the causes of air crashes in pakistan; a research based project of business research method

8/7/2019 The Causes of Air Crashes in Pakistan; a research based project of business research method

1/39

0

The Causes of AirCrashes (Air Disasters)

Occurred in the

Territory of Pakistan.A Survey based project of Business Research Method

Report

On

Aslam A., Khalid A., Sharjeel-ur-Rehman M., Batool Y., Khan G. N.

5th semester, BS Aviation Management, Aviation department, Superior

University, Lahore.


2/39

1

Business Research Method

Course:

BS (Hons.) in Aviation Management

5TH

Semester

Course Instructor:

Sir Nadeem Iqbal

Submitted By:

Arslan Khalid BAM-9222

M.Sharjeel-ur-Rehman BAM-9225

Arslan Aslam BAM-9234

Yumna Batool BAM-9242

Gulnawaz Khan BAM-9248


3/39

2

Report On

The Causes of Air Crashes (Aircraft Disasters) Occurred

In the Territory Of Pakistan

Research Conducted By

Khalid A., Sharjeel-ur-Rehman M., Aslam A., Batool Y., Khan G. N.

Aviators, 5Th

Semester, BS (Hons.)in Aviation Management,

Aviation Department, College of Business and Management Sciences, Superior University,

Lahore.


4/39

3


5/39

4

Contents Page no.

Abstract..05

Introduction.06

Purpose Statement...........................................................................08

Significance of the Research.08

Objectives.....09

Research questions and hypotheses...09

Methodology

Site and Sample..12

Data Collection Method...12

Data Analysis.....13

Rliability.13

Graphical representation of variables..13

Correlations.21

Regression36

Conclusion...38


6/39

5

ABSTRACT

This research based report is to find out the Causes of Air crashes occurred in Pakistan to

bring the facts about the air crashes in front of common people. The study is quantitative in

nature (Positivism paradigm). After reading the previous literature on a global scale, we focus

on some causes of air crashes as independent variables like pilot errors, technical faults,

organizational factors, safety and security issues and weather conditions, in our research and

the dependent variable; air crashes, that is affected by independent variables. Hypotheses were

also made to test the relationships of factors affecting the air crashes in Pakistan. Data for the

research is collected from Lahore, Pakistan through self- administered questionnaires filled by

the professionals including ATCOs, Pilots and CEOs of aviation organizations. Collected data was

analyzed through SPSS (Statistical Package for Social Sciences) and the conclusion is experiment

based.


7/39

6

Introduction

Firstly an air crash is defined as serious air accidents (crash) means ; An aviation accident is

defined in the Convention on International Civil Aviation Annex 13 as an occurrence associated

with the operation of an aircraft which takes place between the time any person boards the

aircraft with the intention of flight and all such persons have disembarked, in which a person is

fatally or seriously injured, the aircraft sustains damage or structural failure or the aircraft is

missing or is completely inaccessible.

Humans, by nature, make mistakes and 70% to 80 % crashes both in civil and military aviation

are due to human error.(OHare, Wiggins, Batt, & Morrison, 1994; Wiegmann and Shappell,

1999; Yacavone, 1993). The air crashes due to mechanical failure has been decreased since last

40 years and human error has declined at much slower rate. (Shappell & Wiegmann, 1996).

When a plane goes down, the initial concern is to find survivors and save lives. But immediately

thereafter the investigators focus changes to assessing the cause. It is vital for investigators to

find the reasons behind crashes so that similar disasters can be prevented. But the causes of

airplane crashes today are rarely traced to just one problem, and they are not easy to

determine amidst the chaos and wreckage of a downed airplane. Complex factors generally

combine to bring down a plane. Bad weather, like thunderstorms or fog, can compound pilot

error, while small mechanical problems can affect other aspects of a plane's ability to function.

There are so many causes of air crashes like safety and security issues, organizational factors,

bird strike, terrorism etc. (NTSB Classification)

3 air crashes have been occurred during four months in 2010.

