The captain left the aircraft by this exit during a gap between the

passengers disembarking. When it appeared that all the passengers had left the aircraft, the

remaining cabin crew members also used this escape route.

The port forward main door was also used. The chute did not inflate at first, after it as deployed,

and the flight engineer climbed down and straightened it out at the bottom; it almost immediately

caught fire and burst. 1 passenger escaped jumping from this doorway after the chute collapsed.

3 flight crew members egressed through the cockpit windows.

The evacuation took place in an orderly manner, but when the rear galley door and starboard

overwing exits became unusable, some momentary confusion resulted among those passengers

who had to revise their escape routes. Conditions in the cabin were quite good in the early

stages. But they deteriorated rapidly when the explosion occurred. As the evacuation

progressed, dense black smoke advanced forward up the cabin from the rear as the fire took

deeper and deeper hold. Smoke eventually reduced visibility to zero in the forward galley area.

The captain stated it was completely overpowering. There was some difficulty in helping

passengers at the rear of the aircraft, which was the first part of the fuselage to be overwhelmed

by the fire. it was in this area that the stewardess was last seen alive attending to the passengers

who ultimately succumbed.

The evacuation of passengers had been largely completed by the time airport Fire and Rescue

Service began to provide assistance. The fire service prevented the fuel in the starboard tanks

from catching fire but the rear fuselage and port wing was burned out.
B-9

AIRCRAFT FACTORS

The aircraft was a B707-465 registered as G-ARWE, operated by BOAC.

The cabin was fitted with a main entry door at the front with a service door opposite. There were

2 overwing exits above each wing. There was an entry door at the rear port side and a service

door opposite.

ENVIRONMENTAL CONDITIONS

The weather conditions were clear and fine at the time of the accident.

INJURIES TO OCCUPANTS

Of the 11 crew and 116 passengers aboard, 1 crew member and 4 passengers suffered fatal

injuries. 38 passengers suffered serious injuries. 10 crew and 74 passengers escaped with minor

or no injuries.

4 of the passengers and one stewardess were overcome by heat and smoke in the rear of the

aircraft and did not escape.

38 passengers sustained injuries during the evacuation.

2. Fire Penetration Mechanism

After the aircraft had come to a stop on the runway, there was an explosion from the port wing

which increased the intensity of the fire and blew fragments of the wing to the starboard side of

the aircraft. This would have spread the external fire over the outer surface of the fuselage.

There were more explosions and fuel, which was released from the port tanks, spread underneath

the aircraft at the rear and greatly enlarged the area of the fire. Internally smoke was observed as

coming from the rear of the cabin and spreading forward.

The spread of fire under the rear of the fuselage combined with the outer surface fire would have

rapidly burnt through the fuselage skin, initially at the rear of the cabin.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin.

However there was insufficient information to be conclusive about other burnthrough areas.

3. Location of Injuries and Scenarios

Due to lack of detailed information on the location of the occupants during the evacuation, this

accident has been taken as one scenario containing the whole aircraft.

4. Accident Scenarios and Survivability Chains

This accident is considered as one scenario.
B-10

Scenario 1 contains the whole fuselage. It was not subjected to any impact, but the fire entered

at the rear and propagated forward. The scenario contains the 5 flight crew, 6 cabin crew, and

116 passengers.

5. Effect of Later Requirements

For Scenario 1, it is assessed that later requirements would have improved flammability

standards such that the occupants would have had additional time to escape. It is assessed that

two of the fatalities would have escaped with non-fatal injuries.

The survivability chain for Scenario 1 therefore becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with additional time to make their way to the available exits.

84 38

FIRE

127

5

SCENARIO 1

84 40

FIRE

127

3

SCENARIO 1
B-11

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 84 38 5

M 87 38 2

L 89 38 0

For 2 minutes protection:

S I F

H 84 39 4

M 92 35 0

L 100 27 0

For 4 minutes protection:

S I F

H 84 41 2

M 100 27 0

L 116 11 0

For 8 minutes protection:

S I F

H 84 41 2

M 108 19 0

L 127 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 84 40 3

M 86 40 1

L 89 38 0

For 2 minutes protection:

S I F

H 84 40 3

M 92 35 0

L 100 27 0

For 4 minutes protection:
B-12

S I F

H 84 41 2

M 100 27 0

L 116 11 0

For 8 minutes protection:

S I F

H 84 42 1

M 108 19 0

L 127 0 0

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 3 2

2 minutes 5 3

4 minutes 5 3

8 minutes 5 3
B-13

AIRCRAFT: SVC10 DATE OF ACCIDENT: 18th April ‘72

REGISTRATION: 5X-UVA LOCATION OF ACCIDENT: ADDIS ABABA

1. Description of Accident

RESUME

A Super VC10 was taking off from Addis Ababa on 18-Apr-1972. Just prior to decision speed

the nosewheel tyre hit a jacking pad that has fallen from a Cessna 185 a few hours earlier. The

tyre burst and the crew initiated an aborted take-off but were unable to stop the aircraft before

the end of the runway.

The aircraft slid down an embankment at the end of the runway and struck a steel lattice tower

which ruptured the fuel tank. The spilling fuel ignited and the aircraft broke into three sections

as it came to rest.

Survivors evacuated the aircraft through the fuselage breaks as the left emergency exits were

jammed by impact damage and the right side exits were blocked by fire. 10 people had to walk

away from the aircraft between streams of fuel which subsequently caught fire and trapped them.

Of the 11 crew and 96 passengers aboard, 8 crew and 35 passengers suffered fatal injuries.

IMPACT

After the nosewheel tyre burst the aircraft continued down the runway, veering slightly to the

right as it did so. A few seconds later the No.1 rear main tyre failed. After crossing a storm

drain located at the end of the runway both undercarriage bogies were damaged and the No.2

rear and No.3 front tyres burst. The aircraft became momentarily airborne as it left the lip of the

embankment on which the runway was laid. As it did so, the left outer wing of the aircraft struck

a steel lattice tower which ruptured the No.1A fuel tank and severed electrical cable looms in the

leading edge of the wing. The aircraft fell heavily on to the ground below the runway level and

broke up immediately on impact into three major portions, namely the tail empennage with the

engines attached; the centre section and wings; and the forward part of the fuselage. After

sliding a short distance the aircraft came to rest.

FIRE

Fire initially broke out when the left outer wing struck the lattice tower and the No.1A fuel tank

was ruptured. The released fuel was ignited either by sparks generated as a result of the wing

hitting the tower or by arcing due to disruption of electrical cable looms. There was evidence of

burning on the ground from the point of impact with the tower to the final resting position,

indicating that the fire trailed behind the aircraft for the whole distance.

According to the statements of survivors, fire appears to have started almost immediately after

impact towards the rear and underside of the main cabin. There the heat was described as being

intense at floor level.
B-14

Fire also broke out immediately after impact on the right side by the wing root. This prevented

the emergency exits on that side being used. Fire eventually consumed the main cabin area, the

forward fuselage, the left wing and the right wing root. The tail unit together with the engines

were unburnt though extensively scorched.

EVACUATION

The crew consisted of a Captain, First Officer, Navigating Officer, Flight Engineer and 7 cabin

crew. There were 96 passengers aboard.

In the main, the evacuation of the aircraft by the passengers and crew was self effected.

Considerable selfless assistance was rendered by members of the cabin staff and also some of the

passengers, some of whom died as a result of their efforts in this respect when they would have

otherwise survived. The evacuation was facilitated considerably by the fortuitous fracture of the

left forward fuselage, allowing relatively easy egress. Had it not been for this fracture casualties

may well have been greater, as the left emergency exits were jammed by impact damage and the

right side exits were blocked by fire.

Those who managed to get clear of the aircraft to the left side found their way blocked by a

barbed wire fence. This forced most passengers and surviving members of the crew to walk

down the slope alongside two main streams of fuel flowing from the aircraft. This fuel

subsequently caught fire, trapping a number of people, believed to be about 10 in number.

AIRCRAFT FACTORS

The aircraft was a Super VC10 registered as 5X-UVA, operated by East African Airways and

had been maintained in accordance with an approved maintenance schedule.

The aircraft was constructed in 1966 and went into service with East African Airways

Corporation in that same year, having been issued with both a United Kingdom and an East

African Certificate of Airworthiness.

[This series aircraft can be configured for up to 187 passenger seats.]

The fuselage was fitted with 2 doors at the front and rear and 2 overwing emergency exits above

each wing.

ENVIRONMENTAL CONDITIONS

A weather observation made shortly after the accident gave the following information: wind 9

knots, temperature 21C, visibility 7-10km.

INJURIES TO OCCUPANTS

It appears that all those on board survived the impact, but some subsequently succumbed to the

effects of the fire.

33 occupants were fatally injured by fire before evacuating. 10 cabin occupants succumbed to

fire following evacuation.
B-15

2. Fire Penetration Mechanism

According to the statements of survivors, the fire appears to have started after impact towards the

rear and underside of the main cabin. There the heat was described as being intense at floor

level. This would be characterised by a burnthrough of the lower fuselage skin allowing the fire

to enter under the cabin floor and propagate into the passenger cabin.

Fire was also able to enter the cabin directly through fuselage breaks at either end of the wing

root.

Based on the above it is assessed that the prime burnthrough route was through the rear

underside of the fuselage skin. However there was insufficient information to be conclusive

about detailed burnthrough areas. The fire also entered through fuselage breaks.

3. Location of Injuries and Scenarios

Scenario 1

Scenario 2

Note: Survivors escaped

through fuselage breaks.
B-16

4. Accident Scenarios and Survivability Chains

This accident is divided into two separate scenarios.

Scenario 1 contains the main cabin area. Evacuation was carried out through a fuselage break

because the left exits were jammed and the right exits were blocked by fire. The scenario

contains the 97 occupants including crew and passengers.

Scenario 2 contains 10 occupants who evacuated the aircraft but became trapped between two

streams of burning fuel.

5. Effect of Later Requirements

For Scenario 1, it is assessed that later requirements would have improved flammability

standards such that the occupants would have had additional time to escape. It is assessed that an

additional eight occupants would have successfully evacuated.

The survivability chain for Scenario 1 therefore becomes:

6 0

FIRE

97

33

SCENARIO 1

0 0

FIRE

10

10

SCENARIO 2

7 0

FIRE

97

25

SCENARIO 1
B-17

It is assumed that later requirements would not have affected the situation in Scenario 2 in which

all fatalities occurred outside the cabin environment.

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with more time to make their way to the fuselage break. Fire would also have

entered through the breaks in the fuselage which would not be affected by a fire-hardened

fuselage. It is therefore assessed that ten occupants would still have succumbed to fire even with

perfect fuselage fire hardening.

Due to insufficient detail on serious injuries, they have been assigned to zero throughout this

accident.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 64 0 33

M 69 0 28

L 77 0 20

For 2 minutes protection:

S I F

H 64 0 33

M 79 0 18

L 87 0 10

For 4 minutes protection:

S I F

H 64 0 33

M 79 0 18

L 87 0 10

For 8 minutes protection:

S I F

H 64 0 33

M 79 0 18

L 87 0 10
B-18

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 72 0 25

M 74 0 23

L 88 0 10

For 2 minutes protection:

S I F

H 72 0 25

M 79 0 18

L 89 0 8

For 4 minutes protection:

S I F

H 72 0 25

M 79 0 18

L 89 0 8

For 8 minutes protection:

S I F

H 72 0 25

M 79 0 18

L 89 0 8

Scenario 2

It is assessed that a fire-hardened fuselage would not have affected the situation in Scenario 2 in

which all fatalities occurred outside the cabin environment.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 5 2

2 minutes 15 7

4 minutes 15 7

8 minutes 15 7
B-19

AIRCRAFT: DC9 DATE OF ACCIDENT: 20th December ‘72

REGISTRATION: N954N LOCATION OF ACCIDENT: CHICAGO

1. Description of Accident

RESUME

A North Central Airlines DC-9-31 was taking off under poor visibility in fog. A Delta Airlines

Convair CV-880 was taxying across the runway at the same time due to poor air traffic control.

The DC-9 collided with the tail of the CV-880 and as a result was unable to climb and landed

back on the runway. The undercarriage collapsed and the aircraft caught fire.

There were 4 crew and 41 passengers aboard. 9 passengers failed to escape the cabin fire

because they could not locate the exits in dense smoke and poor lighting conditions.

IMPACT

After the collision, the captain decided that his aircraft could not maintain flight, at which time

he took control and flew the aircraft back onto the runway.

The nose and main undercarriage collapsed and the aircraft came to a stop upright with the

fuselage resting on the runway.

Passengers described the collision as being a slight bump. The subsequent touch down of the

aircraft and the crash slide were described as being comparable to normal landing. Deceleration

forces were described as being very slight with some side-to-side motion. None of the

passengers reported being propelled into the seat in front of them.

FIRE

Shortly after impact, the DC-9 was engulfed in flames around the aft section of the aircraft and

the fuselage was subsequently gutted by fire.

Smoke developed very rapidly which reduced the ability of the occupants to find emergency

exits routes and made a co-ordinated crew response extremely important.

The control tower saw a flash but could not see the aircraft burning.

The first fire trucks were reported at the scene within 2 minutes. At the time of their arrival all

survivors were already out of the aircraft and had moved away from the wreckage.

Firefighters extinguished the fire in 16 minutes.

EVACUATION

The crew consisted of a captain, first officer and 2 stewardesses. There were 41 passengers

aboard.
B-20

The accident occurred at night. The cabin lights went out as the aircraft came to a stop and the

emergency cabin standby lights were powered by rechargeable 2.5 volt nickel-cadmium batteries

which produced a low light intensity when combined with the dense smoke. The extreme

darkness reportedly made the location of emergency exits very difficult.

After the aircraft came to a stop smoke began to enter the cabin almost immediately. Some

passengers stated that initially there was some pushing and shoving, but generally there was very

little panic. Passengers reported having to get lower and lower toward the floor in order to

breathe. The smoke was very dense, according to survivor accounts.

One stewardess was seated in the forward jump seat and the other stewardess was seated in seat

15B. After impact and during the slide, the rear stewardess opened the left forward overwing

exit at row 12. After the aircraft had stopped, she exited and called to the passengers to follow.

4 passengers followed her out through the exit.

The forward stewardess opened the main entry door after the aircraft stopped. The escape slide

deployed but did not inflate because the lanyard was wrapped around the neck of the inflation

bottle. The stewardess stated that she was then pushed out of the aircraft. From the outside she

called out to the passengers and assisted them down to the ground.

The first officer escaped from the aircraft through the sliding window on the right side of the

cockpit. He went around the nose of the aircraft to the main entry door and from the ground he

assisted passengers escaping through that door.

The captain entered the cabin through the cockpit door and called to the passengers to come

forward. He then went outside through the main entry door. From a position outside the aircraft,

he assisted passengers down to the ground. Then, re-entering the aircraft, the captain assisted

other passengers through the main entry door. The rest of the survivors deplaned through the

main entry door.

Most of the passengers indicated that their biggest obstacles in evacuating the aircraft were

smoke and the lack of emergency lighting. Also the supervision of the evacuation by the flight

and cabin crew members from a position outside the aircraft delayed egress of some of the

passengers.

A passenger opened the right forward overwing exit through which he made his escape.

The rear tail cone emergency exit was not used. The galley exit door and the two aft overwing

exits were not opened.

The 9 passengers remaining were found in the following locations by firemen:

- 1 male passenger in the tail cone aft of the pressure bulkhead

- 1 male passenger in the rear rest room

- 1 female passenger in the cockpit

- 1 male passenger halfway in the cockpit
B-21

- 5 female passengers (including 1 invalid) seated along the left side of the cabin area.

The 4 passengers who left their seats apparently attempted to find an exit but were unable to do

so.

AIRCRAFT FACTORS

Aircraft N954N was a McDonnell Douglas DC-9-31, owned and operated by North Central

Airlines, Inc. The aircraft was certificated, maintained and equipped in accordance with

approved company procedures and FAA regulations. The aircraft had 22,000 lbs of Jet A

aviation kerosene on board.

The aircraft was manufactured as serial number 47159 on 27-Dec-1967.

The fuselage was fitted with a main entry door at the front port side with a service door opposite.

There were two overwing exits above each wing. The rear tail cone was also fitted with an

emergency exit.

ENVIRONMENTAL CONDITIONS

The accident occurred in fog at night with a visibility of 1/4 mile.

INJURIES TO OCCUPANTS

9 of the 10 fatally injured passengers failed to escape from the aircraft. They received no

traumatic injuries but succumbed instead to the effects of smoke inhalation or burns or both. Of

the passengers who had left their seats, 2 were found in the cockpit area and 2 were found in the

aft section. They apparently attempted to find an exit but were unable to do so in dense smoke

and poor lighting conditions. 5 others remained in their seats.

The 10th fatally injured passenger succumbed 5 days later.

13 passengers and 2 crew were injured.

2. Fire Penetration Mechanism

The subsequent touch down of the aircraft and the crash slide were described as being

comparable to normal landing. Deceleration forces were described as being very slight with

some side-to-side motion. None of the passengers reported being propelled into the seat in front

of them. It is therefore assumed that the fuselage was not ruptured by the impact forces.

Shortly after impact, the DC-9 was engulfed in flames around the aft section of the aircraft and

after the aircraft came to a stop smoke began to enter the cabin. It was the smoke that dominated

the evacuation time rather than flames. It is therefore assumed that the lower surface of the

fuselage had burnt through rapidly and that smoke from under the cabin floor propagated into the

passenger cabin and hindered attempts to locate the available exits.
B-22

Based on the above it is assessed that the prime burnthrough route was through the lower aft

fuselage skin. However there was insufficient information to be conclusive about detail

burnthrough areas.

3. Location of Injuries and Scenarios

4. Accident Scenarios and Survivability Chains

This accident is divided into two separate scenarios.

Two passengers were initially in

the main cabin but were found

in the cockpit area having failed

to locate an exit in dense smoke.

Scenario 2

Scenario 1
B-23

Scenario 1 contains the flight deck area and two flight crew. It was subjected to the fire but the

occupants escaped with minor or no injuries.

Scenario 2 contains the main passenger cabin, which suffered internal fire and had only three of

the seven exits available for egress. It includes all passengers and flight attendants. Smoke was

very dense and hampered attempts to locate open exits.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in Scenario 1 in which

there were no injuries sustained.

For Scenario 2, it is assessed that floor proximity lighting would have enabled two of the nine

fatalities to find an available exit, i.e., the two passengers found in the cockpit who walked past

the open main entry door.

The survivability chain for Scenario 2 therefore becomes:

2 0

FIRE

2

0

SCENARIO 1

19 15

FIRE

43

9

SCENARIO 2

21 15

FIRE

43

7

SCENARIO 2
B-24

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as no occupants sustained injuries.

Scenario 2

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with more time to locate the available exits.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 19 15 9

M 22 15 6

L 24 15 4

For 2 minutes protection:

S I F

H 19 15 9

M 25 14 4

L 31 12 0

For 4 minutes protection:

S I F

H 19 15 9

M 29 14 0

L 43 0 0

For 8 minutes protection:

S I F

H 19 15 9

M 39 4 0

L 43 0 0
B-25

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 21 15 7

M 23 16 4

L 25 18 0

For 2 minutes protection:

S I F

H 21 15 7

M 28 13 2

L 31 12 0

For 4 minutes protection:

S I F

H 21 15 7

M 38 5 0

L 43 0 0

For 8 minutes protection:

S I F

H 21 15 7

M 41 2 0

L 43 0 0

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 3 3

2 minutes 5 5

4 minutes 9 7

8 minutes 9 7
B-26

AIRCRAFT: B707 DATE OF ACCIDENT: 22nd January ‘73

REGISTRATION: JY-ADO LOCATION OF ACCIDENT: KANO,

NIGERIA

1. Description of Accident

RESUME

On 22-Jan-1973 an Aila B707 registered as JY-ADO was landing in poor visibility at Kano

airport, Nigeria.

