Doc.9966 FRMS Manual for Regulators

8/3/2019 Doc.9966 FRMS Manual for Regulators

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Fatigue Risk Management Systems

2011 Edition

Manual for Regulators

Doc 9966 - UNEDITED VERSION


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Overview

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ii Contents

CONTENTS

FRMSManualforRegulators..................................................................................................................1

Chapter1:Introductiontofatigueriskmanagementsystems(FRMS)....................................................11

1.1Whatisafatigueriskmanagementsystem?..................................................................................... 11

1.2WhytheaviationindustryisintroducingFRMS................................................................................. 11

1.3 ICAOStandardsandRecommendedPracticesforfatiguemanagement.......................................... 13

1.3.1 Section4.10ofAnnex6,PartI.............................................................................................. 15

4.10.1.................................................................................................................................... 15

4.10.2.................................................................................................................................... 15

4.10.3.................................................................................................................................... 15

4.10.4.................................................................................................................................... 16

4.10.5.................................................................................................................................... 16

4.10.6....................................................................................................................................

164.10.7.................................................................................................................................... 17

4.10.8.................................................................................................................................... 17

1.3.2 Appendix8,Annex6,PartI................................................................................................... 18

1.4Structureofthismanual..................................................................................................................... 18

Chapter2:ScienceforFRMS..................................................................................................................21

2.1IntroductiontoscienceforFRMS....................................................................................................... 21

2.2Essentialsleepscience....................................................................................................................... 21

2.2.1Whatishappeninginthebrainduringsleep............................................................................ 21

2.2.2Theissueofsleepquality.......................................................................................................... 25

2.2.3Consequencesofnotgettingenoughsleep.............................................................................. 26

2.3Introductiontocircadianrhythms...................................................................................................... 29

2.3.1Examplesofcircadianrhythm................................................................................................... 29

2.3.2Thecircadianbodyclockandsleep.......................................................................................... 210

2.3.3Sensitivityofthecircadianbodyclocktolight......................................................................... 212

2.3.4Shiftwork.................................................................................................................................. 213

2.3.5Jet

lag

........................................................................................................................................

214

2.4SummaryofessentialscienceforFRMS............................................................................................. 217

Chapter3:FRMSpolicyanddocumentation...........................................................................................31

3.1IntroductiontoFRMSpolicyanddocumentation.............................................................................. 31


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Contents iii

3.2Appendix8,1.1: FRMSpolicy............................................................................................................ 33

3.2.1ScopeoftheFRMS.................................................................................................................... 33

3.3ExamplesofFRMSpolicystatements................................................................................................ 35

3.3.1FRMSpolicystatementforamajoraircarrier.......................................................................... 35

3.3.2FRMSpolicystatementforasmalleroperator

providingmedicalevacuationservices....................................................................................... 36

3.4Appendix8,1.2:FRMSdocumentation............................................................................................. 37

3.4.1ExampleofTermsofReferenceforaFatigueSafetyActionGroup......................................... 38

Chapter4:FatigueRiskManagement(FRM)Processes..........................................................................41

4.1IntroductiontoFRMprocesses.......................................................................................................... 41

4.2FRM

Processes

Step

1:

Identify

the

operations

covered

....................................................................

44

4.3FRMProcessesStep2:Gatherdataandinformation........................................................................ 44

4.4FRMProcessesStep3:Hazardidentification..................................................................................... 46

4.4.1Predictivehazardidentificationprocesses............................................................................... 46

4.4.2Proactivehazardidentificationprocesses................................................................................ 49

4.4.3Reactivehazardidentificationprocesses.................................................................................. 413

4.5FRMProcessesStep4:Riskassessment............................................................................................. 414

4.6FRMProcessesStep5:Riskmitigation............................................................................................... 416

4.7Example:SettingupFRMprocessesforanewULRroute................................................................. 418

4.7.1:Step1Identifytheoperation................................................................................................ 419

4.7.2:Step2Gatherdataandinformation..................................................................................... 419

4.7.3:Step3Identifyhazards.......................................................................................................... 421

4.7.4:Step4Assesssafetyrisk........................................................................................................ 422

4.7.5:Step5Selectandimplementcontrolsandmitigations........................................................ 422

4.7.5:Step6Monitoreffectivenessofcontrolsandmitigations................................................... 422

4.7.6:LinkingtoFRMSsafetyassuranceprocesses........................................................................... 423

Chapter5:FRMSsafetyassuranceprocesses..........................................................................................51

5.1IntroductiontoFRMSsafetyassuranceprocesses............................................................................. 51

5.2FRMS

Safety

Assurance

Processes

Step

1:

Collect

and

review

data

..................................................