The beech craft plane crashed in Karachi was due to engine failure. (Butt C.M.A. 2010) A bird

strike is the likely cause for the crash of a Russian-made Il-76 cargo plane in Pakistan that killed

all eight crewmembers on board. (Tamazashvili D. director of the Georgian airline 2010)

Approximately 80% of air crashes occurs during landing and takeoff. Mid air disaster are very


8/39

7

rare. Pilot error is supposed to be a major cause of air crashes. Terrorist activity like bomb

blasts is a major cause of air crashes, e.g. Lockerbie disaster in 1988. Mid-air collisions and

structural failures are rare but they do happen.A survey of1,843 plane crashes between 1950 and

2006 determined the causes of the accidents ;Pilot Error 53% Mechanical Failure 21%

Weather 11% Other Human Error (e.g. lack of communication, improper maintenance etc) 8%

Sabotage and Terrorism 6% Other Causes 1%. 72 0f 75 air accidents are due to pilot factors such

as poor judgment , divided attention and failure to make correct judgments and organizational

structure or the system itself , of which the pilot and the other aircrew are only a part, plays an

equal role for air crashes.(Bureau of Air Safety Investigation, (BASI)1996.)

Air crashes occurred are due to pilot error whether pilot error related to weather and it is

related to mechanical failure, Sabotage includes explosive devices, shoot downs and hijackingsmay be a cause of air crashes. (PlaneCrashInfo.com database)

A major airline disaster was in 2006, when a 27-year-old Fokker plane crashed into a wheat field

in Multan two minutes after taking off. The same year, Pakistan International Airlines

discontinued use of Fokker planes. The reason was safety issues. (The Associated Press, 2006).

A passenger jet Air Blue A320 crashed into the hills overlooking Pakistan's capital amid poor

weather Wednesday, killing all 152 people on board and blazing a path of devastation strewn

with body parts and twisted metal wreckage. The Pakistan Airline Pilot Association

said the plane appeared to have strayed off course, possibly because of the poor weather.

Our research will be beneficial not only for Pakistani but all the people will be aware of it. This

research will determine the facts about the air crashes in Pakistani context and no research has

been conducted before on air crashes in Pakistani context except the inquiry team of Civil

Aviation Authority of Pakistan and media news. Many investigations and researches had been

conducted on air crashes that occurred in foreign countries but no research has been done onair crashes happened in Pakistan. When an air disaster occurs in Pakistan, foreign investigations

team demands black box for investigation and they investigates properly (they decode the cock

pit voice recorders and find out facts) but we (people) dont get the realities about air crashes

Actually General Aviation is both too diverse and its accident reports too limited in content, The

organizations behind each General Aviation operation are limited to few people, and flight data


9/39

8

are rarely recorded that may allow an analysis of the communication and actions prior to an

accident. This research will bring facts about air crashes. This study aims to find out the causes

of air disasters occurred in the territory of Pakistan.

Purpose Statement

The purpose of this survey based study is to determine the Causes of Air crashes that

happened in the territory of Pakistan. The aim of this study is evaluate how many air crashes

happened due to pilot errors, Technical faults, safety and security issues, organizational factors

etc. To find out the most frequent cause of air crashes occurred in Pakistan, is also the purpose

of this research.

Significance of the Study

Independent media culture is to be found in Pakistan; Pakistanis consult media to be aware of

the environment. When an air disaster happens in Pakistan, and there is a question mark in the

minds of the people; why and how did it happen, what was the reason behind it, media focuses

on sayings of some officials that draw out the causes of an air disaster for answering the

people. Investigation team or inquiry team of CAAP (Civil Aviation Authority of Pakistan)

investigates the happenings very consciously and report the authority but people did not find

the facts about air crashes; what actually was reason behind an air crash. Only very small

number of people knew the true facts about air crashes and they dont appear in the media.

Some persons with strong aviation background define the causes with their own opinions but

there is doubt in them.

Our research will be helpful to bring the reality in front of Pakistanis. It will also be helpful for

aviators and non aviators because research on air crashes has not been conducted in Pakistan

before except CAA Inquiry team. People focus on independent media so they didnt get the

realities and our research will provide the facts.


10/39

9

Objectives of the Research

To determine the causes of air disasters happened in Pakistan.

To indentify the opinions of Pilots, ATCOs, CEOs of aviation industries about the air

crashes in Pakistan. To compare the present study in Pakistan from study world wide about air crashes.

To make people aware with facts and figures about air disasters occurred in Pakistan.

Research Questions and Hypotheses

Research Questions

Main Question

What are the causes of air crashesoccurred in the territory of Pakistan?

Sub Questions

What are the opinions of professionals from aviation sector about the air crashes in

Pakistan?