The aircraft touched nosewheel first steady and heavy with main wheels barely in contact with

the runway. The nosewheel entrenched itself then collapsed. The main gear contacted later in

rapid deceleration, pierced the main wings and the aircraft collapsed along the runway centreline.

A fire broke out and after a prolonged pause the passengers and crew evacuated.

Of the 202 occupants aboard, 176 suffered fatal injuries as a result of the fire.

IMPACT

As the undercarriage collapsed, indications are that the right hand main landing gear truck beam

separated shortly after touchdown and the right hand main landing gear oleo dug through the

tarmac surface. All four right hand main landing gear wheel rims were bent and broken, in

varying degrees, indicating an unusually high loading during initial touchdown on the right hand

main landing gear.

Inspection of the right hand main landing gear trunnion and wing box structure during the

investigation indicated that the right hand main landing gear separated in an aft direction. There

was no evidence to indicate that the right hand wing tanks opened up during the landing gear

separation sequence.

At approximately 1100 feet from the runway threshold there is evidence that No. 1 and 2 engines

dug heavily into the runway. Evidence indicates that the left hand outboard wing separated

shortly after engine contact. There are indications that the No. 3 and No. 4 engines, the right

hand outboard flap, aft fuselage and right hand horizontal stabiliser also contacted the runway.

The aeroplane proceeded down the runway in a shallow swerve to the right crossing the runway

right hand edge approximately 2300 feet from runway threshold. The aeroplane continued on

across a grassy strip coming to rest across a drainage ditch opposite the 3500 foot mark and 500

feet to the right of the runway centreline. The aeroplane had turned approximately 140 degrees

to the right as it came to rest.

FIRE

The left hand outboard wing separation occurred at a point just inboard of the No, 1 engine strut.

Shortly thereafter a severe fire occurred on the left hand wing which continued as the aircraft

slid, until it came to rest on a grassy strip over a drainage ditch.
B-27

The fuselage forward of the aft pressure bulkhead and the wings were almost completely

destroyed by fire.

EVACUATION

There were 3 flight crew, 8 cabin crew and 191 passengers aboard.

Once the aircraft came to a stop, the cockpit windows were opened and the crew exited to assist

passengers out of the cabin.

There was a prolonged pause when nothing seemed to be happening to evacuating passengers,

then an overwing exit was activated and a mass of passengers came through, in doing so they

crushed a steward to death. This movement of a bulk of passengers from post-impact lethargy to

safety coincided with the spread of fire.

Interviews with the surviving flight stewards indicated that a mass of people in the galley area

prevented opening the galley door. Further statements verified the fact that four of the stewards

were near the forward end of the passenger cabin and one steward was near the aft entry door at

the time the aircraft impacted the runway. The steward who was stationed in the aft cabin

section stated that he was unable to open the aft left hand entry door and escaped from the right

hand aft galley exit. The stewards at the forward end of the cabin indicated that fire entered the

cabin as the left hand forward entry door was opened and they escaped through the fire.

Investigation at the scene revealed that both station 990 emergency exits were still in place after

the fire had been extinguished.

None of the cabin crew spoke the language of the passengers.

AIRCRAFT FACTORS

The aircraft was a Boeing 707 registered as JY-ADO and operated by Aila Royal Jordanian

Airlines.

The cabin was fitted with a passenger entry door at the front on the port side and a service door

opposite. There were 2 overwing emergency exits above each wing and 1 each side near the

wing trailing edge (Stn 990). There was an entry door at the rear on the port side and a service

door opposite.

ENVIRONMENTAL CONDITIONS

The visibility along the runway was around 200 to 400 metres.

INJURIES TO OCCUPANTS

There has been no report available to the accident investigators to indicate that autopsies were

performed. Therefore, the official cause for passenger deaths is not known. It appears that fire

was the major cause of fatalities.

1 crew member and 175 passengers suffered fatal injuries.

10 crew members and 16 passengers suffered serious injuries.
B-28

2. Fire Penetration Mechanism

The stewards at the forward end of the cabin indicated that fire entered the cabin as the left-hand

forward entry door was opened.

In addition there was extensive fire on the port wing, which can be assumed to have propagated

into the cabin by burning through the fuselage side in that area. None of the port overwing exits

had been opened.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin

in the port wing root area. However there was insufficient information to be conclusive about

detailed burnthrough areas. Fire also entered through the opened port forward entry door.

3. Location of Injuries and Scenarios

4. Accident Scenarios and Survivability Chains

This accident is divided into two separate scenarios.

Scenario 2

Scenario 1
B-29

Scenario 1 contains the flight deck area and the three flight crew. The occupants were able to

escape through the cockpit windows.

Scenario 2 contains the main passenger cabin, which suffered internal fire and had only three of

the ten exits available for egress. It includes all passengers and flight attendants. Many fatalities

were found crowded in the galley area and overcome by smoke.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in Scenario 1, which

contained only the flight deck area.

For Scenario 2, it is assessed that later requirements would have improved flammability

standards such that the occupants would have had additional time to escape. It is assessed that an

additional 41 occupants would have evacuated and 41 of the seriously injured would have

escaped with minor or no injuries.

The survivability chain for Scenario 2 therefore becomes:

0 3

FIRE

3

0

SCENARIO 1

0 2

FIRE

19

17

SCENARIO 2

41

FIRE

23

199

135

SCENARIO 2
B-30

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as all occupants already had access to the cockpit windows for evacuation and were only injured

when they re-entered the cabin in order to assist passengers.

Scenario 2

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with more time to use the available exits. Twenty-three occupants evacuated in 60

seconds, i.e., say 11 in 30 seconds. Assuming a constant evacuation rate, it is assessed that an

additional maximum of 11 occupants would have escaped for each additional 30 seconds of

protection. Further, 1/10 of the occupants who were seriously injured would escape with minor

or no injuries for each additional 30 seconds of protection. Because fire also entered through the

front main entry door no additional benefit was assigned after 4 minutes of burnthrough

protection.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 0 25 174

M 2 28 169

L 3 31 165

For 2 minutes protection:

S I F

H 1 30 168

M 15 34 150

L 28 39 132

For 4 minutes protection:

S I F

H 2 37 160

M 46 29 124

L 89 22 88

For 8 minutes protection:

S I F

H 2 37 160

M 46 29 124

L 89 22 88
B-31

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 47 19 133

M 49 22 128

L 50 25 124

For 2 minutes protection:

S I F

H 48 24 127

M 66 24 109

L 84 24 91

For 4 minutes protection:

S I F

H 49 31 119

M 91 25 83

L 132 20 47

For 8 minutes protection:

S I F

H 49 31 119

M 91 25 83

L 132 20 47

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 7 7

2 minutes 26 26

4 minutes 52 52

8 minutes 52 52
B-32

AIRCRAFT: B707 DATE OF ACCIDENT: 30th January ‘74

REGISTRATION: N454PA LOCATION OF ACCIDENT: PAGO PAGO,

AMERICAN SAMOA

1. Description of Accident

RESUME

On 30-Jan-74, B707-321B was making an ILS approach at night to Pago Pago International

Airport in American Samoa. The aircraft encountered destabilising wind changes which resulted

in an excessive descent rate and as a result the aircraft crashed short of the runway.

A fire broke out and the occupants could not open all the emergency exits. Of the 101

occupants, 97 suffered fatal injuries.

The aircraft was destroyed by the impact and subsequent fire.

IMPACT

Due to destabilising wind changes which resulted in an excessive descent rate the aircraft

crashed into trees 3,865 feet short of the runway and then struck the ground.

The undercarriage landing gear was extended at the time of impact.

There was progressive destruction of the aircraft during its travel through the vegetation and as it

slid over the ground. The fuselage remained intact except for the forward nose fuselage

structure.

Passengers who survived the accident said that the impact forces were slightly more severe than

a normal landing. No damage to the cabin interior was reported.

FIRE

Fire was evident during the last 350 feet of the wreckage pattern. The fuselage from the aft

pressure bulkhead forward through the cockpit area was gutted by fire and the passenger cabin

floor and contents were consumed. From the wing trailing edge forward, the top of the fuselage

and the fuselage sidewalls were consumed by fire down to a point about 4 feet above the window

line. The interior of the rear fuselage aft of the rear pressure bulkhead was not damaged by fire.

The response of the fire department was hampered by the weather, obstacles across the response

route and the uncertainty of whether the fire was from an aircraft or a house. However it is

doubtful that any of the occupants remaining in the aircraft were still alive when the fire and

rescue personnel arrived at the scene.

EVACUATION

There were 10 crew and 91 passengers aboard. The crew consisted of a captain, first officer,

third officer, flight engineer and 6 cabin crew.
B-33

Large fires were seen outside the right side of the aircraft. One person opened an overwing exit

on the right side of the aircraft; flames came in through the exit, and he closed it. Other

survivors opened the left overwing exits, and all the survivors except the first officer escaped

through those exits. The wing was described as very hot and several survivors fell into flaming

fuel at the trailing edge.

The first officer was assisted in his escape by two other cockpit crewmembers and left the

aircraft through a hole in the cockpit wall.

The surviving passengers reported that some passengers rushed toward the front and rear of the

cabin before the aircraft stopped. The survivors did not hear instructions regarding escape from

the aircraft after the accident. Most of the survivors suffered burns and other injuries after they

escaped from the cabin.

Post accident investigation revealed that the forward and the rear entry doors were not opened or

used for escape. The forward door was opened about 2 to 3 inches, but the aft door was closed.

The forward galley service door could not be identified in the wreckage. The rear galley service

door was found in place and locked.

It is possible that the flight attendants were overcome by smoke or that they tried to open the

exits and did not redirect passengers to alternate exits. It is also possible that the passengers

crowded around doors and for that reason the flight attendants were unable to open the exits.

It is unlikely that all of the passengers could have escaped from the aircraft through the 2 left

overwing exits. However it is possible that there would have been more survivors had the

passengers acted according to preflight instructions and proceeded to the nearest exit, instead of

moving toward the main exits through which they had originally entered.

The movement of most of the passengers to the front and rear exits indicates that they either did

not comprehend the pretakeoff briefing or they reacted to the emergency without thinking.

AIRCRAFT FACTORS

The aircraft was a B707 registered as N454PA, operated by Pan American World Airways. The

aircraft was certificated, equipped and maintained in accordance with FAA regulations.

The aircraft had 117,000 lbs of Jet A-1 fuel aboard.

There were two floor level exits located in the front of the cabin and two floor level exits located

in the rear of the cabin. Each door was a plug type that had to be opened inward and then rotated

outboard. Each floor level exit was fitted with an automatically deployable and inflatable

emergency evacuation slide. Two emergency exits were located over each wing. These exits

were not fitted with evacuation slides.

The aircraft was configured as a 146 passenger capacity aircraft with some cargo on board as

well.
B-34

The first class section contained four rows of two double seat units for a total capacity of 16

passengers. Located forward of the first class section were two galley units and two lavatories

on the right side of the cabin and a galley unit, console bar, and two flight attendant jump seats

on the left side of the cabin. Each of the jump seats were double occupancy, rear-facing seats

fitted with seat belts but no shoulder harnesses. A cabin divider was installed between the first

class and economy class sections of the cabin. The economy class section contained twenty rows

of two triple seat units one row of two double seat units and two rows of single triple seat units

for a total capacity of 130 passengers. At the rear of the economy class cabin there were three

galley units, a carry-on baggage compartment, three lavatories and a double forward-facing flight

attendant jumpseat. The jumpseat was fitted with seat belts and shoulder harnesses. None of the

jumpseat locations afforded a view of the passenger compartment.

ENVIRONMENTAL CONDITIONS

The accident occurred at night, below clouds, in rain. After the crash the rain became heavier.

INJURIES TO OCCUPANTS

Of the 101 occupants, 97 suffered fatal injuries. 9 passengers and 1 crew member survived the

crash and fire. 1 passenger died the next day, the crew member and 3 passengers died 3 days

after the accident. 1 passenger died 9 days after the accident but at that time 'fatalities' had to

occur within 7 days of the accident so it was counted as a survivor. [However for consistency,

the current definition of a fatality has been used and hence this passenger has been determined to

have sustained fatal injuries.]

Except for the Third Officer, all fatally injured persons died of smoke inhalation, massive 1st,

2nd and 3rd degree burns and complications from those massive burns. The Third Officer

survived the crash but died later of traumatic leg and arm injuries and severe burns.

Toxicological examinations of the casualties revealed significant levels of carbon monoxide and

hydrogen cyanide which are normal byproducts of aircraft fires.

2. Fire Penetration Mechanism

The fuselage remained intact as it came to rest. A fuel-fed fire broke out along the whole of the

right-hand side and it can be assumed that this pool of fire burnt through the underside of the

fuselage and then entered the passenger cabin from below. Indeed large parts of the right

fuselage sidewall were eventually consumed by the flames as was the cabin roof.

The fire services were delayed in their efforts to reach the site and as a result the fire became

quite severe. However it was unlikely that there were any further survivors to be rescued.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin

lower surface. However there was insufficient information to be conclusive about other

burnthrough areas.
B-35

3. Location of Injuries and Scenarios

4. Accident Scenarios and Survivability Chains

This accident is divided into two separate scenarios.

Scenario 2

Scenario 1
B-36

Scenario 1 contains the flight deck area. It was subjected to the initial impact which was not

severe but did create a hole in the forward skin that the third officer used to crawl out from and

escape. The scenario contains the four flight crew.

Scenario 2 contains the main passenger cabin, which suffered internal fire and had only the two

left overwing exits available for egress. It includes all passengers and flight attendants. Survivor

statements indicate that the cabin occupants were moving up and down the cabin trying to locate

and open exits. Most were found overcome by smoke crowded near the exits.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in Scenario 1, which

contained only the flight deck area.

For Scenario 2, it is assessed that many were injured outside the aircraft in the external fire and

hence later requirements would have only had a modest effect.

3

1

IMPACT

FIRE FIRE

3

0

0 0 1

4

0

0

SCENARIO 1

0 4

FIRE

97

93

SCENARIO 2
B-37

The survivability chain for Scenario 2 therefore becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the flight crew with more time to either help open the forward main passenger door or follow the

third officer out of the hole in the cockpit wall. The high, median, and low prediction from the

use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 004

M022

L 301

For 2 minutes protection:

S I F

H 004

M121

L 220

For 4 minutes protection:

S I F

H 004

M220

L 220

0 8

FIRE

97

89

SCENARIO 2
B-38

For 8 minutes protection:

S I F

H 004

M220

L 220

Scenario 2

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and smoke and

provided the occupants with more time to use the available overwing exits or to open the forward

entry door. However, little benefit has been assigned due to the panic behaviour of the occupants

and because those evacuating had to exit close to the external fire and risked injury outside the

cabin environment.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 0 4 93

M 1 8 88

L 2 12 83

For 2 minutes protection:

S I F

H 0 4 93

M 1 8 88

L 2 12 83

For 4 minutes protection:

S I F

H 0 4 93

M 1 8 88

L 2 12 83

For 8 minutes protection:

S I F

H 0 4 93

M 1 8 88

L 2 12 83

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:
B-39

For 30 seconds protection:

S I F

H 0 8 89

M 1 12 84

L 2 16 79

For 2 minutes protection:

S I F

H 0 8 89

M 1 12 84

L 2 16 79

For 4 minutes protection:

S I F

H 0 8 89

M 1 12 84

L 2 16 79

For 8 minutes protection:

S I F

H 0 8 89

M 1 12 84

L 2 16 79

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 7 7

2 minutes 8 8

4 minutes 9 9

8 minutes 9 9
B-40

AIRCRAFT: CARAVELLE DATE OF ACCIDENT: 15th March ‘74

REGISTRATION: OY-STK LOCATION OF ACCIDENT: TEHERAN,

IRAN

1. Description of Accident

RESUME

On 15-Mar-74, a Stirling Airways Caravelle registered as OY-STK was taxying at Teheran/

Mehrabad International Airport, Teheran, Iran.

Shortly before the aircraft was going to initiate a left turn towards the run-up area two loud

noises were heard in the aircraft and the right wing dropped to the ground and struck the runway.

The aircraft came to a stop 90 m further on and a heavy fire developed.

Evacuation of the aircraft was carried out through exits on the left side of the aircraft.

Preliminary investigation revealed that the right landing gear collapsed due to structural failure

of a fitting (lower 'candelabra'). A rupture of the fuel tank resulted and the JP 1 fuel escaping

from the tank ignited before the aircraft came to a stop. The source of the ignition was not

determined.

There were 4 crew and 92 passengers aboard. 15 passengers suffered fatal injuries.

IMPACT

The aircraft was taxying at the time of the accident and there was no impact.

FIRE

After refuelling at Teheran/Mehrabad International Airport, the aircraft was cleared to taxi for

take-off. Due to some construction work it was cleared to back track on the runway to the takeoff position. Whilst the aircraft was taxying on the runway, it was requested by the ATC to

expedite taxying and to clear the runway on the run-up area close to the runway threshold

because another aircraft was on final approach.

Shortly before the aircraft was going to initiate a left turn towards the run-up area 2 loud noises

were heard in the aircraft and the right wing dropped to the ground and struck the runway.

The aircraft came to a stop 90m further on and a heavy fire developed.

Preliminary investigation revealed that the right landing gear collapsed due to structural failure

of a fitting (lower 'candelabra'). A rupture of the fuel tank resulted and the JP 1 fuel escaping

from the tank ignited before the aircraft came to a stop. The source of the ignition was not

determined.

EVACUATION

There were 4 crew and 92 passengers aboard.
B-41

Evacuation of the aircraft was carried out through exits on the left side of the aircraft.

Evacuation time was thought to be approximately 2 minutes.

AIRCRAFT FACTORS

The aircraft was a Caravelle 10B3 registered as OY-STK and operated by Stirling Airways.

The aircraft was carrying JP 1 fuel.

There was an up-and-over main entry door at the front port side with a service door opposite.

Two emergency exits were located over each wing.

ENVIRONMENTAL CONDITIONS

The accident occurred during daylight with little or no prevailing wind.

INJURIES TO OCCUPANTS

There were 4 crew and 92 passengers aboard. 15 passengers suffered fatal injuries.

2. Fire Penetration Mechanism

As the aircraft came to a stop, leaking fuel formed a pool next to the fuselage on the starboard

side and ignited.

It can be concluded that with a pool fire on the starboard side of the fuselage, the skin would

have been burnt through from underneath after approximately 30 seconds, causing smoke and

flames in the cabin. This can be assumed to be during the evacuation period as it was estimated

that evacuation took 2 minutes.

With this type of fire, penetration would have been initially through the lower fuselage skin and

later into the passenger cabin through the floor. Once smoke was present in the cabin the

occupants would have become disorientated and unable to locate the open exits.

Based on the above it is assessed that the prime burnthrough route was through the lower

fuselage skin. However there was insufficient information to be conclusive about detailed

burnthrough areas.

3. Location of Injuries and Scenarios

Because of the absence of documentary evidence on details of the evacuation, the whole fuselage

volume has been taken as a single scenario which includes all occupants.

4. Accident Scenarios and Survivability Chains

This accident is taken as one scenario.
B-42

Scenario 1 contains the whole aircraft and encompasses 4 crew and 92 passengers.

5. Effect of Later Requirements

It is assumed that later requirements would have provided additional time for evacuation such

that an additional two occupants would have located open exits and evacuated successfully.

It is assessed that this would result in the survivability chain becoming:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the passengers with additional time to locate and use the available exits.