54

5.3FRMSSafetyAssuranceProcessesStep2:EvaluateFRMSperformance.......................................... 55

5.4FRMSSafetyAssuranceProcessesStep3:Identifyemerginghazards.............................................. 56

5.5FRMSSafetyAssuranceProcessesStep4:IdentifychangesaffectingFRMS..................................... 56

5.6FRMSSafetyAssuranceProcessesStep5:ImproveeffectivenessofFRMS...................................... 57

5.7AssigningResponsibilityforFRMSSafetyAssuranceprocesses........................................................ 57

5.8ExamplesofFRMSsafetyassuranceprocessesinteractingwithFRMprocesses.............................. 58

4.7.6:

4.7.7:


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iv Contents

Chapter6:FRMSpromotionprocesses...................................................................................................61

6.1 IntroductiontoFRMSpromotionprocesses...................................................................................... 61

6.2 FRMStrainingprogrammes............................................................................................................... 62

6.2.1 Whoneedstobetrained...................................................................................................... 62

6.2.2 Curriculum............................................................................................................................ 62

6.2.3 FRMStrainingformatsandfrequency.................................................................................. 66

6.2.4 FRMStrainingevaluation...................................................................................................... 66

6.2.5 FRMStrainingdocumentation.............................................................................................. 67

6.3 FRMSCommunicationsplan.............................................................................................................. 67

Chapter7:DecidingtoofferFRMSregulations.......................................................................................71

7.1 IstheStatessafetyoversightsystemmatureenough?.................................................................... 71

7.2Dowehaveadequateresources?...................................................................................................... 72

7.3If

we

offer

FRMS,

can

we

pay

less

attention

to

our

prescriptive

regulations?

..................................

73

7.4WhatiftheStatealreadyhasaprocesstoapprove

anFRMSand/oroperatorswithanapprovedFRMS?....................................................................... 73

7.5Whenshouldtheoperatorapplyforavariationand

whenshouldtheyberequiredtoimplementanFRMS?................................................................... 74

7.6HowwillweassesstheacceptabilityoftheoperatorproposedouterlimitsoftheirFRMS?..........74

7.7WhataretheaspectsofanoperationforwhichFRMSouterlimitshavetobedetermined?.........75

7.8WhydontwedevelopregulationsthatrequireFRMStobeacomponentofSMS?........................ 76

7.9TheFRMSprovisionsrequirethatsignificantdeviationsinscheduledand

actualflighttimes,dutyperiodsandrestperiods,andreasonsforthose

significantdeviations,berecordedbyoperators.Howdowemonitorthat?.................................. 76

Chapter8:TheFRMSapprovalprocess..................................................................................................81

8.1APhasedapproachtoFRMSimplementation................................................................................... 81

8.1.1 PhaseI:Planning................................................................................................................... 81

8.1.2 PhaseII:ImplementreactiveFRMprocesses....................................................................... 83

8.1.3 PhaseIII:ImplementproactiveandpredictiveFRMprocesses............................................ 83

8.1.4 PhaseIV:ImplementFRMSsafetyassuranceprocesses...................................................... 83

8.1.5 OperationalExampleofstagedFRMSimplementation....................................................... 84

8.2 FRMSApprovalprocess..................................................................................................................... 86

8.2.1 RegulatoryMilestone1Notificationbytheoperator....................................................... 87

8.2.2 RegulatoryMilestone2ReviewofFRMSplan,policyanddocumentation....................... 87

Regulatorydocumentation............................................................................................................. 87

1. ReviewofFRMSplan................................................................................................................... 87

2. ReviewoftheinitialFRMSpolicyanddocumentationproposal................................................ 88


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Contents v

8.2.3 RegulatoryMilestone3ReviewofinitialFRMprocesses.................................................. 89

8.2.4 RegulatoryMilestone4ApprovalofFRMS........................................................................ 810

Chapter9: OversightofanFRMS...........................................................................................................91

9.1Regulatoryplanningfunctions........................................................................................................... 91

9.2 SpecialrequirementsforFRMSoversight......................................................................................... 91

9.3Enforcement...................................................................................................................................... 92

AppendixA:Glossary.............................................................................................................................A1

AppendixB:Measuringcrewmemberfatigue........................................................................................B1

B1 Crewmembersrecalloffatigue......................................................................................................... B1

B1.1 Fatiguereportingforms........................................................................................................ B1

B1.2 Retrospectivesurveys........................................................................................................... B3

B2Monitoring

crewmember

fatigue

during

flight

operations

...............................................................

B

4

B2.1 Subjectivefatigueandsleepinessratings............................................................................. B4

B2.2 Objectiveperformancemeasurement................................................................................. B7

B2.3 Monitoringsleep................................................................................................................... B8

B2.4 Monitoringthecircadianbodyclockcycle........................................................................... B13

B3 Evaluatingthecontributionoffatiguetosafetyevents.................................................................... B16

AppendixC:ProceduresforControlledRestontheFlightDeck..............................................................C1

AppendixD:ExampleofanFRMSEvaluationForm................................................................................D1


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Chapter1.IntroductiontoFRMS 11

Uneditedversion

Chapter1.Introductiontofatigueriskmanagementsystems(FRMS)1.1 Whatisafatigueriskmanagementsystem?ICAOhasdefinedfatigueas:

A physiological state of reduced mental or

physicalperformance capability resultingfrom

sleep loss or extended wakefulness, circadian

phase, or workload (mental and/or physical

activity) that can impair a crew members

alertness and ability to safely operate an

aircraftorperformsafetyrelatedduties.

