FATIGUE OCCURRENCE, PERCEPTION, KNOWLEDGE AND

THE UTILIZATION OF ITS COPING MECHANISMS BY

COMMERCIAL AIRCREW IN NIGERIA

SUBMITTED BY

DR OSAGIE KENNETH COLE

DEPARTMENT OF COMMUNITY HEALTH AND PRIMARY CARE ,LAGOS

UNIVERSITY TEACHING HOSPITAL,IDI-ARABA LAGOS

TO

THE NATIONAL POSTGRADUATE MEDICAL COLLEGE OF

NIGERIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS

FOR THE AWARD OF THE FINAL FELLOWSHIP OF THE

FACULTY OF PUBLIC HEALTH (FMCPH).

NOVEMBER 2012

DECLARATION

I hereby declare that this Research work titled “FATIGUE OCCURRENCE, PERCEPTION,

KNOWLEDGE AND THE UTILIZATION OF ITS COPING MECHANISMS BY COMMERCIAL

AIRCREW IN NIGERIA” is my original work and was done by me under appropriate

supervision, and any assistance given has been duly acknowledged.

I also declare that this dissertation has not been submitted anywhere else in part or in

full for any other examination.

……………………………………….. ………………………..

Dr Osagie Kenneth Cole Date

Department of Community Health

and primary care ,

Lagos University Teaching Hospital

Idi Araba ,Lagos state

ii

CERTIFICATION

I hereby certify that this study titled “FATIGUE OCCURRENCE, PERCEPTION,

KNOWLEDGE AND THE UTILIZATION OF ITS COPING MECHANISMS BY COMMERCIAL

AIRCREW IN NIGERIA” was carried out by Dr Osagie Kenneth Cole under my direct

supervision and to the best of my knowledge has not been submitted for any other

examination or for publication in any journal.

Prof A T Onajole …………………………….…

(MPH,FMCPH) Signature and date

Department of Community Health

Lagos University Teaching Hospital

Idi-Araba, Lagos

Dr K A Odeyemi …………………………………

(MPH,FMCPH) Signature and date

Head of Department,

Department of Community Health

Lagos University Teaching Hospital

Idi-Araba, Lagos

iii

ACKNOWLEDGEMENTS

I wish to most sincerely thank the Almighty God who strengthened me, gave

exceedingly abundant grace and opened unbelievable windows of opportunity to make

this project a reality. My Father, if not for your grace!

I will also like to extend my profound gratitude to my vibrant and good natured

supervisor, Professor AT Onajole for thoroughly supervising and guiding me through

this work. Sir, you are an inspirational leader and an extraordinary mentor. God bless

you. My appreciation also goes to our “mum in the house” and my Head of

department Dr KA Odeyemi for her patience and guidance through my residency

training. To Dr BE Ogunnowo, thank you for always being there. The three of you

have molded me and made me so much better. May the Lord continue to increase you

all in wisdom and understanding.

My appreciation also goes to Dr Olufunlayo and other Lecturers/consultants in the

department for their invaluable contribution to this dissertation and my residency

training as a whole. My special thanks to Drs Abisoye Oyeyemi and Tomi Odugbemi

for painstakingly reading through my work and making useful contributions. You both

have remained my reliable “cousins”.

I owe a debt of gratitude to the DG, NCAA Dr Harold Demuren for opening the doors

of the aviation industry and providing very useful counsel. To the DGM, aero medicals,

Dr T Haggai , thank you for sharing tons of research materials from your “treasure

trove”. In addition, access to aircrew would have been a nightmare without your help.

May God bless you abundantly.

iv

To the staff of KUPA medical centre and the in house research assistants, your

contribution were invaluable.

To my dear colleagues in the department and to the members of staff, thank you for

making my residency a pleasant and rewarding experience.

To my darling booh, Achere I cannot thank you enough for your Love, support,

prayers and sacrifice throughout the course of the Residency programme and

especially when putting this work together. May God bless you mightily. To my

wonderful children, Esohe and Osaze, thanks for being patient and understanding

when Daddy had to do his work. To my beloved parents Gp Capt (rtd) and Mrs Osaze

Cole and my siblings, your remarkable support and encouragement helped in no small

way. Thank you and may the good Lord bless you all.

v

TABLE OF CONTENTS

Pages

DECLARATION II

CERTIFICATION III

ACKNOWLEDGEMENTS IV

TABLE OF CONTENTS VI

ABBREVIATIONS VII

LIST OF TABLES VIII

LIST OF FIGURES IX

SUMMARY x

CHAPTER ONE: INTRODUCTION 1

Overview 1

Statement of the problem 3

Justification 5

Aim and Objectives 7

CHAPTER TWO: LITERATURE REVIEW 8

Introduction 8

Classification of fatigue 9

Indicators of fatigue 11

Factors responsible for pilot fatigue 12

Effect of fatigue on aircrew performance 17

Stress and fatigue in flying operations 19

Aircrew fatigue coping mechanisms 21

CHAPTER THREE: METHODOLOGY 32

Back ground to study area 31

Study design 32

vi

Study population 33

Sample size estimation 33

Data collection tools and techniques 35

Data analysis 39

Ethical Consideration 40

Limitation of the study 41

CHAPTER FOUR: RESULTS 44

CHAPTER FIVE: DISCUSSION 78

Conclusion 89

Recommendations 91

References 92

Appendix A: Questionnaire 104

Appendix B: In-depth interview guide for regulators/management 111

Appendix C: In-depth interview guide for aircrew 114

Appendix D: Registered airlines in with AOC 117

vii

ABBREVIATIONS

AMSL Above mean sea level

AOC Air Operators Certificate

ATC Air traffic control

ATPL Air transport pilot’s license

CPL Commercial pilot’s license

EEG Electro encephalogram

FAA Federal Aviation Authority

FAAN Federal airports authority of Nigeria

FAST Fatigue avoidance scheduling tool

FTL Flight time limitation

ICAO International Civil Aviation Organization

IFR Instrument flight rating

MMIA Murtala Muhammed international Airport

NASA National Aeronautics and Space Administration

NCAA Nigerian Civil Aviation Authority

NTSB National transport and Safety Board

SAFE System for Aircrew Fatigue Evaluation

UCL University College London

UN United Nations

viii

LIST OF TABLES

Tables Pages

Table 1: Socio-demographic characteristic of respondents 43

Table 2: Social history of respondents 44

Table 3: Occupational characteristics of respondents 45

Table 4: Emotionally stressful issues reported by respondents 47

Table 5: Reported commuting time among respondents 48

Table 6: Time of last episode of fatigue experienced by respondents 51

Table 7: Levels of physical fatigue experienced by respondents 52

Table 8: Levels of mental fatigue experienced by respondents 54

Table 9: Graded fatigue level of respondents 56

Table 10: Percieved effect of fatigue on flying tasks among captains 57

and co pilots

Table 11: Perception of performance on flight operations among captains 58

and co pilots in the last one month

Table 12: Respondents knowledge of fatigue coping mechanisms 59

Table 13: Utilization of the various coping mechanisms 62

Table 14: Respondents’ perception of effectiveness of coping mechanisms 63

Table 15: Association between respondents’ socio demographics 64

characteristics and fatigue level experienced

Table 16: Association between respondents’ occupational characteristics 66

and fatigue levels experienced

Table 17: Association between respondents’ smoking and fatigue 68

ix

Table 18: Association between respondents’ alcohol use and fatigue 69

Table 19: Association between respondents’ type of aircraft qualified on 70

and fatigue

X

LIST OF FIGURES

Figures Pages

Figure 1: Perception of respondents on the need for review of regulations

to reduce flying hours 49

Figure 2: Distribution of respondents who reported ever being fatigued 50

Figure 3: Distribution of respondents who have had cause to utilize coping

mechanisms 61

xi

SUMMARY

Introduction: Fatigue induced human error is a significant cause of accidents and

incidents in the aviation industry with major consequences for public health safety.

Fatigue is also the largest identifiable and preventable cause of accidents in air

transport operations. This study was carried out to determine the level of fatigue

being experienced by aircrew operating in Nigeria as well as their knowledge and

utilization of fatigue coping mechanisms.

Materials and methods: The study was a descriptive cross sectional study of aircrew

fatigue and coping mechanisms in the Nigerian aviation industry. All consenting

subjects were studied. Quantitative data were collected using a pre tested semi

structured , self administered questionnaire and were analyzed using Epi info and

winpepi statistical soft ware. In-depth interviews were also conducted on ten

representatives from both aircrew and regulators of the industry.

Results: A total of 190 respondents participated in the study and were made up of

86 captains, 50 co-pilots, 2 flight engineers and 52 flight attendants. Sixty nine

percent of all aircrew were fatigued . A higher proportion of aircrew deployed to long

haul duties were fatigued compared to those in short haul . Graded fatigue levels

showed that 53.7% of aircrew were mildly fatigued, 26.1% moderately fatigued and

20.2% were severely fatigued. Respondents knowledge of fatigue coping mechanism

was fair. Crew work rest/scheduling had the highest knowledge with 85.3% while

cockpit naps had the least knowledge with 28.9%.

xii

Regarding the utilization of these mechanisms, scheduling was the most utilized

(78.3%), followed by activity breaks (76.1%). The least utilized method was listening

to music (35.1%).

Conclusion: Fatigue levels were relatively high at 69% with a fair utilization rate of

fatigue coping mechanisms ranging between 35.1%-78.3% .

Recommendation: There is a need for regulations to establish appropriate flight

time limits which will be based on total duty time (commencing when aircrew report

for duty) and not based on number of sectors flown . In addition, the NCAA would

need to evolve better monitoring methods for both Airline operators and aircrew to

ensure they strictly adhere to regulations.

xiii

CHAPTER ONE

1.0 INTRODUCTION

1.1 Overview

Fatigue is defined as “an experience of tiredness, dislike of present activity, and

unwillingness to continue” or as a “disinclination to continue to performing the task at

hand and a progressive withdrawal of attention” from environmental demands.1 As a

‘gradual and cumulative process, fatigue reflects vigilance decrement and decreased

capacity to perform, along with subjective states that are associated with this

decreased performance.1 It diminishes the ability of the individual to perform a

particular task by altering alertness and vigilance ,together with the motivational and

subjective states that occur during this transition. As a consequence, there is reduced

competence and willingness to develop or maintain goal directed behavior aimed at

adequate performance.1

While there is no standard way to assess it, fatigue can be measured objectively as

well as subjectively. Objective fatigue measures focus on physiological processes or

performance such as reaction time or number of errors . Subjective ways to assess

fatigue include diary studies, interviews, and questionnaires. Often, questionnaires are

used in large scale studies because of their shortness and self report format.2,3 There

are certain tell tale signs or indicators of fatigue and these include delayed reaction

times, reduced vigilance, impaired hand-eye coordination, reduced ability for complex

decision making, reduced ability to communicate, poor team dynamics and risk of

micro-sleeps. These signs often form the basis for various validated self rating scales

used in the repetitive measurement of fatigue.2

Fatigue is a significant cause of accidents and incidents in a broad range of industries

including road transport, aviation, rail, sea-borne cargo, mining, manufacturing,

building, hospitality and healthcare. Worker’s susceptibility to fatigue is increased by

tasks where attention must be sustained for long period, and those which are long,

repetitive, paced, difficult, boring and monotonous.3 Fatigue has led to many human

errors. Mistakes made by fatigued shift workers in the early morning hours were

critical factors in the Chernobyl nuclear reactor meltdown in which lack of action by

shift workers in the early hours of the morning led to disastrous consequences.4 The

Exxon Valdez oil spill was caused primarily by the failure of the third mate to properly

manoeuvre the vessel because of fatigue and excessive workload. These incidents

had catastrophic consequences.4

Fatigue-induced human errors bring major consequences for public safety, as well as

for the workers involved. It has been estimated that in the U.S., fatigue contributes

to between 20- 40 per % of all commercial vehicle crashes, causing the loss of more

than 15,000 lives.5 Falling asleep at the wheel due to fatigue has been implicated in

24% of heavy-vehicle road accidents in South Africa .6 In Ghana, a survey of drivers

in some selected motor parks in Accra revealed that 10-20% of all single accidents

are caused by fatigue.6 Globally, it is estimated that 20% of all road traffic fatalities

are caused by driver fatigue.5

Extreme fatigue may cause a person to “disengage” briefly into a “micro-sleep”.

When this happens at a critical time, an accident may result. Micro-sleeps have been

observed in train drivers and airline pilots during periods of critical operations, with

the drivers and pilots sometimes being unaware that it was happening.7 These micro

sleeps often result in lapses in attention, slowed reaction time, increase in errors,

short-term memory impairment, lack of situational awareness, and impaired decision

making.7 Some studies have documented that effects of sleep loss can be likened to

the effects of alcohol consumption on the body often resulting in performance

decrements.6,7

Wakefulness prolonged by as little as three hours can also produce performance

decrements, while the consequences of even one to two hours of nightly sleep loss

over a week may result in decrements in daytime function leading to human error,

accidents, and catastrophic events. Working at night has a greater impact than

working the same number of hours in the daytime.8 Aircrew fatigue is a significant

problem in modern aviation operations, largely because of the unpredictable work

hours, long duty periods, circadian disruptions, and insufficient sleep that are

commonplace in commercial flight operations. This is due in part to the fact that an

escalation in the demand for aviation services has occurred.2

1.2 Statement of the Problem

The aviation industry requires twenty four hours a day activities to meet operational

demands. These round the clock requirements often puts a lot of pressure on aircrew

globally in both long and short haul operations.9 The Nigerian Aviation Industry is

currently experiencing steady growth in spite of the harsh economic climate. The

Federal Airports Authority of Nigeria (FAAN) reported that in 1998, domestic

passenger traffic stood at 3,093,000. It rose to 4,618,000 in 2000, and 6,424,000 in

2004 and by 2008, it had reached 10,993,647.9 This indicates an increase in demand

for air transportation which has been consistent in the past decade.

Aircrew must be available to support twenty four hours a day operations to meet the

demands of this growing industry. This poses a challenge to human physiology and

could have safety implications. Throughout aviation history, operational capabilities

and technology have evolved dramatically while human physiological capabilities have

not.10 Humans are central to aviation operations and continue to perform critical

functions to meet industry requirements. As a result the present contingent of pilots

face serious fatigue related difficulties associated with greater workloads and

heightened scheduling demands.3 Therefore, human physiological capabilities and

limitations remain crucial factors in maintaining safety and productivity in aviation.

While the full impact of this situation is presently unclear, accident statistics, aviator

surveys and expert opinions indicate that aircrew fatigue is a significant problem that

poses a serious threat to flight safety.3 A November 2007 report by the National

Transportation Safety Board indicates that air crew fatigue is a much larger, and more

widespread, problem than previously reported. The report indicates that from 1993 to

2007, there were 10 major airline crashes caused by aircrew fatigue around the

world, resulting in 260 fatalities. In a French study, 60% of Long Haul Flight pilots

and 49% of Short Haul Flight pilots reported being fatigued as evidenced by

reduction in alertness and attention, and a lack of concentration. 8,9

A 2011 report by British researchers revealed that Britain’s airline pilots are suffering

significant fatigue.10 Their report shows that of a sample of 492 pilots (two thirds of

them Captains), 45 per cent were suffering significant fatigue. Forty percent (40%)

found themselves having to fly more than the regulation hours at least twice a month

to cope with the volume of flights.10,11 In a similar study carried out in Taiwan, 75% of

short haul commercial pilots were reported to be severely fatigued. About 80% of

them also felt their judgment was impaired during flying.4

Pilot fatigue has steadily increased along with fatigue related concerns over air

safety.3 Accident statistics, reports from pilots themselves, and operational flight

studies all show that fatigue is a growing concern within aviation operations and that

fatigue is the largest identifiable and preventable cause of accidents in air transport

operations.4

1.3 Justification for the Study

The Nigerian Aviation industry is itself beginning to experience this increasing

competitiveness due to visible growth in the industry with more Airlines coming on

board and more routes opening up (both domestic and international).12 This in

addition to the drive for decent profits by airlines is likely to increase the work load

for aircrew and inevitably lead to higher levels of fatigue. Higher fatigue levels would

make the pilot more error prone thereby raising concerns about flight safety.7,13 This

study aims to examine the extent of aircrew fatigue in the rapidly evolving Nigerian

aviation industry with a view to proffering solutions.

Tired pilots are having an adverse effect on flight safety due to cognitive slowness,

concentration difficulties resulting in missing radio calls or navigational checkpoints

and error proneness.3 These effects have contributed to a growing number of

incidents and accidents in aviation.3,11

Several studies have highlighted both the presence of fatigue and its adverse effect

on aircrew performance.4,13 There is however a gap in terms of the availability of local

studies in capturing the Nigerian aviation industry’s experience concerning aircrew

fatigue. Information is also limited with regards to the utilization and perceived

effectiveness of fatigue coping mechanisms among aircrew. It is based on the need to

fill this gap and an interest in aviation and public health safety that this study was

conceived. The findings of this study will provide baseline data to make evidence

based decisions and design appropriate interventions.

1.4 OBJECTIVES

1.4.1 GENERAL OBJECTIVE

To assess the perception and occurrence of fatigue and the knowledge and utilization

of coping mechanisms among aircrew in the commercial aviation industry.

1.4.2 SPECIFIC OBJECTIVES

1.To assess levels of fatigue among aircrew in the commercial aviation industry in

Nigeria.

2. To determine the effect of fatigue on various aspects of flight operations among

aircrew in the commercial aviation industry in Nigeria.

3.To determine the level of knowledge of fatigue coping mechanisms in use during

flight operations among aircrew in the commercial aviation industry in Nigeria.

4. To determine the utilization of fatigue coping mechanisms during flight operations

among aircrew in the commercial aviation industry in Nigeria.

5. To determine aircrew perception of the effectiveness of fatigue coping mechanisms

in use during flight operations.

