Claude PreitnerSenior Medical Officer Civil Aviation Authority

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!”

1993 DC8 @ Guantanamo Bay 1994 Air Algerie 737 @ Coventry 1997 Korean Air 747 @ Guam 1999 American Airlines MD82 @ Little Rock 2001 Crossair BAe 146 @ Zurich 2002 Challenger 604 @ Birmingham 2004 MK Airlines 747 @ Halifax 2004 Corporate Bae Jetstream 31 @

Kirkville 2004 Med Air Lear 35a @ San Bernardino 2005 Loganaira BN Islander @ Machrihanish

“The effects of fatigue are particularly prevalent when all these three factors overlap...”

The crew had:

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.

“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

No biochemical markers for fatigue, no breathanalyzer, no blood component

Electrical registration of

◦ heart activity (ECG)◦ brain activity (EEG)◦ eye movement (EOG)◦ body core temperature◦ measurement of blood- and urine content of enzymes

and hormones

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

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)

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.

Sleep loss, i.e < ~ 8 h per day

Continuous hours awake◦ 17 h awake ~ 0.05 alcohol◦ 22 h awake ~ 0.08 alcohol – legal limit◦ 24 h awake ~ 0.10 alcohol

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

Drowsystate

REM

Stage 1

Stage 2

Stage 3

Stage 4

1 2 3 4 5 6 7 8

HOURS

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)

◦ 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.

From Pack et al. (1995)

International Data (N=6,052)

100

200

300

400

500

600

700

800

900

1000

1100

1200

Midnight 6 a.m. Noon 6 p.m. Midnight

Time of day

Nu

mb

er

of

acc

iden

ts

Shift work Jet Lag

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

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

Different people adapt at different rates

“Evening-people” adapt faster than “morning-people”

Ability to adapt decreases with age

Sleep lossCircadian Rhythms

Effects of fatigue in aviation operations

Fatigue

LACK OF FATIGUE LEGISLATIONKILLS 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.

The New York Timeshttp://www.nytimes.com/ GLOBAL EDITION - Since 1879

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 Fatigue management on most wanted list Regulating flight duty time limit is not enough

SARPS Implementation via local (NZ) legislation

Part 141 requirement for operators to have a fatigue management system as part or SMS ?

Address:

◦ Duration of work (time on task fatigue)◦ Duration of rest

Do not generally address:

◦ Workload◦ Circadian rhythms disruption◦ Sleep opportunities◦ Schedules◦ Life away from work◦ Safety risks associated with fatigued

crewmembers32

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.

Training / EducationStudents !!

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

Preventive strategies◦ Used before duty and on layovers to reduce

adverse effects of fatigue, sleep loss, and circadian disruption (scheduling)

Operational strategies◦ Used in-flight to maintain alertness and

performance

Begin a trip /a shift as rested as possible

At home & Layovers◦ Maximize sleep 1-2

days before departing on trip

Strategic napping can be very effective◦ 45 minutes or less, if

just before duty

Alcohol consumption can have “major disruptive effects” on sleep quality

Exercise regularly, but avoid just before bedtime

Avoid TV or thrillers before bedtime

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

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

Sensible nutrition and stay hydrated

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