Fatigue isamajorhumanfactorshazardbecause it

affectsmost

aspects

of

acrewmembers

ability

to

dotheirjob.Itthereforehasimplicationsforsafety.

A Fatigue Risk Management System (FRMS) is

definedas:

A datadriven means of continuously

monitoring and managing fatiguerelated

safetyrisks,baseduponscientificprinciplesand

knowledge as well as operational experience

that aims to ensure relevant personnel are

performingat

adequate

levels

of

alertness.

AnFRMSaimstoensurethatflightandcabincrew

members are sufficiently alert so they can operate

to a satisfactory level of performance. It applies

principles and processes from Safety Management

Systems (SMS)tomanagetherisksassociatedwith

crewmember fatigue. Like SMS, FRMS seeks to

achieve a realistic balance between safety,

productivity, and costs. It seeks to proactively

identify opportunities to improve operational

processes

and

reduce

risk,

as

well

as

identifying

deficiencies after adverse events. The structure of

anFRMSasdescribedhere ismodelledontheSMS

framework. The core activities are safety risk

management (described in the SARPS as FRM

processes) and safety assurance (described in the

SARPs as FRMS safety assurance processes). These

coreactivitiesaregovernedbyanFRMSpolicyand

supported by FRMS promotion processes. The

entire system must be documented to the

satisfactionoftheStateoftheOperator.

Both SMS and FRMS rely on the concept of an

effectivesafetyreportingculture1,wherepersonnel

havebeentrainedandareconstantlyencouragedto

reporthazardswheneverobservedintheoperating

environment.Toencouragethereportingoffatigue

hazards by all personnel involved in an FRMS, an

operatormustclearlydistinguishbetween:

unintentional human errors, which are

acceptedasanormalpartofhumanbehaviour

and

are

recognized

and

managed

within

theFRMS;and

deliberate violations of rules and established

procedures. An operator should have

processes independent of the FRMS to deal

withintentionalnoncompliance.

Toencourageanongoingcommitmentbypersonnel

toreporting fatiguehazards,theorganizationmust

takeappropriateactioninresponsetothosereports.

Whenaneffectivesafetyreportingsystemexists,a

largepercentageofsafetyreportsfromoperational

personnelrelateto identifiedorperceivedhazards,insteadoferrorsoradverseevents.

1.2 WhytheAviationIndustryisIntroducingFRMSThe traditional regulatory approach to managing

crewmemberfatiguehasbeentoprescribelimitson

maximumdaily,monthly,andyearlyflightandduty

hours, and require minimum breaks within and

between

duty

periods.

This

approach

comes

from

a

longhistoryof limitsonworkinghoursdatingback

to the industrial revolution. It entered the

transportationsector intheearly20thcentury ina

series of regulations that limited working hours in

rail, road and aviation operations . The approach

1SeeICAOSafetyManagementManual(Doc9859).

[Back to Overview][Back to Contents]


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12 IntroductiontoFRMS

Uneditedversion

reflects early understanding that long unbroken

periodsofworkcouldproducefatigue(nowknown

astimeontaskfatigue),andthatsufficienttimeis

needed to recover from work demands and to

attendtononworkaspectsoflife.

In

the

second

half

of

the

20th

century,

scientific

evidencebeganaccumulatingthat implicatedother

causes of fatigue in addition to timeontask,

particularlyin24/7operations.Themostsignificant

newunderstandingconcerns:

the vital importance of adequate sleep (not

just rest) for restoring and maintaining all

aspectsofwakingfunction;and

daily rhythms in theability to performmental

andphysicalwork,andinsleeppropensity(the

ability to fallasleep and stayasleep), that are

driven by the daily cycle of the circadian

biologicalclockinthebrain.

This new knowledge is particularly relevant in the

aviationindustrywhichisuniqueincombining24/7

operationswithtransmeridianflight.

In parallel, understanding of human error and its

role in accident causation has increased. Typically,

accidents and incidents result from interactions

between organizational processes (i.e. workplace

conditionsthat

lead

crewmembers

to

commit

active

failures), and latent conditions that can penetrate

current defenses and have adverse effects on

safety2. The FRMS approach is designed to apply

thisnewknowledgefromfatiguescienceandsafety

science. It is intended to provide an equivalent, or

enhancedlevelofsafetywhilealsoofferinggreater

operationalflexibility.