Which factor like pilot errors, organizational factors, weather conditions, affects more

for being cause of air crashes in Pakistan?

What are acceptable causes of air crashes according to people in Pakistani context?

How much safety and security issues affects on air crashes?

How air crashes can be reduced?


11/39

10

Hypothesis

Theoretical framework

Independent variables Dependent variable

1. H0= There is no relationship between pilot error and air crashes occurred in Pakistan.

H1= There is a relationship between pilot error and air crashes occurred in Pakistan.

The correlation shows the value less than 0.05 between pilot error and air crashes soH1

is accepted andH0is rejected, referred as figure1.1, on page # 25.

Weather

conditions

Technical

errors

Safety and

security issues

Organizational

factors

Pilot

errors

Air crashes

occurrence in

Pakistan


12/39

11

2. H0= There is no relationship between technical faults and air crashes occurred.

H1= There is a relationship between technical faults and air crashes occurred.

The correlation between technical faults and air crashes shows the value less than 0.05

soH1 is accepted andH0 is rejected, referred as figure1.2, on page # 29.

3. H0= There is no relationship between weather and air crashes occurred in Pakistan.

H1= There is a relationship between weather and air crashes occurred in Pakistan.

The correlation between weather and air crashes shows the value less than 0.05 so H1

is accepted andH0 is rejected, referred as figure1.3, on page # 32.

4. H0= There is no relationship between organizational factors and air crashes occurred in

Pakistan.

H1= There is a relationship between organizational factors and air crashes occurred in

Pakistan.

The correlation between organizational factors and air crashes shows the value less than

0.05 soH1is accepted andH0 is rejected, referred as figure1.4, on page # 34.

5. H0= There is no relationship between safety and security issues and air crashes in

Pakistan.

H1= There is a relationship between safety and security issues and air crashes in

Pakistan.

The correlation between safety and security issues and air crashes shows the value

greater than 0.05 so H1 is rejected andH0is accepted, referred as figure1.5, on page #

35.


13/39

12

Methodology of the Study

Site and Sample

Data for this research is collected from Lahore, Pakistan. Our population is aviation

organizations and the samples for data collection are: Hybrid Aviation and Lahore Flying Club

at Walton aerodrome Lahore, Allama Iqbal International airport (CAA of Pakistan) and Scaled

Aviation Industries (pvt.) Limited at Walton aerodrome. The data was collected from the

employees of aviation sector including both males and females. All these people are

professionals; ATCOs (air traffic control officers), Pilots, CEOs of aviation organizations. There

were senior air traffic controllers (SATCOs), assistant air traffic control officers (AATCOs), CEOs

of aviation organizations, pilots including Commercial and Cadet Pilots and PAF retired pilots for

data collection.

We chose simple random, convenience sampling techniques (non probability) and snow ball

sampling technique. (Probability)

Methods of Data Collection

This research is quantitative in nature, so a questionnaire was developed and took respondents

views/opinions on self administered questionnaires. Close ended questions were asked in the

questionnaire. Every variable (whether independent or dependent) has 3 to 6 questions, total

we have 28 questions in the questionnaire to measure the variables.

The number of total filled questionnaires is 28.


14/39

13

Data Analysis Procedures

Reliability of the Data

Scale: ALL VARIABLES

Case Processing Summary

N %

Cases Valid 22 78.6

Excludeda

6 21.4

Total 28 100.0

Reliability Statistics

Cronbach's

Alpha N of Items

.775 34

Frequency Distribution and Bar charts of Nominal and Ordinal

Variables

Gender (nominal) variable

FrequenciesStatistics

Gender

N Valid 28

Missing 0

Gender

Frequency Percent Valid Percent

Cumulative

Percent

Valid Male 27 96.4 96.4 96.4

Female 1 3.6 3.6 100.0

Total 28 100.0 100.0


15/39

14

Interactive Graph (Gender)

In above bar chart graph, the vertical column of male side is showing the numbders of

males who filled questionnaire who are 27 and other column shows number of females

which is only 1 as shown in the tables above.

