Claude Preitner
Senior Medical Officer
Civil Aviation Authority
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Why talk about fatigue
management
What is fatigue
Effect of fatigue
Physiology of sleep
Management of
fatigue
“The nose is down, the wing low, the plane is
diving and turning. I've been asleep with open
eyes... I kick left rudder and pull the stick
back... My eyes jump to the altimeter...I'm at
1600 feet. The turn-indicator leans over the
left - the airspeed drops - the ball rolls
quickly to the side...My plane is getting out of
control!”
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1993
1994
1997
1999
2001
2002
2004
2004
2004
2005
DC8 @ Guantanamo Bay
Air Algerie 737 @ Coventry
Korean Air 747 @ Guam
American Airlines MD82 @ Little Rock
Crossair BAe 146 @ Zurich
Challenger 604 @ Birmingham
MK Airlines 747 @ Halifax
Corporate Bae Jetstream 31 @ Kirkville
Med Air Lear 35a @ San Bernardino
Loganaira BN Islander @ Machrihanish
“The effects of fatigue are particularly prevalent
when all these three factors overlap...”
The crew had:
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limited sleep in the previous 48 hours
been awake more than 19 hours during both day
and night periods
to be at a high level of alertness during a period of
time (3-5 PM) associated with sleepiness.
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“Inability to function at one’s optimum
level, because physical and mental exertion
exceeds existing capacity” (P. Gander)
Multifactorial:
◦ Work duration and intensity (time on task fatigue)
◦ Inadequate recovery sleep, which has cumulative and dose
dependant effects
◦ Working at inappropriate times in the circadian cycle
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No biochemical markers for fatigue, no
breathanalyzer, no blood component
Electrical registration of
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heart activity (ECG)
brain activity (EEG)
eye movement (EOG)
body core temperature
measurement of blood- and urine content of enzymes and
hormones
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ECG showed increased parasympathetic regulatory
trend, most pronounced during return flight
(indication for drowsiness)
EEG showed signs of increased sleepiness, most
pronounced during return flight
Microsleeps (sleep-periods of more than 8 sec
duration) were found in pilots 5 times /hour in
average during the last part of the return flight
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Overtime  higher injury rate
◦ >12 h per day  37 % increase
◦ >60 h /week  23 % increase
(Dembe A & al, Occup Environ Med 2005:62:588-595)
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Safety and productivity reduced at night
Bhopal, Three Mile Island, Chernobyl, Exxon
Valdez: all at night !
Junior doctors: 70% more than 50 h/week, 13
% more than 70 h per week. 42% clinical error
in past 6 months.
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Sleep loss, i.e < ~ 8 h per day
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Continuous hours awake
◦ 17 h awake ~ 0.05 alcohol
◦ 22 h awake ~ 0.08 alcohol – legal limit
◦ 24 h awake ~ 0.10 alcohol
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Sleep quality: sleep apnoea, micturition,
pain, infant crying etc.
Circadian cycle upset [jet lag – night duty]
Lack of patience / snappy
More forgetful
Instrument cross check breaks down
Reduced Situational Awareness
Slows reaction time
Reduced G tolerance
Micro-sleeps
Sleep Cycle
Awake
Drowsy
state
REM
Stage 1
Stage 2
Stage 3
Stage 4
1
2
3
4
5
HOURS
6
7
8
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Prior sleep
Prior wakefulness / stress
Alcohol / coffee / tea /coca
Environmental/work conditions
Medications
Age
Circadian phase
 Body functions follow a pattern through the day
and night, fluctuating over app. 25 h (free run)
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Hormones
Alertness
Heart rate
Body temperature
Bowel function
 Body responds to “zeitgebers”’ (e.g. light)
 Moving to a new light/dark schedule
(e.g. shift work or time zone change)
can create desynchronization
Circadian Rhythm - Efficiency
The distribution, by time of day, of 6,052 vehicular accidents that
were judged by investigators to be fatigue related.
International Data (N=6,052)
1200
1100
Number of accidents
1000
900
800
700
600
500
400
300
200
100
Midnight
6 a.m.