CHAPTER TWO

2.0 LITERATURE REVIEW

2.1 Introduction

Fatigue is an expected and ubiquitous aspect of life. For the average individual,

fatigue presents a minor inconvenience, resolved with a nap or by stopping whatever

activity that brought it on. Typically, there are no significant consequences. However,

if that person is involved in safety-related activities such as operating a motor vehicle,

piloting an aircraft, performing surgery, or running a nuclear reactor, the

consequences of fatigue can be disastrous.12

Defining fatigue in humans is extremely difficult due to the large variability of causes.

Causes of fatigue can range from boredom to circadian rhythm disruption to heavy

physical exertion.12 In lay terms, fatigue can simply be defined as weariness.

However, from an operational standpoint a more accurate definition might be:

“Fatigue is a condition characterized by increased discomfort with lessened capacity

for work, reduced efficiency of accomplishment, loss of power or capacity to respond

to stimulation, and is usually accompanied by a feeling of tiredness.12

One of the more widely accepted definitions in the industry is that given by the

International Civil Aviation Organization (ICAO) which defines fatigue as “A

physiological state of reduced mental or physical performance capability resulting from

sleep loss or extended wakefulness and/or physical activity that impair a crew

member’s ability to safely operate an aircraft.” 4

Fatigue in the aviation environment can be defined in terms of its symptoms which

consist of impaired mood, forgetfulness, reduced vigilance, poor decision making,

slowed reaction time, poor communication, nodding off or becoming fixated,

apathetic or lethargic. 4

Fatigue can develop from a variety of sources. The important factor is not what

causes the fatigue but rather the negative impact fatigue has on a person’s ability to

perform tasks.13 A long day of mental stimulation such as studying for an examination

or processing data for a report can be as fatiguing as manual labor. They may feel

different—a sore body instead of a headache and bleary eyes—but the end effect is

the same, an inability to function normally.13

Fatigue leads to a decrease in an individual’s ability to carry out tasks. Some studies

have demonstrated significant impairment in a person’s ability to carry out tasks that

require manual dexterity, concentration, and higher order intellectual processing.13,14

Fatigue may happen acutely, which is to say in a relatively short time (hours) after

some significant physical or mental activity or, it may occur gradually over several

days or weeks.13 Typically, this situation occurs with someone who does not get

sufficient sleep over a prolonged period of time (as with sleep apnea, jet lag, or shift

work) or someone who is involved in ongoing physical or mental activity with

insufficient rest.12

2.2 CLASSIFICATION OF FATIGUE

There are mainly three types of fatigue.

Physical Fatigue - Physical fatigue refers to various physical issues such as muscle

soreness, lack of oxygen, poor nutrition and tiredness often caused by lack of sleep or

illness.14

Mental Fatigue -It is associated with task demanding intense concentration,

cognitive information processing or other high cognitive skills. Such metal fatigue can

be seen in examples such as single pilot flying in Instrument Flight Rules (IFR) at

night. Mental fatigue can arise from prolonged activity as well.14

Emotional Fatigue-Emotional fatigue can be also known as ‘burnout’ which simply

refers to the wearying effect of working under psychologically disagreeable tasks. This

type of fatigue can be seen when individuals start complaining of boredom or

routine.14

In addition to the above classification, fatigue can also be grouped based on duration

of occurrence into acute and chronic fatigue.14 Acute fatigue is associated with

physical activity or mental activity between two regular sleep periods. The loss of both

coordination and awareness of errors are some of the first signs signaling the

development of fatigue.14 This tiredness is felt, for example, at night after being

awake for 12 to 15 hours in a day. With adequate rest or sleep, typically after one

regular sleep period, the aircrew member will overcome this fatigue.14,15 Acute fatigue

is characterized by inattention, distractibility, errors in timing, neglect of secondary

tasks, loss of accuracy and control, lack of awareness of poor performance, and

irritability.15

Chronic fatigue is much more serious than acute fatigue and it occurs over a longer

period of time, and is typically the result of inadequate recovery from successive

periods of acute fatigue.15 Besides physical tiredness, a mental tiredness also

develops. It may take several weeks of rest to completely eliminate chronic fatigue;

and there may be underlying social causes, such as family or financial difficulties, that

must be addressed before any amount of rest will significantly impact this person's

recovery.14 It is critical that the crew member or the airline authorities identify

chronic fatigue early and have the aviation medicine specialist treat the crew member

appropriately.14 Chronic fatigue is characterized by insomnia, depressed mood,

irritability, loss of appetite, weight loss, poor judgment, slowed reaction time, poor

motivation and performance on the job.15 If chronic fatigue proceeds untreated for

too long, the individual will eventually "shut down" and cease functioning. This is

called motivational exhaustion or burn out. 14,15

2.3 INDICATORS OF FATIGUE

Certain indicators serve as pointers to the onset of fatigue and these may include

difficulty in concentrating, a dull and sluggish appearance and an attempt to conserve

energy by reducing body movements to a minimum.16 Others include a careless

appearance, lack of coordination, confusion, irritability and cognitive deficits seen

before physical effects are felt.16 In general, fatigued individuals look less attentive,

move slowly, both physically and mentally and are at times confused.16 They may

also show an alteration in mood, either depressed or irritable and withdrawn. The

fatigued individual will often appear impaired to others before he or she is actually

aware of being physically fatigued. Consequently, it is important that crew members

watch each other for signs of fatigue when on operations where the threat of fatigue

is high.16

2.4 FACTORS RESPONSIBLE FOR PILOT FATIGUE

Pilots and aircrew members are constantly confronted with long duty days, early

departures, late arrivals, and non-standard work hours that include night duty and

rotating schedules. Thus, it has been suggested that aircrew fatigue is a function of

scheduling and workload.17

In many ways, pilots face fatigue factors similar to those encountered by industrial

shift workers except that pilots face many additional complications. Akersted points

out that when work hours are in conflict with human biological programming,

alertness impairments often result.18

The two primary components to be considered in this programming are (1) the body’s

circadian timing system or the body’s internal clock, and (2) the homeostatic

mechanism or recent sleep history (which includes the amount of time since the last

sleep period and the amount of prior sleep).18 There is a high degree of interaction

between the circadian and homeostatic factors that influence on-the-job alertness

from one time period to the next, as well as the quality of off-duty sleep that

underlies the ability to properly execute subsequent flight tasks. 5,18

2.4.1 Circadian Factors

There is a known biological propensity towards sleepiness and inactivity at night,

whereas arousal and heightened activation more naturally occur during the day.19

These physiologically-based phenomena are controlled by the suprachiasmatic nuclei

of the hypothalamus which drives self sustaining alertness and performance

rhythms.19 These rhythms peak in the late afternoon (during the day) and trough in

the predawn or early morning hours (at night). The body temperature rhythm, which

in shift workers often coincides with performance rhythms, peaks at approximately

5pm and dips at around 5am.20

Conversely, melatonin levels, which are inversely-related to alertness, tend to be

lowest at 4pm and highest at 4am.21 Similarly, there are a variety of other internal

rhythms that coincide with daytime alertness and night time sleepiness. For instance,

blood pressure and plasma adrenaline levels are higher during the day than at night

while plasma growth hormone and cortisol show the opposite pattern.22

A recent survey revealed that in-flight drowsiness is more problematic on night flights

compared to day flights, and electrophysiological evaluations have indicated that

micro sleeps in the cockpit are more frequent at night than during the day.22 In

addition, studies on pilots have shown that attention lapses and flight-control

deviations are more frequent and more severe when flights overlap the subjective

night times of crew members.22 Some researchers found that lapses on a probe

vigilance task during long-haul flight operations were approximately 5 times greater

during night time segments as during daytime segments.22 Furthermore, although

vigilance deteriorated simply as a function of time on task and the number of

consecutive flight segments, the rate of deterioration was steeper during night flights

than during day flights.23,24 Another group of researchers found that the majority of

fatigue-related flight incidents in one sample of NASA’s Aviation Safety Reports

System occurred between midnight and 0600 in the morning.25 Furthermore, a study

on circadian rhythm of pilots reported that simulator flight performance at 4am in the

morning degraded to 75–100% below what was typical at 3pm in the afternoon.25

Thus, the impact of circadian factors on pilots engaged in what might be considered

routine shift work is clear. These circadian factors are compounded by extended

periods of continuous wakefulness, but even under conditions of moderate to severe

sleep loss, the impact of the circadian timing system remains clear.26

Studies of flight performance in a variety of sleep-deprivation experiments have

shown that increases in fatigue-related degradations are clearly more problematic at

one time of day than another.27 It has been demonstrated that helicopter pilot

performance was intact at 0100 (after 17h of continuous wakefulness), but severely

degraded only hours later between 0500 and 1000 in the morning.27 Afterwards,

despite continuing sleep deprivation, performance actually tended to improve, but

never returned to baseline levels. This temporary improvement was most likely

because of the circadian-mediated afternoon increase in arousal that preceded a

subsequent worsening of performance. 27

2.4.2 Homeostatic Factors

The homeostatic regulation of sleep and wakefulness is primarily a function of two

factors. The first is the amount (and quality) of sleep obtained prior to a given period

of performance and the second is the amount of continuous wakefulness prior to the

period of performance.28 These factors are discussed as follows;

Sleep quality -Sufficient daily sleep, a key component in the homeostatic regulation

of alertness, is often one of the first casualties in aviation operations.28 In general

terms, pilots suffer from work-related sleep disturbances in the same manner as do

industrial shift workers who primarily complain about their sleep or the lack thereof.28

Needless to say, insufficient sleep is central to the homeostatically-based drowsiness

and inattention that is known to be problematic in shift worker operations. Similarly,

long-haul pilots and crew frequently experience shortened sleep, reduced sleep

efficiency, and/or changes in sleep architecture that prevent full recovery during the

layovers between flight segments.29,30,31

Furthermore, the sleep of these individuals is often compromised by late arrival and

early departures as well as by constant schedule or time-zone changes.32 Sleep after

eastward flights is particularly problematic in part because the rate of circadian

resynchronization is 50% slower following eastward transitions than after westbound

travel across multiple time zones.33,34 Following eastward time-zone shifts, sleep

patterns are more variable and fragmented primarily because limited layover periods

require crew members to attempt sleep at an earlier than normal biological time,

which is difficult to accomplish. In addition, an earlier than normal rise time on the

following morning creates a significantly shortened sleep period. 35

Short-haul pilots also experience duty-related sleep difficulties. Some researchers

reported that while on trips, the sleep onset of these individuals was delayed, the

sleep period was shorter than normal, and the wake-up time was almost an hour and

a half earlier than usual.36 Although the average duty day for these domestic

commercial pilots was 10 hours, a third of the duty days was greater than 12hours,

restricting the available time for sufficient off-duty sleep.36 Regional airline pilots (with

duty periods averaging 11 hours) and corporative/executive pilots (who average 9

hours per day) also routinely face this problem.37 While long-haul pilots associate their

on the-job fatigue primarily with night flights and jet lag, short-haul pilots attribute

their fatigue-related problems more to prolonged duty periods and early wakeup.37,38

Continuous wakefulness - Long duty periods obviously contribute to sleep

deprivation, and working around the clock is complicated by circadian factors.39

Simply remaining awake and on the job for 18 to 21 hours can produce performance

changes similar to those seen with blood alcohol concentrations of 0.05–0.08%.39

Some studies conducted in the US found that the probability of a commercial airline

accident increases significantly as a function of time on duty.12,40 Although only 10%

of pilot duty hours were found to exceed 10 hours in duration, 20% of all US

commercial aviation mishaps appear to occur at the 10th hour and beyond. Only 1%

of duty time exceeds 13 hours or more, but 5% of the mishaps occur within this time

frame. Such findings are disconcerting in light of the fact that several investigators

have reported continuous wakefulness periods ranging from 19 to 22 hours on

outbound international commercial flights.41,42,43

Also, duty days for domestic commercial pilots often reach 10 to 12 hours or more.44

Regional airline pilots sometimes average 11 hours per day and corporative/executive

pilots have been found to average 9 hours per day.18,45 Long duty cycles and

consequent lengthy periods of continuous wakefulness also occur in sustained military

operations where duty days sometimes extend beyond 20 hours and the mission itself

can be over 35 hours in duration.45,46 Thus, in addition to circadian disruptions and

acute or cumulative sleep deprivation, prolonged periods of continuous wakefulness

contribute substantially to pilot fatigue.45,46

2.5 EFFECT OF FATIGUE ON AIRCREW PEFORMANCE

The precise nature of fatigue is diverse and insidious. As fatigue increases, accuracy

and timing degrades, lower standards of performance are unconsciously accepted, the

ability to integrate information into a meaningful overall pattern is degraded and a

narrowing of attention occurs that leads to forgetting or ignoring important aspects of

tasks.47

Generally, as sleepiness increases, performance becomes less consistent, especially

during the night hours.48 Problem solving and reasoning are slower than normal while

psychomotor skills are also diminished.47 It has been suggested that the ability to

assess risk degrades with increasing sleep loss, and that individuals become less

concerned with negative consequences.48 In addition, the fatigued individual tends to

withdraw from social interaction with others, especially in a highly automated

environment, and the ability to effectively divide resources between tasks is lost .47 All

these aspects of performance are integral to the effective functioning of individuals

performing complex tasks, such as operating aircraft.47,48

It has been reported for many years that mood changes also occur with sleep

deprivation.17 The reduced ability to control mood and behavior is reflected in the

reports of increased irritability, impatience, reduced social inhibitions, inappropriate

interpersonal behavior and childlike humour.17 It has been shown that mood is more

negatively affected when the tasks being performed are more demanding and

complex.17 It has also been well demonstrated that the biological limits imposed by

fatigue will impair the performance of even the most highly skilled and motivated

individuals13. The effects of fatigue cannot be overcome by training or experience. In

addition, the impact of fatigue cannot be negated by monetary or other incentives.13

Fatigue causes pilots during flying operations to become preoccupied with one task at

the neglect of other tasks often leading to a degrading of situational awareness and

reduced alertness and vigilance.47 The all important task of monitoring and scanning

the flight environment then becomes compromised.47 Furthermore, feelings of

indifference or carelessness to operational performance or the outcome of the flight

leading to acceptance of lower standards of performance is commonly observed.47 In

some instances, communication is hampered leading to poor crew coordination and an

ineffective crew resource management practice .47

Severe Fatigue among aviators can also lead to increased feelings of difficulty in

carrying out flight activities.48 This may cause a pilot to ignore important tasks due to

the perception that the tasks are too difficult to manage.48 There is a Degradation in

flying and perceptual-motor skills such as hand-eye coordination.48 This can slow

down reaction time or sensitivity to time on task leading to inconsistent

performance.48 Short term memory loss and inability to recall information from long

term memory may cause a pilot to forget important Air Traffic Control (ATC)

information and also result in an inability to integrate information efficiently.48 In

addition, micro sleeps which is the result of stress and fatigue can cause a brief

disengagement from the flight environment with potentially catastrophic

consequences.48

Fatigued aircrew may also suffer from impaired judgment, illogical reasoning and

poor decision making ability.49 For example, difficulty processing critical information

and choosing among alternatives may lead to optimum response decrements or

degradations in response accuracy. 49 Impaired ability to judge performance of self

and performance of other crew members does occasionally occur leading to difficulty

in recognizing performance impairment and dangerous situations.49 Fatigued pilots

are unable to recognize quickly enough when a situation is deteriorating and when an

original plan of action is no longer appropriate to that situation and must be

changed.49

Studies have shown that a cause and effect relationship does exist between pilot

fatigue and vulnerability to pilot error.50 These studies are supported by accident

reports citing pilot fatigue as a cause. Examples include Korea Air flight 801 at Guam

International Airport in 1999 and American International flight 808 at Guantanamo

Bay, Cuba in 1993. Others are a DHC 8-400 at Buffalo in 2009, Boeing 737-800 at

Keflavik in 2004, a Learjet in San Bernardino in 2004 and a host of others. All of these

mishaps had a very heavy casualty toll. 1,11,51

2.6 STRESS AND FATIGUE IN FLYING OPERATIONS

Stress and fatigue in flight operations adversely affect mission execution and aviation

safety. Consequently, aircrew members must be familiar with the effects of stress and

fatigue on the body and how their behavior and lifestyles may reduce or, alternatively,

increase the amount of stress and fatigue that they experience. 48

Stress is the nonspecific response of the body to any demand placed upon it. About

1926, an Austrian physician identified what he believed was a consistent pattern of

mind-body reactions that he called "the nonspecific response of the body to any

demand." He later referred to this pattern as the "rate of wear and tear on the body."

In search of a term that best described these concepts, he turned to the physical

sciences and borrowed the term "stress." 48 His definition incorporates two very

important basic points: stress is a physiological phenomenon involving actual changes

in the body’s chemistry and function, and stress involves some perceived or actual

demand for action.48

A lot of the stress is triggered by stressors. A stressor is any stimulus or event that

requires an individual to adjust or adapt in some way—emotionally, physiologically, or

behaviorally. Stressors may be psychosocial, environmental, physiological, and

cognitive. Psychosocial stressors are quite important and are typically encountered by

aircrew. 48 Psychosocial stressors are life events such as job stress, Illness and family

issues. These stressors may trigger adaptation or change in one’s lifestyle, career,

and/or interaction with others. 48

Work responsibilities can be a significant source of stress for aircrew members.

Regardless of job assignment, carrying out assigned duties often produces stress.

Conflict in the workplace, low morale and unit cohesion, boredom, fatigue, over

tasking, and poorly defined responsibilities are all potentially debilitating job

stressors.48 Aircrew members who lack confidence in their ability or who have

problems communicating and cooperating with others experience considerable stress.