Designation (Nominal) variable

FrequenciesStatistics

Designation

N Valid 27

Missing 1


16/39

15

Frequency Percent Valid Percent

Cumulative

Percent

Valid ATCO 10 35.7 37.0 37.0

CEO 2 7.1 7.4 44.4

Pilots 13 46.4 48.1 92.6

Retd. PAF Pilots 2 7.1 7.4 100.0

Total 27 96.4 100.0

Missing 56 1 3.6

Total 28 100.0

Interactive Graph

In the graph and table above, shows that designations and their number from which we

collect data. Most of the data was collected from pilots wich were 13 and we also

collected data from ATCOs which were 10. PAF retired pilots and CEOs of aviationindustries are equal in quantity (2).

Designation


17/39

16

Five Figure Summary of Variable (Scale) and their Histograms

Organization (Scale) Variable

Frequencies Interactive Graph

The above table shows the five figure summary of scale variable named Organization.In

the table, we calculate/describe five figure summary which includes mean value, mode,

median, minimum value and maximum value which values are 2.19, 1a, 2.00,1 and 5

respectively and the histogram above describes the peak value or curve shape for the

organizations which indicates that maximum value that are in between 1 to 4.75 and

above 5 are lower values of organizations like other aviation organizations.

Statistics

Organization

N Valid 27

Missing 1

Mean 2.19

Median 2.00

Mode 1a

Minimum 1

Maximum5


18/39

17

Pilot Error (Scale variable)


In above table, shows the five figures summary of Pilot error. Mean value of pilot error

variable 2.41, median 2.40, mode, maximum 3, minimum 1 are shown in the above

table. The histogram shows high and low values for pilot error such as from 2 to 3.3 are

agreed that pilot error is a reason for air crashes in Pakistan an values less than 2 are

disagreed and above 4 are those that are strongly agreed.

Statistics

Piloterror

N Valid 28

Missing 0

Mean 2.41

Median 2.40

Mode 2a

Minimum 1

Maximum 3

Percentiles 25 2.20

50 2.40

75 2.80


19/39


20/39

19

Organizational Factors Variable


Safety and Security Issues Variable


Statistics

Organizationalfactors

N Valid 28

Missing 0

Mean 1.9768

Median 1.9167

Mode 1.67a

Minimum 1.17

Maximum 3.17

Percentiles 25 1.6667

50 1.9167

75 2.2292

Statistics

Safetyandsecurityissues

N Valid 28

Missing 0

Mean 2.12

Median 2.25

Mode 2

Minimum 1

Maximum 4

Percentiles 25 1.75

50 2.25

75 2.50


21/39

20

Air Crashes Variable

Frequencies Interactive GraphStatistics

Aircrashes

N Valid 28

Missing 0

Mean 2.46

Median 2.33

Mode 2

Minimum 1

Maximum 4

Percentiles 25 2.00

50 2.33

75 2.67

In all above histograms and their tables, five figures summary of scale variables are

given in tables and their high (peak) and low values of variables are shown like from1.5

to 3.5 are the values of agreed people and minimum numbers of people that are not

agreed less than 1.5 are not agreed with the causes of air crashes in Pakistan and above

3.5 shows that there is strongly agree ness with air crashes.The adequate vertical curve

shows that data is distributed equally.


22/39

21

Correlations between Variables with Scatter plot (graph) and tests

applications

Pilot Error and Technical Faults

Interactive Graph

This graph shows a correlation between pilot error and technical faults and a linear and

quadratic relations were applied and by seeing the difference between the values given

in the graph like, 0.172-0.11=0.062 which is greater than 0.05 and spearmans test is

applied on it which details are shown below in the table.

Nonparametric CorrelationsCorrelations

Piloterror Technicalfaults

Spearman's rho Piloterror Correlation Coefficient 1.000 .174

Sig. (2-tailed) . .377

N 28 28

Technicalfaults Correlation Coefficient .174 1.000

Sig. (2-tailed) .377 .

N 28 28


23/39

22

Pilot Error andWeather Conditions

Interactive Graph

The above graph explains the correlation of pilot error and weather conditions and the

values of linear and quadratic relations are 0.003-0.002=0.001 which is less than 0.05 so

Pearsons test was applied on it which is shown in the table below.Less than 0.05

represents that H0 is rejected and H1 is accepted which means that there is a

relationship between the pilot error and weather conditions.