Noon
Time of day
From Pack et al. (1995)
6 p.m.
Midnight
Shift work
Jet Lag
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Crossing multiple time zones
changes the zeitgebers
The body’s normal circadian
rhythms are disrupted
Different physiological
functions are out of step with
each other
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The internal clock cannot adapt
immediately to a new time or to a duty/rest
schedule change
The more time zone you cross, the longer it
takes
Faster adaptation with westward flights
because biological clock is longer than 24
hours
Faster adaptation when duty days
progressively begin later each day
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Different people
adapt at different
rates
“Evening-people”
adapt faster than
“morning-people”
Ability to adapt
decreases with age
Circadian
Rhythms
Sleep loss
Fatigue
Effects of fatigue
in aviation operations
The New York Times
http://www.nytimes.com/
GLOBAL EDITION
- Since 1879
LACK OF FATIGUE LEGISLATION
KILLS 300 IN RUNWAY EXCURSION
Even after aviation
authorities were gathered
in safety seminar, early
this year in Brazil, nothing
was done. There is no
fatigue legislation and no
one is even preoccupied
for the increased work
hours for pilots and
crewmembers. Market is
dictating new labor rules
everyday and authorities
around the world are too
startled to react, or play
the game of the capitals.
In efforts to cut costs,
pilots are asked to be
more productive, or they
will be left jobless.
Manufacturers are
suggesting bizarre
solutions too, they are
offering new harnesses
for passengers to travel
standing up, and went as
far as proposing only one
pilot in the cockpit during
long-range flights.
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Fatigue management SARPS, in Annexe 6 operation of aircraft - Part 1 - International Air
Transport – Aeroplanes
Current proposal for amendment by the Fatigue
Risk Management Task Force (FRMSTF)
FAA
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Fatigue management on most wanted list
Regulating flight duty time limit is not enough
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SARPS Implementation via local (NZ) legislation
Part 141 requirement for operators to have a
fatigue management system as part or SMS ?
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Address:
◦ Duration of work (time on task fatigue)
◦ Duration of rest
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Do not generally address:
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Workload
Circadian rhythms disruption
Sleep opportunities
Schedules
Life away from work
Safety risks associated with fatigued
crewmembers
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An integral part of SMS designed to limit the
degradation of alertness of the crew due to fatigue.
Science-based process and flexible.
Increase safety by reducing errors, incidents and
accidents caused by low levels of alert.
Regulations
Company
Policies &
Procedures
Training / Education
Students !!
Individual
Coping
Strategies
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Encourage reporting of fatigue
Allow withdraw from duty
Nap permitted <45 ‘ (middle to long haul)
Shift work: rotate forward i.e Morning evening,
night
Code of conduct for
off duty rest
◦ Students
◦ Instructors
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Preventive strategies
◦ Used before duty and on layovers to reduce adverse
effects of fatigue, sleep loss, and circadian
disruption (scheduling)
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Operational strategies
◦ Used in-flight to maintain alertness and
performance
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Begin a trip /a shift as
rested as possible
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At home & Layovers
◦ Maximize sleep 1-2 days
before departing on trip
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Strategic napping can
be very effective
◦ 45 minutes or less, if
just before duty
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Alcohol consumption can have “major disruptive
effects” on sleep quality
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Exercise regularly, but avoid just before bedtime
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Avoid TV or thrillers before bedtime
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If you can’t fall asleep in 30 minutes, get up and
engage in some relaxing activity
◦ Don’t just lay in bed and be frustrated
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Strategic caffeine consumption
◦ Best not to constantly drink caffeine before, during
and after duty
◦ Use it to best increase alertness
◦ Don’t use it when already alert (start of duty or
after a nap)
◦ Avoid caffeine near bedtime
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Sensible nutrition and stay hydrated
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A fatigued pilot has nothing to do in cockpit
A pilot will – at best – declare himself unfit for duty
due to fatigue one day too late
A pilot should be nearly as alert for duty on the last
day as on the first