Prescriptive flight and duty time limits represent a

somewhat simplistic view of safety being inside

the

limits

is

safe

while

being

outside

the

limits

isunsafe and they represent a single defensive

strategy.Whiletheyareadequateforsometypesof

operations,theyareaonesizefitsallapproachthat

2Gander,P.H.,Hartley,L.,Powell,D.,Cabon,P.,

Hitchcock,E.,Mills,A.,Popkin,S.(2011).Fatiguerisk

managementI:organizationalfactors.AccidentAnalysis

andPrevention43:573590.

does not take into account operational differences

ordifferencesamongcrewmembers.

In contrast, an FRMS employs multilayered

defensivestrategiestomanagefatiguerelatedrisks

regardless of their source. It includes datadriven,

ongoingadaptive

processes

that

can

identify

fatigue

hazardsandthendevelop, implementandevaluate

controls and mitigation strategies. These include

both organizational and personal mitigation

strategies. While an FRMS is based on scientific

principles, its application within various aviation

contexts requires operational experience and

knowledge.AnFRMSshouldnotbeprovidedtoan

operatorbyaconsultant;itneedstobedeveloped,

understood and managed by people who have

comprehensive experience in the complex

operational environment to which it will apply. In

thisway,meaningfulinterpretationscanbemadeof

whatvariousdataanalysesmaymean inparticular

contexts, and workable operational strategies can

bedeveloped.

The cost and complexity of an FRMS may not be

justifiedforoperationsthatremain insidetheflight

anddutytime limitsandwhere fatiguerelatedrisk

is low. Some operators may therefore choose to

placeonlycertainpartsoftheiroperationsunderan

FRMSornotimplementanFRMSatall.Nonetheless,

wherean

FRMS

is

not

implemented,

it

remains

the

operators responsibility to manage fatigue risks

throughtheirexistingsafetymanagementprocesses.

Itwouldbeamisconceptiontothinkofanoperator

with an FRMS as having no flight and duty time

limitations. In fact, an operator continues to have

flight and duty time limitations but these are

identified through their own FRMS processes,

specific to a defined operational context, and are

continually evaluated and updated in response to

their own risk assessments and the data the

operator

is

collecting.

It

is

up

to

the

regulator

toassess whether the risk assessments, mitigations

andthedatacollectedareappropriate,andthatthe

flight and duty time limitations identified are

reasonable responses as evidenced in safety

performance indicators. This means that FRMS

necessitatesperformancebasedregulation.


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IntroductiontoFRMS 13

Uneditedversion

In essence, FRMS regulations will define a process

foroperatorsandregulatorstomanagefatiguerisk,

rather than prescribing limits that cannot consider

aspects specific to the organization or operating

environment.

1.3 ICAOStandardsandRecommendedPracticesforFatigueManagementThis section describes the Standards and

Recommended Practices (SARPs) relating to the

management of fatigue experienced by flight and

cabin crew. These SARPs provide a highlevel

regulatory framework for both prescriptive flight

and duty limitations and FRMS as methods for

managing fatigue risk. Both methods share two

importantbasic

features:

1.Theyare required to take into consideration the

dynamics of transient and cumulative sleep loss

and recovery, the circadian biological clock, and

the impact of workload on fatigue, along with

operationalrequirements.

2.Becausefatigueisaffectedbyallwakingactivities

notonlyworkdemands,regulations forbothare

necessarily predicated on the need for shared

responsibility

between

the

operator

and

individualcrewmembersfor itsmanagement.So,

whether complying with prescriptive flight and

dutylimitationsorusingandFRMS,operatorsare

responsible for providing schedules that allow

crewmembers to perform at adequate levels of

alertness and crewmembers are responsible for

using that time to start work wellrested. The

requirement for shared responsibility in relation

toFRMSisdiscussedfurtherinChapter3.

FRMS

also

shares

the

building

blocks

of

SMS.

This

means that an FRMS is predicated on: effective

safetyreporting;seniormanagementcommitment;

a process of continuous monitoring; a process for

investigation of safety occurrences that aims to

identifysafetydeficienciesratherthanapportioning

blame; the sharing of information and best

practices; integrated training for operational

personnel; effective implementation of standard

operatingprocedures(SOPs);andacommitmentto

continuous improvement. So, together, the

foundations

of

prescriptive

flight

and

duty

time

limitations and SMS form the building blocks of

FRMS(seeTable1).

Prescriptiveflightanddutytimelimitations

Addressestransientand

cumulativefatigue

Sharedoperatorindividual

responsibility

SMS Effectivesafetyreporting

Seniormanagementcommitment

Continuousmonitoringprocess

Investigationofsafetyoccurrences

Sharingof

information

Integratedtraining

EffectiveimplementationofSOPs

Continuousimprovement

Table1:FRMSbuildingblocks

However, an FRMS, as a management system

focused on fatigue, also has added requirements

beyond that which would be expected of an

operatorcomplyingwithprescriptiveflightandduty

time limitations and managing their fatigue risks

through

their

SMS.

In

meeting

these

additional

FRMSspecific requirements, an operator with an

approved FRMS may move outside the prescribed

limits.Therefore,thefatiguemanagementSARPsin

Section 4.10, Annex 6, Part I, include particular

Standards that enable the effective regulation of

FRMS.Theseare,inturn,supportedbyAppendix8,

whichdetailstherequirementsforanFRMS.