Faulty aircraft maintenance also imposes stress on the aviator. Flight crews may not

trust those who service their aircraft to perform proper maintenance. As a result, crew

members may experience anxiety during flight operations that adversely affects the

cohesion and morale of the aviation unit.48

Although the family can be a source of emotional strength for crew members, it can

also cause stress. Family commitments may adversely affect performance, particularly

when duty assignments separate crew members from their families. The crew

member’s concern for family may become a distraction during flight operations or

increase fatigue or irritability. The potential dangers of flight operations also act as a

stressor on families and may cause tension in spousal relationships. This is

particularly the case for the families of new, inexperienced personnel.48

2.7 AIRCREW FATIGUE COPING MECHANISMS

Scheduling demands and human physiological makeup are at the heart of fatigue-

related problems in aviation. The multiple flight legs, long duty hours, limited time off,

less-than-optimal sleeping conditions, and jet lag that have become so common

throughout modern aviation pose significant challenges for the basic biological

capabilities of pilots and crews.50 Humans simply were not designed to operate

effectively on the pressured 24/7 schedules that often define today’s flight operations,

whether these consist of short haul commercial flights, long-range transoceanic

operations, or around-the-clock military missions.50 Because of this, a well-planned,

science-based, fatigue-management strategy is crucial for fighting the acute sleep

loss, the sustained periods of wakefulness, and the circadian factors that are primary

contributors to fatigue-related flight mishaps.50

First, educational efforts are essential for ensuring a thorough understanding of the

causes and effects of aircrew fatigue, and second, scientifically valid fatigue

countermeasures are indispensable for matching human capabilities to increasingly-

difficult job pressures.50

2.7.1 Education

Education about the dangers of fatigue, the causes of sleepiness on the flight deck,

and the importance of sleep and proper sleep hygiene is one of the keys to addressing

fatigue in operational aviation contexts.50 Ultimately, the pilots themselves and those

scheduling routes and missions must be convinced that sleep and circadian rhythms

are important and that quality off-duty sleep is the best possible protection against on

the job fatigue.50,51 Recent studies have made it clear that as little as 1 to 2 hours of

sleep restriction almost immediately degrade vigilance and performance in subsequent

duty periods. 52,53

Regular educational programs should continue to educate aircrews on the fact that

fatigue is a physiological problem that cannot be overcome by motivation, training, or

will power.52 In addition, it should be emphasized that people cannot reliably judge

their own level of fatigue-related impairment and that there are wide individual

differences in fatigue susceptibility that cannot be reliably predicted.50 There is no

one-size-fits-all ‘magic bullet’ (other than adequate sleep) that can counter fatigue for

every person in every situation. 53

Aircrew and schedulers should ensure that adequate off-duty sleep is given the

priority it deserves.53 Aircrew need at least 8 hours of sleep per day either in a

consolidated block, or in a series of naps whenever possible and adhere to good sleep

habits to optimize sleep quantity and quality.53

2.7.2 On- board Sleep

One technique for minimizing the impact of sleep loss and continuous duty is the

implementation of short out-of-cockpit sleep opportunities (known as ‘bunk sleeps’).

These sleep periods are extremely helpful for sustaining the alertness and

performance of long-haul crews.53 When in-flight bunk sleep is implemented, one or

more pilots retire(s) to a specially-designated area in the passenger compartment for

a sleep break while other qualified crew members maintain control of the aircraft.53

For commercial pilots in the United States, the Federal Aviation Administration (FAA)

requires augmented crews (at least 3 pilots) and on-board rest facilities for flights

longer than 12 hours so that pilots can partially attenuate the homeostatic sleep drive

between take-offs and landings.49,51

Depending on the length of the flight and the number of crew members on board,

bunk-sleep periods can range from 2 to 4 hours in duration. 39 They are scheduled

only during the cruise segment of the flight since this is a time of relatively-low work

load. In some military operations, an out-of-cockpit sleep strategy can be

implemented in multi-crew aircraft. 39

2.7.3 Cockpit Naps

A strategy related to out-of-cockpit bunk sleep is the cockpit nap. When cockpit naps

are implemented, one pilot actually sleeps in his/her cockpit seat (rather than moving

to another part of the aircraft) while the other pilot flies the aircraft.53 Many

international airlines now utilize cockpit napping on long flights, and cockpit napping is

sometimes authorized for US military flight operations as well.53 A 1994 NASA study

has shown that naps of up to 40 minutes in duration are both safe and effective for

long-haul pilots.54 However, cockpit napping has not yet been approved for US

commercial aviators despite the fact that the general public in the US has indicated

support for cockpit napping as an in-flight fatigue-mitigation strategy. 55

2.7.4 Controlled rest breaks

Tasks requiring sustained attention, such as monitoring aircraft systems and flight

progress, can pose significant problems for already-fatigued personnel.56 This is in

part why pilots often implement some type of work break strategy to help sustain

alertness during lengthy flights. There is evidence from some fatigue studies that

frequent rest breaks can improve physical comfort and reduce eye strain during

prolonged, repetitious tasks. 56,57 Other studies have also shown that simply offering

pilots a 10 minute hourly break during a 6 hour simulated night flight significantly

reduced slow eye movements, theta-band activity, unintended sleep episodes, and

subjective sleepiness ratings.57 Although positive benefits were transient lasting

between 15 to 20 minutes, they were noteworthy and particularly evident near the

time of the circadian trough.57

Rest breaks it would seem are helpful, but it may be that their effectiveness is

partially attributable to physiological factors as well as to the temporary relief of

mental boredom or physical discomfort. 57 In a study conducted in North America,

researchers found that simply assuming a more upright posture, as opposed to

remaining seated, reduced the amount of slow-wave EEG activity and enhanced

performance on a 10 minute vigilance task during the later part of a 28 hour sleep-

deprivation cycle. 58 It appears that periodic breaks involving nothing more than

simply leaving the flight deck and conversing with other crew members during long-

duration flights can help to sustain alertness in the cockpit.58,59

2.7.5 Optimum crew work-rest scheduling

Since scheduling factors are often cited as the number one contributor to pilot fatigue,

the development and implementation of more ‘human centered’ work routines should

be considered paramount for promoting on the job alertness.55 However, crew

scheduling practices in aviation have yet to incorporate the advanced knowledge of

fatigue, sleep, and circadian rhythms that has been gained over the past 20 years.59

Efforts need to be made to develop schedules that recognize sleep as being essential

for optimum functioning.

Breaks are also important for preserving sustained attention, while recovery periods

during each work cycle as being necessary to ensure full recovery from fatiguing work

conditions.25 In addition, crew schedules should include weekly recovery days to

ensure recuperation from cumulative fatigue. Scheduling practices ought to take into

account the facts that circadian factors influence both sleep and performance factors.

Under certain conditions, these two factors can interact to create sudden and

dangerous lapses in vigilance.53 Also, it must be recognized that training,

professionalism, motivation, and increased monetary incentives will have little impact

on the basic physiological nature of circadian and homeostatic determinants of

operator alertness.54

It is important to note that flight crews are made up of individuals who are

differentially affected by sleep disruptions, long duty periods, circadian rhythms, and

other potentially problematic factors.25 Thus, ‘one size fits all’ scheduling practices will

not meet the needs of all aircrew.

New computerized scheduling tools such as the Fatigue Avoidance Scheduling Tool

(FAST) and the System for Aircrew Fatigue Evaluation (SAFE) can ease the process of

developing and implementing new schedules by allowing planners to better appreciate

the impact of fatigue inducing factors and the potential benefits of appropriate

counter-fatigue strategies.60,61 Once validated across a wide array of aviation

applications, these easy-to-use computerized scheduling tools will no doubt contribute

to successful aviation alertness management.

2.7.6 Melatonin and bright light

Both melatonin administration and bright light exposure may help to overcome jet lag

and shift lag in aviation operations involving rapid schedule changes. 62 With regard to

melatonin, there is a substantial amount of research which indicates that appropriate

administration of this hormone can improve circadian adaptation to new time

schedules.22 There also is evidence that melatonin possesses weak hypnotic

properties that may facilitate out-of-phase sleep.62 Since melatonin is not considered

a drug, it is widely available for use with few restrictions. Melatonin use is however

controversial as improper use could lead to alertness and performance decrements.62

In the light of this, leading researchers in aviation fatigue concluded that ‘melatonin

use is unacceptable for aviators.63 Melatonin is currently not an approved substance

for use in military aviation.63

Properly-timed bright light is an alternative strategy for resynchronizing circadian

rhythms after schedule changes, but the proper intensity, timing, and/or duration of

bright light exposures remains difficult to determine.64 However, the difficulties in

appropriate timing of both methods suggest that perhaps the safest self administered

resynchronization strategy is to use natural sunlight exposure and nap.65

While pilots suffering from shift lag may not be able to take advantage of a similar

strategy, they can at least be cautioned to avoid light exposure (or to minimize it with

very dark glasses) before a period of daytime sleep. 65

2.7.7 Sleep-promoting compounds

When sleep opportunities are available but compromised due to operational factors,

the hypnotics temazepam, zolpidem, and zaleplon are usually considered.53 Although

the use of prescription (and over-the-counter) hypnotics and sedatives is discouraged

throughout aviation, they are sometimes authorized to enhance pre-mission or

recovery sleep on the ground (hypnotics are never authorized for the promotion of in-

flight naps or rest periods).53 In the US, the Federal Air Surgeon recently approved the

ground use of zolpidem as long as it is not administered more than twice a week or

within 24h of flight; however, zolpidem cannot be used in overcoming circadian

disruptions.66 In military aviation, the use of hypnotics is slightly more liberal, and in

this context, temazepam, zolpidem, and zaleplon are all three occasionally

authorized.66 Choosing the best hypnotic for each situation requires consideration of a

variety of factors.

From a strictly pharmacological standpoint, temazepam is best for maintaining sleep

for relatively long periods during the night and/or for optimizing the daytime sleep of

night working personnel.66 The facilitation of daytime sleep with temazepam resulted

in improved performance during subsequent night time simulator flights.66 Zolpidem

and zaleplon are better for promoting an earlier-than usual sleep onset in preparation

for early morning wake ups or for inducing and maintaining short naps.

Since both compounds have shorter half lives than temazepam, the probability of

post-sleep sedation is reduced.66 It was found that both mood and performance

during a sustained period of wakefulness was bolstered more by a zolpidem-induced

prophylactic nap than by a ‘natural’ nap or a simple rest period. Zolpidem prolonged

the sleep during the 2 hour sleep opportunity by almost 30minutes .67 In general,

hypnotics can help to minimize sleep disruptions associated with circadian factors (jet

lag and shift lag), and with proper planning, they can be used without undue concern

about post-sleep hangover effects. 67

The choice of compound depends on when the new sleep opportunity becomes

available and whether there is a high probability that the sleep period will be

unexpectedly truncated as is sometimes the case with military aviators.67 As it is

sometimes difficult to make such determinations, with the exception of some military

applications, the use of hypnotics is discouraged or often completely banned within

the aviation context.66,67

2.7.8 Alertness-enhancing compounds

When sleepiness becomes a problem in the flight environment, caffeine is often used

as the ‘first line’ pharmacological fatigue countermeasure in both civil and military

aviation.66 Numerous studies have shown that caffeine increases vigilance and

improves performance in sleep-deprived individuals, especially those who normally do

not consume high doses of caffeine.66,68

In commercial aviation, caffeine (generally in the form of coffee, tea, or soft drinks)

and some ‘dietary supplements’ are the only alertness-enhancing substances allowed,

whereas in military aviation, prescription alertness-enhancing medications are

periodically authorized, particularly for lengthy missions during continuous and

sustained operations.68 The most widely used prescription stimulant within military

aviation contexts is dextroamphetamine, a compound with powerful, reliable, and safe

alertness-sustaining effects.28 Properly-administered dextroamphetamine has been

shown to sustain pilot performance at near well-rested levels for over 50–55 hours

without sleep.28 It is for this reason that the US military has authorized the use of

Dexedrine at various times since World War II. More recently, modafinil has been

introduced into limited aviation operations.68

In December 2003 modafinil was authorized for use in extended Air Force dual-crew

bomber missions. Although modafinil has not been as well-tested in operational

contexts as dextroamphetamine, two studies to date have shown that it is capable of

significantly attenuating fatigue-related decrements in pilot performance throughout

30 to 40 hours of continuous wakefulness.28,68 The attractiveness of modafinil over

dextroamphetamine is that it has relatively low abuse potential, and it produces few

cardiovascular side effects.28 However, both medications can be life-saving in

sustained aviation operations devoid of sleep opportunities. Both modafinil and

dextroamphetamine are carefully regulated by trained physicians (flight surgeons),

and they are used only when all other counter-fatigue strategies have been

exhausted.68

CHAPTER THREE

3.0 METHODOLOGY

3.1 Background to the study area

This study was carried out in the Murtala Muhammed International Airport (MMIA)

Lagos. It involved local Airlines operating both domestic and international flights who

also use MMIA as their hub. Murtala Muhammed International Airport is located in

Ikeja, Lagos State, Nigeria and it is the major airport serving the city of Lagos,

southwestern Nigeria and the entire nation. Originally known as Lagos International

Airport, it was renamed midway during construction after a former Nigerian military

head of state Murtala Muhammed. The international terminal was modeled after

Amsterdam's Schiphol Airport. The airport opened officially on 15th March 1979. It is

the main base for Nigeria's flag carrier airlines, Air Nigeria and Arik Air.11 The airport

is run by the Federal Airports Authority of Nigeria (FAAN), while the Nigerian civil

aviation authority (NCAA) is responsible for Regulation of safety of aircraft

operations, air navigation and aerodrome operations.69

Murtala Muhammed International Airport which lies within coordinates 06°34′38″N

003°19′16″E consists of an international and a domestic terminal, located about

one kilometer from each other. Both terminals share the same runways. The runways

are made of asphalt, with the longer one measuring 12,794 ft with direction

18R/36L, while the other measures 8,999 ft with direction 18R/36L. The airport

elevation above mean sea Level (AMSL) is 135 ft.

The present domestic terminal used to be the old Ikeja Airport. International

operations moved to the new international airport when it was ready while domestic

operations moved to the Ikeja Airport, which became the domestic airport. The

domestic operations were relocated to the old Lagos domestic terminal in 2000 after a

fire. A new domestic privately funded terminal known as MMA2 has been constructed

and was commissioned on 7 April 2007. In 2009, the airport served over 5.5 million

passengers.11 The Federal Government has given approval for the expansion of the

departure and arrival halls of the MMIA to accommodate the ever increasing traffic at

the airport. The airport includes the headquarters of the Federal Airports Authority of

Nigeria (FAAN). The Lagos office of the Nigerian Civil Aviation Authority (NCAA) is

located in Aviation House on the grounds of the airport.

Between 2003 and 2008, there was a 23.4% increase in passenger traffic. Total

aircraft movement also increased from 62,439 to 84,588 flights during the same

period and by 2009, it had reached 192,828.11 About 16 local airlines with Air

Operator Certificates (AOC) issued by the NCAA are authorized to operate flights in

the Nigerian aviation industry. Of the 16 airlines, 13 have MMIA as their hub and thus

have the bulk of their operations based in the Lagos area.

3.2 Study Design

The study design was a descriptive cross sectional study.

3.3 Study population

This consists of individuals who are licensed pilots, flight engineers and cabin crew

working with local commercial airlines and are involved in flight duties in both the long

and short haul categories. According to the NCAA, there are over 250 registered

aircrew in both the long and short haul categories. 70

Inclusion Criteria

Licensed local and expatriate pilots, flight engineers and cabin crew in active

service over the last 6 months in the local aviation industry .

Exclusion Criteria

Military/Combat pilots- Military pilots have rigorous flying schedules and are

exposed to stressors distinct from what is experienced in commercial aviation.

Some military aircraft types also differ in configuration from the conventional

commercial jets .

Expatriate pilots working for foreign airlines that commute into Nigeria – This

category of aircrew operate from different locations under a separate sets of

regulations and flying conditions and are therefore not eligible.

Pilots in the presidential air fleet- The presidential air fleet does not schedule

flights like it is done in the commercial aviation sector. The flights are fewer

and are taken by military pilots.

Pilots of smaller aircraft owned by individuals and used privately- Pilots of

smaller private airplanes are more likely to operate fewer flights and would

therefore not be exposed to the rigors of commercial aviation

Nigerian pilots working for foreign based airlines- These individuals though

Nigerians operate from foreign locations under conditions distinct from those in

operation in Nigeria and so do not qualify.

Pilots who work for local airlines which are not yet fully operational- There are

some new airlines who have not fully commenced operations yet but operate

occasional charter flights. Their pilots are not fully exposed to the commercial

aviation industry.

3.4 Sample size Estimation

The minimum sample size estimation was determined by applying the formulae for

descriptive studies with populations less than 10,000.71 No known previous study has

been done on aircrew fatigue in the Nigerian civil aviation industry therefore, a

prevalence rate of 50% was used to determine the minimum sample size using the

formula below:

n=Z2pq

d2

Where:

n= the desired sample size

z= the standard normal deviate i.e. 1.96 at 95% confidence interval

p= prevalence rate (50% or 0.5)

q= 1.0 – p (which is 0.5)

d= degree of accuracy or margin of error (0.05)

n = (1.96)2 (0.5)2 (0.05)2

n = 384

Since N, the entire population of registered aircrew was less than 10,000, the final

sample estimate (nf) is :

nf = n 1 + n

(N)

Where:

nf= the desired sample size (since the population is less than 10,000)

n = sample size when population is more than 10,000

N = estimate of the population size

384 1 + 384 250

384 2.54

= 151.18 approximately 151.

In view of the relatively small size of the total study population, all respondents who

consented were studied. 71 Consequently total sampling was carried out.

3.5 DATA COLLECTION TOOLS AND TECHNIQUES

Data was collected using quantitative and qualitative techniques.

3.5.1 Quantitative data techniques

A pre-tested, semi structured, validated, self administered questionnaire was used for

quantitative data collection.72,73 The questionnaire was adopted from the Fatigue in

Aeronautics scale, a validated self rating instrument developed by Aircraft

manufacturer Airbus in conjunction with Universite Rene Escartes and the chadler

fatigue scale .72,73 The adopted instrument was slightly modified to cover the specific

objectives of the study.

The questionnaire consisted of five sections lettered A to E .