CorrelationsCorrelations

Piloterror

Weathercondition

s

Piloterror Pearson Correlation 1 .048

Sig. (2-tailed) .809

N 28 28

Weatherconditions Pearson Correlation .048 1


N 28 28


24/39


25/39

24

Pilot Error and Safety and Security issue

Interactive Graph


Piloterror

Safetyandsecurity

issues

Piloterror Pearson Correlation 1 .369


N 28 28

Safetyandsecurityissues Pearson Correlation .369 1


N 28 28


26/39

25

Pilot Error and Air Crashes

Interactive Graph

This graph shows a correlation between pilot error and air crashes and a linear and


in the graph 0.073-0.014=0.059 which is greater than 0.05 and spearmans test is

applied on it which details are shown below in the table. The value greather than 0.05

represents that H0 is accepted H1 is rejected which means that there is no relationship

between air crashes and pilot error in Pakistan.


Piloterror Aircrashes

Spearman's rho Piloterror Correlation Coefficient 1.000 .021


N 28 28

Aircrashes Correlation Coefficient .021 1.000


N 28 28

Figure 1.1


27/39

26

Technical Faults andWeather Conditions

Interactive Graph

Correlations

Correlations

Technicalfaults

Weathercondition

s

Technicalfaults Pearson Correlation 1 .197


N 28 28

Weatherconditions Pearson Correlation .197 1


N 28 28


28/39

27

Technical Faults and Organizational Factors

Interactive Graph

Correlations

Correlations

Technicalfaults

Organizationalfac

tors



N 28 28

Organizationalfactors Pearson Correlation .348 1


N 28 28


29/39

28

Technical Faults and Safety and Security Issues

Interactive Graph


Technicalfaults

Safetyandsecurity

issues

Technicalfaults Pearson Correlation 1 .549**


N 28 28

Safetyandsecurityissues Pearson Correlation .549**

1


N 28 28


30/39

29

Technical Factors and Air Crashes

Interactive Graph

This graph shows a correlation between technical faults and air crashes and a linear and


in the graph 0.095-0.087=

0.008 which is less than 0.05 and pearsons test is applied on itwhich details are shown below in the table. The value less than 0.05 represents that H0

is rejected and H1 is accepted which means that there is a relationship between air

crashes and technical faults in Pakistan.


Technicalfaults Aircrashes



N 28 28

Aircrashes Pearson Correlation .295 1


N 28 28

Figure1.2


31/39

30

Weather Conditions and Organizational Factors

Interactive Graph


Weathercondition

s

Organizationalfac

tors

Weatherconditions Pearson Correlation 1 .367


N 28 28

Organizationalfactors Pearson Correlation .367 1


N 28 28


32/39

31

Weather Conditions and Safety and Security Issues

Interactive Graph


Weathercondition

s

Safetyandsecurity

issues

Weatherconditions Pearson Correlation 1 .105


N 28 28



N 28 28


33/39

32

Weather Conditions and Air Crashes

Interactive Graph

This graph shows a correlation between weather conditions and air crashes and a linear

and quadratic relations were applied and by seeing the difference between the values

given in the graph 0.207-.0201=0.006 which is less than 0.05 and pearsons test is

applied on it which details are shown below in the table. The value less than 0.05


relationship between weather conditions and air crashes in Pakistan.

Correlations

Correlations

Weathercondition

s Aircrashes

Weatherconditions Pearson Correlation 1 .448*


N 28 28

Aircrashes Pearson Correlation .448*

1


N 28 28

Figure 1.3


34/39

33

Organizational Factors and Safety and Security Issues

Interactive Graph

Correlations

CorrelationsOrganizationalfac

tors

Safetyandsecurity

issues

Organizationalfactors Pearson Correlation 1 .187


N 28 28



N 28 28


35/39

34

Organizational Factors and Air Crashes

Interactive Graph

This graph shows a correlation between organizational factors and air crashes and a

linear and quadratic relations were applied and by seeing the difference between the

values given in the graph 0.005-0.024=0.019 which is less than 0.05 and pearsons test is

applied on it which details are shown below in the table. The value less than 0.05


relationship between organizational factors and air crashes in Pakistan.


Organizationalfac

tors Aircrashes

Organizationalfactors Pearson Correlation 1 .068


N 28 28

Aircrashes Pearson Correlation .068 1


N 28 28

Figure 1.4


36/39

35

Safety and Security Issues and Air Crashes

Interactive Graph

This graph shows a correlation between safety and security issues and air crashes and a

linear and quadratic relations were applied and by seeing the difference between the

values given in the graph 0.077-0.006=0.071 which is greater than 0.05 andspearmans

test is applied on it which details are shown below in the table. The value greater than

0.05 represents that H0 is accepted and H1 is rejected which means that there is no

relationship between safety and security issues and air crashes in Pakistan.