In the absence of detail information on serious injuries, these have been assigned to zero

throughout this accident.

83 0

FIRE

96

13

SCENARIO 3

81 0

FIRE

96

15

SCENARIO 1
B-43

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 81 0 15

M 88 0 8

L 96 0 0

For 2 minutes protection:

S I F

H 81 0 15

M 92 0 4

L 96 0 0

For 4 minutes protection:

S I F

H 81 0 15

M 96 0 0

L 96 0 0

For 8 minutes protection:

S I F

H 81 0 15

M 96 0 0

L 96 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 83 0 13

M 90 0 6

L 96 0 0

For 2 minutes protection:

S I F

H 83 0 13

M 94 0 2

L 96 0 0

For 4 minutes protection:
B-44

S I F

H 83 0 13

M 96 0 0

L 96 0 0

For 8 minutes protection:

S I F

H 83 0 13

M 96 0 0

L 96 0 0

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 7 7

2 minutes 11 11

4 minutes 15 13

8 minutes 15 13
C-1

APPENDIX CACCIDENT RATIONALES 8 TO 17

The rationale for each accident that was analysed appears in this appendix. Each accident is

presented with the following sections:

• Description of the accident reproduced from the Survivable Accidents Database.

• A description of the fire penetration mechanism using relevant extracts from the database

together with any assessments and assumptions made.

• A diagram showing the location of occupants and scenario boundaries.

• Survivability chains for each scenario.

• Effect of later requirements.

• Effect of a fire-hardened fuselage.

The accidents are presented in reverse chronological order.

Key to injury location diagrams:

Exit

Exit used

for

evacuation
C-2

AIRCRAFT: B737 DATE OF ACCIDENT: 17th December ‘78

REGISTRATION: VT-EAL LOCATION OF ACCIDENT: HYDERABAD,

INDIA

1. Description of Accident

RESUME

Indian Airlines B737 registered as VT-EAL was taking off from Hyderabad Airport on 17-Dec78. The leading edge devices did not deploy and as a result the aircraft became aerodynamically

unstable. The take-off was aborted and the aircraft was flared for a belly landing with

undercarriage retracted. The aircraft belly landed in nose up, left wing low attitude, on the centre

line of the runway. It slid for 3080 feet, hit a boundary fence, crossed a drain and ploughed in

rough terrain negotiating with small boulders and came to rest. Fire broke out on impact.

The aircraft was completely destroyed by fire.

There were 6 crew and 126 passengers aboard, of which 1 passenger suffered fatal burn injuries,

1 cabin attendant and 3 passengers were seriously injured.

3 persons cutting grass near the boundary fence of the airport were killed.

IMPACT

The leading edge devices did not deploy and as a result the aircraft experienced a severe shudder

and became aerodynamically unstable. The aircraft did not gain any height and started to sink.

The take-off was aborted and the aircraft was flared for a belly landing with undercarriage

retracted. The aircraft belly landed in nose up, left wing low attitude, on the centre line of the

runway.

The aircraft slid for 3080 feet, hit a boundary fence, crossed a drain and ploughed in rough

terrain negotiating with small boulders and came to rest.

As the aircraft slid into rough terrain it began breaking up, shed the port engine, starboard engine

and engine accessories. The rest of the aircraft remained intact.

The ground markings included drag marks at a distance of 7185 ft from the beginning of the

runway, indicating first contact of the aircraft. On the right hand side a second drag mark was

found at a distance of 7293 ft. A third drag mark was observed at a distance of 7385 ft. It was

concluded that the first and second were caused by the port engine and the third by the starboard

engine. A centre traverse mark was intermittent and was caused by the fuselage. Debris was

found littered alongside the tracks.

ATF spillage could be inferred from the soakage in the overrun area.

The undercarriage was found in the retracted position and appeared to be locked. The main

wheels were lying fore and aft instead of one above the other.
C-3

FIRE

The fire appeared initially at the trailing edge of the port wing and spread to the starboard side of

the aircraft. Fuel from tanks leaked and collected underneath the starboard side and due to wind

the fire intensified. At first the right wing became engulfed in fire and later the middle and

forward portions of the fuselage. The upholstery of the aircraft was burnt in 2 hours. Witnesses

stated that at times the fire subsided and again flared due to bursting of fuel tanks.

The interior of the passenger cabin and cockpit areas were completely burnt out.

Fire fighting operations were not successful because the fire crew could not get close to the

wreckage quickly enough. This was partly due to their perception that the aircraft was at the end

of the runway where, in fact, it was significantly further into the rough terrain and the crew were

not acquainted with the terrain in that area. The fire engines could not get past a drain and had to

fight the fire from some distance.

EVACUATION

The crew consisted of a Captain, Co-pilot and 4 cabin crew. There was also a pilot who

occupied the observer's seat.

There were 126 passengers aboard.

The Captain said he was unable, due to preoccupancy, to announce emergency and order

passenger evacuation. The emergency drill was not adopted and the control tower was not

alerted. The fire crew, however, observed the crash landing and proceeded at once to the site.

[The accident report did not state which doors were used in the evacuation.]

AIRCRAFT FACTORS

The aircraft was a basic series B737-200 registered as VT-EAL and operated by Indian Airlines.

It was maintained and operated in accordance with airworthiness requirements.

The aircraft was manufactured in 1970 as serial number 20485.Airworthiness Certificate number

1576 was issued on 9-Mar-1971 on the strength of FAA Export Certificate of Airworthiness

E9894.

The aircraft was carrying Jet-A fuel.

The aircraft was fitted with a main entry door in the cabin at the front on the port side with a

service door opposite. There was an entry door at the rear on the port side with a service door

opposite. There was a single overwing emergency exit above each wing.

ENVIRONMENTAL CONDITIONS

On the day of the accident the weather was reported to be: wind 120 deg, 10 knots, visibility 10

km, temperature 23 C.
C-4

INJURIES TO OCCUPANTS

There were 6 crew and 126 passengers aboard, of which 1 passenger suffered fatal burn injuries,

1 cabin attendant and 3 passengers were seriously injured.

As a result of the fire, one passenger suffered serious burn injuries all over his body. He was

admitted to hospital but died 3 days later.

Other serious and minor injuries were attributed to the impact:

1 passenger received a fracture injury on her tibia and her fibula was injured.

1 passenger suffered a fracture of the bone below his left knee.

1 passenger received a fracture of her left hand.

1 passenger received a fracture of his left leg.

1 passenger sustained a fracture of his left heel bone.

1 stewardess received injury narrowing the space between her 11th and 12th vertebrae.

1 stewardess received incised injury on her forehead.

There were 14 passengers (all male) who received minor injuries.

2. Fire Penetration Mechanism

The fire appeared initially at the trailing edge of the port wing and spread to the starboard side of

the aircraft. Fuel from tanks leaked and collected underneath the starboard side and due to wind

the fire intensified. At first the right wing became engulfed in fire and later the middle and

forward portions of the fuselage.

It can be reasonably assumed that the ignited fuel that collected either side of the fuselage would

have burnt through the fuselage under surface in the area of the wing root/fuselage junction.

There were no breaks in the fuselage due to impact forces.

Once the skin was penetrated, smoke and flames would have entered the passenger cabin through

the cabin floor.

As only one passenger was reported to have suffered (and later died of) burn injuries, it can be

assumed that the evacuation was nearly completed before the entry of smoke and fire became a

threat to the occupants. Details of the evacuation process did not appear in the official accident

report.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin.

However there was insufficient information to be conclusive about other burnthrough areas.
C-5

3. Location of Injuries and Scenarios

4. Accident Scenarios and Survivability Chains

This accident is divided into four separate scenarios.

Seriously injured flight

attendant was arbitrarily

assigned to this position.

Her location has no effect

on this analysis.

Pilot who occupied the

observer's seat has been

counted as a passenger for

the purpose of this analysis.

Note: The accident

report did not state

which doors were used

in the evacuation.
C-6

Scenario 1 contains the flight deck area, which was subjected to the initial impact. The scenario

contains two flight crew and a pilot in the observer's seat.

Scenario 2 contains the forward flight attendant area and encompasses two flight attendants.

Scenario 3 contains the main passenger cabin, which suffered internal fire after the initial

impact. The scenario contains 125 passengers.

3 0

IMPACT

3

0

SCENARIO 1

2 0

IMPACT

2

0

SCENARIO 2

122 3

IMPACT

FIRE FIRE

1

0

121 3 0

125

0

0

SCENARIO 3
C-7

Scenario 4 contains the rear flight attendant area and encompasses two flight attendants.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in scenarios 1, 2, and 4

in which all injuries were related to the impact.

For Scenario 3, it is assessed that later requirements would have provided additional time to

escape for the only occupant injured by the fire. In this event it is assessed that the injuries

would have been less severe and therefore not fatal.

The survivability chain for Scenario 3 therefore becomes:

122

3

IMPACT

FIRE FIRE

0

1

121 3 0

125

0

0

SCENARIO 3

1

1*

IMPACT

2

0

SCENARIO 4

* The seriously injured flight

attendant was arbitrarily assigned

a seat position. Her location has

no effect on this analysis.
C-8

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as there were no injuries.

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as there were no injuries.

Scenario 3

It is concluded that a fire-hardened fuselage would have provided sufficient time for the

passenger with burn injuries to escape with lesser injuries.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 121 3 1

M 121 4 0

L 121 4 0

For 2 minutes protection:

S I F

H 121 3 1

M 121 4 0

L 121 4 0

For 4 minutes protection:

S I F

H 121 3 1

M 121 4 0

L 121 4 0

For 8 minutes protection:

S I F

H 121 3 1

M 121 4 0

L 121 4 0
C-9

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 121 4 0

M 122 3 0

L 122 3 0

For 2 minutes protection:

S I F

H 121 4 0

M 122 3 0

L 122 3 0

For 4 minutes protection:

S I F

H 121 4 0

M 122 3 0

L 122 3 0

For 8 minutes protection:

S I F

H 121 4 0

M 122 3 0

L 122 3 0

Scenario 4

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 4

as the only injury was related to the impact.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 1 0

2 minutes 1 0

4 minutes 1 0

8 minutes 1 0
C-10

AIRCRAFT: DC8 DATE OF ACCIDENT: 7th October ‘79

REGISTRATION: HB-IDE LOCATION OF ACCIDENT: ATHENS

1. Description of Accident

RESUME

On 7-Oct-79, a DC-8-62 was landing at night on a wet runway at Athens Airport, Greece.

After a late and fast touchdown and after ineffective breaking, the aircraft overshot the runway

end and the overrun area, fell down a slope of 4 m and caught fire.

Of the 154 occupants, 14 suffered fatal injuries as a result of the fire.

The aircraft was destroyed by impact and fire.

IMPACT

Touch down was at approximately 500m from the displaced runway threshold. There was a very

short flare phase with the effect that the nose wheel touched down almost simultaneously with

the main landing gear. Immediately after touch down the captain selected idle reverse on all 4

engines and took control of the aircraft from the co-pilot. The co-pilot set normal reverse. A

few seconds later brake application was initiated which gave an impression of almost normal

braking conditions.

At approximately 500-600m before the end of the runway braking efficiency dropped and full

braking was applied. In spite of this action braking efficiency dropped to almost nil within

seconds. Still the impression prevailed that with reverse deceleration it would be possible to stop

the aircraft before the runway end. At approximately 300m before the runway end a first doubt

came up about this fact. The captain tried to test directional steering capability by turning the

nose wheel slightly to the left. No rotation of the aircraft was felt. In this condition the aircraft

was skidding the remaining distance of the runway and with a speed of approximately 20-25

knots overran the runway end.

After rolling over the asphalt overrun area of approximately 65m length, the aircraft fell

approximately 4m onto a bitumen road which crossed the runway axis almost rectangularly.

The first impact occurred with the nose wheel within reach of the road. The second impact must

have occurred with the afterbody/tail on the end of the overrun area. Approximately at the same

time the nose wheel was bent backwards due to the terrain which rises by about 0.5 m. The main

landing gear struck the ground between a bank and the road. The aircraft skidded further before

coming to a halt, the tail being approximately 76.5m from the end of the runway.

The aircraft was destroyed by the hard impact in the vicinity of the road and by the ensuing fire.

The left wing was broken in front of the No. 1 engine. The fuselage was broken in front of the

vertical stabiliser. The nose wheel was bent backwards. The right and left main landing gear
C-11

were torn off the wing structure with parts of the rear spar bent backwards and twisted by

approximately 90° for the left and by approximately 180° for the right.

The aircraft was carrying 40 packages of radio active material for medical purposes. Experts

found that the packages were for the most part destroyed due to the ensuing fire. However no

leakage of radio active materials occurred into the atmosphere.

FIRE

As soon as the aircraft overshot the runway and stopped outside the airport's boundary, fire broke

out at the right main part of the fuselage. The impact forced the right main landing gear to bend

backwards by approximately 180° and tore open the fuel tanks of the right wing. Fuel from

these tanks started to flow and the fire was extended not only to the aircraft, but to the road at the

right side of the aircraft. This meant that access to the aircraft's right side was impossible.

The fire fighting service was in action in approximately 3 minutes and 3 of the fire fighting cars

which had turrets began action without any delay combating the fire from the edge of the slope.

3 cars from the US base fire brigade fought the fire at the tail and the right side of the aircraft.

Another fire service took over the left side from which passengers were still evacuating.

While the fire had begun to be under control some small explosions were heard, probably from

exploding oxygen bottles and fire covered the aircraft completely.

One rescuer equipped with fire proof equipment and smoke mask did not enter the aircraft

because he was waiting for a specific order. This was not given because the rescue crew were

out of the protective range of the turrets.

The fire was under control within about 25 minutes and extinguished after about 2 hours from

the initial crash. A total of 20 fire fighting cars and 75 fire crew took part in the operation.

EVACUATION

There were 3 flight crew, 7 cabin crew and 144 passengers aboard.

As soon as the aircraft came to rest, the captain left the aircraft through the cockpit window in

order to assist passengers as they came out of the forward exit. The crew opened the left front

and rear doors. The front door opened normally, and the slide worked quickly. The rear door

had some difficulty in opening, probably because of deformation, it was opened with some

delay. The slide did not deploy.

The crew was giving the appropriate instructions for quick evacuation and passengers were

leaving the aircraft normally at the front. However the loss of the PA system meant that no

information regarding the use of the exits could be transmitted. As a result confusion was

created to the passengers in the central area of the aircraft who could not use the overwing exits

due to the external fire.
C-12

According to crew and passenger statements, approximately 120-130 passengers left the aircraft

through the left front exit. The exit doors and emergency exits at the right side of the aircraft

were not used. Overwing exits at the left side were not used either because, according to the

flight attendants' statements, there was external fire in that area. The delay in opening the rear

door resulted in passengers moving back and forth. The rear of the cabin had more smoke than

the front part due to the lack of draught.

The passengers were finally directed to the front door. The front slide failed after it had been

used by 40-50 passengers and the passengers were then jumping from a height of 1.70 metres.

11 passengers sustained minor injuries due not only to the height but also to the fact that they

were jumping on each other. The evacuation lasted approximately 3.5 to 4.5 minutes. The copilot re-entered the aircraft after the last passenger was out to search for passengers. He couldn't

see anything because of smoke.

According to witness statement as well as the Swissair boarding cards, the 14 dead persons were

seated at the rear part of the aircraft between the 21st and 26th row. It seems that these

passengers hadn't tried to leave the aircraft, considering the evacuation had been completed from

the rear door, as stated by the flight attendant. 5 of the dead were seated in row 25. Many

passengers walked through that area and no one had reported any difficulties in passing through.

It was calculated that the evacuation lasted approximately 3.5 to 4.5 minutes.

AIRCRAFT FACTORS

The aircraft was a DC-8-62 registered as HB-IDE, operated by Swissair.

The aircraft was manufactured as serial number 45919 and delivered on 22-Nov-1967.

The aircraft had 4 exit doors, 2 at the front part and 2 at the rear part of the cabin, 4 overwing

emergency exits and 2 sliding windows in the cockpit.

ENVIRONMENTAL CONDITIONS

The accident occurred at night on a wet runway. Wind was 090°, 17 knots. Visibility was 7 km

in light rain. The temperature was 18C.

INJURIES TO OCCUPANTS

Of the 10 crew and 144 passengers aboard, 14 passengers suffered fatal injuries.

Fourteen fatalities were found sitting in rows 21-26. The forensic medical postmortem reports

testify that the death of 14 passengers was caused by burns of third degree on the whole body.

11 passengers suffered minor injuries during evacuation.

2. Fire Penetration Mechanism

As the aircraft came to a stop, leaking fuel ignited and extended along the entire starboard side of

the fuselage. In addition the port overwing exit doors were not opened because the cabin crew

saw fire in that area.
C-13

It can be concluded that with fire on both sides of the fuselage, the skin would have burnt

through after approximately 30 seconds, causing smoke and flames in the cabin. This can be

assumed to be during the evacuation period as it was estimated that evacuation took 3.5 to 4.5

minutes. Indeed, fire services were on scene in 3 minutes and saw passengers still evacuating.

With this typical pool fire environment, fire penetration would have been initially through the

lower fuselage skin, baggage bay, or undercarriage bay and later into the passenger cabin

through the floor. Once smoke was present in the cabin, the occupants would have become

disorientated and unable to locate the open exits. It was considered that occupants were not

rendered immobile by the impact forces as movement was reported of passengers back and forth

during the delay in opening the rear port door.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin.

However there was insufficient information to be conclusive about other burnthrough areas.

3. Location of Injuries and Scenarios

Scenario 6

Scenario 5

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-14

4. Accident Scenarios and Survivability Chains

This accident is divided into six separate scenarios:

Scenario 1 contains the flight deck area encompassing the three flight crew who were not

injured.

Scenario 2 contains the forward flight attendant area with four flight attendants, all of who

escaped uninjured.

Scenario 3 contains the front section of the passenger cabin from seat row 1 to seat row 20

inclusive. A uniform distribution of passengers was assumed; therefore this scenario contains an

estimated 92 passengers, all of whom evacuated without injury.

3 0

FIRE

3

0

SCENARIO 1

4 0

FIRE

4

0

SCENARIO 2

92 0

FIRE

92

0

SCENARIO 3
C-15

Scenario 4 contains the midsection of the passenger cabin from seat row 21 to seat row 26

inclusive. A uniform distribution of passengers was assumed; therefore this scenario contains an

estimated 27 passengers, 14 of whom succumbed to the fire.

Scenario 5 contains the rear section of the passenger cabin from seat row 27 to the end (taken as

seat row 32 with 3 abreast in the tapered fuselage) inclusive. A uniform distribution of

passengers was assumed; therefore this scenario contains an estimated 25 passengers, all of

whom evacuated without injury.

Scenario 6 contains the rear flight attendant area encompassing three flight attendants, all of

whom evacuated without injury.

13 0

FIRE

27

14

SCENARIO 4

25 0

FIRE

25

0

SCENARIO 5

3 0

FIRE

3

0

SCENARIO 6
C-16

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in scenarios 1, 2, 3, 5,

and 6 which already had sufficient time for successful evacuation.

For Scenario 4, it is assessed that later requirements would have improved passenger orientation

and an additional eight passengers would have been able to locate the useable exits. The

survivability chain for Scenario 4 becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as there was already sufficient time for a successful evacuation.

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as there was already sufficient time for a successful evacuation.

Scenario 3

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 3

as there was already sufficient time for a successful evacuation.