Section A : This section obtained the demographic and social characteristics which

included age, sex, marital status, religion, smoking, alcohol consumption,

employment category and time spent commuting to and from work daily .

Section B : Occupational information which includes the area of specialty, duration of

practice in specialty, number of flying hours logged so far was obtained in the second

section of the questionnaire.

Section C: This section measures responses to 10 items related to Physical fatigue

and 10 items for mental fatigue thus allowing for a rating of overall fatigue levels

among aircrew .72,73 For each measured item, the respondent was asked to report

his/her perceived fatigue level with respect to the statement by choosing a number

from 0 to 4, with 0 standing for none, 1 for small, 2 for moderate, 3 for high, and 4

for very high.

Section D: This section looked at how fatigue hinders performance on various flying

tasks. Performance on 9 kinds of these tasks was rated using a scale of not at all,

mildly, moderately and a great deal.73

Section E : In this section, questions regarding the utilization and perception of

fatigue coping mechanism were assessed. The perceived effectiveness of these

mechanisms was also looked at using a scale of high, moderate, low and don’t know

over a series of 11 options. 73

3.5.2 Qualitative data techniques

In-depth Interviews were used for qualitative data collection. Meetings were set up

with some of the stake holders in the industry as well as aircrew with a view to

acquiring better insight into issues of fatigue, demands of duty and rest scheduling

from various stakeholders. Two sets of protocol each with 12 questions were used for

the interviews. (see appendices B and C) There were slight variations to suit the

peculiarities of both the aircrew and the regulators. These protocols guided the

administration and implementation of interviews to ensure consistency and thus

increase the reliability of the findings.

The following persons were interviewed

Director general , NCAA

Director of licensing, NCAA

Deputy General manager (Aero medicals) NCAA

Chief Pilots of Aero contractors and Arik Air

One Aircrew representative (pilots) from Aero contractors, Arik Air , First

nation airways, Dana Air and Associated aviation.

3.5.3 Pre testing of questionnaire

The questionnaire was pretested on 15 military transport pilots of the Nigerian Air

Force Mobility command’s 201 Heavy Airlift Group, Lagos. The in depth interview

protocols were also pre tested on the same group. The pretest was carried out to

assess the readability, ease of understanding and to assess the completion time of the

questionnaire. Findings from the pretest were used to modify the instruments as

appropriate.

3.5.4 Quantitative data collection

Data collection for the study spanned over 4 months from December 3rd 2011 to

March 30th 2012.

Prior to the commencement of data collection, concerted efforts were made to

sensitize the various airline managements about the study and to solicit for access to

the various category of aircrew. The questionnaires were administered in the privacy

of the crew rooms of the various airlines within the vicinity of both the local and

international airports. Aircrew were approached in their crew rooms before and after

flights. Those coming to their airline offices to attend to various administrative

concerns were also approached to fill the questionnaire. One in-house administrative

staff in each of the airlines was recruited to assist with questionnaire distribution and

collection. (Access for research assistants from outside the industry could not be

guaranteed by the airlines in view of the prevailing security challenges in the

country). The questionnaires were distributed in unmarked envelopes and returned

sealed. They were retrieved immediately they were filled. For Participants who were

unable to answer the questionnaire immediately, marked boxes with slit holes were

provided in the crew rooms for their convenience. The boxes were emptied daily by

the in-house research assistants over the duration of the study. Where necessary, the

research assistants followed up on aircrew in their airlines to enhance the collection of

filled instruments.

3.5.5 Qualitative data collection

A total of 10 individuals were selected for the in-depth interview. They were all

approached about 2 weeks earlier to fix appointments for days that were convenient

for them. At the appointed dates, the various stake holders were briefed in detail on

the purpose of the interview, the reasons for their inclusion in the study and the

expected duration of the interview. The interviews were meant to ascertain levels of

compliance by the airlines and enforcement efforts being made by the NCAA. The

views of aircrew concerning fatigue coping mechanisms and other related issues were

also sought.

A written informed consent was obtained from each interviewee before the

commencement of the interview. Permission was also sought to take notes and for the

use of a tape recorder. Participants were assured that information received would be

treated in confidence. Names of individuals or their respective organizations were not

used during the transcription and review of data.

3.6 Data Analysis

The analysis of data obtained from this survey was done using the Epi info version

3.5.1(2008) and Winpepi statistical softwares . Analyzed data were presented in form

of frequency tables, cross-tabulations and pie charts. Pearson’s chi-squared test and

Fisher’s exact test were employed to test for association between categorical

variables. A p value < 0.05 was considered statistically significant. 72 Fatigue was

measured using the Fatigue in Aeronautics scale in which a maximum score of 80 is

obtainable with 40-48 being graded as mild fatigue, 49-56 as moderate and 57 and

above as severe fatigue.72,73

In the analysis of the results of the in depth interviews, the information collected from

the various participants were compared. The tape recordings of the interviews were

transcribed and organized under thematic headings. Content analysis was employed

to identify responses and findings were noted. Where necessary, quotes from the

respondents were included to give credence to the results. On grounds of

confidentiality, efforts were made to ensure that respondents were not identifiable

from their quotes. The interview records were transcribed within 24 hours of the

conduct of an interview.

Indicators

Proportion of aircrew who perceived they were fatigued

Proportion of aircrew who perceived that their performance on various flying

tasks was affected by fatigue

Proportion of aircrew who had knowledge of fatigue coping mechanisms used

during flight operations.

Proportion of aircrew who perceived fatigue coping mechanisms to be effective.

3.7 ETHICAL CONSIDERATION

3.7.1 Ethical approval

The study proposal was approved by the Research and Ethics Committee of Lagos

University Teaching Hospital, Idi-Araba before the commencement of the study. (See

attached) Permission was obtained from the managements of the NCAA, FAAN and

managements of all the airlines to carry out the study.

3.7.2 Individual Informed Consent

A written informed consent was attached to each questionnaire. The respondents

were assured of the highest level of confidentiality on information given and

individual names or names of their respective airlines were not be required.

Respondents were informed of their right to opt out of the study at any point they

choose to if they so desired. A similar consent form was also used in the conduct of

the in depth interviews.

3.8 Limitations of the Study

1.Assessement of Aircrew Fatigue levels was based on self reported symptoms by the

respondents.

2. The study required the recall of fatigue related experiences by respondents giving

room for recall bias.

3. Some of the questions were sensitive with implications for flight safety and thus

might have been under reported.

CHAPTER FOUR

RESULTS

A validated semi structured and self administered questionnaire was used to collect

data from respondents who are captains ,co-pilots ,flight engineers and cabin crew in

the aviation industry. In total, 231 questionnaires were distributed with 190 returned

giving a response rate of 82.2%.

TABLE 1: SOCIO-DEMOGRAPHIC CHARACTERISTICS OF RESPONDENTS

Variable Frequency (n=190) Percent %

Sex

Male 145 76.3

Female 45 23.7

Age Group

24 and below 9 4.7

25-34 76 40.0

35-44 32 16.8

45–54 51 26.8

55 and above 22 11.6

Mean Age (yrs) 45. 5 ± 11.6

Marital Status

Single 71 37.4

Married 112 58.9

Others (Divorced / Separated/ Widowed) 7 3.7

Religion

Christianity 150 78.9

Islam 29 15.3

Others (Atheists, Traditionalists) 11 5.8

Nationality

Nigerian 132 69.5

Non Nigerian 58 30.5

Most of the respondents (76.3%) were male. The population had a mean age of 45.5 ±11.6 .

Age group 25-34 had the highest number of aircrew at 40% while those less than 24 years

had the least representation at 4.7% of respondents. About 59% were married while

foreigners accounted for over 30 % of the study population.

TABLE 2: SOCIAL AND MEDICAL HISTORY OF RESPONDENTS

Social and Medical history Frequency Percent %

Smoking Status (Tobacco) (n=190)

Yes 19 10.0

No

No response

170

1

89.4

0.6

Alcohol Consumption (n=190)

Yes 88 46.3

No 102 53.7

Currently on Medication (n=190)

Yes 27 14.2

No 163 85.5

Type of Medication Currently on (n = 27)

Anti-hypertensive 16 58.1

Anti-diabetic 4 15.4

Anti malaria 4 15.4

Others (e.g. Antibiotics, analgesics) 3 11.1

Nineteen (10%) of respondents were smokers while 46.3% take alcohol. A little over 14% of

the respondents were on medication. Of this number, more than half (58.1%) are on anti

hypertensives, while 4 (15.4%) were on anti diabetic medication.

TABLE 3 : OCCUPATIONAL CHARACTERISTICS OF RESPONDENTS

Occupational Characteristics Frequency

(n=190)

Percent %

Current Function

Captain 86 45.2

Co-pilot 50 26.3

Flight engineer 2 1.1

Cabin crew 52 27.4

No. of Years in current position

<10 136 71.6

10-20 32 16.8

>20 22 11.6

Mean No. of years in current position 8.5 ±9.0

Nature of flying duty

*Short haul 133 70.0

*Long haul 57 30.0

Aircraft Type qualified on

Helicopter 43 23.9

Heavy jet engine 110 58.5

Light jet engine 30 16.0

Light propeller engine 3 1.6

Type of Professional license held

Air Transport Pilot License 93 48.9

Commercial Pilot License 44 26.8

Flight Engineer License 2 23.2

Cabin crew License 51 1.1

Mean number of years professional license held

10.7 ± 9.9 SD

Mean No. of Hrs flown daily in The last month 8.6 ± 5.2

Maximum No. of Flying Hrs/day recommended

by aircrew

6.5 ± 3.8

*Short haul flights are those lasting about 2 hours per leg and are usually domestic routes

while long haul flights last over 5-6 hours and are often international routes.

Captains were in the majority and made up over 45 % of respondents while flight engineers

were only 1.1%. The bulk of the respondents (71.6%) have spent less than 10 years 11.6%

have spent over 20 years in their current positions. Most air crew ( 70%) were deployed to

short haul duties while the remaining 30% are in the long haul category. The Respondents are

type rated on various aircraft types with 58.5% deployed to heavy jet engine aircraft.

Concerning change of regulations, 41% of aircrew believe there is a need to change

regulations to reduce flying hours.

TABLE 4 : EMOTIONALLY STRESSFUL ISSUES REPORTED BY RESPONDENTS IN THE

LAST SIX MONTHS

Emotionally stressful issues Frequency (n=190) Percent %

Bereavement 13 6.9

Marital problems 6 3.2

Job Stress 25 13.2

Major financial Challenges 20 10.5

Personal injuries or illness 1 0.5

Poor health of a loved one 8 4.2

Pregnancy 9 4.7

Multiple responses allowed

Job stress was the stressful event most experienced among respondents at 13.2% while

financial challenges followed closely at 10.5% . The least experienced was personal injuries or

illness at less than 1%. Other stressful issues were bereavement (6.9%), pregnancy(4.7%),

poor health of a loved one (4.2%) and marital problems (3.2%).

TABLE 5: REPORTED COMMUTING TIME AMONG RESPONDENTS

Respondents commuting time to work Frequency

(n=190)

Percent

No. of Hrs needed to commute from home to work

(hr)

<1 136 71.6

1-2 46 24.2

>2 8 4.2

Most of the respondents (71.6%) required less than an hour to commute from home to work

while 24.2% of them spend between 1-2 hours. The remaining 4.2% spend over 2 hours on

their way to work.

FIGURE 1: PERCEPTION OF RESPONDENTS ON THE NEED FOR REVIEW OF

REGULATIONS TO REDUCE FLYING HOURS

Figure 1 shows that 41% of aircrew believe that there should be a revision of regulation to

reduce the number of daily flying hours while the remaining 59% are of the view that

regulations do not need to be revised.

78 (41%)YES

112 (59%)NO

FIGURE 2: FREQUENCY OF FATIGUE AMONG RESPONDENTS

In figure 2 above, 69% of aircrew admitted to having experienced fatigue while carrying out

their duties .

58 (31%)NO

131 (69%)YES

TABLE 6: TIME OF LAST EPISODE OF FATIGUE EXPERIENCED BY RESPONDENTS

Out of the 131 aircrew who have experienced fatigue, 99 (75.6%) of the them had their last

episode less than 4 weeks from the date of filling the questionnaire. The remaining 32 (24.4%)

of them experienced theirs from 4 weeks and beyond. The mean last episode of fatigue was

4.8 weeks.

Last episode of fatigue (wks) Frequency Percent

n = 131

< 4 weeks 99 75.6

4 weeks and above 32 24.4

Mean Last episode of fatigue (wks) 4.8±6.8

TABLE 7: LEVELS OF PHYSICAL FATIGUE EXPERIENCED BY RESPONDENTS

*Physical and mental fatigue indicators were used in assessing the combined fatigue score in

table 9 which was graded into mild moderate and severe . Various levels of exposure to these

indicators were graded from 0-4 with a maximum attainable score of 80 (See 3.6 data

analysis) .

Fatigue level

Physical Fatigue None

(%)

Slight

(%)

Moderate

(%)

High

(%)

Very

High (%)

Total

*Physical Fatigue

Indicators

Smarting

eyes/Irritation

40(30.5) 21(16.0) 32(24.4) 30(22.9) 8(6.2) 131(100)

Yawning 21(16.0) 24(18.3) 19(14.5) 38(29.3) 29(22.2) 131(100)

Headache 26(19.8) 24(18.3) 33(25.1) 41(31.2) 7(5.6) 131(100)

Effort to maintain

wakefulness

25(19.0) 23(17.6) 27(20.6) 38(29.3) 18(13.8) 131 (100)

Decreased verbal

communication

27(20.6) 27(20.6) 34(25.9) 38(29.3) 7(5.6) 131(100)

Feeling of Lethargy 33(25.1) 19(14.5) 27(20.6) 40(30.5) 12(9.2) 131(100)

Difficulty evaluating

time

33(25.1) 22(16.7) 31(23.6) 37(28.3) 8(6.2) 131(100)

Nodding off or

becoming fixated

33(25.1) 12(9.1) 19(14.5) 37(28.3) 30(22.9) 131(100)

Slowed reaction time 33(25.1) 15(11.4) 26(19.8) 45 (35.4) 11(8.3) 131(100)

Impaired mood 32(24.4) 24(18.3) 20(15.2) 41(31.2) 14(10.6) 131(100)

About 23 % of aircrew experienced “very high” levels of nodding off /being fixated while

22.2% experienced yawning. Efforts to maintain wakefulness was experienced at very high

levels in 13.7% of the respondents. Slowed reaction time was found to be the most significant

in the experiences recorded with a high outcome at 35.4% . In the moderate category, the

experience that occurred the most was decreased verbal communication (25.9%) followed

closely by headache (25.1%) and smarting eyes (24.4%).

TABLE 8 : LEVELS OF MENTAL FATIGUE EXPERIENCED BY RESPONDENTS

*Physical and mental fatigue indicators were used in assessing the combined fatigue score in

table 9 which was graded into mild moderate and severe . Various levels of exposure to these

indicators were graded from 0-4 with a maximum attainable score of 80 (See 3.6 data

analysis) .

Fatigue level

Mental Fatigue None

(%)

Slight

(%)

Moderate

(%)

High

(%)

Very

High

(%)

Total

*Mental Fatigue

indicators

Redundancy of some

actions

31(23.6) 26(19.8) 36(27.4) 32(24.4) 6(4.5) 131(100)

Difficulty in making

decisions

30(23.9) 21(16.0) 33(25.1) 38(29.0) 8(6.2) 131(100)

Slips, lapses, minor

errors

26(19.8) 25(19.0) 25(19.0) 45(35.4) 9(6.8) 131(100)

Lack of coherence or

reasoning

32(24.4) 24(18.3) 39(29.7) 30(22.9) 6(4.5) 131(100)

Tendency to delay

decision making

29(22.1) 20(15.2) 31(23.6) 39(29.7) 12(9.2) 131(100)

Difficulty in oral

expression

30(22.9) 28(21.3) 38(29.0) 30(22.9) 5(3.8) 131(100)

Slow understanding 25(19.0) 24(18.3) 34(25.9) 41(31.2) 19(14.5) 131(100)

Easily distracted 26(19.8) 22(16.7) 21(16.0) 47(35.8) 16(12.2) 131(100)

Decline in attention 25(19.0) 22(16.7) 16(12.2) 51(38.9) 17(12.9) 131(100)

Sluggish actions and

movements

25(19.0) 21(16.0) 25(19.0) 47(35.8) 13(9.9) 131(100)

In the very high category,14.5% of the respondents experienced slow understanding while

12.9% had decline in attention . In the high category, 38.9% had a decline in attention while

35.8% were easily distracted. Another 35.8% felt their actions and movements became

sluggish. Also worthy of note is that 35.4% admitted to have experienced slips and minor

errors.

TABLE 9: COMBINED AND GRADED FATIGUE LEVEL OF RESPONDENTS

Fatigue levels Frequency

(n=131)

Percent

Mild 71 53.7

Moderate 34 26.1

Severe 26 20.2

In table 9 above, fatigue level of respondents is shown. Based on their last experience of

fatigue, 53.7% were found to be mildly fatigued, 26.1% were moderately fatigued while the

remaining 20.2 % were severely fatigued .

TABLE 10: LEVEL OF PERCIEVED EFFECT OF FATIGUE ON FLYING TASKS AMONG

CAPTAINS AND CO- PILOTS

Level of perceived effect of Fatigue on

flying tasks

Flying Tasks Mild

(%)

Moderate

(%)

A Great deal

(%)

Total

Flight path monitoring 66(71.2) 27(28.1) 1(0.7) 93(100)

Manual flying 60(64.0) 31(33.8) 2(2.2) 93(100)

Utilization of aircraft automation 64(69.1) 26(27.3) 3(3.6) 93(100)

Radio Communication 58(61.2) 35(37.4) 0(0.0) 93(100)

Crew resources management 60(64.0) 32(35.3) 1(0.7) 93(100)

Use of Check-list 61(65.5) 31(33.1) 1(0.7) 93(100)

Selecting and entering data 53(56.8) 38(41.0) 2(2.2) 93(100)

Take off 61(66.2) 31(33.1) 1(0.7) 93(100)

Landing 54(58.0) 36(38.4) 3(3.6) 93(100)

Landing and utilization of aircraft automation had the highest percentages (3.6% each) for

those who perceived that fatigue affected them a great deal. In 41% of respondents, data

selection and entry was moderately affected ,while the landing was also moderately affected in

38.4% of respondents. Crew resource management (35.3%), take off (33.1%), use of check

list (33.1%) and communication(37.4%) were also moderately affected by fatigue.