Safetyandsecurity

issues Aircrashes

Spearman's rho Safetyandsecurityissues Correlation Coefficient 1.000 .204


N 28 28

Aircrashes Correlation Coefficient .204 1.000


N 28 28

Figure 1.5


37/39

36

Regression

Variables Entered/Removedb

Model Variables Entered

Variables

Removed Method

1 Safetyandsecurity

issues,

Weathercondition

s, Piloterror,

Organizationalfac

tors,

Technicalfaultsa

. Enter

a. All requested variables entered.

b. Dependent Variable: Aircrashes

Model Summary

Model R R Square

Adjusted R

Square

Std. Error of the

Estimate

1 .543a

.295 .135 .529

a. Predictors: (Constant), Safetyandsecurityissues, Weatherconditions,

Piloterror, Organizationalfactors, Technicalfaults

ANOVAb

Model Sum of Squares df Mean Square F Sig.

1 Regression 2.577 5 .515 1.839 .147a

Residual 6.165 22 .280

Total 8.742 27

a. Predictors: (Constant), Safetyandsecurityissues, Weatherconditions, Piloterror,

Organizationalfactors, Technicalfaults

b. Dependent Variable: Aircrashes


38/39

37

Coefficientsa

Model

Unstandardized Coefficients

Standardized

Coefficients

t Sig.B Std. Error Beta

1 (Constant) 1.685 .623 2.705 .013

Piloterror .118 .212 .112 .555 .585

Technicalfaults .296 .208 .322 1.423 .169

Weatherconditions .366 .149 .477 2.459 .022

Organizationalfactors -.305 .282 -.225 -1.081 .291

Safetyandsecurityissues -.132 .199 -.146 -.662 .515

a. Dependent Variable: Aircrashes

We have theformula as shown below;

y= a + bx1 + cx2 + dx3 +ex4..

y= Dependent Variable; Air Crashes

a= Constant

b, c, d= Slope cooeficient

x1,x2,x3= Independent variable

According to the above formula, we have;

Air crashes = Constant + a (Pilot Error) + b (Technical Faults) + c (Weather

Conditions) + d (Organizational Factors) +e (Safety and Security Issues)

Air crashes = 1.685 + 0.118x1+ 0.296x2+ 0.366x3 + ( 0.305) x4 + ( 0.132) x5

Our research regression shows that the independent variables that we have used in this

research have 13.5% impact on air crashes (dependent variable) as shown above model

summary table.

In this quantitative research, conduction of research is taken as a limitation of this

research; we have researched limited to the Pakistan relative to our topic anyone who


39/39

38

can do conduct his research on The causes of Air crashes outside the Pakistan, is a

delimitation of this research.

Conclusion

Experiments and surveys show that the air crashes that have been occurred in the

territory of Pakistan are due to pilot errors, weather conditions, technical faults and

organizational factors and there is no relationship between safety and security issues

and air crashes that have been happened in Pakistan.We test the hypotheses and

concluded that safety and security issues dont become cause of air crashes in Pakistan,

mostly people disagreed with this to be reason for air crashes. We concluded that

according to our research 50% people are agreed with that air crashes are unavoidable,

32.1% are disagreed with that statemnet and 17.84% answered neutral. 46.42% peolple

said that the rate of air crashes is not increasing in Pakistan with the passage of time,

14.2% dont know about it and 39.2% targeted population are agreed with increasing

the rate of air crashesin Paskistan.

93% persons said that the ratio of air crashes in Pakistan can be reduced by identifying

hazards and controlling incidents, this can be accomplished by adopting SMS (Safety

Management Strategies) from ICAO document of safety SMS (Safety Management

Manual). ICAO has demended the Safety Manual from all Contracting states upto 2012.

SOPs (Standard Operating Procedures) should be followed almost in every operation

related to aviation. There should be proper management system in the airlines existing

in Pakistan that is not only necessary for safe conduct of flight but it should be useful for

the airline.

the causes of air crashes in pakistan; a research based project of business research method

Documents