Scenario 4

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with additional time to use the available exits.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

21 0

FIRE

27

6

SCENARIO 4
C-17

For 30 seconds protection:

S I F

H 13 0 14

M 13 4 10

L 14 13 0

For 2 minutes protection:

S I F

H 13 0 14

M 15 6 6

L 18 9 0

For 4 minutes protection:

S I F

H 13 0 14

M 18 4 5

L 24 3 0

For 8 minutes protection:

S I F

H 13 0 14

M 20 4 3

L 27 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 21 0 6

M 21 3 3

L 21 6 0

For 2 minutes protection:

S I F

H 21 2 4

M 23 4 0

L 23 4 0
C-18

For 4 minutes protection:

S I F

H 26 1 0

M 25 2 0

L 25 2 0

For 8 minutes protection:

S I F

H 27 0 0

M 27 0 0

L 27 0 0

Scenario 5

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 5

as there was already sufficient time for a successful evacuation.

Scenario 6

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 5

as there was already sufficient time for a successful evacuation.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 4 3

2 minutes 8 6

4 minutes 9 6

8 minutes 11 6
C-19

AIRCRAFT: DC10 DATE OF ACCIDENT: 13th September ‘82

REGISTRATION: EC-DEG LOCATION OF ACCIDENT: MALAGA

1. Description of Accident

RESUME

On 13-Sep-82 a Spantax DC-10-30F registered as EC-DEG was taking off from Malaga Airport

in Spain.

The pilot aborted the takeoff because of 'vibrations' of unknown origin. The aircraft proceeded

off the end of the runway and struck a number of objects, creating sufficient damage to cause

fuel spillage, but no fire, as it decelerated.

Approximately 700 feet from the end of the runway, the aircraft crossed a road and struck a

house. This impact was quite severe, ripping off the right wing and creating a fireball. The

fireball 'followed' the aircraft until it came to rest approximately 1000-1200 feet beyond the

runway

Of the 13 crew and 381 passengers aboard, 3 crew and 47 passengers suffered fatal injuries. 40

passengers were seriously injured.

IMPACT

The aircraft proceeded off the end of the runway and struck a number of objects, creating

sufficient damage to cause fuel spillage, as it decelerated.

Approximately 700 feet from the end of the runway, the aircraft crossed a road and struck a

house. This impact was quite severe, ripping off the right wing. The fuselage was believed to be

entirely intact at this point, resting on its belly.

FIRE

A large external fuel fire developed on the right hand side of the aircraft aft of the wing area.

The fire size was estimated 25 feet long (fuselage direction) and 50 feet wide. Flames extended

2-21/2 times the height of the fuselage. A much smaller fuel fire formed on the left hand side.

The wind speed was 14 knots. The wind vector was forward to aft and at a slight angle with the

fuselage centre line, tending to bend the flames away from the fuselage.

There are witness accounts that fire broke in through the tail and dense smoke seeped in probably

through a tear in the upper part of the passenger cabin at the height of door 4R.

The aircraft was gutted from the inside-out by fire (the external fuel fire was extinguished by the

fire department).

EVACUATION

There were 2 flight crew, 11 cabin crew and 381 passengers aboard.
C-20

Slides were deployed for the front emergency exits immediately: L1, L2, and R1. Door R2 was

opened later by a passenger (intense fire on that side). After 3 or 4 passengers exited, the slide

that served R2 was disabled by fire. Because that landing gear was sheared off, the slides

formed a shallow angle and occupants were able to 'walk down the slides'.

Door R3 was not opened due to the intense fire on that side. The stewardess in charge of

opening door L3 saw fire on the left side of the plane but decided to open it anyway because she

noted the fire was more intense on the right side. The three stewardesses located toward the

plane's tail tried to open doors L4 and R4 without success according to witness accounts.

The evacuation took place slowly because the passengers picked up their carried luggage before

evacuating. In the third cabin, besides the problems brought about by hand-carried luggage, a

bottleneck resulted due to the number of passengers, most of them on the left aisle, that were

trying to reach door L3. On top of that, evacuation was carried on with difficulty due to the fire

having destroyed the L3 slide.

The lack of visibility, due to the fire and smoke, and the cabin dividers made it impossible to

have a view of the plane as a whole, and consequently, three different evacuations were carried

out. One from each cabin.

The 91 passengers in the first cabin left the plane through doors L1, R1 and L2. The 122 in the

second cabin left through doors L2, L3 and some through R2. The third cabin was occupied by

167 passengers. On these, the 117 that evacuated the plane did so by using door L3 which was

affected by the fire through most of the process. The L3 slide was rendered useless. The 47

passengers and three crew members that died occupied the third cabin.

AIRCRAFT FACTORS

The aircraft was a DC-10-30F registered as EC-DEG and operated by Spantax.

The cabin was fitted with 4 passenger doors down each side.

ENVIRONMENTAL CONDITIONS

The accident occurred in daylight. The prevailing weather conditions at the time of the accident

were dry, no cloud and wind at 14 kt.

INJURIES TO OCCUPANTS

Of the 13 crew and 381 passengers aboard, 3 crew and 47 passengers suffered fatal fire injuries.

40 passengers were seriously injured.

2. Fire Penetration Mechanism

When the aircraft came to a stop, a large external fuel fire developed on the right-hand side of

the fuselage aft of the wing area and a much smaller fuel fire formed on the left-hand side.

The wind direction was forward to aft and at a slight angle with the fuselage centre line, tending

to bend the flames of the large fire away from the fuselage side. However, it can be assumed
C-21

that flames from the smaller fire were being directed onto the fuselage side at the rear of the

cabin and would have caused a burnthrough from the left side.

In addition, smoke was seeping in through a tear in the upper part of the passenger cabin at the

height of door 4R. It is assessed, however, that there was no immediate burnthrough in this area.

The wreckage was described as being gutted from the inside out by fire. It is assumed that this

would have occurred well after the evacuation was complete.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin

at the rear on the left side. However there was insufficient information to be conclusive about

detail burnthrough areas.

3. Location of Injuries and Scenarios

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-22

4. Accident Scenarios and Survivability Chains

This accident is divided into four separate scenarios.

Scenario 1 contains the flight deck area where all occupants successfully evacuated. The

scenario contains the two flight crew.

Scenario 2 contains the forward passenger cabin area where all occupants successfully

evacuated. The scenario contains 91 passengers and 4 flight attendants.

Scenario 3 contains the mid passenger cabin area where all occupants successfully evacuated.

To account for all passengers it has been assumed that there were 123 passengers (instead of the

122 quoted in the accident report) and 4 flight attendants in this scenario.

127

0

FIRE

127

0

SCENARIO 3

2 0

FIRE

2

0

SCENARIO 1

95 0

FIRE

95

0

SCENARIO 2
C-23

Scenario 4 contains the rear passenger cabin area where 50 occupants did not have sufficient

time to make their way to the open L3 exit. The scenario contains 167 passengers and 3 flight

attendants.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in scenarios 1, 2, and 3

which already had sufficient time for successful evacuation.

For Scenario 4, it is assumed that later requirements would have provided an additional 30

seconds of evacuation time to those in the rear passenger cabin area who only had L3 as an

available exit. The evacuation rate on this exit was such that an additional 10 occupants would

have been able to evacuate given an additional 30 seconds.

The survivability chain for Scenario 4 therefore becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as no injuries were sustained.

80 40

FIRE

170

50

SCENARIO 4

90 40

FIRE

170

40

SCENARIO 4
C-24

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as no injuries were sustained.

Scenario 3

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 3

as no injuries were sustained.

Scenario 4

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the passengers with additional time to make their way to the open L3 exit. It is further assessed

that smoke was entering through the tear above door L4 and therefore approximately 10

occupants would still have succumbed even with perfect fire hardening.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 80 40 50

M 84 42 44

L 100 40 30

For 2 minutes protection:

S I F

H 80 40 50

M 93 44 33

L 112 48 10

For 4 minutes protection:

S I F

H 80 40 50

M 104 38 28

L 144 16 10

For 8 minutes protection:

S I F

H 80 40 50

M 111 33 26

L 144 16 10
C-25

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 90 40 40

M 94 42 34

L 110 40 20

For 2 minutes protection:

S I F

H 90 40 40

M 102 42 26

L 118 42 10

For 4 minutes protection:

S I F

H 90 40 40

M 112 37 21

L 146 14 10

For 8 minutes protection:

S I F

H 90 40 40

M 115 37 18

L 146 14 10

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 6 6

2 minutes 17 14

4 minutes 22 19

8 minutes 24 22
C-26

AIRCRAFT: B727 DATE OF ACCIDENT: 7th December ‘83

REGISTRATION: EC-CFJ LOCATION OF ACCIDENT: MADRID,

SPAIN

1. Description of Accident

RESUME

On 07-Dec-1983 an Iberia B727-200 registered as EC-CFJ was taking off from Madrid-Barajas

Airport, Spain in fog conditions.

As the aircraft reached V1 speed, it collided with a DC-9 which had taxied onto the runway in

error due to the poor visibility.

The aircraft spun round, caught fire and was destroyed.

Of the 9 crew and 84 passengers aboard, 1 crew member and 50 passengers suffered fatal

injuries. 4 crew and 26 passengers suffered serious injuries. 4 crew and 8 passengers escaped

with minor or no injuries.

IMPACT

The DC-9 aircraft was on the flight runway, because the visibility conditions due to fog in the

zone through which the aircraft had taxied prevented the crew from obtaining sufficient visual

references in order to determine that it was not the correct route which they should have been

taking to reach the head of the runway.

At the moment of impact the B727 had just reached Vl and was travelling substantially on the

runway axis.

The port side of the aircraft's fuselage on a level with the partitioning bulkhead between the crew

and passenger cabins collided with the port wingtip of the DC-9 which had invaded the flight

runway.

The effect of this initial impact was to instantly cause the other aircraft to swing round, leaving it

practically parallel with, but in the opposite direction to, the B727, which lost its port wing and

landing gear. The B727 continued along the runway, swinging round and moving over until it

came to a halt at 460 m from the point of impact on the left hand edge of the runway, facing the

opposite way to the direction of take-off.

FIRE

Fire broke out on the initial impact due to the breaking off of the port wing and the consequent

leakage of fuel, which subsequently destroyed the whole aircraft.

The fire and the smoke generated affected the passengers of the B727 throughout the seconds

which passed from when the collision occurred until the aircraft came to a complete stop and its

evacuation.
C-27

EVACUATION

There were 9 crew and 84 passengers aboard.

The instantaneous fire which broke out on the port side of the aircraft and the plane's subsequent

violent swing round incapacitated the victims who were unable to reach the exits.

AIRCRAFT FACTORS

The aircraft was a B727-200 registered as EC-CFJ and operated by the Iberia Company.

The cabin was fitted with a passenger entry door at the front port side, a service door on the

starboard side, 2 overwing emergency exits above each wing and service door at either side at

the rear. The cockpit had sliding windows on each side.

ENVIRONMENTAL CONDITIONS

The accident occurred during the hours of daylight but in fog.

INJURIES TO OCCUPANTS

Of the 9 crew and 84 passengers aboard, 1 crew member and 50 passengers suffered fatal

injuries. 4 crew and 26 passengers suffered serious injuries. 4 crew and 8 passengers escaped

with minor or no injuries.

5 people died instantly as a result of the impact of the DC-9's port wing with the B727's fuselage.

The traumatic injuries both of the survivors and of the fatalities were produced as a result of:

(a) The initial impact of the port wing tip of the DC-9 with the part of the B727's fuselage

level with the bulkhead separating the crew compartment from the passenger cabin.

(b) The dynamic forces generated by the accelerations at the commencement and end of the

aircraft's turn through 180 deg.

The effects of the smoke and fire which broke out on collision, plus the traumatic injuries,

incapacitated a large number of victims, preventing them from evacuating the aircraft.

2. Fire Penetration Mechanism

Fire broke out on the initial impact due to the breaking off of the port wing and the consequent

leakage of fuel. The fire was instantaneous and on the port side of the aircraft. The fire and the

smoke generated affected the passengers throughout the seconds which passed from when the

collision occurred until the aircraft came to a complete stop and its evacuation.

It is assessed that some fire and smoke could have entered the cabin through ruptures in the

fuselage side caused by the impact. In addition, there was a pool fire around the aircraft as it

came to a stop and it is assumed that this fire would have burnt through the fuselage during the

evacuation.

The pool of ignited fuel subsequently destroyed the whole aircraft.
C-28

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin.

However there was insufficient information to be conclusive about detail burnthrough areas. It is

additionally assessed that fire could have also entered the fuselage through ruptures.

3. Location of Injuries and Scenarios

Scenario 1

Note: The accident report

did not indicate which of

the exits were used for

evacuation.
C-29

4. Accident Scenarios and Survivability Chains

Due to insufficient documentary detail, this accident is considered as one scenario containing the

whole aircraft.

Scenario 1 contains the whole aircraft.

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation because the occupants

who did not evacuate were incapacitated during the violent swing through 180 degrees and were

unable to attempt an evacuation.

6. Effect of a Fire-Hardened Fuselage

It is assumed that a fire-hardened fuselage would not have affected the situation because the

occupants who did not evacuate were incapacitated during the violent swing through 180 degrees

and were unable to attempt an evacuation.

88

0

IMPACT

FIRE FIRE

46

30

12 0 0

93

0

5

SCENARIO 1
C-30

AIRCRAFT: B737 DATE OF ACCIDENT: 30th August ‘84

REGISTRATION: TJ-CBD LOCATION OF ACCIDENT: DOUALA,

CAMEROON

1. Description of Accident

RESUME

Before take-off the right engine failed with significant damage to the engine and the right wing

between the fuselage and the engine pod. Fragments from a high pressure compressor disc

perforated the right integral wing tank.

Fuel leaked onto the ground and ignited. Fire destroyed the aircraft.

There was no impact damage.

There were 118 occupants aboard, of which 2 suffered fatal injuries due to fire outside the cabin

environment.

2. Fire Penetration Mechanism

There is very little data available on this particular accident, but it may be assumed that once the

leaked fuel under the fuselage ignited, the fuselage would have burnt through along the lower

surface.

Once the fuselage was penetrated, fire and smoke would have propagated up through the floor

and then into the passenger cabin.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin.

However there was insufficient information about other burnthrough areas.

3. Location of Injuries and Scenarios

There is insufficient data to identify the location of injuries except for the fact that the two fire

fatalities occurred outside the cabin environment.

Therefore the accident is considered as two scenarios, one containing the two external fire

fatalities and one containing the remainder of the occupants.

4. Accident Scenarios and Survivability Chains

This accident is considered as two separate scenarios.
C-31

Scenario 1 contains the two occupants fatally injured outside the cabin environment.

Scenario 2 contains the remainder of the occupants.

5. Effect of Later Requirements

Due to lack of data, no assumptions can be made about the effect of later requirements.

6. Effect of a Fire-Hardened Fuselage

As the only fire fatalities occurred outside the cabin environment, it is concluded that a firehardened fuselage would have had no benefit in this accident.

0 0

FIRE

2

2

SCENARIO 1

116 0

FIRE

116

0

SCENARIO 2
C-32

AIRCRAFT: B737 DATE OF ACCIDENT: 22nd August ‘85

REGISTRATION: G-BGJL LOCATION OF ACCIDENT: MANCHESTER

1. Description of Accident

RESUME

At 0612 hrs G-BGJL, carrying 131 passengers and 6 crew on a charter flight to Corfu, began its

take-off from runway 24 at Manchester with the co-pilot handling. About thirty six seconds

later, as the airspeed passed 125 knots, the left engine suffered an uncontained failure, which

punctured a wing fuel tank access panel. Fuel leaking from the wing ignited and burnt as a large

plume of fire trailing directly behind the engine. The crew heard a 'thud', and believing that they

had suffered a tyre-burst or bird-strike, abandoned the take-off immediately, intending to clear

the runway to the right. They had no indication of fire until 9 seconds later, when the left engine

fire warning occurred. After an exchange with Air Traffic Control, during which the fire was

confirmed, the commander warned his crew of an evacuation from the right side of the aircraft,

by making a broadcast over the cabin address system, and brought the aircraft to a halt in the

entrance to link Delta.

As the aircraft turned off, a wind of 7 knots from 250° carried the fire onto and around the rear

fuselage. After the aircraft stopped the hull was penetrated rapidly and smoke, possibly with

some flame transients, entered the cabin through the aft right door which was opened shortly

before the aircraft came to a halt. Subsequently fire developed within the cabin. Despite the

prompt attendance of the airport fire service, the aircraft was destroyed and 55 persons on board

lost their lives.

The cause of the accident was an uncontained failure of the left engine, initiated by a failure of

the No 9 combustor can which had been the subject of a repair. A section of the combustor can,

which was ejected forcibly from the engine, struck and fractured an underwing fuel tank access

panel. The fire which resulted developed catastrophically, primarily because of adverse

orientation of the parked aircraft relative to the wind, even though the wind was light.

IMPACT

There was no disruption to the passenger cabin as a result of impact in this accident.

FIRE

G-BGJL began its take-off from runway 24 at Manchester with the co-pilot handling. About

thirty six seconds later, as the airspeed passed 125 knots, the left engine suffered an uncontained

failure, which punctured a wing fuel tank access panel. Fuel leaking from the wing ignited and

burnt as a large plume of fire trailing directly behind the engine. The crew heard a 'thud', and

believing that they had suffered a tyre-burst or bird-strike, abandoned the take-off immediately.

After the aircraft stopped the hull was penetrated rapidly and smoke, possibly with some flame

transients, entered the cabin through the aft right door which was opened shortly before the

aircraft came to a halt. Subsequently fire developed within the cabin.
C-33

Fire was first spotted 10 seconds after the bang. The port engine and wing caught fire. Fuel

leaking from the wing ignited and burnt as a large plume of fire trailing directly behind the

engine. Upon turning, the fire spread under the fuselage because of wind and totally engulfed

the aft fuselage. The aircraft was extensively damaged by fire. Most of the light alloy

components in the aft region of the left engine nacelle were melted or burnt away. The left wing

lower aft surfaces, large sections of the trailing edge flaps inboard of the engine and the lower

surfaces of the flaps outboard of the engine were melted, and the remaining regions of the left

inner wing and the main landing gear bay were superficially fire-damaged.

The rear fuselage was extensively burnt between the wing trailing edge and the rear doors; a

large part of the left fuselage side between frames 787 and 887 (approximately seat rows 17 to

21) was completely burnt away. The whole of the fuselage aft of the rear cargo door and the tail

section had collapsed onto the ground.

Analysis of the wreckage has shown that the fire initially penetrated the skins on the left side in

the vicinity of seat rows 17 to 19, below the level of the cabin floor. Having breached the outer

skin, the only barrier which prevented the fire gaining access to the cavity formed between the

outer skin and the cargo bay side-liner panels, which communicated directly with the cabin

interior above via floor level air-conditioning grills, was a 1 inch thick fibreglass wool acoustic

insulation blanket contained in a thin plastic bag.

Most of the passenger cabin ceiling and crown skins were burnt and all of the overhead luggage

bins were destroyed. The support beams which carried the cabin floor above the rear cargo hold

were burnt away in the central aisle area and on the right side of the cabin, allowing most of the

cabin floor above the hold to collapse down onto the baggage. Most of the cabin interior fittings

and seats in this section of the cabin were destroyed completely or were very extensively

damaged. The interior fittings in the centre and forward sections of the cabin were generally less

severely affected by the fire. However, there was considerable local variability, particularly in

the severity of seat damage. Notably, seats 8C and 9C (left aisle seats just forward of the

overwing exits) were completely destroyed, whereas the adjoining seats were relatively intact.