TABLE 11: PERCEPTION OF PERFORMANCE ON FLIGHT OPERATIONS AMONG

FATIGUED CAPTAINS AND CO-PILOTS IN THE LAST ONE MONTH

Of the 93 fatigued pilots and co-pilots, 2 (2%) felt that their performance was unsatisfactory

in flight path monitoring. Another 2 (2.2%) were also unsatisfied with their utilization of

aircraft automation. Between 21 and 44 % of aircrew thought that they performed fairly in the

various flying tasks. Also, between 54 and 76 % of the respondents felt that their performance

on these tasks were good.

Performance on Operations

Flying Tasks/Operations Unsatisfactory Fair Good Total

Flight path monitoring 2(2.2) 20(21.6) 71(76.3) 93(100)

Manual flying 1(0.7) 25(27.3) 67(71.9) 93(100)

Utilization of aircraft

automation

2(2.2) 20(21.6) 71(76.3) 93(100)

Communication 0(0.0) 27(29.5) 66(74.1) 93(100)

Crew resources management 1(0.7) 29(30.9) 63(67.6) 93(100)

Use of Check-list 1(0.7) 23(25.2) 68(73.4) 93(100)

Selecting and entering data 1(0.7) 30(31.9) 62(66.7) 93(100)

Take off 1(0.7) 36(38.8) 56(60.4) 93(100)

Landing 2(2.2) 40(43.9) 51(54.7) 93(100)

TABLE12 : RESPONDENTS’ KNOWLEDGE OF FATIGUE COPING MECHANISMS

Majority of respondents appear to be familiar with crew work rest scheduling (85.3%),followed

by controlled rest breaks (68.9%). Some others (42.9%) were familiar with moving around in

their seats while 41.3% were aware of activity breaks. The coping mechanism with the lowest

knowledge among aircrew is the use of cockpit naps (28.9%).

Coping Mechanisms Knowledge Frequency

(n=190)

Percent

On board sleep 98 51.5

Cockpit naps 55 28.9

Controlled rest breaks 131 68.9

Crew work rest/scheduling 162 85.3

Alertness enhancing compounds (stimulants) 126 66.3

Activity break 78 41.3

Move around in seat

Music

Cold exposure

Bright light

81

62

56

69

42.9

32.6

29.4

36.3

(Multiple responses were applicable)

FIGURE 3: DISTRIBUTION OF RESPONDENTS WHO HAVE HAD CAUSE TO UTILIZE

COPING MECHANISM

Among respondents, 70% (134) agree that they have had cause to utilize fatigue coping

mechanisms in the course of their duty. The remaining 30% (56) have not.

134 (70%)YES

56 (30%)NO

TABLE 13 : UTILIZATION OF THE VARIOUS COPING MECHANISMS

Coping mechanism Frequency Percent

(n=134)

On board sleeps 98 74.7

Cockpit naps 55 41.1

Controlled rest breaks 71 53.0

Scheduling 105 78.3

Alertness Compounds 68 50.8

Activity breaks 102 76.1

Move in seat 81 60.4

Music 47 35.1

Cold Exposure 63 47.0

Bright light 51 38.0

(Multiple responses were applicable)

Among the respondents who utilized coping mechanisms, crew work rest scheduling was the

method most utilized (78.3%) followed by activity breaks (76.1%). The least utilized method

was listening to music (35.1%).

TABLE 14: RESPONDENTS’ PERCEPTION OF EFFECTIVENESS OF COPING MECHANISM

Perception of effectiveness of Coping Mechanism

Coping

Mechanism Used

before

Not

Effective

(%)

Slightly

(%)

Moderately

(%)

Very

Effective

(%)

Total

On board sleep 12(12.3) 18(18.4) 25(25.5) 43(43.8) 98(100)

Cockpit naps 5(9.0) 10(18.1) 8(14.5) 32(58.1) 55(100)

Controlled rest

breaks

2(1.1) 28(14.8) 62(32.8) 18(9.5) 71(100)

Crew work

rest/scheduling

0(0.0) 1(0.9) 17(16.2) 87(82.9) 105(100)

Alertness enhancing

compounds

15(22.0) 17(25.2) 12(17.6) 24(35.2) 68(100)

Activity break 7(6.8) 11(10.7) 48(41.0) 36(34.3) 102(100)

Move around in seat 16(19.7) 42(51.8) 16(19.7) 7(8.6) 81 (100)

Listening to

music/Radio

16(34.0) 24(51.0) 5(10.6) 2(4.2) 47(100)

Exposure to cold air 17(26.9) 26(41.3) 14(22.2) 6(9.6) 63(100)

Bright light 21(41.1) 18(35.3) 9(17.7) 3(5.9) 51(100)

Table 14 highlights respondents perception of the effectiveness of fatigue coping mechanisms.

82.9% found crew /work rest scheduling to be a very effective method of coping with fatigue

while another 58.1% of those who utilized felt that it was also very effective. Among aircrew

who utilized bright lights, 41.1% found it ineffective while 34% of those who listened to music

as a coping measure found them ineffective.

TABLE 15: ASSOCIATION BETWEEN RESPONDENTS’ SOCIO-DEMOGRAPHIC

CHARACTERISTICS AND FATIGUE LEVEL EXPERIENCED

Variable Graded Fatigue Levels X2 P value

Mild Moderate Severe Total

Sex 1.13 0.569

Male 52(51.7) 26(26.6) 21(21.7) 99(100)

Female 18(60.0) 9(24.4) 5(15.6) 32 (100)

Total 71(53.7) 34(26.1) 26(20.2) 131(100)

Age Group 13.91 0.083

<24 5(88.9) 0(0.0) 1(11.1) 6 (100)

25-34 26(47.3) 17(31.6) 11(21.1) 54(100)

35-44 12(54.5) 5(22.7) 5(22.7) 22(100)

45-54 17(51.0) 8(22.4) 9(26.5) 34(100)

>55 11(73.3) 4(26.6) 0(0.0) 15(100)

Total 71(53.7) 34(26.1) 26(20.2) 131(100)

Mean Age

(yr)

41.0±12.4 40.7±11.3 38.8±10.1 0.459* 0.633

Marital Status 2.14 0.717

Single 25(55.1) 11(24.6) 9(20.3) 45(100)

Married 42(51.8) 22(26.8) 18(21.4) 82(100)

Separated or

widowed

3(71.4) 1(28.6) 0(0.0) 4(100)

Total 71(53.7) 34(26.1) 26(20.2) 131(100)

Nationality

0.60 0.739

Nigerian 49(53.8) 25(27.3) 17 (18.9) 91 (100)

Others 22 (53.6) 9 (23.2) 9 (23.2) 40 (100)

Total 71 (53.7) 34 (26.1) 26 (20.2) 131(100)

*F test

Table 15 examines possible associations between respondents’ socio demographic

characteristics and fatigue levels. Mild and moderate fatigue levels appeared to be similar in

distribution amongst males and females. Severe fatigue on the other hand appeared to have a

slightly larger percentage in male as compared to female air crew (21.7% : 15.6%). Age group

44-55 had the highest percentage of respondents with severe fatigue ( 26.5%) while those

above 55 didn’t have any aircrew member with severe fatigue. The distribution of the various

levels of fatigue in married and single respondents was quite similar. Foreign aircrew appeared

to have a slightly higher percentage of individuals with severe fatigue compared to their

Nigerian counterparts. There was however no statistically significant association between any

of the socio demographic characteristics and fatigue levels. (p>0.05)

TABLE 16: ASSOCIATION BETWEEN RESPONDENTS’ OCCUPATIONAL

CHARACTERISTICS AND FATIGUE LEVEL EXPERIENCED

Occupational

characteristics

Fatigue Level X2 P value

Mild Moderate Severe Total

Current Function 3.20 0.787

Captain 29(50.0) 17(29.8) 12(20.0) 58(100)

Co-pilot 21(60.0) 7(20.0) 7(20.0) 35(100)

Flight engineer 1(50.0) 0.(0.0) 1(50.0) 2(100)

Cabin crew 19(53.3) 10(26.9) 7(19.2) 36(100)

Total 71(53.7) 34(26.1) 26(20.2) 131(100)

No. of Years in current

position

<10 53(55.9) 24(25.7) 17(18.4) 94(100) 6.50 0.163

10-20 9(41.9) 5(22.6) 7(35.5) 21(100)

>20 9(57.1) 5(33.3) 2(9.5) 16(100)

Total 71(53.7) 34(26.1) 26(20.2) 131(100)

Mean No. of yrs spent in

current position

7.8±8.7 9.7±10.4 8.1±7.3 0.76* 0.468

Nature of flying duty

Short haul 52(56.5) 22(24.4) 17(19.1) 90(100) 1.31 0.514

Long haul 19(47.4) 13(29.8) 9(22.8) 41(100)

Total 71(53.7) 35(26.1) 26(20.2) 131(100)

Mean No. of Hrs flown in

the last month

73.2±108.9 64.0±35.8 61.2±35.5 0.40* 0.687

No. of Hrs needed to

commute from home to

work (hr)

<1 54(57.8) 21(22.2) 19(20.0) 94(100) 7.02 0.136

1-2 14(42.2) 11(33.3) 7(24.4) 32(100)

>2 3(50.0) 3(50.0) 0(0.0) 6(100)

Total 71(53.7) 35(26.1) 26(20.2) 131(100)

*F test

Table 16 compares for association between respondents’ occupational characteristics and

fatigue levels. Captains, co pilots and cabin crew appear to have similar percentages of severe

fatigue. Respondents who have spent 10-20 years in their current positions experienced the

highest percentage of severe fatigue (35.5%) followed by those who have spent less than 10

years (18.4%). In the long haul category, 22.8% of aircrew are severely fatigued as compared

to 19.1% in the short haul category. There is no statistically significant association between

occupational characteristics and levels of fatigue. (p>0.05)

TABLE 17: ASSOCIATION BETWEEN RESPONDENTS’ SMOKING AND FATIGUE

Fatigue X2 P value

Smokes Yes No Total 2.00 0.339

Yes 14(73.7) 5(26.5) 19(100)

No 117(68.6) 53(31.4) 170(100)

Total 131(69.0) 58(31.0) 189(100)

This table looks at association between smoking and fatigue. 73.7% of those who smoke were

fatigued while 68.6% of those who do not smoke were also fatigued. There is no statistically

significant association between smoking and fatigue. (p>0.05)

TABLE 18: ASSOCIATION BETWEEN RESPONDENTS’ ALCOHOL USE AND FATIGUE

Fatigue X2 P value

Alcohol Yes No Total 2.50 0.058

Yes 66(75.0) 22(25.0) 88(100)

No 65(64.4) 36(35.6) 101(100)

Total 131(69.3) 58(30.7) 189(100)

The association between fatigue levels and alcohol use was examined. While 75% of aircrew

who take alcohol were fatigued, 64.4% of those who do not take alcohol were also fatigued.

There is no statistically significant association between alcohol consumption and fatigue.

(p>0.05)

TABLE 19: ASSOCIATION BETWEEN RESPONDENTS’ TYPES OF AIRCRAFT QUALIFIED

ON AND FATIGUE

Variable Fatigue X2 P value

Yes No Total

Type of Aircraft 6.9 0.397

Helicopter 29(66.7) 14(33.3) 43(100)

Jet-Heavy 79(72.5) 31(27.5) 110(100)

Jet-Light 19(63.3) 11(36.7) 30(100)

Turbo-Light 1(33.3) 2(66.7) 3(100)

Total 131(69.0) 58(31.0) 189(100)

*Fisher’s exact p-value

Aircrew who work in heavy jet engine aircraft had the highest proportion of individuals who

were fatigued (72.5%). This was followed by helicopter aircrew (66.7%). There is however no

statistically significant association between types of aircraft operated and fatigue. (p>0.05)

4.1 FINDINGS FROM QUALITATIVE SURVEY (INDEPTH INTERVIEWS)

4.1.1 Safety reporting systems

A confidential safety reporting system exists and apparently is in use in the Nigerian

aviation industry where fatigue and other safety related occurrences can be reported.

Some of the respondents interviewed are aware of this system and have utilized it at

one time or the other. Some of their comments are as follows;

“ We actually have confidential safety reporting systems in place. These systems allow

pilots to anonymously report incidents directly involving them or other members of

their crew. You can either fill a form and submit to the NCAA or you can make your

report on line or by telephone. We are also obligated to report to the NCAA any major

compromise of safety on the path of the airlines we work for. There is also the

voluntary non punitive reporting format which is left to the discretion of aircrew. I

think the process is effective because we use feedback from these reports to improve

on safety practices in airline operations”

“ I guess we could say a confidential reporting system exists. Aircrew are encouraged

to report safety breaches among a range of other issues. I haven’t had course to use

it though. We are usually reminded about its importance during crew resource

management training . There is a format for reporting issues anonymously on line.

You can also report in person at the NCAA headquarters “

“The issue of safety reporting systems is a serious one. As a matter of fact, aircrew

are duty bound to report in writing to the relevant authorities, any issue that

threatens flight safety. This is meant to keep both the aircrew and aircraft operators

in check and minimize the compromise of standards. In addition, most modern

airplanes nowadays have onboard computers that register errors committed by pilots

while in flight and these data can be retrieved by the airline operators for review

afterwards”

“ Yes I am aware of the safety reporting channels. It can be done in person or on line.

Your identity can be protected if you want. That encourages people to bring forward

vital information when the need arises. I have had reason to file an observation on

line before. You see, I had this chap on my crew whom I observed to have failing

vision. Now clearly I was concerned about the potential effect of that in an emergency

situation. Something was done about it so I guess they read all that stuff we write”

“ I think there are several options for aircrew to report near misses or incidents that

have a bearing on flight safety. Not too sure how the system works exactly. But I am

a bit of a green horn in the industry and haven’t had any reason to make any reports

yet”

One of the younger aircrew interviewed didn’t seem very familiar with the system . It

was the view of some interviewees that the system is flexible and exists in several

forms. There is the voluntary non punitive confidential system where aircrew can fill a

confidential form to report fatigue related occurrences and other human factor

related incidents either involving them or

other aircrew. It can also be reported by telephone or over the internet. Aircrew are

duty bound to report unsafe practices or compromise of safety standards by the

airlines they work for. In addition, there is a mandatory occurrence reporting system

where aircrew are obligated to report major mechanical faults developed by aircraft in

flight.

The onboard computers in the aircraft also log some errors that may have been

inadvertently committed by aircrew such as hard landing, pitch excess, over speed

and exceeding bank angle. The data collected is utilized by airline authorities for

enhancement of safety.

4.1.2 Aircrew flight scheduling and discretion time flying

Flight scheduling is a pre emptive coping mechanism and is routinely carried out by

airline dispatchers and is designed to ensure that aircrew do not exceed the

designated daily duty time to mitigate fatigue. This is in keeping with the prescriptions

of the National civil aviation regulation which sanctions both erring pilots and airlines

who do not comply. Punishments could include a 90 day license suspension for pilots.

Some of the interviewees commented thus; “Our airline dispatchers are responsible

for preparing flight schedules and in planning duty, they factor in reasonable rest

periods in between flights to ensure that aircrew had allowance for at least 8 hours of

uninterrupted sleep and the schedule must be designed as far as possible not to

overrun flight duty limits. It is also the responsibility of aircrew to ensure that they

sleep well the night before a flight. Flight crew members are expected to keep track of

all his flight and duty records and when he becomes aware that a flight assignment

will exceed flight duty time limitations, he is expected to notify the operator and not

accept such an assignment.”

“It is our responsibility as regulators to carry out periodic checks to ensure that the

airlines comply with existing regulations pertaining to flight scheduling. This is an

integral part of our safety net because we cannot have over worked pilots in the air

in this country. The overall compliance levels among the airlines is satisfactory

however, pilots are duty bound to decline taking flights which contravene the

regulations and report same to us at the NCAA.“

A staff of the NCAA said ; “The regulations stipulate that any aircrew that has to

exceed his duty hours can only do so with the express permission of the DG NCAA.

The pilots know better. They won’t try it because we will take their license . Safety is

key in our operations and we would not hesitate to sanction erring pilots and airlines.”

A Pilot summed his views as follows; “ Flying into discretion time is a sensitive issue

for this industry. Because of the very busy nature and unpredictability of our work,

honestly there are overlaps and we sometimes find ourselves exceeding the

prescribed duty limits. But this isn’t an everyday affair. Going by the book, the pilot in

command is instructed to file a report each time they exercise discretion but I am not

sure how regularly this is happens” .

A senior pilot said “ It is a bit of a challenge in Nigeria for aircrew to strictly adhere to

duty time limitations. I’ll tell you why ; For starters, logistic problems are

unpredictable. Jet A1 is sometimes scarce and that can make refueling in between

flights a tough cookie. Personally I have had to wait for up to 3 hours before. That

kind of wait flames you out. Occasionally, VIP movement causes ground delays, but

this is mostly an Abuja problem. Rarely, an aircraft could also develop a little fault

requiring quick repairs and this could add to delays. We have no direct control over

some of these factors”

One regulator said “ Flight time limitation is something we try to adhere to based on

the stipulations of the civil aviation act. We schedule flights with the limitations of a

pilot as a human being in perspective. In fact these days, the pilots can work in shifts

of two weeks on and two weeks off to allow room for proper rest. But you will agree

with me that there are some issues we have no direct control over such as aircraft

traffic at the busy Lagos airports. When the air traffic is heavy, aircraft have to queue

to takeoff or land. If an aircraft is on approach for landing and the aerodrome is busy,

air traffic controllers will put that aircraft in a holding pattern and ask it to circle in the

outer marker until there is space and it is guided in to land. Waiting to refuel the

airplane is also an issue when aviation gas is scare”.

