fatigue occurrence, perception, knowledge and …
TRANSCRIPT
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