The survivors statement indicated that the smoke suddenly emanated from the rear of the cabin

just before the aircraft stopped. Many passengers reported holding their breath as smoke hit

them and that one breath of the thick black smoke caused breathing problems and lung pain. A

passenger from seat 6A saw a sheet of flame inside the cabin. It seemed to be near the centre of

the aircraft and separated the front half from the back. Another passenger from 6B, after seeing

foam being sprayed over the fire on the left side of the aircraft, tried to move into the aisle but it

was jammed with people and it was difficult to move. On turning he saw flames shooting in

through the side windows and up through the floor area. The flames were several feet in length

and continual.

The fire station crash alarm was initiated by ATC immediately the fire was observed from the

tower. However, many fire crew personnel heard the bang, saw the fire and started to respond

before the alarm had sounded.
C-34

RIV2 arrived at the scene approximately 25 seconds after the aircraft had stopped. It was

positioned on the left side of the aircraft and foam was applied initially onto the left side of the

fuselage and then onto the left engine. RIV1 arrived shortly after RIV2, positioned off the nose

slightly on the left side, and discharged the whole of its foam along the left side of the fuselage

with the intention of protecting passengers, who by then were evacuating from the L1 chute, and

cooling the left side of the fuselage.

Approximately 7 minutes into the incident, after it became clear that no more passengers were

likely to emerge unaided, a team with breathing apparatus made an entry via the R1 door.

Conditions inside the cabin at that time were very bad, with thick smoke and a serious fire in

progress at the rear of the cabin. Shortly after entering, an explosion occurred which blew one of

the firemen out of the door onto the tarmac. The officer in charge was by that time becoming

increasingly concerned about the reducing water supplies, especially with regard to the potential

loss of water supplying sidelines deployed within the cabin, and directed that there would be no

more attempts to gain entry until there was a reliable supply of water. In the interim, sidelines

were used on the exterior only. At about this time a fire was seen to flash briefly along the cabin.

By approximately 11 minutes into the incident, the internal fire appeared to have spread forward

throughout the cabin, where breaches in the roof could be seen. J1 was dispatched to replenish

with water from the hydrant system: the vehicle was positioned at three hydrants in succession,

but no water could be obtained from any of them. This resulted in a delay of about 10 minutes,

after which J1 returned to the scene empty. It was then dispatched to the hydrant behind the fire

station, where replenishment was successful.

The GMC fire appliances arrived at the aircraft approximately 13 minutes into the incident.

Initially, the Station Officer (SO) in charge experienced some difficulty in identifying the officer

commanding the airport fire service, resulting in some delay before the water requirements were

identified and the transfer of the 1600 gallons of water from the GMC appliances to J2 could

begin. Using a sideline from the newly replenished J2 tender, a two man team with breathing

apparatus was then able to make an entry via the R1 door using a short ladder, and, for the first

time, were in a position to begin addressing the internal fire.

EVACUATION

During the take-off run the commander made the routine call of "eighty knots" which was

confirmed by the co-pilot, and 12 seconds later a 'thump' or 'thud' was heard. Believing that they

had suffered a tyre-burst or bird-strike, the crew abandoned the take-off immediately, intending

to clear the runway. They had no indication of fire until 9 seconds later, when the left engine fire

warning occurred. After an exchange with Air Traffic Control, during which the fire was

confirmed, the commander warned his crew of an evacuation from the right side of the aircraft,

by making a broadcast over the cabin address system; "Evacuate on the starboard side please."

As the aircraft's groundspeed reduced through 17 Kt., 10 seconds before it stopped, the purser

opened the flight deck door and said, "Say again", seeking confirmation of the evacuation order.

The commander repeated, "Evacuate on the starboard side", 8 seconds before the aircraft came to

a halt.
C-35

The passenger evacuation drill, a non-memory drill was called for by the commander and was

read from the Quick Reference Handbook by the co-pilot. Before they were able to complete the

drill the commander saw fuel and fire spreading forward on the left side of the aircraft, opened

the co-pilot's sliding window on the right side of the flight deck and ordered him to evacuate the

aircraft. This the co-pilot did by means of a fabric escape strap secured above the sliding

window and he was followed down to the ground by the commander.

The purser and stewardess seated in the left of the forward galley area during the take-off run

heard a 'thud' which they too thought was a tyre burst. They were aware that the take-off had

been abandoned. There were sounds of distress in the cabin and the purser leaned inboard in an

attempt to improve his view and saw passengers standing up. He made a Public Address

announcement for passengers " to sit down and to remain strapped in", released his harness and

went into the forward part of the cabin. He saw fire outside the aircraft on the left side coming

up over the leading edge of the wing and flowing back over the wing's top surface. There was no

smoke or fire apparent to him in the cabin at that time.

Passengers in rows 1-3 appear to have been initially oblivious of the fire which issued from the

engine after the 'thud'. However, most of those seated aft of row 5, and in particular those aft of

row 14 on the left side, were immediately aware of an intense fire. The flames were seen to

cause some 'cracking and melting' of the windows, with some associated smoke in the aft cabin

before the aircraft stopped. These effects, with the accompanying radiant heat, caused some

passengers to stand up in alarm. A male passenger shouted "sit down, stay calm". Similar calls

were then made by others seated mainly on the right side of the aircraft. Many sat down, but

some found the pressure to move into the aisle irresistible.

After the purser had confirmed the evacuation with the commander he repeated the evacuation

call a number of times over the PA system. Then, as the aircraft was coming to a halt, he went to

the right front (R1) door to open it and release the inflatable escape slide. The door unlocked

normally but as it was moving out through the aperture the slide container lid jammed on the

doorframe preventing further movement of the door. After spending a short time trying to clear

the restriction he postponed further effort and crossed to the L1 door. He cracked it open,

ascertained that the forward spread of the fire was slow enough to allow evacuation from that

door, opened it fully and confirmed the inflation of the slide manually. This was achieved about

25 seconds after the aircraft had stopped and coincident with the initiation of foam discharge

from the first fire vehicle to arrive. Evacuation began on the left side under the supervision of

the No 4 stewardess, who had to pull free some passengers who had become jammed together

between the forward galley bulkheads in order to start the flow.

The purser returned to the R1 door, lifted the slide pack in order to close the slide container lid,

and cleared the obstruction. He succeeded in opening the door about 1 minute 10 seconds after

the aircraft stopped and again confirmed the automatic inflation of the slide by pulling the

manual inflation handle. Evacuation was carried out from this exit supervised by the purser.

Smoke emanating from the cabin quickly reached the galley area and became rapidly more dense

and acrid. When the smoke began to threaten severe incapacitation, the forward cabin crew

vacated the aircraft by the slides at their respective doors.
C-36

As the aircraft came to a halt and at the instigation of other passengers, a young woman sitting in

seat 10F, beside the right overwing exit, attempted to open it by pulling on her right hand armrest which was mounted on the exit hatch. Her companion in seat 10E, the centre seat of a row

of three, stood up and reached across to pull the handle located at the top of the hatch marked

"Emergency Pull". The hatch, weighing 48 lb., fell into the aircraft to lay across the passenger in

10F, trapping her in her seat. With the assistance of a man in row 11 behind the women, the

hatch was removed and placed on vacant seat 11D. The passengers in 10F and 10E then left the

aircraft cabin through the overwing exit onto the wing followed by other survivors. This exit

was open about 45 seconds after the aircraft stopped.

During the latter stages of the abandoned take-off, and just as the aircraft turned towards taxiway

link Delta, the right rear door was seen by external witnesses to be open, with the slide deployed

and inflated. A stewardess was initially visible in the doorway but the door and slide were

obscured by thick black smoke as the aircraft stopped. No one escaped through this door. Two

passengers remember seeing one of the two stewardesses from the rear of the aircraft struggling

to direct passengers in the rear aisle. Neither rear stewardess survived.

As the aircraft stopped, the aft cabin was suddenly filled with thick black smoke which induced

panic amongst passengers in that area, with a consequent rapid forward movement down the

aisle. Many passengers stumbled and collapsed in the aisle, forcing others to go over the seatbacks towards the centre cabin area, which was clear up until the time the right overwing exit

was opened. A passenger from the front row of seats looked back as he waited to exit the

aircraft, and was aware of a mass of people tangled together and struggling in the centre section,

apparently incapable of moving forward, he stated "people were howling and screaming".

The smoke quickly moved forward and passengers from seats 6A and 6B, waiting to get into the

aisle, said they couldn't see and it became very hot as they entered the aisle to get to the forward

exits. Passengers behind them either climbed over seats to get forward, or felt their way down

the aisle by way of the seat. People seated in seats 7A and B could not see the exit when they

reached it, but had to feel the walls to find a gap. A female passenger from seat 15A who

climbed over seats to move towards the front exit was pushed past the exit by a mass of bodies.

People all around her were collapsing on the floor. She fell to the ground unconscious just

outside the doorway. She revived and pulled herself out.

At least 15 passengers reported going over seats or climbing over other collapsing passengers in

the aisles. Of these 15 passenger survivors, at least 11 used the starboard overwing exit to

escape, which represents some 44 percent of those who used the congested aisle. Many

passengers who ultimately got out the starboard overwing exit, collapsed temporarily within or

adjacent to this exit due to incapacitation; e.g. passengers from seats 12D, 14F, 15A and 8B.

With regard to the exits used during the evacuation, some 15-17 used the left forward exit, 34-36

used the right forward exit. Some 27 passengers (including two infants) used the right overwing

exit. Survivors indicated hesitation by some to exit the left front on the side of the fire, which

slowed evacuation out of the doors.
C-37

The first people were out the left front door at 30 seconds from stopping and, out the right front

door at 90 seconds from stopping. The overwing exit was opened 45 seconds from stopping.

Passengers stopped using the left front door when the right front door was opened due to the

presence of fire on the left side. In 3.5 to 4 minutes after stopping, all survivors (except one 14

year old boy from seat 12D found by the fireman 5.5 minutes after their arrival) were off the

aircraft. From the statements of the survivors, it is evident that the effects of the fire on the left

side of the aircraft rapidly instilled fear and alarm in many passengers, particularly those in the

aft/left cabin - i.e. row 14 aft. These effects appear to have been marked heat radiation through

the windows together with "cracking, melting and smoking" of the window transparency panels,

which motivated some passengers from the aft cabin to enter the aisle and move forward before

the purser's 'sit down' announcement on the PA, and therefore before the evacuation call 14

seconds prior to the aircraft stopping.

The left rear door was opened by firemen some time after the fire had been extinguished.

The air and ground movements controllers in the tower had seen the fire and smoke trailing

behind the aircraft and had initiated 'full emergency' action. The air controller activated the

alarm siren connected directly to the aerodrome fire service station (Manchester International

Airport Fire Service - MIAFS), and gave brief details of the emergency to the MIAFS

watchroom over the direct telephone link.

Members of the MIAFS heard a bang and saw an aircraft decelerating on runway 24. Black

smoke and flames were trailing from the left side of the aircraft and the firemen had already

initiated their response when the crash alarm siren sounded.

Two Rapid Intervention Vehicles (RIVs) attended first, one arriving at the aircraft coincident

with, the other just after the L1 door had opened and its slide deployed, as passengers were about

to start to evacuate. About 30 to 40 seconds later, as two major foam tenders took up position,

the R1 door was opened fully and its slide deployed.

Many survivors from the front six rows of seats described a roll of thick black smoke clinging to

the ceiling and moving rapidly forwards along the cabin. On reaching the forward bulkheads it

curled down, began moving aft, lowering and filling the cabin. Some of these passengers

became engulfed in the smoke despite their close proximity to the forward exits. All described a

single breath as burning and painful, immediately causing choking. Some used clothing or hands

over their mouths in an attempt to filter the smoke; others attempted to hold their breath. They

experienced drowsiness and disorientation, and were forced to feel their way along the seat rows

towards the exits, whilst being jostled and pushed. Many, even in the forward cabin, resorted to

going over the seat backs in order to avoid the congested aisle.

At the start of evacuation from the L1 door, the stewardess stated that passengers seemed to be

jammed in the cabin aisle and entrance to the galley (i.e. between the twin forward bulkheads).

She cleared the jam by pulling one young passenger forwards and the flow then started. Later

she saw a young girl lying on the floor of the forward aisle. She pushed another youth back,

pulled the girl forward by her collar and pushed her down the slide. As the passengers came

forward through the bulkhead aperture so the smoke built up in the forward galley area. She
C-38

recalled feeling a body slump against her legs, bent down and, due to improved visibility near the

floor, saw that it was another girl passenger. Her face was black with soot, eyes fixed and

dilated with no signs of breathing. The stewardess considered giving her the kiss of life when a

fireman down below shouted for her to throw the girl down to him. With great difficulty she

lifted her by the waist and threw her onto the chute. After being forced down by the smoke onto

her hands and knees, the stewardess felt around for other passengers back as far as the galley

cabin entrance. She was considering getting her smokehood when a fireman shouted at her to

jump, concerned that she would perish if she delayed. Having been unable to locate any further

passengers, she went down the slide.

The Purser stated that, after getting the R1 door open at his second attempt and initiating

evacuation from this exit, the smoke began entering the galley area.

Very rapidly the area around the overwing exit became a mass of bodies pushing forward to the

exit. People all around were falling and collapsing to the floor. Many passengers who ultimately

got out of the right overwing exit, nevertheless collapsed temporarily within, or adjacent to it.

The exit was blocked with "people's bodies lying half-in and half-out of the aircraft". A male

passenger, from 16C, died after becoming lodged in this right overwing exit. A young boy, from

12D, was pulled out over this man's body by a fireman about 5 minutes after the aircraft stopped.

Several of the survivors who used the overwing exit were impeded by becoming entangled in the

ditching strap. However, one passenger recalled catching hold of it as she collapsed, to recover

consciousness with her head outside the exit.

Of the 24 passengers who escaped from the right overwing (not including the 2 young children

and the young boy pulled clear) some 11 passengers (46%) went over the seats as opposed to

using the congested aisle to get there.

AIRCRAFT

The aircraft was fitted with 130 passenger seats, two double and one single cabin crew seats.

One of the double crew seats was forward of door L1 facing rearwards and the other double aft

of door L3 facing forwards. In the forward passenger cabin a pair of full height galley bulkheads

were positioned just aft of the two doors, L1 and R1. In the aft end of the cabin a full height

stowage unit was located just forward of door R3 with a single crew seat mounted on the rear of

it, facing aft.

This configuration was in compliance with British Airways Configuration Modification No

25C211, Drawing No 1-54378 certified by the British Airways authorised engineer as being in

compliance with the appropriate regulations on the 20 November 1981.

This drawing specifies a seating pitch of:

 Rows 1-9 Rows 9-10 Rows 10-22

Pitch 30 ins 31 ins 29 ins
C-39

In addition, this drawing specified that seats 10A and 10F, should be of a type modified to

prevent the seat-backs from hinging forward and row 9 seats should have no recline, in order that

access to both overwing exits should not be impeded. The seat backs of row 9, in common with

the majority of seats, could be folded forwards to create more room for the upper body of any

person moving between rows 9 and 10 to the overwing exits.

The aisle aperture between the twin forward bulkheads in this configuration was 22 inches wide.

The aircraft was equipped with four main cabin doors ('Type I'), two overwing emergency exits

('Type III') and two sliding-window emergency exits on the Flight Deck. Each main door

incorporated a slide pack.

The overwing emergency exits were located at either side of row 10 and were intended for

ground evacuation of centre cabin passengers, or as the primary exits for use after a sea-ditching.

For the latter purpose, these exits were each equipped with a webbing-type escape rope/lifeline,

anchored to the upper/forward corner of the aperture, with a snap-hook on the other end for

attachment to a lug located on the upper surface of each wing near the trailing edge. These

lifelines were some 17 feet in length and designed to provide evacuees with a means of

stabilising themselves while on the wing upper surface prior to boarding the rafts. For ground

evacuation, arrows painted on the upper surface of each wing were intended to lead evacuees to

the trailing edge and down the extended flaps.

On pulling the overwing exit hatch release handle the hatch, weighing 48 lb., pivots inboard

about its lower edge and requires lifting to remove it from the aperture to make the exit available.

The Flight Deck had two sliding-window emergency exits for use by the pilots, with two

associated webbing-type escape ropes stored in the overhead above the windows.

The cabin crew stations at the forward and aft passenger doors (i.e. left) were each equipped with

an interphone and passenger address microphone. The forward cabin crew were also provided

with two 'Scott' smokehoods, located in a cupboard stowage facing their bench-seat. One 1.5 Kg

capacity Bromochlorodifluoromethane (BCF) fire extinguisher bottle (discharge duration 15

seconds) was also located in a stowage locker facing this seat. The other three smokehoods, for

use by the cabin crew, were stored in the overhead 'bin' at row 18 (right). One 1.5 lb. capacity

water fire extinguisher was stored in this area of the cabin within the right overhead at row 20. A

further two, 1.5 Kg BCF extinguishers were located on the aft wall of the rear right bulkhead.

Two megaphones were available for cabin crew use, one stored in the forward left overhead bin

at row 2 and the other in the aft right overhead at row 18.

Ten portable oxygen bottles were stored in the cabin overheads; two (for crew use) were located

at row 2 right, two units either side of the aisle at row 10 (for passengers) and four units within

the overhead at rows 20-21 right, of which three were designated for crew use.
C-40

ENVIRONMENTAL CONDITIONS

The accident happened during daylight. The weather recorded at Manchester Airport at 0550 hrs

was:

Surface Wind: 270°/5 Kt Visibility: 25 km Cloud :1 okta at 1,400 feet Temperature: + 13 C

QNH *:1014 millibars*(Corrected mean sea level pressure setting)

The weather recorded at 0620 hrs was:

Surface Wind: 260°/6 Kt Visibility :1,000 metres in smoke Cloud: 1 okta at 1,400 feet

Temperature: + 13 C QNH: 1015 millibars

The Manchester Automatic Terminal Information Service (ATIS), information 'C' was received

by the crew prior to starting engines. This gave the surface wind as 280°/6 Kt., variable 240°-

320°. When ATC cleared the aircraft for take-off, they passed a surface wind of 250° at 7 Kt.

The runway was dry.

INJURIES TO OCCUPANTS

The major cause of the fatalities was rapid incapacitation due to the inhalation of the dense

toxic/irritant smoke atmosphere within the cabin.

A marked deposition of carbon particles was found within the trachea of all victims, with some

congestion of the mucosa (mucus lining) in 17 cases ("marked congestion" in the case of one

passenger) with many instances of "excess mucus". The lungs of all fatalities showed marked

general congestion and oedema (fluid), with carbon particles in the air passages, consistent with

the inhalation of smoke. There was no evidence of organic disease which could have caused the

death of any of the victims.

Blood samples were analysed to determine carboxyhaemoglobin and cyanide levels. In addition,

hydrocarbon absorption was measured, including benzene and toluene, these two being the most

prevalent volatiles found in all fatalities. Many other minor trace volatiles were found, including

acetaldehyde.

Of the 54 occupants who expired on the aircraft, 43 (80%) had cyanide levels in excess of 135

micrograms/100 ml which would have led to incapacitation. Of these, 21 had levels above 270

micrograms/100 ml, the fatal threshold. Forty passengers (74%) had levels of

carboxyhaemoglobin in excess of 30% saturation which would also be expected to cause

incapacitation. Of these, 13 passengers had levels in excess of 50%, which is generally accepted

as the fatal threshold. From information in the accident report and from the AAIB, it was

determined that 9 passengers had absorbed less than the incapacitating levels of carbon

monoxide and hydrogen cyanide stated above, and died from direct thermal assault. The

remaining 48 passengers who died on board did so as a result of smoke/toxic gas inhalation.