The prevalent feeling among the pilots is that logistics problems such as ground

delays in refueling in between flights significantly increases their total duty time.

Delays as long as 3 hours were reported. This makes them fly into their discretion

time and exceed prescribed duty time.

A younger pilot felt that the scheduling of duty wasn’t done fairly sometimes. In some

of the airlines, older pilots seemed to have a better deal as they took fewer weekend

and night flights.

One of the pilots said “ I flew several sectors during the last week and got back to

base late on Friday quite tired. I had looked forward to a restful weekend but was

called up by the airline dispatcher the following morning to take an emergency flight

on Saturday to Owerri to pick up stranded passengers as their own aircraft developed

a technical glitch” .

A senior pilot shared his views on the matter as follows ; “ Although the operational

exigencies of running an airline can be unpredictable, having a robust number of

pilots on strength would help alleviate fatigue a great deal . But it is not that straight

forward. It costs a lot of money and time to train pilots. Trained pilots still need to

work to gain experience. A lot of training is on going to bridge existing gaps, but this

takes time. A major part of that training takes place overseas. A lot of expatriate

pilots have are also been hired to bridge the gap. So far, I don’t think we are doing

badly. We will get there “.

” I have had my CPL for close to three years now with nearly 300 hours under my

belt. To be a captain with ATPL, I need to log in 1500 flying hours. That’s a long way

to go. I really don’t mind the hours so I can garner experience but not at the expense

of safety.”

While the NCAA obviously, frowns at pilots flying into their discretion time routinely,

it does seem that the interests of some airlines and the sometimes unpredictable

nature of aviation operations makes it difficult not flying into discretion time pretty

often.

On the issue of duty time, an expatriate pilot expressed his frustrations thus “ In

Nigeria, the number of sectors you fly is what is used to assess the amount of work a

pilot has done. (A sector is the trip from one point of take off to the point of landing

e.g. Lagos to Abuja is one sector ) This is wrong because in between sectors, technical

and logistic challenges spring up especially because of the erratic supply of Jet A-1

fuel here. When they are resolved, then you go on and complete the sectors allotted

to you for the day”. He also added that “ In developed countries, it is the number of

hours you have spent at work from the time you reported for duty that count in spite

of whatever challenges may arise. Once the specified number of hours are reached,

you are replaced by another pilot. This really is the issue you should address in your

paper. That’s where the real fatigue comes from “ . In the short haul category, most

sectors last between 30 -75 minutes.

4.1.3 Utilization of coping strategies

Most respondents appear familiar with a range of coping strategies useful in mitigating

fatigue while in flight. Some of the more commonly used strategies include engaging

other flight deck crew in stimulating conversation, coffee breaks, and taking brief

walks around the aircraft on the tarmac after landing particularly for those in the short

haul category.

“ I am aware of a couple of fatigue coping strategies and I also use them quite a bit. I

like to take leg stretches especially by the third or fourth sector. Coffee breaks are

also quite helpful. In addition, I like to chat with other members of my crew. The

European soccer league for instance features prominently in our discussions. Nothing

beats a good night’s sleep before a flight though”.

“ Fatigue counter measures are useful tools in reducing the effects of fatigue on

aircrew but personally I don’t use them much. I fly domestic routes for now. Some of

the measures are not allowed in domestic or short haul routes such as cockpit naps

and bunk sleeps. But on a very busy day, I may catch a few minutes nap with the co

operation of the second pilot. Personally, I like to drink a lot of coffee. The caffeine

keeps me awake. Nibbling on biscuits and sandwiches also helps me fight tiredness.”

“ I fly on international routes and I must tell you it gets really boring. After takeoff

when the aircraft must have gained sufficient altitude, there isn’t much too much left

to do. Staring at the cockpit instrument lights gets one sleepy. As a means of fighting

off sleep, we take walks within the cabin in turns. Depending on the duration of flight,

we carry extra pilots. This makes it possible to take turns to nap. Bunk beds are also

provided for this purpose in cabins adjacent to the cockpit. Usually, pilots have

structured breaks lasting up to an hour where they take turns to sleep. Pilots in the

long haul category are however allowed to have both cockpit naps and on board

sleeps”.

“ I have tried a number of strategies to fight off fatigue . Coffee and power horse

drink are my favorite method, but a good night’s rest really helps me. Walks within

the cabin are also good but Cold air worsens the sleep urge. I am aware bright lights

within the cockpit are supposed to keep one awake, but that doesn’t work very well

for me. Rest breaks are also scheduled for pilots especially in long haul flights. “

4.1.4 Regular training for aircrew

On the issue of air crew training a pilot gave his experiences as follows; “regular

trainings to improve competence and safety of aircrew are conducted regularly. In

fact, some of the trainings are a requirement for renewal of aircrew licenses.”

“We organize regular human performance and limitation training for crew members

as well as Crew resource management training. It touches on Coordination, judgment

and time perception. Crew resource management training also helps the crew

members to operate cordially with respect for the views of all other members of crew

as it pertains to issues of flight safety. Although, the captain has command of the

airplane, he is obligated to listen to the views of his co pilot . Accidents have occurred

in the past due to the dogged resolve of some pilots to continue an action in flight

that compromised flight safety in spite of repeated warnings from their co pilots”.

“ As part of regulations, airlines are meant to organize trainings for their aircrew in

crew resource management as well as safety and emergency management. Fatigue

usually features in these programmes. One of the key messages passed across is that

in the man-machine interphase, man is the weakest link. That is to say man has a

limit and this limit is not to be exceeded in terms of how long he can effectively and

safely fly an airplane for. Fatigue mitigation is also part of the training and it helps

aircrew handle fatigue better. I feel a lot more can still be done in this area.”

“It is the part of our responsibility at the NCAA to ensure that the airlines conduct

regular trainings for their aircrew. Crew resource management training helps aircrew

recognize when they have reached their human limits and to work better with other

members of their team. It is a criteria for recertification of airlines and renewal of

aircrew licenses. We have an input in these trainings and as much as possible try to

ensure the objectives of the trainings are met. It could be challenging maintaining

standards, but we are not doing badly “

4.1.5 Alcohol, drugs and flying duties

The National Civil Aviation authority has very strict regulations concerning the use of

drugs and alcohol by duty aircrew in view of its potentially catastrophic consequences

on flight safety.

A staff of the regulatory body said “Acting as a flight crew member while under the

influence of liquor or other psychoactive substances or alcoholic beverage

consumption within 8 hours of duty attracts an immediate emergency revocation of

the aircrew’s license.” He went on further to state that “ All licensed air crew are

subject to these regulations and are to submit to periodic and spot checks that assess

blood levels of alcohol and psychoactive substances. Any person subject to these

regulations who refuses to submit to such tests may have their licenses suspended or

revoked for periods of up to 1 year after the date of refusal.”

Some of the interviewed Aircrew alluded to the fact that both their airlines and the

NCAA carry out random toxicology screens and breathalyzer tests on them. ” Our

airline carries out random alcohol checks on aircrew especially pilots. There is really

no definite pattern . They do the breathalyzer tests and on rear occasions they check

our blood for drugs. The blood test is often during our annual medicals. The NCAA

also comes in to screen for drugs and alcohol but not as regularly as the airline does”

“ We carry out alcohol and drug tests routinely on the pilots. In addition, we also test

them on suspicision and following accidents. Drinking and flying don’t go together and

we have a zero tolerance for breaking this rule. You are not supposed to consume

alcohol the night before a flight but we even prefer a 24 hrs safe window. Drugs are

even worse, narcotics I mean. If you are caught as a drug user, then your career in is

over. The sanctions for drug offences are quite severe. The NCAA regulations stipulate

that any aircrew involved in the manufacture, transportation or possession of any

narcotic drugs or stimulant substances will have his license revoked. Also, being

aware of an air crew involved and not telling attracts sanctions as well. “

“ To begin with even if it is a prescription drug, it should only be used after due

consultations with your aero medical examiner or aviation medicine specialist. This is

because drugs may have side effects that will make a person drowsy and this is

dangerous to flying operations. If the need arises, the specialist may take the pilot off

flying long enough to allow him ample time to complete his medication or even

ground him from flying out rightly. As for alcoholic beverages, of course you are

allowed to drink but it must not get to the point where you get drunk. The safety rule

is that no drinks allowed the night before a flight. From time to time, we get

surprised alcohol tests but not regularly. Hard drugs are a no go area ”

“ You cannot drink and fly just as you cannot drink and drive. Flying under the

influence can get a pilot fired instantly. It simply is an accident waiting to happen. You

are allowed to smoke regular cigarettes but not while flying. The authorities carry out

random checks to screen for aircrew who might be under the influence of drugs or

alcohol. It would be plain foolishness for a pilot to operate an aircraft when drunk. I

don’t expect anyone worth their onions to compromise safety to such an extent”

“ Pilots aren’t supposed to drink on duty. It is an offence going by regulations and

could result in forfeiture of the offender’s license for a designated period of time.

Because of the potentially disastrous consequences, the NCAA and the various airlines

take it seriously. Prescription medication is however allowed but you must run it by

your aviation doctor first. The airlines arrange to have pilots tested and refusal to be

tested could result in a revocation of licenses for periods of up to a year . Testing

positive for alcohol leads to suspension of licenses for periods from up to 3 months. “

CHAPTER FIVE

5.1 DISCUSSION

The socio - demographic variables revealed that there was a higher proportion of male

to female workers in the study population in the ratio of 3:1 that is 76.3% to 23.7%

respectively. This differential is perhaps explained by the fact that males dominate the

aviation sector in most parts of the world .

The mean age of respondents in the study is 45.5 years with the majority falling into

the 25-35 year age group (40%). This is similar to the findings of another fatigue

study conducted in France in which 47 years was the mean age of aircrew.73 Age

group 46-55 had the second highest representation with 26.8% while those aged 36-

45 followed with 16.8% and those over 55 with 11.6%. Respondents aged less than

24 had the least representation in the group with only 4.7%.

A good number of aircrew that participated in the study are married (58.9%) while

37.4% are single and the remaining 3.7% are either divorced or widowed. The fairly

sizable number of singles in the group can be explained by the recent increase in

recruitment and training of young aircrew by most airlines to meet growing manpower

needs in the industry.

Around 30% of respondents are made up of expatriate aircrew while the remaining

69.5% are Nigerians. A similar study carried out in Taiwan also found that 26.3% of

aircrew were foreigners.4 The robust presence of expatriates is attributable to the

rapid growth being experienced in the aviation industry and the inability of available

local pilots to meet the immediate needs of the various airlines.

About 10 % of aircrew are smokers while 46.3 % of them consume alcohol. 12.6 % of

the respondents are on various types of medication. The majority of those in this

category are on anti hypertensive (66.7%), while another 16.7 % are on anti diabetic

medication. The notable number of aircrew on anti hypertensive medication could be

due to the presence of aircrew above 55 years who are likely to continue flying into

their mid 60s. It follows that the risk of developing high blood pressure increases with

age. 12

The stressful event most experienced among the respondents was trouble in the work

place (12%) while financial problems followed with 10.5%. Other events were

bereavement (6.9%), pregnancy (4.7%), poor health of a loved one (4.2%), marital

problems (3.2%) and personal illness (0.5%). It is important to recognize that

emotional stress can become overwhelming at times and present a serious threat to

aviation safety.7 Studies have shown that emotionally stressful issues especially family

related events may adversely affect performance particularly when duty assignments

separate crew members from their families.7,48 The crew members concern for family

may become a distraction during flight operations or increase fatigue or irritability.

The potential dangers of flight operations also act as a stressor on families and may

cause tension in spousal relationships. This is particularly the case for the families of

new, inexperienced personnel.48

Of the 190 respondents who participated in the study, 86 were captains, 50 were co-

pilots, 2 flight engineers and the remaining 52 were flight attendants. The high

proportion of captains relative to other aircrew in the study could be as a result of the

employment of several expatriate helicopter pilots to meet the demands of the oil and

gas industry in Nigeria. Most helicopter operations require a captain and co pilot and

hardly any cabin crew. Flight engineers were found to be proportionately fewer

compared to the other aircrew. This can be explained by the fact that many of the

modern commercial jets now in use have electronically advanced avionics systems

that are “self diagnosing” and can give pilots instructions as to how to solve technical

problems that may arise thus eliminating the need for flight engineers. Only some of

the older aircraft or flights with problems still carry flight engineers routinely.

Those who have spent over 20 years in their current positions made up 11.6% of the

group while the bulk of the respondents (71.6%) have spent less than 10 years

suggestive of a relatively young work force at least in terms of work exposure in their

current positions. Among the aircrew, 70% are currently deployed to short haul duties

while the remaining 30% are in the long haul category. In a similar study that

examined fatigue in long and short haul pilots in Europe, 72% were in long haul

flights while the remaining 28% were in short haul flights.73 This reverse is likely due

to the fact that the airport where that study was conducted is more of a hub for

regional and international flights.

The Respondents are type rated on various aircraft types as follows ; helicopter

(23.9%),heavy jet engine (58.5%),light jet engine (16.0%) and light turbo-prop

(1.6%). Since area of specialization was by choice, there was no obvious reason for

the disparity observed among the various aircraft platforms currently manned by

aircrew.

On the issue of change of regulations, 41.1% of aircrew believe there is a need to

change regulations to reduce flying hours while the remaining 58.9% did not. In a

similar study that examined the prevalence of fatigue among commercial pilots in the

United Kingdom, a higher percentage of scheduled pilots (73%) were of the view that

regulations be changed to reduce flying hours.5 The mean number of hours flown

daily in the last month among respondents was 8.6 hours while the mean maximum

number of flying hours recommended per day is 6.5 hours . This is still within the

accepted limits of Flight Time Limitations (FTL) for aircrew which is 190 hours for any

28 consecutive calendar days or 60 hours in any 7 consecutive calendar days. This

comes to 8.5 hours daily.69 In a recent study that reviewed the effect of fatigue on

aircrew ,it was found that as duration in flight increases, so risk of incidents and

accidents increase.69 In addition, other factors have to be taken into consideration

such as early starts, late finishes, consecutive duties, multiple sectors and overnight

duty. 74

Most of the respondents (71.6%) require less than an hour to commute from home to

work while 24.2% of them spend between 1-2 hours. The remaining 4.2% spend over

2 hours on their way to work. Time spent commuting or in traffic is important because

those with lengthy travel durations or those who encounter traffic jams might be

already fatigued at the time they resume for duty. It is an established fact that fatigue

is worsened when physical and/or mental stress is present.48

A look at the distribution of respondents who have ever been fatigued in the course of

their duty shows that about 70% of them admitted to having experienced fatigue

while the remaining 31% have not. This is similar to the findings of another study on

the prevalence of fatigue among commercial pilots which found that 75% of

respondents reported that they had been fatigued in the course of work.5 The findings

of a survey of regional airline pilots conducted in Taiwan also reports high fatigue

levels of 85.4% among aircrew.4 A 2011 study on British airline pilots however found

lower proportions of fatigued aircrew. Of a sample of 492 pilots (two thirds of them

Captains) 45 % were suffering significant fatigue. And 40 per cent found themselves

having to fly more than the regulation hours at least twice a month to cope with the

volume of flights. 10

In this study, it was found that 67.6% of aircrew in the short haul category were

fatigued as compared to 78.8% of those serving in the long haul category. In a similar

French study, self-reported manifestations of fatigue was seen in 49% of short haul

crew and 60% of long haul crew and this included reduction in alertness and

attention, and a lack of concentration.73 In both studies, the long haul category had

proportionately more individuals who were fatigued compared to the short haul. This

difference was possibly because in-flight drowsiness is more problematic on night

flights and micro sleeps are more frequent at night than in the day. Long haul flights

are more likely to occur at night and are linked with a distortion of normal circadian

rhythms as pilots crossing time zones are sleep deprived.22

Of the 131 aircrew in this study who were fatigued, 99 (75.6%) of them had their last

episode less than 4 weeks from the date of filling the questionnaire. The remaining 32

(24.4%) of them had their experiences from 4 weeks and beyond. In a similar study,

it was also observed that majority of aircrew had experienced a recent episode less

than 4 weeks prior to the conduct of the study. This suggests that aircrew fatigue has

a fairly regular occurrence.5

In this study, Physical fatigue indicators were experienced among fatigued aircrew in

high proportions. The indicator most experienced was yawning at 84% while the least

experienced was smarting of the eyes/irritation at about 70%. Of concern among

these indicators was the finding that about 75% of respondents had admitted to

varying degrees of nodding off while in flight. A fatigue study carried out on regional

pilots in Malaysia revealed that an alarming 93% of the respondents admitted that

they had experienced nodding off during a flight at some time.76 These findings are

consistent with a survey of airline Pilots conducted in 1999 in the US which found that

84.6% of the respondents serving oceanic flights had at least some experience of

nodding off.4 Again, this is similar to another study in which 80% of the respondents

had also experienced nodding. 72 These nod offs or micro sleeps as they are

sometimes referred to results in lapses of attention, slowed reaction time and

increase in errors with serious implications for flight safety.7

Mental fatigue indicators were equally experienced at varying levels in high

proportions. The most frequent mental fatigue manifestations observed in this study

were slow understanding(81%),decline in attention(81%) and sluggish actions(81%).

The least experienced indicator was lack of coherence (75.6%). Also of interest

among these indicators is difficulty in making decisions (76.1%). In a study on short

haul commercial pilots, the findings were similar. 89% of low cost pilots and 77% of

scheduled pilots admitted to difficulty in making decisions and impaired judgments

when fatigued.5 These studies show that many modern day short-haul commercial

pilots have to grapple with difficulty in making decisions when fatigued. The potential

for more accidents with pilots operating when fatigued is high.5

A review of the graded fatigue levels among respondents showed that 53.7% of

aircrew were mildly fatigued, 26.1% moderately fatigued and 20.2% were severely

fatigued. This is somewhat in contrast to a similar study that examined fatigue

prevalence among aircrew in which 75% of fatigued respondents were severely

fatigued .73

Majority of the captains and co pilots (between 57%-71%) felt that fatigue had only a

mild effect on their ability to perform some crucial flying tasks. A smaller proportion

(between 27%-41%) felt that fatigue had a moderate effect on their performance.