1.3.1 Section4.10ofAnnex6,PartI:The

SARPs

related

to

fatigue

management

of

flight

andcabincrewareasfollows:


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Uneditedversion

Annex6,PartI4.10FatigueManagement

4.10.1 The State of the Operator shall establish regulations for the purpose of managing fatigue. These

regulationsshallbebaseduponscientificprinciplesandknowledge,withtheaimofensuringthatflightandcabin

crew members are performing at an adequate level of alertness. Accordingly, the State of the Operator shall

establish:

a) regulationsforflighttime,flightdutyperiod,dutyperiodandrestperiodlimitations;and

b) where authorizing an operator to use a Fatigue Risk Management System (FRMS) to manage fatigue,

FRMSregulations.

4.10.2 TheStateoftheOperatorshallrequirethattheoperator,incompliancewith4.10.1andforthepurposes

ofmanagingitsfatiguerelatedsafetyrisks,establisheither:

a) flight time, flight duty period, duty period and rest period limitation that are within the prescriptive

fatiguemanagementregulationsestablishedbytheStateoftheOperator;or

b) aFatigueRiskManagementSystem(FRMS)incompliancewith4.10.6foralloperations;or

c)

anFRMS

in

compliance

with

4.10.6

for

part

of

its

operations

and

the

requirements

of

4.10.2

a)

for

the

remainderofitsoperations.

4.10.3 Wheretheoperatoradoptsprescriptivefatiguemanagementregulationsforpartorallofitsoperations,

theStateoftheOperatormayapprove,inexceptionalcircumstances,variationstotheseregulationsonthebasis

ofariskassessmentprovidedbytheoperator.Approvedvariationsshallprovidealevelofsafetyequivalentto,or

betterthan,thatachievedthroughtheprescriptivefatiguemanagementregulations.

4.10.4 TheStateoftheOperatorshallapproveanoperatorsFRMSbefore itmaytaketheplaceofanyorallof

theprescriptivefatiguemanagementregulations.AnapprovedFRMSshallprovidealevelofsafetyequivalentto,

orbetterthan,theprescriptivefatiguemanagementregulations.

4.10.5 StatesthatapproveanoperatorsFRMSshallestablishaprocesstoensurethatanFRMSprovidesalevel

ofsafetyequivalentto,orbetterthan,theprescriptivefatiguemanagementregulations.Aspartofthisprocess,

theStateoftheOperatorshall:

a) requirethattheoperatorestablishmaximumvaluesforflighttimesand/orflightdutyperiods(s)andduty

period(s),andminimumvaluesforrestperiods.Thesevaluesshallbebaseduponscientificprinciplesand

knowledge,subjecttosafetyassuranceprocesses,andacceptabletotheStateoftheOperator;

b)mandateadecreaseinmaximumvaluesandanincreaseinminimumvaluesintheeventthattheoperators

dataindicatesthesevaluesaretoohighortoolow,respectively;and

c) approve any increase in maximum values or decrease in minimum values only after evaluating the

operatorsjustification for such changes, based on accumulated FRMS experience and fatiguerelated

data.

4.10.6

Wherean

operator

implements

an

FRMS

to

manage

fatigue

related

safety

risks,

the

operator

shall,

as

a

minimum:

a) incorporatescientificprinciplesandknowledgewithintheFRMS;

b) identifyfatiguerelatedsafetyhazardsandtheresultingrisksonanongoingbasis;

c) ensurethatremedialactions,necessarytoeffectivelymitigatetherisksassociatedwiththehazards,are

implementedpromptly;

d) provideforcontinuousmonitoringandregularassessmentofthemitigationoffatiguerisksachievedby

suchactions;and

e) provideforcontinuousimprovementtotheoverallperformanceoftheFRMS.


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Uneditedversion

4.10.7 Recommendation.Statesshouldrequirethat,whereanoperatorhasanFRMS,itisintegratedwiththeoperatorsSMS.

4.10.8 An operator shall maintain records for all its flight and cabin crew members of flight time, flight duty

periods,dutyperiods,andrestperiodsforaperiodoftimespecifiedbytheStateoftheOperator.

TheintentofeachoftheseSARPsisdiscussedbelow.

STANDARD INTENT4.10.1 Standard 4.10.1 stipulates the States responsibilities for establishing regulations for fatigue

management. The establishment of regulations for prescriptive limitations remains mandatory,

whiletheestablishmentofregulationsforFRMSisoptionalfortheState.Bothtypesofregulations

need to address the known scientific principles, including the dynamics of transient and

cumulativesleeplossandrecovery,thecircadianbiologicalclock,andthe impactofworkloadon

fatigue,

along

with

knowledge

gained

from

specific

research

and

operational

experience

and

requirements.Further,bothtypesofregulationsneedtoemphasizethatwithinanoperation,the

responsibility for managing fatigue risks is shared between management and individual

crewmembers(discussedinChapter3).