One eventual fatality, a 31 year old man from seat 8B had superficial burns over 24 percent of

his body, was taken off the aircraft alive 33 minutes after the aircraft stopped. He died after 6

days in hospital because of severe pulmonary (lung) damage and associated pneumonia.
C-41

2. Fire Penetration Mechanism

As the aircraft came to a stop, the spilling, ignited fuel collected in a pool under the wing on the

left side, directly behind the port engine. The wind direction was such that flames were directed

onto the fuselage side and as a result the rear fuselage was extensively burnt. A large part of the

left fuselage side approximately between seat rows 17 and 21 was burnt through and allowed fire

and smoke to enter the passenger cabin. One passenger reportedly saw flames shooting in

through the side windows and up through the floor area.

Analysis of the wreckage has shown that the fire initially penetrated the skins on the left side

below the level of the cabin floor. Having breached the outer skin, the only barrier to the fire

gaining access to the cavity, formed between the outer skin and the cargo bay side liner panels,

was a 1-inch-thick fibreglass wool acoustic insulation blanket contained in a thin plastic bag.

This cavity communicated directly with the cabin interior above via floor level air conditioning

grills.

The aft right door was opened shortly before the aircraft came to a halt and this allowed some

flame transients to enter the cabin. No occupants were able to use this exit as a means to escape.

As fire and smoke entered the cabin at the rear, it rapidly propagated forward. Many survivors

described a roll of thick, black smoke clinging to the ceiling and moving rapidly forward along

the cabin. On reaching the forward bulkheads it curled down, began moving aft, lowering and

filling the cabin. Some passengers became engulfed in the smoke despite their close proximity

to the forward exits and were forced to feel their way out. Others succumbed to the smoke and

died of asphyxiation.

Based on the above, it is assessed that the prime burnthrough route was through the fuselage skin

and windows on the left side.
C-42

3. Location of Injuries and Scenarios

Scenario 4

Scenario 6

Scenario 5

Scenario 3

Scenario 2

Scenario 1
C-43

4. Accident Scenarios and Survivability Chains

This accident is divided into six separate scenarios.
C-44

Scenario 1 contains the flight deck area. It was the area furthest from the point of entry of the

fire and therefore had the most time available for evacuation. The scenario contains the two

flight crew who exited through the right cockpit window.

Scenario 2 contains the forward flight attendant area. The flight attendants were initially seated

rearward facing and stayed close to their respective exits throughout the whole evacuation period

as they directed passengers out. Indeed, they each finally evacuated through their assigned exits

when they considered it unsafe to remain. As a result they both survived uninjured.

Scenario 3 contains the front section of the passenger cabin from seat row 1 to seat row 5

inclusive and the left side of row 6. This area had both the L1 and R1 exits open and useable.

The occupants executed a successful evacuation uninjured. It is assumed that the unknown

injuries were minor.

SCENARIO 1

2 0

FIRE

2

0

FIRE

2 0

2

0

SCENARIO 2

33 0

33

0

SCENARIO 3

FIRE
C-45

Scenario 4 contains the front section of the passenger cabin from seat row 7 to seat row 8

inclusive and the right side of row 6. Occupants in this area made their way to the L1 and R1

exits. Those further from the exits had a longer exposure to the fire and smoke and were either

injured or asphyxiated. It is assumed that the unknown injuries were minor.

Scenario 5 contains the midsection of the passenger cabin from seat row 9 to seat row 15

inclusive. This area had only the R2 overwing exit open and useable. Those occupants closest

to the exits executed a successful evacuation. Those further away had a longer exposure to the

fire smoke and were either injured by fire or overcome by smoke and toxic gas. It is assumed

that the unknown injuries were minor. The numbers include two infants who were carried out of

the aircraft uninjured.

Scenario 6 contains the rear section of the passenger cabin from seat row 15 to seat row 22

inclusive as well as the two rear flight attendants. This area had only the R2 overwing exit open

and useable and was the area in which the fire burnt through and entered the cabin. All

occupants from this section had a significant distance to travel before reaching the overwing exit.

Further, visibility was severely restricted by dense black smoke and location of exits was almost

impossible. As a result, most of the occupants either died as a result of burns or were overcome

by the smoke and toxic gas. It is assumed that the three unknown injuries next to the point of

fire entry were serious and all other unknown injuries were minor. The numbers include an

infant who was asphyxiated in the cabin.

FIRE

24 5

13

SCENARIO 5

42

SCENARIO 4

FIRE

5

4 6

15
C-46

5. Effect of Later Requirements

It is assumed that later requirements would not have affected the situation in scenarios 1, 2, and 3

which already had sufficient time for successful evacuation.

For scenarios 4, 5, and 6 it is assessed that later requirements would have improved flammability

standards such that the occupants would have had an additional 30 seconds of time to escape. It

is assessed that this would result in the survivability chains for Scenarios 4, 5, and 6 becoming:

1 2

FIRE

15

2

SCENARIO 4

30 2

FIRE

42

10

SCENARIO 5

2 4

FIRE

43

37

SCENARIO 6
C-47

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as there was already sufficient time for a successful evacuation.

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as there was already sufficient time for the flight attendants to direct passengers and then

evacuate themselves successfully.

Scenario 3

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 3

as there was already sufficient time for a successful evacuation.

Scenario 4

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the passengers with additional time to locate and use the two forward exits.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 465

M573

L 5 10 0

7 6

FIRE

43

30

SCENARIO 6
C-48

For 2 minutes protection:

S I F

H 465

M762

L 960

For 4 minutes protection:

S I F

H 573

M951

L 13 2 0

For 8 minutes protection:

S I F

H 861

M 11 4 0

L 15 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 11 2 2

M 12 2 1

L 15 0 0

For 2 minutes protection:

S I F

H 11 2 2

M 13 2 0

L 15 0 0

For 4 minutes protection:

S I F

H 11 3 1

M 14 1 0

L 15 0 0
C-49

For 8 minutes protection:

S I F

H 14 1 1

M 15 0 0

L 15 0 0

Scenario 5

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with additional time to use the available overwing exit.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 24 5 13

M 27 6 9

L 32 5 5

For 2 minutes protection:

S I F

H 26 5 11

M 31 8 3

L 33 9 0

For 4 minutes protection:

S I F

H 25 12 5

M 34 6 2

L 39 3 0

For 8 minutes protection:

S I F

H 25 12 5

M 37 3 2

L 42 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:
C-50

For 30 seconds protection:

S I F

H 31 3 8

M 33 4 5

L 42 0 0

For 2 minutes protection:

S I F

H 31 8 3

M 34 6 2

L 42 0 0

For 4 minutes protection:

S I F

H 31 10 1

M 37 5 0

L 42 0 0

For 8 minutes protection:

S I F

H 31 11 0

M 37 5 0

L 42 0 0

Scenario 6

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

the occupants with additional time to move forward and use the available overwing exit.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 3 5 35

M 4 8 31

L 5 15 23
C-51

For 2 minutes protection:

S I F

H 9 4 30

M 17 13 13

L 31 12 0

For 4 minutes protection:

S I F

H 8 4 27

M 20 13 10

L 35 8 0

For 8 minutes protection:

S I F

H 8 8 27

M 20 13 10

L 43 0 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 8 7 28

M 14 10 19

L 23 12 8

For 2 minutes protection:

S I F

H 11 4 28

M 21 12 10

L 33 8 2

For 4 minutes protection:

S I F

H 10 9 24

M 34 7 2

L 43 0 0
C-52

For 8 minutes protection:

S I F

H 10 9 24

M 34 7 2

L 43 0 0

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 12 17

2 minutes 37 30

4 minutes 42 40

8 minutes 43 40
C-53

AIRCRAFT: A320 DATE OF ACCIDENT: 26th June ‘88

REGISTRATION: F-GKFC LOCATION OF ACCIDENT: HABSHEIM

1. Description of Accident

RESUME

During an airshow on 26-Jun-88, A320 F-GKFC made a level pass at about 30 ft, gear and flaps

out, engines almost at idle and 130 passengers on board. After the go-around, the aircraft hit

trees at the end of the runway. The right wing broke up and a fire erupted.

All passengers evacuated the aircraft except 3 who suffered fatal injuries as a result of the fire.

IMPACT

The aircraft touched the trees shortly after the end of the runway at 12:45.40; at this time, engine

speed was around 83% Nl, the pitch attitude of the aircraft was 14 deg.

The first contact between the aircraft and the trees was made by the rear section of the fuselage,

the tailplane, then the engine nacelles and the main landing gear.

The aircraft sank slowly into the forest. The tip of the right wing then the right wing itself broke,

finally the aircraft came to rest.

FIRE

As the right wing broke fuel was projected forward and fire immediately broke out and

penetrated the cabin as soon as the aircraft came to rest. Fuel flowed under the cabin and as a

result fire also raged around the left wing.

EVACUATION

There were 2 flight crew, 4 cabin crew and 130 passengers on board.

As soon as the aircraft came to rest, the stewards stationed at the forward and aft doors, seeing

the fire on the right of the aircraft, opened the left doors.

The normal lighting went off and the emergency lighting did not come on due to a design error in

its automatic illumination program.

The captain declared that he made several attempts to trigger the evacuation signal; but it seems

that this signal did not work, as nobody in the cabin heard it.

The purser wished to broadcast a message via the public address but could not find the handset,

which apparently, had been torn from its support, maybe due to the fragility of this support and

of the attachment of the electrical lead.

A passenger stated that he had wanted to open the left wing emergency exit but could not reach

it. The opening of this exit would have been very dangerous, as fire was raging around the left

wing level.
C-54

The left forward door was blocked by branches after it had started to open correctly. The escape

slide started to deploy partly outside and partly inside the cabin.

The purser, with the help of at least one passenger and an air hostess from another airline (who

was in the cockpit as a passenger during the flight), pushed the door. The door opened suddenly

and the purser and the passenger fell out of the aircraft and were covered by the escape slide.

The passengers started to panic and push in the front of the cabin. The passenger hostess then

started to evacuate the passengers, but the first ones were blocked by branches in the escape

slide. The other passengers jumped out beside the escape slide but they very quickly piled up on

top of each other again due to the branches.

The hostess then stopped evacuation for a short while so that the passengers who had already

jumped had time to extricate themselves. Meanwhile, on the outside, the purser, with the help of

another air hostess, tore away the branches from across the escape slide to free the blocked

passengers. After a certain time, the hostess herself left the aircraft suffering from the effects of

the smoke.

The hostess stationed in the centre of the aircraft at 12D was pushed into the aisle by the

passenger in 12F, who was seriously burnt, was then carried forward while at the same time

helping a passenger whose clothes were on fire.

She arrived at the left forward door (L1), no doubt after the evacuation of the previous hostess,

and took her place.

After the evacuation of the last persons to arrive at this door, she called into the cabin to find out

if anyone was still there but did not get any reply; by this time, the smoke, very thick, and flames

made any visual inspection impossible. On the order of the captain, who had just evacuated the

injured first officer, she then left the aircraft.

The captain then returned to the cockpit to get an antismoke mask with the intention of going

through the cabin, but in turn had to leave, before he could don the equipment, suffering from the

effects of the fumes.

Note that the cabin attendants either were not able to use the antismoke masks during the

evacuation or did not think of doing so. They were, in fact, more occupied in opening the doors

as quickly as possible so as to speed up passenger evacuation.

The left aft door was opened without any problems and the escape slide was correctly deployed.

The steward ordered the passengers to come toward him to evacuate and at the same time

reassured them verbally. This, combined with the absence of smoke at the rear of the cabin,

certainly contributed toward the good evacuation via this door.

After several passengers had used the escape slide it was punctured on the branches. The

steward asked his colleague to descend to help to receive the passengers. Evacuation continued

without panic with spontaneous help from one passenger, especially for the evacuation of an

elderly person who had difficulty in moving.
C-55

After the last passengers had left the aircraft, the hostess returned to go through the cabin but the

flames and smoke had reached the galley; she was able only to shout out in the direction of the

cabin.

During the evacuation, the stewards and hostesses could not see what was happening at the other

end of the aircraft due to the fire around the left wing. Therefore, after the end of evacuation via

their door, they went round the wing toward the front or the rear to see if they could be of any

help at the other door.

It has not been possible to determine the time it took to evacuate the survivors.

All passengers were able to leave the aircraft, except three who succumbed to the fire.

AIRCRAFT FACTORS

The aircraft was an A320-100, registered as F-GFKC and operated by Air Charter International.

The aircraft obtained its Certificate of Airworthiness on 22-Jun-1988 and was delivered on 24-

Jun-1988.

The aircraft was fitted with two doors at the front and two doors at the rear of the passenger

cabin. In addition there were 2 overwing emergency exits over each wing.

ENVIRONMENTAL CONDITIONS

The accident happened in daylight during an airshow. Visibility was 8km and wind was 010 deg

at 6 kts.

INJURIES TO OCCUPANTS

All passengers were able to leave the aircraft, except three who succumbed to the fire:

A young handicapped boy in seat 4F who seems to have remained in his seat.

A little girl located at 5C who, according to her young brother (carried away by the flow of the

other passengers), had not been able to open her seat belt and was blocked by the back of her

seat, which was tilted over onto her.

A woman travelling in seat 10B who, according to her husband, had reached the left forward

door; as her body was found near that of the little girl, we can reasonably assume that she went

back into the cabin to help the little girl and was overcome by the fumes.

2. Fire Penetration Mechanism

As the right wing broke, fuel was projected forward and fire immediately broke out and

penetrated the cabin as soon as the aircraft came to rest. Burnthrough is therefore assumed to be

initially from the right side.
C-56

Fuel flowed under the cabin and as a result fire also raged around the left wing. It can be

assumed that the pool fire under the cabin centre section and left wing root would have added to

the initial burnthrough on the right side.

The fuselage was found completely burnt out and this is taken to mean that the fuselage skin had

been consumed by the fire mainly after the evacuation had taken place.

Based on the above it is assessed that the prime burnthrough route was through the fuselage skin

on the right side. However there was insufficient information to be conclusive about detailed

burnthrough areas.

3. Location of Injuries and Scenarios

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-57

4. Accident Scenarios and Survivability Chains

This accident is divided into four separate scenarios:

Scenario 1 contains the flight deck area. It was the area furthest from the point of entry of the

fire and the only injury was to the first officer during the impact. The scenario contains the two

flight crew and an observer air hostess.

Scenario 2 contains the forward flight attendant area. The flight attendants were seated rearward

facing and they both survived uninjured.

Scenario 3 contains the main passenger cabin in which there were 129 passengers and a flight

attendant in 12D.

2 1

IMPACT

3

0

SCENARIO 1

2 0

FIRE

2

0

SCENARIO 2

92 35

FIRE

130

3

SCENARIO 3
C-58

Scenario 4 contains the rear flight attendant area where there was one flight attendant who

escaped uninjured.

5. Effect of Later Requirements

It is assumed that seat blocking would have been fitted on an aircraft of this age. Further there

was no mention of passenger disorientation so no benefit was assumed for floor proximity

lighting. It was, however, assumed that later requirements on material heat release would have

saved some serious injuries in Scenario 3.

It is therefore assessed that the survivability chain for Scenario 3 becomes:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as injuries were related to the impact.

FIRE

97 30

130

3

SCENARIO 3

1 0

FIRE

1

0

SCENARIO 4
C-59

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as there were no injuries.

Scenario 3

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and provided

occupants with additional time to go back and assist some of the remaining passengers to safety.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 92 35 3

M 97 31 2

L 99 30 1

For 2 minutes protection:

S I F

H 92 35 3

M 102 27 1

L 107 23 0

For 4 minutes protection:

S I F

H 92 35 3

M 109 21 0

L 122 8 0

For 8 minutes protection:

S I F

H 92 35 3

M 113 17 0

L 130 0 0
C-60

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 97 30 3

M 102 26 2

L 104 25 1

For 2 minutes protection:

S I F

H 97 30 3

M 104 25 1

L 110 20 0

For 4 minutes protection:

S I F

H 97 30 3

M 112 17 1

L 126 4 0

For 8 minutes protection:

S I F

H 97 30 3

M 115 15 0

L 130 0 0

Scenario 4

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 4

as there were no injuries.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 1 1

2 minutes 2 2

4 minutes 3 2

8 minutes 3 3
C-61

AIRCRAFT: B727 DATE OF ACCIDENT: 31st August ‘88

REGISTRATION: N473DA LOCATION OF ACCIDENT: DALLAS-FW,

TEXAS

1. Description of Accident

RESUME

On 31-Aug-88, B727-232 registered as N473DA was taking off from Dallas-Fort Worth

International Airport, Texas. The slats and flaps were not properly configured and as a result the

aircraft did not gain altitude after rotation.

The aeroplane struck an instrument landing system (ILS) localiser antenna array approximately

1000 feet beyond the end of the runway and came to rest about 3200 feet beyond the departure

end of the runway. The flight was airborne approximately 22 seconds from lift-off to the first

ground impact near the ILS localiser antenna. The aeroplane was destroyed by impact forces and

the postcrash fire.

The combination of jammed left aft service door and the intense impenetrable fire trapped 12

occupants.

Of the 108 occupants aboard, 12 passengers and 2 crew members were killed by fire, 21

passengers and 5 crew members were seriously injured and 68 passengers sustained minor or no

injuries.

IMPACT

The aeroplane struck the instrument landing system (ILS) localiser antenna array approximately

1000 feet beyond the end of runway 18L, and came to rest about 3200 feet beyond the departure

end of the runway. The flight was airborne approximately 22 seconds from lift-off to the first

ground impact near the ILS localiser antenna.

The fuselage had separated into three major sections: (1) the forward section consisted of the

nose forward of fuselage station (FS)-420 [just aft of seat row 1]; (2) the centre fuselage section

included the body structure between FS-420 and FS-950c [between seat rows 27 & 28]; and (3)

the aft fuselage section extended from FS-950c aft to the end of the No. 2 engine tailpipe.

The forward fuselage section had rotated to the left about 45 deg. The entire lower fuselage

structure sustained various degrees of tearing, buckling and general overall distortion. Some

sooting was noted in the area between the first officer's side window and the separation.

The centre fuselage section came to rest right side up and was supported by the left wing and

right wing centre section.
C-62

FIRE

The external fire was initiated when the right wing and tail struck the localiser antenna array.

The fire intensified when the aircraft struck the lip of a depression in the terrain. Flames not

only impinged on the right side of the fuselage but extended around the fuselage, heating the

inboard wing area on the left side. The forward door of the aft cargo compartment was torn off

at its hinges, causing a large opening in that area through which fire entered the cargo area before

the aircraft came to rest. The fire burned through the floor.

Fire also entered the cabin through the aft break in the fuselage and later through a burnthrough

in the centre wing box area.

The left side forward of FS-720e [between seat rows 17 & 18] showed no evidence of fire

damage and all passenger windows were intact. However, the left side between FS-720e and FS950c had sustained varying degrees of fire damage. In the general area of FS-950c, some

fuselage structure had been consumed by fire.

The right side of the centre fuselage section between FS-420 and FS-950c also contained fire

damage with some fuselage areas totally consumed by fire. All passenger windows on the right

side were missing or melted.

The fuselage crown between FS-450 [between seat rows 2 & 3] and FS-680 [between seat rows

13 & 14] from the top of the passenger window line on the right side to the top of the Delta logo

on the left side was consumed by fire. Another area of the top fuselage, between FS-720c

[between seat rows 16 & 17] and FS-840 [between seat rows 21 & 22], was consumed by fire

from the top of the right forward overwing emergency exit door to the fuselage centreline.

The aft fuselage section had rolled to the left and rotated counterclockwise about 45 deg. The aft

fuselage skin structure between FS-950c and FS-950e [between seat rows 28 & 29] on the left

side was consumed by fire. The aft fuselage skin structure on the right side between FS-950e

and FS-1030 [between seat rows 31 & 32] was found laying on the ground alongside the

fuselage. The centre aft fuselage section generally sustained various degrees of breakup and fire

damage.