Only between 1-4% felt that fatigue affected them a great deal. Among the flying

tasks, flight path monitoring, utilization of aircraft automation and take off were

perceived to have the highest effect. A similar study reported selecting and entering

data, use of checklist, and flight path monitoring as the flying tasks most impacted by

fatigue. Take off and landing are the most crucial aspects of flight as most aircraft

incidents or accidents occur during these times. This puts some pressure on aircrew

further impacting on existing fatigue from other sources. In their perception of how

they performed on the same 9 tasks, between 54-76% of pilots felt that their

performance on these tasks were good. 21-44% of aircrew performed fairly. Only 0-

2.2% felt their performance was unsatisfactory. The possibility of under reporting by

respondents can however not be ruled out.

Respondents knowledge of fatigue coping mechanisms was fair. Crew work/rest

scheduling had the highest knowledge with 85.3% while knowledge of controlled rest

breaks and the use of alertness enhancing compounds were also relatively high.

Cockpit naps had the least knowledge with 28.9%. Findings from a European study

also found crew work rest scheduling to have the highest knowledge among

respondents.38 However, there was a uniformly high knowledge of most of the fatigue

coping mechanism among crew members. The similarity in both studies with regards

to the high knowledge of crew work rest scheduling is probably as a result of the

emphasis placed on adequate rest as the best remedy for dealing with fatigue by

ICAO, the lead UN organ saddled with the responsibility of ensuring best global

practices in aviation.

Regarding the utilization of these mechanisms, scheduling was the most utilized

(78.3%),followed by activity breaks(76.1%). The least utilized method was listening

to music (35.1%). In a similar study, rest and sleep management were the primary

strategies used to cope with fatigue in both long haul and short haul flights. 38

In this study, some of the other additional coping mechanism adapted by aircrew in

an effort to mitigate fatigue include engaging other crew members in stimulating

conversation, brief walks on the tarmac during stopovers and snacking. Although

cockpit naps are not allowed in short haul flights, some of the pilots in this study

admitted to taking short naps . This is similar to the findings in an Asian study in

which about half of the respondents reported that they had taken such a nap during

the past 3 months (after notifying his/her co-pilot).4

Energy drinks are also becoming more popular among pilots as a non pharmacological

alertness enhancing compound. In a similar study, some of the mechanisms adapted

by aircrew to mitigate fatigue include upright posture, avoidance of heavy meals,

certain cold remedies containing stimulants and going to bed at the same time each

night. 75 In spite of all these, the only reliable remedy is for aircrew to have adequate

sleep in between flights. 75

Among aircrew who utilized various coping mechanisms, their perception of the

effectiveness of those mechanisms varied. Of the coping mechanisms perceived to be

“very effective”, crew work/rest scheduling had the highest proportion at 82.9%.

followed by cockpit naps (58.1%). This is consistent with the findings of a similar

study in which crew/rest scheduling was the most utilized at over 93%.38 The

mechanism perceived to be the least effective was listening to music (4.2%). In the

“moderately effective” category, Controlled rest breaks had the highest

proportion(32.8%) while move around in seats had the highest proportion in the

“slightly effective” category. Over 41% of respondents however felt being exposed to

bright light was not effective at all followed by listening to music (34%). None of the

respondents found crew work/rest scheduling to be ineffective.

The association between sex and levels of fatigue showed a near even distribution in

the proportions of those fatigued. A higher proportion of females were however more

mildly fatigued than males (60% to 51.7%). For moderate fatigue, males were slightly

more fatigued than females (26.6% to 24.4%) while for severe fatigue, males were

also more fatigued than females (21.7% to 15.6%) There was however no statistically

significant difference between sex and levels of fatigue. These findings however differ

from the findings of a similar study in which all the females were fatigued compared

to a smaller proportion of male aircrew (100% to 62.3%) giving the impression that

the male sex is protective.5

Age group 45-55 have the highest proportion of respondents with severe fatigue.

Proportions of those severely fatigued appears to decline with lower age groups,

though fewer people are severely fatigued. Those in age group 25-34 had the highest

proportion of moderately fatigued crew members while age group < 24 had the

highest proportion of mildly fatigued aircrew. The differences were however not

statistically different. In a similar study, it was found that younger pilots seemed

better able to resist fatigue compared to older ones as pilots below 35 years had

lower levels of fatigue.73 In this study, aircrew below 35 years also had slightly lower

levels of severe fatigue compared to the older age groups.

There were no obvious differences in the fatigue levels of single and married crew

members. Marital status thus did not have an impact on graded fatigue levels.

Expatriate aircrew appeared to have a higher proportion of individuals with severe

fatigue compared to their Nigerian counterparts (23.2% to 18.9%). As for moderate

fatigue, the reverse was the case as Nigerian aircrew were more moderately fatigued

(27.3% to 23.2%). Mild fatigue had very similar outcomes (53.8% to 53.6%).

However no statistically significant association was observed. In another study carried

out on aircrew in Taiwan, the outcomes were similar as both local and expatriate

aircrew had no statistically significant differences in fatigue levels.4

Captains, co pilots and cabin crew appeared to have similar percentages of severe

fatigue (20%:20%:19.2%) while captains have the highest proportion of moderately

fatigued individuals (29.8%). Many of the respondents in all the work duration

categories were mildly fatigued (42-57%). Just over 35% of crew members over 20

years in position were severely fatigued while 19.1 % of aircrew in the short haul

category were severely fatigued as compared to 22.8% in the long haul category.

There is no statistically significant association between any of the occupational

characteristics and levels of fatigue. This buttresses the assumption that work

experience and the nature of duty performed does not have an effect on the fatigue.12

Fatigue did not have any effect on smoking and alcohol consumption as there was no

statistically significant association between them. Among aircraft specialties,

helicopter crew members had the highest proportion of those with mild and moderate

fatigue (59.1% and 29.5%). Noise and vibration are believed to play a contributory

role in the level of fatigue experienced in helicopter operations.6 Pilots of heavy jet

engine aircraft are challenged with monitoring multiple display panels which also

worsens fatigue levels. 21.1% of crew members in this category were severely

fatigued.

5.2 CONCLUSION

About 70% of respondents admitted to having experienced fatigue while carrying out

their duty. Of this fairly high proportion of fatigued aircrew,75.6% of them had their

most recent episode of fatigue less than 4 weeks from when they participated in the

study. Based on their last experience of fatigue, 53.7% were found to be mildly

fatigued, 26.1% moderately fatigued while the remaining 20.2 % were severely

fatigued . Aircrew serving in the long haul category were more fatigued than those in

the short haul category (78.8%:67.6%) but there was however no statistically

significant difference. Generally, captains and co pilots rated themselves highly in how

well they perceived they performed on 9 crucial flying tasks. Between 54-76% of

them felt their performance on these tasks were good.

Respondents’ knowledge of fatigue coping mechanisms was varied ranging between

29.6% and 83.5%. Crew work/rest scheduling had the highest knowledge while the

cockpit naps have the lowest. Utilization was however high with over 70% of crew

members having had cause to utilize coping mechanisms. The most utilized

mechanism was crew work/rest scheduling (78.3%) while the least utilized was

listening to music (35.1%). Respondents’ perception of the effectiveness of these

mechanisms was also varied. While 82.9% of respondents found crew work/rest

scheduling to be very effective, 41% found exposure to bright light not effective at all.

Male aircrew seemed to experience more moderate and severe fatigue than their

female counterparts while married and single respondents had similar levels of

fatigue. Expatriate crew member had higher proportions of severely fatigued

individuals. There was however no significant association between these socio

demographic characteristics and fatigue levels.

Captains, co-pilots and cabin crew all had similar levels of severe fatigue while long

haul pilots had slightly higher levels of severe fatigue compared to short haul. The

was no statistically significant difference between smoking and fatigue as well as

alcohol and fatigue.

5.3 RECOMMENDATIONS

The following recommendations are made based on findings from this study;

1.The NCAA should develop regulations that establish appropriate flight time limits

which will be based on duty time and not sectors flown .

2. The NCAA should improve on enforcement of existing regulations concerning

discretion time flying and other safety related issues among airlines and individual

aircrew.

3. The NCAA should incorporate more training to highlight the dangers of fatigue

during flight and to promote the utilization of flight coping mechanisms for aircrew.

REFERENCES

1. Sharma RC, Shrivastava JK. Jet Lag and Cabin Crew. Indian Journal of Aerospace

Medicine. 2004:48(1), 10-14.

2. Caldwell JA, Mallis MM, Caldwell JL, Paul MA, Miller JC, & Neri DF. Fatigue counter

measures in Aviation. Aviation space and environmental medicine journal. 2009: 80

(1), 29-59.

3. Mckellar G. Fatigue issues re-visited; a layman’s look at legalese. Interpilot,

Journal of the International Federation of Airline Pilots : 2009:15(3) 3-4.

4. Jin-Ru YA, Chiung-Chi HA, Hsuan YA, Hero HB. An investigation of fatigue issues on

different flight operations . Journal of Air Transport Management .2009:19 (1) 236–

240.

5. Jackson CA, Earl L. Prevalence of fatigue among commercial pilots. Journal of

Occupational Medicine. 2006 : 56,263–268.

6. Dehart L, Davis J. Fundamentals of Aerospace Medicine, 4th edition: Philadelphia:

Lippincott Williams and Wilkins;2008. 842-843

7. McFarland RA. Human Factors in Air Transportation; Occupational Health and

Safety, 5th edition: New York :McGraw Hill;1995.131

8. Gosh PC . An introduction to human factors in Aviation, 2nd edition: Illinois : Home

press; 2002.67-68

9.Fisher E. Flight Safety foundation;2nd edition: London: Calderon press;2006.36

10. Steptoe A . Pilot fatigue in the UK. British Airline Pilots Association Aviation

Newsletter: 2011,5.17-19.

11. Statistics report from the Federal Airports Authority of Nigeria, A compilation of

Airport information for DNMM at World Aero Data effective 2006-2008,6. Available at

http://www.faannigeria.org/statistics.php. Accessed on 22/6/2011.

12. Rainford DJ, Gradwell DP. Ernsting’s Aviation Medicine, 4th edition: London:

Hodder Arnold ; 2006.773-775

13. Salazar GJ. Medical facts for pilots on Fatigue in Aviation. Federal Aviation

Authority Civil Aerospace Medical Institute brochure. Available at www.faa.gov/pilots/

safety/pilot safety brochures:2003,15.

14. Leigh S, Denise R, Philippa G. Fatigue management in the New Zealand Aviation

Industry, ATSB research and analysis report B:Canberra:ATSB press;2004.23-24.

15. Walton AJ. Manual of Flight and duty times of flight instructors in general Aviation.

New Jersey: John Wiley ; 1997.9-10

16. Caldwell JA, Caldwell JL. Fatigue in aviation: A guide to staying awake at the

stick: Oxford Journal of Occupational Medicine 2003 (7) :1047-9.

17. Dismukes RK , Berman BA, Loukopoulos LD. The limits of expertise: Rethinking

pilot error and the causes of airline accidents. Oxford journal of occupational

Medicine. 2007(6) 23-24.

18. Samuel A, Wegmann HM. Jet lag and sleepiness in aircrew. Journal of clinical

sleep medicine. 1995; (4):30–36.

19. Akerstedt TE. Consensus statement: Fatigue and accidents in transport

operations. Journal of clinical sleep Medicine 2000;9:395.

20. Akerstedt TE. Work hours, sleepiness and accidents. Journal of clinical sleep

medicine. 1995 (2):15–22.

21. Folkard S, Monk TH. Circadian performance rhythms : Hours of Work .1985.(7)

50-52.

22. Arendt J, Deacon S, English J, Hampton S, Morgan L. Melatonin and adjustment to

phase shift. Journal of clinical Sleep medicine. 1995;4 (2) :74–79.

23. Waterhouse J. Jet lag and shift work :Circadian rhythms. Human Factors and

Ergonomics journal. 1999 (8):398–401.

24. Dinges DF, Graeber RC, Connell LJ, Rosekind MR, Powell JW. Fatigue related

reaction time performance in long-haul flight crews. Journal clinical sleep Medicine.

1990;19:117.

25. Dinges DF, Graeber RC, Rosekind MR, Samuel A, Wegmann HM. Principles and

guidelines for duty and rest scheduling in commercial aviation. Moffett Field, CA:

NASA Ames Research Center; 1996. Report No. 1996110404.

26. Lyman EG, Orlady HW. Fatigue and associated performance decrements in air

transport operations. Moffett Field, CA: NASA Ames Research Center; 2001. Report

No.: NASA Contractor Report No. 166167.

27. Klein KE, Bruner H, Holtmann H, Rehme H, Stolze J, Steinhoff WD, et al.

Circadian rhythm of pilots’ efficiency and effects of multiple time zone travel .

Journal of Aerospace Medicine 1990; 41(2):125–32.

28. Caldwell JA, Caldwell JL, Darlington KK. Utility of dextroamphetamine for

attenuating the impact of sleep deprivation in pilots. Aviation Space Environment

Medicine 2003; 74(11):1125–34.

29. Costa G. The problem: shift work. The international journal of Chronobiology.

1997;14(2): 89–98.

30. Dement WC, Seidel WF, Cohen SA, Bliwise NC, Carskadon MA. Sleep and

wakefulness in aircrew before and after transoceanic flights. Aviation and Space

Environment Medicine 1996; 14–28.

31. Nicholson AN, Pascoe PA, Spencer MB, Stone BM, Green RL. Nocturnal sleep and

daytime alertness of aircrew after trans meridian flights. Aviation Space Environment

Medicine 1999;(12):43–52.

32. Sasaki M, Kurosaki Y, Mori A, Endo S. Patterns of sleep wakefulness before and

after trans meridian flights in commercial airline pilots. Aviation Space Environment

Medicine 1986; 57(12 ):B29–B42.

33. Graeber RC, Lauber JK, Connell LJ, Gander PH .International aircrew sleep and

wakefulness after multiple time zone flights: a cooperative study. Aviation Space

Environment Medicine 1986; 57(12):3–9.

34. Aschoff J, Hoffman K, Pohl H, Wever R. Re-entrainment of circadian rhythms after

phase-shifts. The international journal of Chronobiology 2001;2(1):23–78.

35. Klein KE, Wegmann HM .Significance of circadian rhythms in aerospace

operations. France: North Atlantic Treaty Organization Advisory Group for Aerospace

Research and Development; 1993. Report No. 247.

36. Buck A, Borbely AA. Wrist activity monitoring in air crew members: a method for

analyzing sleep quality following trans meridian flights. Journal of Biological Rhythms

1989;4(1):93–94.

37. Rosekind MR, Gander PH, Miller DL, Gregory KG, Smith RM, Weldon KJ, et al.

Fatigue in operational settings: examples from the aviation environment. Human

Factors 1994;36(2): 327–328.

38. Bourgeois-Bougrine S, Carbon P, Gounelle C, Mollard R, Coblentz A. Perceived

fatigue for short- and long-haul flights: a survey of 739 airline pilots. Aviation Space

Environment Medicine 2003;74(10):1072–7.

39. Rosekind MR, Conrad EL, Gregory KB, Miller DL. Crew factors in flight operations

XIII: a survey of fatigue factors in corporate/executive aviation operations.: NASA

AMES Research Center; 2000. NASA/TM-2000-209610.

40. Arnedt JT, Wilde GJ, Munt PW, Maclean AW. How do prolonged wakefulness and

alcohol compare in the effects they produce on a simulated task? Accident Annals of

Preventive Medicine. 2001; 33:337–38.

41. Goode JH. Are pilots at risk of accidents due to fatigue? Journal of Safety

maintenance: 2003; 34 : 309–13.

42. Miller DL . NASA Crew factors in flight operations: Research Center; 2003.

NASA/TM - 819619.

43. Gander PH, Graeber RC, Connell LJ, Gregory KB. Crew factors in flight operations:

VIII. Factors influencing sleep timing and subjective sleep quality in commercial long-

haul flight crews. NASA/AMES; 1991. Report No. NASA Technical Memorandum

103852.

44. Nicholson AN, Pascoe PA, Spencer MB, Stone BM, Green RL. Nocturnal sleep and

daytime alertness of aircrew after trans meridian flights. Aviation Space Environment

Medicine 2006; 5 (12): 43–52.

45. Samuel A, Wegmann HM, Vejvoda M, Drescher J, Gundel A, Manzey D, et al. Two

crew operations: stress and fatigue during long haul night flights. Aviation Space

Environment Medicine. 1997(8):679–87.

46. Rosekind MR, Gander PH, Miller DL, Gregory KG, Smith RM, Weldon KJ, et al.

Fatigue in operational settings: examples from the aviation environment. Human

Factors 1994;36(2): 327–38.

47. Boll PA, Storm WF, French J, Bisson RU, Armstrong SD, Slater T, et al. C-141

aircrew sleep and fatigue during the Persian Gulf conflict: nutrition, metabolic

disorders, and lifestyles of air crew 1993.NATOAGARD-CP533.

48. Williamson H. Stress, fatigue and performance in aviation, 2nd edition. England:

Ash gate Publishing Ltd 2001.43

49.Green RG, Muir H. Human factors for pilots. 4th edition England: Ash gate

Publishing Ltd. 1996.21-22

50. Campbell RD, Bagshaw M. Human performance and limitations in aviation. 2nd

edition. United Kingdom: Blackwell Science Ltd. 1999.305-6

51. Rosekind MR, Gregory KB, Miller DL, Lebacqz JV, Brenner M. Crew fatigue factors

in the Guantanamo Bay Aviation Accident. Journal of clinical Sleep Medicine.