4.10.2 Standard4.10.2aims to makeclearthat,where theStatehas established regulations forFRMS,

operatorsthenhavethreeoptionsformanagingtheirfatiguerisks: a)theycandososolelywithin

theirStatesflightanddutytimelimitationsregulations;b)theycanchoosetoimplementanFRMS

for all operations; or c) they can implement an FRMS in part of their operations and use

prescriptiveflightanddutytime limitations inotheroperations.Therefore,thisStandard intends

to allow the operator to decide which method of fatigue management is most appropriate for

theirspecifictypesofoperations.Giventhischoice, it is likelythatmanyoperatorswillembrace

the

safety

and

operational

benefits

offered

through

an

FRMS

approach

Where the State does not have FRMS regulations, operators must manage their fatiguerelated

riskswithin theconstraintsof theirStatesprescriptive flightanddutytime limitationsorState

approvedvariationstothose limitations.Manywillchoosetodosothroughtheirexistingsafety

management processes. However, an FRMS approach, as described here with its added

requirements,canalsobeappliedwithinprescriptiveflightanddutyperiodlimitations.

4.10.3 It is recognised that prior to the FRMS Standards, many States had approved variations to the

prescribedflightanddutytimelimitationsforoperators.Insomecases,thesevariationsrelateto

very minor extensions and Standard 4.10.3 allows an operator to continue to have minor

extensions to scheduled operations without having to develop and implement a full FRMS.

Approval

of

the

variation

is

subject

to

the

provision

of

a

risk

assessment

acceptable

to

the

regulator.

The intent of Standard 4.10.3 is to minimize regulation through variations and to avoid the

approvalofvariationsthatmeetoperationalimperativesintheabsenceofariskassessment.Itis

notintendedtoofferaquickandeasyalternativetoanFRMSwhenamorecomprehensivefatigue

riskmanagementapproachisrequired.Norisitintendedtobeusedtoaddressdeficienciesdueto

inadequateprescriptiveregulations.Importantly,itonlyappliesinexceptionalcircumstances.


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Uneditedversion

STANDARD INTENT4.10.4 Standard4.10.4meansthatapproval isgivenwhentheoperatorcanclearlydemonstratethatall

FRMSprocessesarefunctioningeffectively.Itisnotsimplygivenbasedonadocumentedplanto

putanFRMS inplaceoradesktopreviewofanFRMSmanual.Standard4.10.4alsomeansthat

operators need to support an iterative approach to developing an FRMS (also described in

Chapter8).

ApprovalfortheoverallFRMScanonlybegivenonceallfourcomponentprocesses(discussedin

Chapters3,4,5and6respectively)aredevelopedandtheStatehasconfidencethattheoperator

canadjustflightanddutytimesappropriately (i.e.bothoverandunderprescriptive limitations),

can put mitigations in place inaccordancewith evidenceprovided through theirFRMS, and the

effectivenessoftheFRMShasbeenprovenovertimeusingthesafetyassuranceprocesses.During

the last phase of development, and prior to gaining approval, the operator will be working to

agreeduponlimitsdeterminedthroughthefatigueriskmanagementprocesses.Theselimitsmay

beoutsideprescriptiveflightanddutyregulationsfortheparticularoperationsonwhichitsinitial

FRMS efforts are focused. This last phase of development is necessary in order to validate the

FRMSsafety

assurance

processes

and

is

essentially

adefined

trial

period

for

the

entire

FRMS.

Onceapprovalhasbeengiven,and intheoperationstowhichtheFRMSapplies,theoperator is

abletouseitsFRMStomoveawayfromflightanddutytimelimitationstoanewlimitthatcanbe

supportedbydatawithintheStateapprovedupperboundaryoftheFRMS(see4.10.5).

ShouldanoperatorseektomisuseanFRMStobenefitfromdutytimesthatcannotbesupported

by scientific principles, collected data and other FRMS processes (i.e. that does not meet the

minimumrequirementsofanFRMSasidentifiedinAppendix8ofAnnex6,PartI),theStatewould

havetowithdrawitsapprovaloftheFRMS.Theoperatorwouldthenberequiredtocomplywith

prescriptivelimitations.

4.10.5

4.10.5

is

a

change

management

SARP,

aiming

to

assist

the

regulator

in

the

successfulintroductionoftheperformancebasedregulationsthatFRMSrequires.

4.10.5a)requirestheoperatortoidentifyanupperboundarywhichflightanddutytimeswillnot

exceed, and a lower boundary under which no rest period will be shortened, even when using

mitigations and processes within an FRMS. It aims to offer an extra layer of insurance and sets

clearexpectationsamongstallstakeholders.

4.10.5b)providesregulatorswitha lessdrasticalternativetowithdrawingapprovalforanFRMS

when an adjustment will suffice to ensure that an equivalent level of safety is maintained. It

intends to be proactive, in that it addresses less serious situations where an operators data

indicatesatrendthatsuggeststhevaluesmaybetoohighortoolow.