The aft cabin floor was completely consumed by fire from approximately station 950d [seat row

28] to station 1130 [just aft of seat row 36] with the exception of the passageway that led to the

left-rear door at the galley. Fire damage to other components was also extensive in this area with

most major interior components destroyed.

The area forward of station 950d had less severe fire damage to the floor and sidewall areas

(continuing through station 740 [between seat rows 18 & 19]). As noted previously, there was a

large area of burnthrough on the cabin floor from approximately station 740 to approximately

station 720d [seat row 17] on the right side. From this point forward to approximately station

400 [just forward of seat row 1], fire damage to the right side of the interior was significantly

more extensive than that of the left side. From station 400 forward, the cabin was free of fire

damage.
C-63

Damage to ceilings, sidewalls, overhead stowage compartments, closets, etc., was closely

correlated to areas of floor and fuselage burnthrough. From station 400 aft, no ceiling panels

were in place including areas where the fuselage crown was present as well as the areas that were

burned through.

All floor exit level door liners were found. The aft right exit had only the lower portion of the

liner present from approximately the top of the escape slide container downward. It was heavily

sooted and showed some signs of melting. The aft left door liner was essentially intact with

heavy charring and melting over the upper third of the surface. Both of the left and right forward

door liners were free of fire damage. The liner on the ventral door was destroyed by fire.

Sidewalls were intact on the left side of the forward cabin from station 380 [forward edge of

starboard service door] to the area of the overwing exit. Many of these panels were melted at the

upper portion above the window, but were in place and otherwise intact. Sidewall panels on the

right side of the cabin in this zone were completely destroyed. Small portions of other right side

wall panels were present near the floor toward the aft part of the cabin. Two sidewall panels on

the left side at approximately stations 950b and c (immediately forward of the separation in the

aft fuselage) were relatively free of fire damage but were heavily sooted.

From station 380 to station 760 [between seat rows 19 & 20] on the left side, there were some

large remnants of overhead stowage units hanging from the structure. These were extensively

burned and melted, however, they were recognisable as overhead stowage units. No other

overhead stowage units were present.

In most areas of the cabin wherever the sidewall and/or ceiling panels were destroyed, the

thermal insulation was also destroyed. The following exceptions were noted:

In the aft right corner of the cabin in the sidewall area just forward of and adjacent to the last row

of seats.

Some small areas over the overhead stowage bin area along the left side of the cabin between

station 380 and 950.

A few sidewall areas on the right side of the cabin near station 720.

The last row triple seats (right side) showed frame burn through and residual cushion fire

blocking layer. Up to and including row 28, all seats were missing, with the exception of the

triple seat in row 30 left side, which had some cushion fire blocking layer remaining, along with

some seat frame structure burnthrough on the seat back cushions. Rows 23 through 26 (right

side) were heavily fire damaged, but some cushion fire blocking layer remained. The seat back

cushions on 23E, 24E, and 26D were burned through. Seats 27D, E, and F were severely

damaged and its common frame was twisted and displaced several feet rearward from the proper

position. Rows 26 and 27 (left side) had fire blocking layer present (frame intact), with the

exception of seat back 26C which was totally destroyed by fire. Row 25 (left side) was missing

(possibly falling down into the hole of the floor area). Rows 23 and 24 (left side) had fire

blocking layer remaining, except for row 24A, B, and C, in which the seat back frame were
C-64

totally destroyed by fire. Seats 22B and C sustained severe damage to the seat bottoms. The

remaining seats in rows 20 through 22 (left side) sustained fire damage to the seat backs, burning

through the seat back frame, but the seat bottom cushions in this area had some fire blocking

remaining. Rows 20 through 22 (right side) sustained fire damage to the seat back frame with

some fire blocking layer remaining, except for row 20, which was pitched forward and bent up

on the frame bottom.

Rows 15 through 19 (right side) sustained severe fire damage, with no fire blocking layer

remaining. Rows 10 through 14 (right side) were destroyed by fire. Rows 10 through 19 (left

side) had some fire blocking layer remaining on the seat back and bottom cushions, with the

exception of rows 15 and 17, which sustained lesser amounts of fire damage.

In the first class section, seat row 1 (left and right sides) was intact with little fire damage. Row

2 (left side) had some fire damage to the seat back and bottom cushions with some fire blocking

layer remaining. Seats 3A and B were twisted with some fire damage. Seats 4A and B were fire

damaged with some cushion fire blocking layer remaining on the seat bottom. Row 3 (right side)

was totally destroyed by fire. Row 4 (right side) was missing.

A number of lives were saved by the use of the fireblocking layer on the passenger seats. An

exact number of additional survivors could not be determined.

The fire services arrived within 5 minutes of notification, the fire was knocked down within 5

minutes and extinguished in about 40 minutes.

EVACUATION

There were 3 flight crew, 4 cabin crew and 101 passengers aboard.

The investigation found that although the fuselage had separated in several places, the occupiable

volume of the cabin was not substantially compromised. Passengers generally stated that impact

forces were not severe. Further, the cause of deaths of the passengers in the aft section of the

cabin were attributed to smoke inhalation and fire rather than impact injuries. Exit from the aft

cabin was hampered by the fire that impinged on the right side of the aeroplane. Exit from the

mid and forward cabin was through breaks in the fuselage and through the left side exits, except

for the left aft service door which was not opened.

The right forward exit door was lodged in the wreckage. The main entry door (left forward) was

open and wedged under the forward fuselage section.

Both overwing exit hatches on the left side were open. The hatch from the forward exit was

found inside the cabin and the hatch from the rear exit was found outside the aircraft.

The right side rear overwing exit hatch was not opened, the hatch from the forward right side

was found in the cabin.

The rear floor level exit on the right hand side was found not opened.
C-65

The left aft service door could not be opened due to deformation of the door frame which

resulted from the aeroplane's repeated impacts with the ground.

A flight attendant, while attempting to open the left aft service door, stowed the girt bar on the

door as per Delta's flight attendant training procedures which address the difficulty in opening a

door following a gear-up landing.

It would have been unlikely for any one person of average strength to open the left aft service

door under the circumstances existing at the time of the attempted evacuation.

The aft airstair was not usable because the aircraft was resting on its fuselage and the airstairs

could not be lowered. Also the rear pressure bulkhead door to the tailcone was jammed closed

due to impact damage.

AIRCRAFT FACTORS

The B727-232 was configured for a three person flightcrew and 149 passengers. The passenger

cabin was configured with 12 first class passenger seats and 137 tourist class seats. A double

occupancy aft facing flight attendant seat was on the aft left side of the cockpit rear bulkhead; a

double occupancy forward facing flight attendant seat was located on the central airstairs door.

A single flight attendant seat was in row 32.

The aircraft was delivered to Delta Air Lines in November 1973 in a passenger configuration. It

was serial number 20750, line number 992. Fire blocking layers were fitted to passenger seats.

This was the first survivable accident following the implementation of floor proximity and fire

blocking rules. It can therefore be assumed that floor proximity lighting was also fitted.

The aircraft had a total of four floor level exits and four overwing emergency exits and a ventral

stairway exit.

ENVIRONMENTAL CONDITIONS

The weather conditions at the time of the accident were: visibility 10 miles, wind 100 deg at 8

knots and temperature 22C.

INJURIES TO OCCUPANTS

Of the 108 persons on board, 12 passengers and two crewmembers were killed, 21 passengers

and five crewmembers were seriously injured, and 68 passengers sustained minor or no injuries.

The cause of death of the 11 passengers and the two flight attendants was determined to be

smoke inhalation. Levels of carboxyhemoglobin (COHb) ranged from 15 to 81 percent. Tests

for drugs and ethanol were negative in all 13 persons. A 14th fatality was a passenger who had

successfully evacuated but later attempted to re-enter the burning aeroplane. This passenger died

of severe burns, 11 days after the accident.
C-66

2. Fire Penetration Mechanism

The fuselage broke into three main sections; the front, mid, and rear with significant breaks

between them. These inter-section breaks were large enough to facilitate passenger egress from

the wreckage during the evacuation.

For the front section, fire entered through the inter-section break.

For the midsection, fire was present along the whole of the right side and also extended round,

under the fuselage and heated the inboard wing area on the left side. Fire entered through the

inter-section breaks at either end and later burnt through in the centre wing box area, presumably

as a result of the pool fire underneath.

For the rear section, fire entered the rear cargo area when the external door was torn off at its

hinges. This fire propagated into the cabin by burning through the floor.

The accident report stated that a number of lives were considered as being saved by the use of

the fire-blocking layer on passenger seats. An exact number of additional survivors could not be

determined.

The fire services arrived within 5 minutes of notification; the fire was knocked down within 5

minutes and extinguished in about 40 minutes.

Based on the above it is assessed that the prime burnthrough route was in the midsection lower

fuselage skin in the wing box area. However there was insufficient information to be conclusive

about detail burnthrough areas.
C-67

3. Location of Injuries and Scenarios

Scenario 5

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-68

4. Accident Scenarios and Survivability Chains

This accident is divided into five separate scenarios.

Scenario 1 contains the flight deck area. It was subjected to the initial impact, which was not

severe, and was not fire damaged. The scenario contains the three flight crew.

Scenario 2 contains the forward flight attendant vestibule area. It was subjected to the initial

impact, which was not severe but was not fire damaged. The scenario contains two flight

attendants who both left the aircraft through the L1 exit.

Scenario 3 contains the front part of passenger cabin from the galleys to the inter-section break

just aft of row 1. All injuries were sustained in the postcrash fire. Both occupants exited through

the break in the wreckage.

1 2

IMPACT

3

0

SCENARIO 1

0

2

FIRE

2

0

SCENARIO 3

0 2

IMPACT

2

0

SCENARIO 2
C-69

Scenario 4 contains the passenger cabin from the front fuselage break just in front of seat row 2

to the rear fuselage break at seat row 27 inclusive. All injuries were sustained from the external

fire which entered the cabin through the breaks in each end and by way of a burnthrough from

underneath the centre wing box area. The two overwing exits L2 and L3 were available for

egress along with fuselage breaks.

Scenario 5 contains the passenger cabin from the rear fuselage break at seat row 28 to the rear of

the cabin. All injuries were sustained from the postcrash fire which entered the cabin by burning

through the cabin floor from the cargo area where the cargo door had been torn off. All

survivors exited through fuselage breaks.

5. Effect of Later Requirements

The aircraft seats were fitted with fire-blocking layers.

It is assumed that later requirements would not have affected the situation in Scenarios 1 and 2 in

which all injuries were related to impact forces.

It is assessed that later requirements would have improved flammability standards such that the

occupants would have had additional time to escape. Bearing in mind that fire was also entering

directly through fuselage breaks, the additional time would have been modest.

In Scenario 3, the fire injuries were seated immediately next to the break (and fire) and so

improved flammability standards would not have prevented injury from the direct assault.

8 0

FIRE

20

12

SCENARIO 5

65

14

FIRE

81

2

SCENARIO 4
C-70

The survivability chain for Scenarios 4 and 5 therefore become:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected injuries in this scenario

because the cause of injury was related to impact.

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected injuries in this scenario

because the cause of injury was related to impact.

Scenario 3

It is concluded that a fire-hardened fuselage would not have affected injuries in this scenario

because fire entered through fuselage breaks and not by burning through the fuselage skin.

Scenario 4

It is concluded that a fire-hardened fuselage would have delayed the entry of fire from the centre

wing box area and provided the occupants with more time to use the available overwing exits.

10 0

FIRE

20

10

SCENARIO 5

70

10

FIRE

81

1

SCENARIO 4
C-71

However, fire also entered through breaks at either end, and it is therefore assessed that the

additional time would have been modest and would not have varied with additional burnthrough

protection time.

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 65 14 2

M 70 10 1

L 74 7 0

For 2 minutes protection:

S I F

H 65 14 2

M 70 10 1

L 74 7 0

For 4 minutes protection:

S I F

H 65 14 2

M 70 10 1

L 74 7 0

For 8 minutes protection:

S I F

H 65 14 2

M 70 10 1

L 74 7 0

For an aircraft configured to the standards appropriate to the latest requirements this assessment

becomes:

For 30 seconds protection:

S I F

H 70 10 1

M 75 6 0

L 78 3 0
C-72

For 2 minutes protection:

S I F

H 70 10 1

M 75 6 0

L 78 3 0

For 4 minutes protection:

S I F

H 70 10 1

M 75 6 0

L 78 3 0

For 8 minutes protection:

S I F

H 70 10 1

M 75 6 0

L 78 3 0

Scenario 5

It is concluded that a fire-hardened fuselage would not have affected injuries in this scenario

because fire entered through fuselage breaks and not by burning through the fuselage skin.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 1 1

2 minutes 1 1

4 minutes 1 1

8 minutes 1 1
C-73

AIRCRAFT: B737 DATE OF ACCIDENT: 1st February ‘91

REGISTRATION: N388US LOCATION OF ACCIDENT: LOS ANGELES, 

CALIFORNIA

1. Description of Accident

RESUME

On 1-Feb-91 a Boeing 737-300 registered as N388US was landing at Los Angeles International

Airport. It collided with a Fairchild Metroliner that was positioned on the same runway awaiting

clearance for take-off.

The aircraft slid to the left side of the runway and into an unoccupied fire station whereupon a

fire broke out. An evacuation took place but 20 passengers and 2 crewmembers were fatally

injured.

IMPACT

The B-737 remained largely intact as a result of the collision with the Metroliner. The aircraft

veered off the runway and into an unoccupied fire station building.

The only parts of the B-737 that separated from the aircraft were the nose cone, nose gear doors

and left pitot tube. The impact with the building destroyed the cockpit and damaged the left

engine and an area of the left wing leading edge. The top and left sides of the cockpit were

crushed inward, and the forward section of the cockpit on the captain's side was crushed in,

down, and to the right. Both forward cockpit windshields were cracked. Several propeller

slashes were on the lower right side of the B-737 fuselage skin in the area of the forward galley

door.

No fuel tank rupture or leakage from the wing or centre tanks of the B-737 was observed. The

fuel which was on fire came from the ruptured fuel cells of the Metroliner which was found

crushed underneath the B-737.

Several passengers noted that the landing appeared to be routine; however, within a few seconds

of touchdown they recalled feeling the aeroplane, move up and down, consistent with heavy

brake applications. They noticed 'an orange glow' through the cabin windows on both sides of

the aeroplane; flight attendants were heard yelling repeated commands 'get down, stay down'.

After the impact with the building, the flight attendants commanded the passengers to release

their seatbelts. The two rear flight attendants and several passengers had unbuckled their

seatbelts after the first impact and were thrown forward when the aeroplane struck the building.

The R1 flight attendant stated that the 'touchdown felt normal' and that shortly thereafter 'I heard

a big metal scrape, and felt like they slammed the brakes real hard'. Within 2 or 3 seconds, the

emergency lights came on and he began to shout commands, 'grab ankles, heads down, stay

down'. He saw the floor in front of him moving up and down about knee high.
C-74

FIRE

After the first impact, and while the aeroplane was still moving, the R1 flight attendant noted that

the cabin became 'really warm', and he observed smoke coming from underneath the floor in

front of him. He also remembered seeing smoke and fire on top of the valet closet in front of

him. He described the smoke as 'very thick'.

On the right side of the fuselage there were a number of small holes burnt through in the lower

quadrant and a large hole had burnt through in the lower belly area.

In the forward cargo compartment, the cargo liner on the left side had very little heat damage

whereas the right forward corner had heavy fire damage. There was slight fire damage to the

cargo liners, the cabin floor, cargo compartment floor and some structure in the area. This area

also housed the crew oxygen cylinder, which was found loose. The cylinder contained heavy

amounts of soot, except for the area of an attaching strap. The pressure gauge and regulator were

extensively fire damaged, and the overpressure and supply lines were broken.

The fire fighters were able to control the fire under the aircraft but fire continued in the cabin.

An area of the top of the B-737's fuselage burnt through in the forward cabin between the first

class and coach sections. This burnthrough was from the inside out. Interior fire damage in this

area was extensive.

The top of the fuselage was also burned away from just aft of the wing to the aft doors. The

fuselage along the floor beams was still attached aft of the wing so eventually the entire tail

section drooped to the ground. At this time the fire fighters were able to advance into the cabin

and extinguish all remaining fires.

The forward passenger door (L1) was jammed shut, and the lower half of the door was displaced

inward approximately 6 inches. There was no fire damage to the exterior of the door. The

forward service door (R1) was open. The door was structurally intact, but its interior had

sustained significant fire and heat damage. The exterior of the door contained soot near its

bottom forward side. The aft passenger door (L3) was open, and both sides of the door were fire

damaged. The aft service door (R3) was open. There was no soot on the interior surface of the

door, and minor amounts of soot were evident on the exterior.

The most extensive interior fire damage was in the rear of the cabin. All interior materials

located at 4 feet or higher were destroyed by the interior fire. The carpet was intact throughout

the cabin with the exception of the first class section. The cabin seats contained fire blocking

material with Poly-Benizol Iomedizal (PBI). Floor proximity emergency lights were installed in

the cabin and based on survivor's statements they functioned during the evacuation. All of the

overhead baggage compartments were found detached and melted onto the seats.

EVACUATION

There were 2 flight crew, 4 cabin crew and 83 passengers aboard. The cabin layout had 128

passenger seats.
C-75

As the aeroplane struck the abandoned fire station and stopped, the R1 flight attendant departed

his jumpseat and went to his exit door. After assessing the area outside the door for fire, he

rotated the handle to the open position and attempted to open the door. During this time he said

that the smoke got so bad that he could no longer see anything. After forcing the door, he was

able to open it about 12 inches and shortly thereafter he was able to open it fully. At that point, a

passenger was standing by the door, and he pushed the passenger out of the aeroplane. The

distance from the door sill to the ground was about 5 feet. Another passenger then passed the R1

flight attendant and jumped out. The flight attendant then attempted to enter the cabin near row

1; however, the smoke and flames were too intense. Returning to the R1 door, he jumped to the

ground.

Several passengers who had been seated in the coach cabin between rows 4 and 13, escaped via

the two overwing emergency exits and the R3 service door. Because of the fire, only two

passengers were able to escape from the left overwing emergency exit. They crawled along the

left wing and jumped from the leading edge of the wing to the ground.

About 37 passengers escaped via the right overwing emergency exit. Their egress was hampered

by the passenger seated in seat 10-F who stated that she was very frightened and 'froze', and was

unable to leave her seat or open the window exit next to her. The male passenger seated in 11-D

climbed over the 10-E seatback and opened the overwing exit; he pushed the passenger seated in

10-F out the window and onto the wing and then followed her. During the subsequent

evacuation through the right overwing exit, two male passengers had an altercation at the open

exit that lasted several seconds.

The outboard seatback at 10-F adjacent to the right overwing exit was found folded forward after

the accident blocking approximately 25 percent of the exit opening. The retaining bolt at the

seat's pivot point was sheared. The timing of this occurrence could not be determined.

Passengers who escaped by the right overwing exit made their way across the right wing and slid

down the extended flaps. They were directed away from the aeroplane by flight attendants and

fire fighters who, they estimated, arrived on scene 1 to 2 minutes after the B-737 struck the

abandoned fire station.

Passengers seated around row 10 stated that prior to departure the flight attendant assigned to the

R1 position conducted a special oral briefing for the persons seated in and around row 10.

Passengers stated that the instructions provided by the R1 flight attendant aided in their

evacuation.

Fifteen passengers seated aft of the overwing area who made their way to the rear of the cabin

reported using the emergency floor path lighting. All of the passengers stated that the cabin

filled with thick black smoke within seconds of the impact with the building.