1996;25:571.

52. Belenky G, Wesensten NJ, Thorne DR, Thomas ML, Sing HC, Redmond DP, et al.

Patterns of performance degradation and restoration during sleep restriction and

subsequent recovery: a sleep dose–response study. Journal of clinical sleep medicine

2003; 12(1):1–12.

53. Van Dongen HPA, Maislin G, Mullington JM, Dinges DF. The cumulative cost of

additional wakefulness: dose–response effects on neurobehavioral functions and sleep

physiology from chronic sleep restriction and total sleep deprivation. Journal of clinical

Sleep medicine. 2003;26(2):117–26.

54. Rosekind MR, Smith RM, Miller DL, Co EL, Gregory KB, Webbon LL, et al. Alertness

management: strategic naps in operational settings. Journal of clinical sleep medicine

1995;4:62–6.

55. Hobbs A, Williamson A. Association between Sleep, errors and contributing factors

in aircraft incidents. Human Factors and Ergonomics journal. 2003 45,2: 186-201.

56. Dinges DF, Powell JW. Sleepiness is more than lapsing . Journal of clinical and

sleep medicine. 1988;17:84.

57. Galinsky TL, Swanson NG ,Sauter SL ,Hurrell JJ, Schleifer LM. A field study of

supplementary rest breaks for data-entry operators. Journal of Ergonomics 2000;43

(5): 622–38.

58. Caldwell JA, Prazinko BF, Caldwell JL. Electroencephalographic activity and

psychomotor task performance in sleep deprived subjects during flying. Journal of

Clinical Neurophysiology 2003;114:23–31.

59. Neri DF, Oyung RL, Colletti LM, Mallis MM, Tam PY, Dinges DF. Controlled activity

as a fatigue countermeasure on the flight deck. Aviation Space Environment Medicine

2002;73(7):654–64.

60. Hursh SR, Redmond DP, Johnson ML, Thorne DR, Belenky TJ, Storm WF, et al.

Fatigue models for applied research in warfighting. Aviation Space Environment

Medicine 2004;75(3 ):44–53.

61. Belyavin A, Spencer MB. Modeling performance and alertness: the QinetiQ

approach. Aviation Space Environment Medicine. 2004; 75(3) 93–103.

62.Wirz-Justice A, Armstrong SM. Melatonin. Nature’s soporific ? Journal of Sleep

medicine 1996;5:137–41.

63. Caldwell JL. The use of melatonin: an information paper. Aviation Space

Environment Medicine. 2000;71:238–44.

64. Dan S, Lewy AJ. Scheduled exposure to light: a potential strategy to reduce jet

lag following trans meridian flight. Journal of Psychopharmacology.2004;20(3):566–8.

65. Stone BM, Turner C. Promoting sleep in shift workers and intercontinental

travelers. Chronology biological International .1997;14(2): 133–43.

66. Caldwell JA. Fatigue in Aviation. Travel Medicine and Infectious Disease (2005) 3,

85–96.

67. Caldwell JA, Caldwell JL. Comparison of the effects of zolpidem-induced

prophylactic nap to placebo naps and forced rest periods in prolonged work schedules.

Journal of clinical Sleep medicine.1998; 21(1):79–90.

68. Committee Report on Military Nutrition Research. Caffeine for the sustainment of

mental task performance: formulations for military operations. Washington, DC:

National Academy Press; 2001.

69. Federal Republic of Nigeria, Civil Aviation Act No 6-2006;part x, article 31

70. A compilation of reports of the directorate of licensing, NCAA. Records for Jan –

June 2011- (unpublished data)

71. Araoye MO. Research Methodology with Statistics for health and social sciences.

1st Edition 2004; Ilorin: Nathadex publishers,117-120

72. Lee KE. Incidence of United States Air Force Aircrew fatigue in the operational

setting. Aviation Space Environment Medicine. 1998 ; 74(11):1125–34.

73. Bourgeois-bougrine S, Cabon P, Gounelle C, Mollard R, Coblentz A. Perceived

fatigue for short and long haul flights: a survey of 739 pilots. Aviation Space

Environment Medicine 2003; 74:1072–7.

74. Stone B, Robertson k. Fatigue and its implications for aircrew :Thirty years

experience of international operations. Aviation Space Environment Medicine. 2008;

75(3) 13–17.

75. Caldwell JA, Caldwell JL, Schmidt RM. Alertness management strategies for

operational context. Sleep Medicine Reviews 2008 ; 12, 257–273.

76. Deros M, Daruis D, Baruhudeen N. Fatigue factors among regional pilots in

Malaysia. International Journal of Medicine and Medical Sciences 2012 (5) :115-122.

APPENDIX A:QUESTIONNAIRE

Fatigue occurrence, perception, knowledge and the utilization of its coping mechanisms among

commercial aircrew in Nigeria.

I am a post graduate medical doctor with the Lagos University Teaching Hospital and I am carrying out a

research project on the topic stated above. This study was conceived to capture the experiences of local

aviators as it pertains to fatigue. Kindly answer each question as sincerely as you can. The information you

provide will be treated with utmost confidence.

SECTION A: PERSONAL INFORMATION

1. Sex: (a) Male [ ] (b) Female [ ]

2. Age: in years (As at last birthday) ………………

3. Marital Status: (a) Single [ ] (b) Married [ ]

(c) Divorced [ ] (d) separated [ ] (e) Widowed [ ]

4. Religion: (a) Christianity [ ] (b) Islam [ ]

(c) Others, please specify ……………………………..

5. Nationality: …………………………………………………

6. Do you smoke ? (a) yes [ ] (b) No [ ]

7. Do you take alcohol ? (a) yes [ ] (b) No [ ]

8. Are currently on any medication ? (a) yes [ ] (b) No [ ]

9. If yes, what class(es) does it belong to ?

(a) Anti hypertensive [ ] (b) Anti diabetic [ ] (c) Anti malaria[ ] (d) Antibiotics [ ]

(e) Allergy and cold medicine [ ] (f) Sleep medicine [ ] (g) Pain medicine [ ]

(h) Others please specify ………………………………………………

10. Have you had to cope with any of the emotionally stressful issues listed below in the last six months ?

(You may tick more than one option as it applies to you)

(a) bereavement [ ] (b) Marital problems [ ] (c) Job Stress [ ]

(d) Major financial issues [ ] (e) Personal injury or illness [ ] (f) Poor health of a loved one [ ]

(g) pregnancy [ ] (I ) Not applicable [ ] (h) Others please specify ………………………………………………

SECTION B: OCCUPATION AND GENERAL INFORMATION

11. Current Function: (a) Captain [ ] (b) Copilot [ ] (c) Flight Engineer [ ] (d) Cabin crew [ ]

12. How long have you worked in your current capacity ? ………………………………………………………

13. What nature of flying duties are you currently assigned to ?

(a) Short haul [ ] (b) Long haul [ ]

14.On which type of aircraft are you qualified at present………………………………….

15.How many years have you held your professional license ?

ATPL [ ] CPL [ ] Flt Engr License [ ] Cabin Crew License [ ] ………………………………

16.How many hours did you spend flying during have your last work day ? ………………………………………

17.Do you believe a revision of regulations to reduce flying hours is needed ? (a) yes [ ] (b) No [ ]

18. If yes, what is the maximum number of flying hours you recommend per day ? …………………………………

19. How long on the average does it take you to commute from home to work ?

(a) less than 1hour [ ] (b) 1-2 hours [ ] (c) over 2hours [ ]

SECTION C: FATIGUE ASSESSMENT

Fatigue is a state of reduced mental or physical performance resulting from sleep loss or extended

wakefulness and/or physical activity that impairs a crew member’s ability to safely perform his/her duties

in an aircraft.

20.Have you ever been fatigued ? (a) yes [ ] (b) No [ ]

21.If yes, when was your last episode of fatigue …………………………… ( If not fatigued, skip to Question 25)

22. Below are a list of items associated with fatigue in aviation. Kindly indicate if you have experienced

them in the last six months. Tick the option that is most appropriate to you (only one option per item is

required)

PHYSICAL FATIGUE ASSESSMENT

ITEMS

None

(0)

Slight

(1)

Moderate

(2)

High

(3)

Very high

(4)

a. Smarting eyes/eye irritation

b. Yawning

c. Headache

d. Efforts to maintain wakefulness

e. Decreased verbal communication

f. Feeling of Lethargy

g. Difficulty evaluating time

h. Nodding off or becoming fixated

i. Slowed reaction time

j. Impaired mood

MENTAL FATIGUE ASSESSMENT ITEMS None

(0)

Slight

(1)

Moderate

(2)

High

(3)

Very high

(4)

SECTION D : EFFECT OF FATIGUE ON FLIGHT OPERATIONS (This section applies to flight deck crew only)

23. In what way did your last episode of fatigue hinder performance of the following flying tasks ? (you

are required to tick only one option per item )

Not at all Mild Moderately A great deal

(a)Flight path monitoring [ ] [ ] [ ] [ ]

(b)Manual flying [ ] [ ] [ ] [ ]

(c)Utilization of aircraft automation [ ] [ ] [ ] [ ]

(d)Communication [ ] [ ] [ ] [ ]

(e)Crew resources management [ ] [ ] [ ] [ ]

(f)Use of Check-list [ ] [ ] [ ] [ ]

(g)Selecting and entering data [ ] [ ] [ ] [ ]

k. Redundancy of some actions

l. Difficulty in making decisions

m. Slips ,lapses, minor errors

n. Lack of coherence or reasoning

o. Tendency to delay decision making

p. Difficulty in oral expression

q. Slow understanding

r. Easily distracted

s. Decline in attention

t. Sluggish actions and movements

(h) Take off [ ] [ ] [ ] [ ]

(i) Landing [ ] [ ] [ ] [ ]

24. How has your performance been on the following tasks in the last one month ? (you are required to

tick only one option per item)

Unsatisfactory Fair Good

(a)Flight path monitoring [ ] [ ] [ ]

(b)Manual flying [ ] [ ] [ ]

(c)Utilization of aircraft automation [ ] [ ] [ ]

(d)Communication [ ] [ ] [ ]

(e)Crew resources management [ ] [ ] [ ]

(f)Check-list [ ] [ ] [ ]

(g)Selecting and entering data [ ] [ ] [ ]

(h) Take off [ ] [ ] [ ]

(i) Landing [ ] [ ] [ ]

SECTION D: PERCEPTION AND UTILIZATION OF FATIGUE COPING MECHANISMS

25.Which Aircrew fatigue coping mechanisms are you familiar with ?

(a)On board sleeps [ ] (b) Cockpit naps [ ] (c) controlled rest breaks [ ]

(d) Crew work rest/scheduling [ ] (e) Alertness enhancing compounds [ ]

(f) Activity breaks [ ] (g) Move around in seat [ ]

(h) Others, please specify …………………………………………………………………………..

26. Have you had cause to utilize any of them? (a) yes [ ] (b) No [ ]

27.If yes, which one(s) have you used and how effective was it ? (only one option per item is required)

Never used Not effective Slightly Moderately Very effective

(a) On board sleeps [ ] [ ] [ ] [ ] [ ]

(b) Cockpit naps [ ] [ ] [ ] [ ] [ ]

(c) controlled rest breaks [ ] [ ] [ ] [ ] [ ]

(d) Crew work rest/scheduling [ ] [ ] [ ] [ ] [ ]

(e) Alertness enhancing compounds [ ] [ ] [ ] [ ] [ ]

(f) Activity breaks [ ] [ ] [ ] [ ] [ ]

(g) Move around in seat [ ] [ ] [ ] [ ] [ ]

(h) Listening to music/radio [ ] [ ] [ ] [ ] [ ]

(i) Exposure to cold air [ ] [ ] [ ] [ ] [ ]

(j) Bright light [ ] [ ] [ ] [ ] [ ]

(k) Others …………………………… [ ] [ ] [ ] [ ] [ ]

CONSENT TO PARTICIPATE IN STUDY ON AIR CREW FATIGUE AND COPING MECHANISMS

Hello sir/madam, my name is Dr Osagie Cole. I am a resident doctor in the department of Community

Medicine and Primary Care of the Lagos University Teaching Hospital,Idi Araba. I am carrying out this

study to learn about the experiences of aircrew in the aviation industry in Nigeria as it pertains to fatigue

(in view of the round the clock requirements of the industry). The study will also take a look at how

effective commonly employed coping mechanisms are from the view point of aircrew.

I would want to assure participants that all of the information obtained from this study will be treated with

utmost confidentiality and that the study is purely academic in nature . The names, addresses or airlines of

participating aircrew are not required .

Kindly append your signature below if you wish to participate.

Thank you.

Statement of individual giving consent

I clearly understand the nature of the research and I also understand that my participation is voluntary and

that I reserve the right to freely opt out of the study if I so desire. I have received a copy of this consent

form

DATE ---------------------------- SIGNATURE-------------------------------------

APPENDIX B-INDEPTH INTERVIEW GUIDE FOR REGULATORS AND AIRLINE

MANAGEMENT

I want to thank you for taking the time to meet with me today.

My name is Dr Osagie Cole and I would like to talk to you about Aircrew Fatigue as it

pertains to local aviators in the aviation industry in Nigeria. As one of the components

of my dissertation, I am interested in learning about how aircrew cope with fatigue

and the roles that various regulating bodies play concerning fatigue in the industry.

The interview should take less than an hour. I will be taping the session because I

don’t want to miss any of your comments. Although I will be taking some notes during

the session, I can’t possibly write fast enough to get it all down. Because we’re on

tape, please be sure to speak up so that we don’t miss your comments. All responses

will be kept confidential. This means that your interview responses will only be used

for research purposes. I will also ensure that any information we include in our report

does not identify you as the respondent. Remember, you don’t have to talk about

anything you don’t want to and you may end the interview at any time. Are there any

questions about what I have just explained?

Are you willing to participate in this interview?

------------------------------------ ---------------

Interviewee Date

QUESTIONS FOR REGULATORS AND AIRLINE MANAGEMENT

1. Please kindly list and explain the strategies/interventions that are in place to

check aircrew fatigue in the Nigerian aviation industry.

2. Which of these strategies/interventions should be promoted and why ?

3. Has any enforcement of these strategies been necessary ? Explain

4. Do you feel that aircrew flight scheduling methods currently in use in the

industry are satisfactory ? Please elaborate

5. Is there a confidential safety reporting system in place for aircrew where

incidents and near misses that are fatigue related can be reported to the

relevant authorities and the identities of those involved protected ? If yes

please give an overview of the system and your assessment of its effectiveness.

6. Are there any clear workplace policies and/or procedures that regularly check

the use of alcohol and drugs that can worsen the effects of fatigue ? Please

explain further.

7. What is the position of regulating authorities on discretion time flying and why ?

8. What is your view on the use of alertness enhancing compounds /stimulants to

counter fatigue? Is there a written policy on this ?

9. Are there regular training exercises conducted for aircrew that address human

factor issues such as the causes and effects of aircrew fatigue ? If yes, is it

mandatory and how regularly are they organized ?

10.Do you take feedback from pilots while designing crew schedules or is it based

only on preset industry standards ? please elaborate.

11.What recommendations do you have for reducing aircrew fatigue ?

12.Is there anything more you would like to add ?

Thank you for your time

APPENDIX C -INDEPTH INTERVIEW GUIDE FOR AIRCREW

I want to thank you for taking the time to meet with me today.

My name is Dr Osagie Cole and I would like to talk to you about Aircrew Fatigue as it

pertains to local aviators in the aviation industry in Nigeria. As one of the components

of my dissertation, I am interested in learning about how aircrew cope with fatigue

and the roles that various regulating bodies play concerning fatigue in the industry.

The interview should take less than an hour. I will be taping the session because I

don’t want to miss any of your comments. Although I will be taking some notes during

the session, I can’t possibly write fast enough to get it all down. Because we’re on

tape, please be sure to speak up so that we don’t miss your comments. All responses

will be kept confidential. This means that your interview responses will only be used

for research purposes. I will also ensure that any information we include in our report

does not identify you as the respondent. Remember, you don’t have to talk about

anything you don’t want to and you may end the interview at any time. Are there any

questions about what I have just explained?

Are you willing to participate in this interview?

------------------------------------ ---------------

Interviewee Date

QUESTIONS FOR AIRCREW

1. Please kindly list and explain the strategies you employ to check fatigue during

flights.

2. Which of these strategies/interventions should be promoted and why ?

3. Do you feel that flight scheduling methods currently in use in the industry are

satisfactory ? Please elaborate

4. Is there a confidential safety reporting system in place for you to report

incidents and near misses that are fatigue related ? If yes please give an

overview of the system and your perception of its effectiveness.

5. Are there any clear workplace policies and/or procedures that regularly check

the use of alcohol and drugs that can worsen the effects of fatigue ? Please

explain further.

6. Have you had to fly into your discretion time? If yes, is it an occasional or

regular occurrence and did it affect you in any way ?

7. What is your view on the use of alertness enhancing compounds /stimulants to

counter fatigue? Is there a written policy on this in Nigeria ?

8. Are there regular training exercises conducted for aircrew that address human

factor issues such as the causes and effects of aircrew fatigue ? Please

elaborate.

9. Do the airlines take feedback from pilots when designing crew schedules or is

it based only on preset industry standards ? please elaborate.

10.Based on your personal experience, do you have any recommendations for

reducing aircrew fatigue ?

11.Is there anything more you would like to add ?

Thank you for your time

APPENDIX D

LIST OF REGISTERED AIRLINES IN NIGERIA WITH AIR OPERATOR CERTIFICATES

1.Aerocontractors

2.Air Nigeria

3.Allied Air

4.Arik Air

5.Associated Aviation

6.Capital Airlines

7.Chanchangi Airlines

8.Dana Air

9.Dornier Aviation Nigeria

10.First Nation Airways

11.IRS Airlines

12.Kabo Air

13.Medview Airlines

14.Overland Airways

15.Pan African Airlines

16.Wings Aviation