4.10.5 c) ensures that operators who have demonstrated the responsible and comprehensive

managementoftheirfatiguerelatedrisksthroughamatureFRMSarenotpreventedfromgaining

itsfullbenefitsbyunnecessarilyrestrictiveconstraints.

4.10.6 4.10.6provideshighlevelminimumrequirementsforanFRMSandnotesmoredetailedminimum

requirementsnotappropriate forthemainbodyoftheAnnex, inAppendix8.Essentially,4.10.6

provides the broad brushstrokes of what an FRMS must have, while Appendix 8 fills in the


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STANDARD INTENTcomponentsinmoreofdetail.ThisStandardispresentedinasimilarformatasSMSStandard3.3.4

(Annex 6, Part I) to reflect the similarities and consistencies in approaches between FRMS and

SMS.

For

the

regulator,

4.10.6

means

that

it

will

be

necessary

to

provide

adequate

assessment

and

oversight of a) to e). Processes and documentation will have to be developed that outline the

Statesapprovalandoversightcriteriainlinewiththeregulationsthataredeveloped.Thismanual

aimstoprovidedetailedinformationtoassisttheregulatorinachievingthis.

4.10.7 4.10.7recognisestherelationshipbetweenFRMSandSMS.BecauseFRMShasasafetyfunction,it

should be complementary to existing safety management processes within an operators SMS.

Ideally, where multiple systems are utilised to identify hazards and manage risk theyshould be

integrated to maximise their combined effectiveness, to ensure resources are being distributed

appropriatelyacrossthesystemsand,wherepossible,toreduceduplicatedprocessesforgreater

systemefficiency.So,anoperatorwishingtoimplementanFRMSandwhoalreadyhassufficiently

matureSMSprocesses inplaceshouldbeabletoreadilyadoptandunderstandthefundamental

processes

of

an

FRMS.

Examples

of

such

maturity

would

include

the

routine

use

of

hazard

identification, risk assessment and mitigation tools, and the existence of an effective reporting

culture(referSMM,227).Wheresuchsystemsarealreadyinplace,itshouldnotbenecessaryfor

anoperatortodevelopentirelynewprocessestoimplementFRMS.Rather,FRMScanbuildupon

theorganisationsexistingriskmanagementandtrainingprocesses.

The importance of coordinating FRMS and existing safety management processes cannot be

overemphasised in order to avoid overlooking or prioritising risks inappropriately. For example,

fromanSMSviewpoint,asuccessionofgroundproximitywarningsatthesamepoint,onthesame

approach,andonthesameflightnumber,maywellbeattributedto inadequatepilottraining in

altitude management and maintenance of the localizer and glide slope. Without the particular

focusand

methods

of

measurement

associated

with

an

FRMS,

it

may

not

be

as

obvious

that

the

succession of ground proximity warnings occurred on flights that were part of a particularly

fatiguing sequence which resulted in tired pilotsnot paying enough attention. Bothpossibilities

needtobeconsideredandthereforethetwosystemsdesignedtodothiscannotworkinisolation.

However,thedegreeofintegrationbetweenanoperatorsSMSanditsFRMSwilldependonmany

factors, including the relative maturity of the two systems, and operational, organisational and

regulatory considerations. Further, given that the level of maturity for each operatorsSMS will

vary significantly, the operator is not required to have an SMS accepted by the State before

establishinganFRMS.Thus,4.10.7isaRecommendedPracticeratherthanaStandard.

Whereanoperatordoesnotwishto implementanFRMSorhashad itsFRMSapprovalrevoked,

theregulatorshouldrequiretheoperatortousetheirSMStomanagefatiguerelatedriskswithin

prescriptivelimitations.

4.10.8 Irrespective of which method of fatigue management is used (i.e. compliance with prescriptive

flightanddutylimitationsorimplementationofanapprovedFRMS),alloperatorsarerequiredto

maintainrecordsofworkingperiods,withorwithoutflightduties,forflightandcabincrew.Itisup

toeachregulatortostipulatetheperiodoftimewhichtheserecordsmuchbekept.


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1.3.2 Appendix8,Annex6,PartIAppendix 8 gives detailed requirements for an

FRMS which must include, at a minimum, the

followingcomponents:

1.FRMS

policy

and

documentation;

2.Fatigueriskmanagementprocesses;

3.FRMSsafetyassuranceprocesses;and

4.FRMSpromotionprocesses.

Table1.1showshowthesecomponentsmaptothe

requirementsofSMS.