The L3 flight attendant stated that she slightly opened her door without difficulty before impact

with the building; however, the outside of the door was ablaze so she closed the door. She had

taken about two steps into the cabin when the building was struck. She did not return to the

door. After the final impact, she attempted to make her way to the overwing exits in accordance
C-76

with company procedure. Because of the number of passengers moving aft, she was only able to

advance forward to the seats at rows 19 and 20 on the left. From there, she directed the

passengers to the rear of the cabin.

After the final impact, the flight attendant who was assigned to the R3 door opened the door,

deploying the emergency slide, and evacuated about 15 passengers. He then exited and directed

passengers away from the aeroplane.

Four of the six exits were used during the emergency evacuation: the R1 forward service door,

and left and right overwing emergency exits, and the R3 service door. The L1 exit was damaged

subsequent to the secondary impact with the abandoned fire station. The L3 exit was opened by

the L3 flight attendant during the slide to a stop between the first and second impacts; however,

because of flames along the left side of the aeroplane, she stated that she closed the door and

elected not to use it thereafter. Investigators found the door open with the slide deployed. It was

determined that ARFF personnel had opened the door well after the accident.

The R1 slide pack did not deploy. It was found below the door in an area where the floor was

burned away. The postcrash examination of the girt bar and its two retaining brackets revealed

that the bolts that secured the retaining brackets to the floor on the inboard side of the door were

bisected (sheared off at floor level). The R3 slide pack deployed as designed when the door was

opened by the R3 flight attendant to initiate the emergency evacuation.

AIRCRAFT FACTORS

The aircraft was a B737-300 registered as N388US operated by USAir.

The aircraft was fitted with two doors at the front and two doors at the rear of the passenger

cabin. In addition there was an overwing emergency exit above each wing.

The aircraft was manufactured in 1985. Although the interior was partially refurbished in 1989,

most of the interior panel were from state-of-the-art materials at the time of original aircraft

manufacture. The cabin seats contained fire blocking material with Poly-Benizol Iomedizal

(PBI). Floor proximity emergency lights were installed in the cabin.

The cabin configuration was predominantly 3 abreast either side of a central isle. The total

passenger capacity was 128.

ENVIRONMENTAL CONDITIONS

The accident happened at night with a visibility of 15 miles. Wind was 260 deg at 6 knots and

the temperature was 14C.

INJURIES TO OCCUPANTS

Of the 89 persons aboard the B-737, 20 passengers, one flight attendant and the captain were

fatally injured. Autopsies of the 19 passengers and one flight attendant who were removed from

the wreckage revealed that they died of asphyxia due to smoke inhalation. One person who

evacuated the aeroplane died as a result of thermal burns a few days later. The captain
C-77

succumbed to multiple traumatic injuries. In addition, one passenger died of thermal burn

injuries 31 days after the

accident.

2. Fire Penetration Mechanism

After the first impact and while the aircraft was still moving, the R1 flight attendant observed

smoke coming from underneath the floor in front of him. As he was positioned rearward facing

in the vestibule area, it is assessed that fire was coming through the floor from the cargo area. It

is considered that the observed smoke appeared too quickly for a burnthrough of the fuselage

skin to have occurred from the burning Metroliner underneath. It is assessed more likely that fire

penetrated into the cargo area through ruptures in the lower fuselage skin.

It was stated that there was little damage to the carpet along the length of the fuselage and it is

therefore concluded that there was no burnthrough in the rear fuselage. However, the roof in that

area burnt through from inside out; hence, it is assessed that once the fire had entered at the front,

it then propagated aft along the cabin and accumulated just rear of the main wing.

On the right side of the fuselage there were a number of small holes burnt through in the lower

quadrant and a large hole had burnt through in the lower belly area. It is assessed that these

penetrations were insignificant compared with the main fire entry path and did not constitute a

significant threat to the occupants.

The firefighters were able to control the fire under the aircraft but not the one in the cabin. Later

in the sequence of events the top of the fuselage burnt through in the forward cabin area between

the first- and coach-class sections from the inside out. Eighteen minutes after the accident

occurred, the top of the fuselage also burned away from just aft of the wing to the aft doors

which caused the entire tail section to droop to the ground and allow firefighters to advance into

the cabin and extinguish all remaining fires.

Based on the above, it is assessed that the prime burnthrough route was through the fuselage

lower skin; however, more significant, non-burnthrough fire entry paths were also present.
C-78

3. Location of Injuries and Scenarios

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-79

4. Accident Scenarios and Survivability Chains

This accident is divided into four separate scenarios.

Scenario 1 contains the flight deck area. It was subjected to substantial impact damage as the

aircraft impacted the fire station building and was crushed. The captain sustained multiple

traumatic injuries. The unknown injury was assumed to be serious and as a result of the fire.

Scenario 2 contains the forward flight attendant vestibule area. This was the area in which fire

first penetrated the passenger cabin. Visibility was restricted by very thick smoke. The scenario

contains two flight attendants. The unknown injury was assumed to be serious and as a result of

the fire.

Scenario 3 contains the passenger cabin from seat row 1 in first class to row 7 in the coach

section inclusive. This was subjected to dense smoke and fire and R1 & R2 were the only usable

exits. It can be assumed that the smoke hindered the occupants’ attempts at locating the exits

1 0

IMPACT

FIRE

0

1

0

2

1

SCENARIO 1

0 1

FIRE

2

1

SCENARIO 2
C-80

and as a result many were overcome. This scenario contains 27 passengers. The unknown

injuries were assumed to be serious and as a result of the fire.

Scenario 4 contains the passenger cabin from seat rows 8 to the rear of the cabin, including the

aft cabin attendant area. This area had the longest time before smoke and fire hampered

evacuation. R2, L2, and R3 exits were available for egress. The scenario contains 56 passengers

and 2 flight attendants. The unknown injuries were assumed to be serious and as a result of the

fire.

5. Effect of Later Requirements

It is assumed that there would be no change to the number of fatalities for Scenarios 1 and 2 had

the aircraft been configured to the standards required by later requirements.

The aircraft was configured with floor proximity lighting and seat fire blocking but did not meet

improved flammability standards.

Additional time would be provided to facilitate escape if the aircraft had been configured to these

improved flammability standards. Furthermore improved access to Type III exits is likely to

have relieved the congestion at the overwing exit. However, due to the intensity of the fire,

which was most probably increased in severity by the release of oxygen, the reduction in

fatalities resulting from these improvements would have been modest.

SCENARIO 3

1 9

FIRE

27

17

53 2

FIRE

58

3

SCENARIO 4
C-81

The survivability chain for Scenarios 1 and 2 are therefore unchanged, and Scenarios 3 and 4

become:

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected injuries in this scenario

because the predominant cause of injury was impact.

Scenarios 2 and 3

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenarios 2

and 3 because it is assessed that fire entered through ruptures in the lower fuselage skin.

Scenario 4

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 4

because it is assessed that fire entered the scenario by propagating along the fuselage from

Scenario 3.

Summary

It is assessed that no benefits would be gained by a fire-hardened fuselage in this accident since

the prime fire entry path was through fuselage ruptures.

6

SCENARIO 3

9

FIRE

27

12

55 1

FIRE

58

2

SCENARIO 4
C-82

AIRCRAFT: A320 DATE OF ACCIDENT: 14th September ‘93

REGISTRATION: D-AIPN LOCATION OF ACCIDENT: WARSAW

1. Description of Accident

RESUME

On 14-Sep-1993 a Lufthansa A320 registered as D-AIPN was landing at Okecie in Warsaw,

Poland.

The pilot in the left seat was subject to check but was the pilot flying at the time of the accident.

The pilot in the right seat was the instructor who was in overall command of the aircraft.

Okecie tower warned the crew of windshear and so the flight crew increased the approach speed

by 20 knots, in accordance with the Flight Manual. A storm front passed through aerodrome

area at that time which produced a tail wind and as a result the aircraft touched down too fast.

The very light touch of the runway surface with the landing gear and lack of compression of the

left landing gear leg (to the extent understood by the aircraft computer as the actual landing)

resulted in delayed deployment of spoilers and thrust reversers. Delay was about 9 seconds.

Thus the braking commenced with delay and in a condition of heavy rain the aircraft did not stop

on the runway.

The aircraft ran off the end of the runway, collided with an embankment and stopped the other

side of it. The aircraft caught fire as a result of the impact.

There were 6 crew and 64 passengers aboard. 1 crew member and 1 passenger suffered fatal

injuries. 2 crew and 49 passengers suffered serious injuries. 3 crew and 14 passengers escaped

with minor or no injuries.

IMPACT

Okecie tower warned the crew of windshear and so the flight crew increased the approach speed

by 20 knots, in accordance with the Flight Manual. A storm front passed through aerodrome

area at that time which produced a tail wind of approximately 20 knots and as a combined result

the aircraft touched down too fast.

After first contact of the right landing gear assembly with the runway the pilot attempted to use

wheel brakes, and when they failed to work, demanded the right-seat pilot to assist.

Automatic systems of the aircraft depend on oleo strut compression and a weight-on-wheels

switch to unlock the use of ground spoilers and engine thrust reversers. Only when the left

landing gear touched the runway were these systems activated. As a result of the light and fast

landing the operation was delayed by about 9 seconds. The systems then began to operate; the

spoilers deployed to full angle (50 deg), the thrust reverser system began to work and N1 of the

engines came to 71%, but the wheel brakes, depending on wheel rotation being equivalent of

circumferential speed of 72 kts began to operate only after about 4 seconds.
C-83

Deceleration of the aircraft progressed in conditions of heavy rain and with a layer of water on

the runway. The aircraft was decelerated with normal performance but on the last 180 metres of

runway deceleration decreased by about 30%. Residual length of the runway (left from the

moment when braking systems had begun to work) was too small to enable the aircraft to stop on

the runway. Seeing the approaching end of runway and the embankment behind it, the pilot tried

to turn the aircraft but only managed to deviate the aircraft a little to the right.

The aircraft ran off the end of runway with a speed of 72 kts and having travelled 90 metres its

left wing collided with the embankment. The aircraft slid over the embankment, destroying an

aerial and stopped right behind the embankment. During this stage the landing gear of the

aircraft and the left engine were destroyed.

The bottom part of the fuselage up to the wing area was found significantly deformed, and

broken in the wing area.

The radar dome and radar antenna were found detached from the aeroplane and destroyed.

The aft part of the fuselage, from aft doors, was found complete, with minor deformation.

The left main landing gear was detached, the wheel assembly partially burnt and no pressure was

found in the tyres. The right main landing gear was partially detached from the fuselage fittings

but otherwise complete. Wheels and tyres were not damaged. The front landing gear detached

from the fuselage but the wheels and tyres were not damaged.

FIRE

In the collision of the aircraft with the embankment and with the aerial located on it, the fuel

tanks of the aircraft were broken and the fuel began to spill on the left side of fuselage. It was

most probably ignited because of contact with hot parts of the damaged left engine or with the

electrical system of the aerial. It caused a fire on the left wing. The fire spread onto an area of

about 600 square metres. Shortly the fire penetrated into passenger cabin, creating smoke at

first, and later filling the whole cabin. In 3 minutes from the emergency call, 5 Aerodrome Fire

Service cars came to the scene. They managed to extinguish the external fire and successfully

evacuated the passengers remaining in the area of danger (and blocking access for the fire

services) to a safe distance.

It was impossible to stop the fire inside the aircraft. Neither the foam introduced through the

open entrance, nor the attempts to open the emergency exits on the left wing and to break into

the cabin were successful. Eventually pouring foam through the broken out cockpit windows

gave a positive result. After 2 minutes from the beginning of the activities on the scene, the tank

in the middle part of wing blew out. For the next 30 minutes extinguishing of the burning

fuselage through the hole created in the roof was continued.

15 minutes after the emergency call four cars of the national fire service came to the aircraft and

entered into action.
C-84

Calculation of the residual fuel, remaining on board at the moment of impact and the amount

drained from the wreckage indicates that about 2900 litres of aviation kerosene JA-1 was burnt

in the fire and due to action of the high temperature of oxygen bottles about 12000 litres of

oxygen was released, which obviously increased the intensity of the fire.

After the fire had been extinguished, about 6000 litres of fuel were drained from the tanks of the

wreckage.

The upper part of the fuselage from the cockpit to the fin and to bottom of the passenger cabin

was burnt out, including cabin furniture and equipment. The cockpit was found burnt out.

EVACUATION

There were 2 flight crew, 4 cabin crew and 64 passengers on

board.

A successful evacuation of passengers, organised by the 4 cabin crew, in conditions of an aircraft

fire, contributed to the rescue of 63 passengers of the 64 on board.

The front and aft passenger doors were found open with escape slides deployed.

During the landing the cabin crew were seated in two pairs, one near to the front entrance and the

other near to aft entrance. Only two were available to act immediately. A stewardess from the

aft pair, due to breathing difficulties, fainted after opening the door and initialisation of the

escape slide and was unable to take part in the further activities, and chief steward (with injured

head), who was in the front part of cabin, remained unconscious all the time during passenger

evacuation. After regaining consciousness he managed to release the injured pilot blocked in the

cockpit, enabling him to leave the aircraft through the open front door. But he was not able to

lift the body of the instructor remaining in the cockpit.

The prompt and successful evacuation of 63 persons out of the passenger cabin during increasing

smoke and intensive fire was directly due to the behaviour of the cabin crew, in spite of their

injuries. The two active cabin attendants played a significant and unquestionable role preventing

the panic and organising the movement of passengers to the exits.

The passenger seated in the utmost left seat in "business class" sustained a fracture of the first

lumbar vertebra and of both hands. This made him probably unable to leave his seat unaided. In

addition, his temporary loss of consciousness during the impact did not allow him to draw the

attention of other passengers and cabin attendants.

The situation would have been significantly more severe if the injured persons needed individual

direct assistance leaving the wreckage or if the type of injuries required immediate intervention,

e.g. because of haemorrhage or need for reanimation. A sufficient number of ambulances did not

come to the scene quickly enough and some injured were carried to the airport by casual means

of transport (e.g., bus).
C-85

AIRCRAFT FACTORS

The aircraft was an A320, registered as D-AIPN and operated by Lufthansa.

The airframe was production serial number 105, manufactured in 1990 with a Certificate of

Airworthiness dated 25-Apr-1990.

The aircraft carried JA-1 kerosene fuel.

At the time of the accident the tyre tread depths were low and may have been a factor in the

inability of the aircraft to stop within the confines of the runway, especially in heavy rain.

The cabin was fitted with two doors at the front and two doors at the rear of the passenger cabin.

In addition there were 2 overwing emergency exits over each wing.

ENVIRONMENTAL CONDITIONS

The accident happened during daylight hours in windshear conditions.

Wind was 150 deg at 12 kts. The ambient temperature was about 20C.

INJURIES TO OCCUPANTS

There were 6 crew and 64 passengers aboard. 1 crew member and 1 passenger suffered fatal

injuries. 2 crew and 49 passengers suffered serious injuries. 3 crew and 14 passengers escaped

with minor or no injuries.

Of the 2-person cockpit crew, the left-seat pilot survived (injured by impact) and the right-seat

pilot was killed outright.

The autopsy of the body of the right-seat indicates that he was killed during the impact due to

collision with cockpit interior elements. It was confirmed by extensive damage to the internal

organs, namely: rupture of pericardial sac and of the main artery wall, rupture of internal

membrane of aorta, perforation of the lungs with broken ribs. Presence of the carbon oxide

haemoglobin or alcohol in the blood of the pilot was not stated. During examination of stomach

contents and kidney neither drugs nor medicines affecting the capacity or capability to perform

pilot duties were discovered.

In the blood of the fatally injured passenger 22.6% of carbonoxide haemoglobin was found, and

in the opinion of the person who performed the autopsy intoxication with carbon oxide in the

environment of the high temperature was the cause of the death.
C-86

The injury profile was as follows:

 spine injuries 21

 head injuries 8

 chest injuries

 (broken ribs) 8

 abdomen contusions 4

 broken limbs 5

 burns 1

 other 9

 Total 56

2. Fire Penetration Mechanism

When the aircraft came to a stop, spilled fuel on the left side of the fuselage ignited and spread

onto an area of about 600 square metres, including the left wing. With this amount of fire

impinging on the fuselage side, it is assessed that it burnt through and penetrated into the

passenger cabin from the left side. Smoke was reported as appearing first and later the fire

entered, eventually filling the whole cabin.

Only one surviving passenger was identified as suffering burn injury and so it is concluded that

the burnthrough occurred toward the end of the evacuation time.

It was stated that the Aerodrome Fire Service cars came onto the accident scene approximately 3

minutes from the emergency call and moved the evacuated passengers away from the aircraft. It

is therefore assessed that evacuation had been completed in 2 to 3 minutes.

One passenger was stated as having immobilising impact injuries and it is assumed that this

person was the eventual fatality, being overcome by the fire.

The wreckage was described as having a hole burnt through the roof and the upper part of the

fuselage burnt out. It is assumed that this was as a result of the intense internal fire burning

through from the inside out and the major burning of fuselage skin would have occurred well

after the evacuation was completed.

Based on the above, it is assessed that the prime burnthrough route was through the fuselage

skin. However there was insufficient information to be conclusive about other burnthrough

areas.
C-87

3. Location of Injuries and Scenarios

Scenario 4

Scenario 3

Scenario 2

Scenario 1
C-88

4. Accident Scenarios and Survivability Chains

This accident is divided into four separate scenarios.

Scenario 1 contains the flight deck area where all injuries were sustained from the impact. The

scenario contains the two flight crew.

Scenario 2 contains the forward flight attendant area where injuries were sustained from the

impact. The scenario contains two flight attendants.

Scenario 3 contains the whole passenger cabin. This has been used because of limited detail on

passenger locations during the accident. The scenario contains all 64 passengers.

14

50

IMPACT

FIRE FIRE

0

0

14 49 1

64

0

0

SCENARIO 3

0 1

IMPACT

2

1

SCENARIO 1

1 1

IMPACT

2

0

SCENARIO 2
C-89

Scenario 4 contains the rear flight attendant area where only minor injuries were sustained from

the impact. The scenario contains two flight attendants.

5. Effect of Later Requirements

The aircraft was manufactured in 1990. It is assumed that lower heat release materials had been

fitted and that seat-blocking layers were already installed. Since there was only one fire fatality

in this accident, any errors in these assumptions would have a minimal effect on the conclusions

of this study.

It is therefore assumed that later requirements would not have affected the situation in any

scenario.

6. Effect of a Fire-Hardened Fuselage

Scenario 1

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 1

as all injuries were sustained as a result of the impact.

Scenario 2

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as all injuries were sustained as a result of the impact.

Scenario 3

It is concluded that a fire-hardened fuselage would have delayed the entry of fire and may have

provided the passengers with additional time to go back and remove the immobilised passenger

who was seated near to the forward passenger door.

2 0

IMPACT

2

0

SCENARIO 4
C-90

The high, median, and low prediction from the use of a fire-hardened fuselage is:

For 30 seconds protection:

S I F

H 14 49 1

M 14 49 1

L 14 50 0

For 2 minutes protection:

S I F

H 14 49 1

M 14 49 1

L 14 50 0

For 4 minutes protection:

S I F

H 14 49 1

M 14 50 0

L 14 50 0

For 8 minutes protection:

S I F

H 14 49 1

M 14 50 0

L 14 50 0

Scenario 4

It is concluded that a fire-hardened fuselage would not have affected the situation in Scenario 2

as all injuries were sustained as a result of the impact.

Summary

The assessed median number of lives saved by a fire-hardened fuselage are:

Burnthrough

Protection Time

Aircraft in its Actual

Configuration

Aircraft Configured to

Later Requirements

30 seconds 0 0

2 minutes 0 0

4 minutes 1 1

8 minutes 1 1