SMSFramework FRMS

1.Safetypolicy

and

objectives

1. FRMSpolicyanddocumentation

2.Safetyrisk

management

2. FRMprocesses

Identificationofhazards Riskassessment Riskmitigation

3.Safety

assurance

3. FRMSsafetyassuranceprocesses

FRMSperformancemonitoring Managementofoperational

andorganizationalchange

ContinuousFRMSimprovement4.Safety

promotion

4. FRMSpromotionprocesses

Trainingprograms FRMScommunicationplan

Table1.1: ComparingSMSandFRMSComponents

ThecoreoperationalactivitiesoftheFRMSarethe

FRM processes and the FRMS safety assurance

processes. They are supported by organizational

arrangements defined in the FRMS policy and

documentation, and by the FRMS promotion

processes.

1.4StructureofthismanualFigure 1.1 shows a basic framework linking the

required components of an FRMS. For ease of

explanation, Figure 1.1 presents a single, central,

functionalgroup,designatedastheFatigueSafety

Action Group, responsible for all of these FRMS

components. The Fatigue Safety Action Group

includes representatives of all stakeholder groups

(management,

scheduling,

and

crewmembers)

andother individuals as needed to ensure that it has

appropriate access to scientific and medical

expertise. However, depending on the

organizationalstructure,someoftheFatigueSafety

ActionGroup functionsasdescribed inthismanual

may be undertaken by other groups within the

organization (discussed further in Chapter 3). The

important thing is that, irrespective of who does

them, all of the component functions required

underanFRMSbeperformed.


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Figure1.1:LinkingtherequiredcomponentsofanFRMS

CommunicationbetweentheFRMSandtheSMS(in

both directions) is necessary to integrate the

management of the fatigue risks into the broader

riskmanagementactivitiesoftheSMS.Evenso,the

regulator

will

need

to

be

able

to

distinguish

the

FRMS activities from the SMS functions to allow

adequatemonitoring.

ThedetailedstructureofanFRMS,andthespecific

waysinwhichitlinkstoanoperatorsSMS,willvary

accordingto:

thesizeoftheorganization;

the type and complexity of the operations

beingmanaged;

therelativematurityoftheFRMSandtheSMS;

and

therelativeimportanceofthefatiguerisks.

The FRMS approach is based on applying scientific

principles and knowledge to manage crewmember

fatigue.Chapter2introducestheessentialscientific

concepts that are needed to provide adequate

oversightofanFRMS.Chapters3,4,5,and6each

deal with one of the required FRMS components.

Chapter 7 discusses considerations for the State

priortomakingthedecisionwhethertoofferFRMS

regulations. Chapter 8 steps though the approval

process

of

an

FRMS,

while

the

continued

oversight

ofanFRMSisdiscussedinChapter9.

AppendicesA,BandCprovideextrainformationto

support the concepts that are provided in the

precedingchapters.Foreaseofreference,Appendix

Aprovidesaglossaryoftermsused inthismanual.

AppendixB provides moredetailed informationon

methods of measuring fatigue as part of the FRM

processespresented in Chapter 8, Appendix Calso

supportsChapter3byprovidingfurtherinformation

on using controlled rest on the flight deck as a

mitigator

of

fatigue

risk.

Finally,

Appendix

D

provides an example of an FRMS evaluation form

foruseintheregulatoryoversightofanFRMS.


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Chapter2.ScienceforFRMS 21

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Chapter2:ScienceforFRMS

2.1 IntroductiontoscienceforFRMS

The FRMS approach represents an opportunity for

operatorstouseadvances inscientificknowledgeto

improvesafetyandincreaseoperationalflexibility.To

provideeffectiveoversight,Statesshouldbeawareof

thescientificprinciplesonwhichtheFRMSapproach

isbased.Thesearereviewedinthischapter.

In Chapter 1, the ICAO definition of crewmember

fatiguewasgivenas:

A physiological state of reduced mental or

physical performance capability resulting

fromsleep

loss

or

extended

wakefulness,

circadianphase,orworkload (mentaland/or

physical activity) that can impair a crew

members alertness and ability to safely

operateanaircraftorperformsafetyrelated

duties.

In flightoperations, fatigue canbemeasuredeither

subjectively by having crewmembers rate how they

feel, or objectively by measuring crewmembers

performance(Chapter4andAppendixB).

Anotherwayofthinkingaboutthisisthatfatigueisa

statethatresultsfromanimbalancebetween:

the physical and mental exertion of all wakingactivities(notonlydutydemands);and

recovery from that exertion, which (except forrecoveryfrommusclefatigue)requiressleep.

Following this line of thinking, to reduce

crewmember fatigue requires reducing the exertion

of waking activities and/or improving sleep. Two

areasofsciencearecentraltothisandarethefocus

ofthischapter.

1.Sleep science particularly the effects of notgetting enough sleep (on one night or across

multiplenights),andhowtorecoverfromthem;

and

2.Circadianrhythmsthestudyofinnaterhythmsdriven by the daily cycle of the circadian

biological clock (a pacemaker in the brain).

Theseinclude:

rhythms in subjective feelings of fatigue andsleepiness;and

rhythms in theability toperformmentalandphysicalwork,whichaffecttheeffortrequired

to reach an acceptable level of performance

(exertion);and

rhythmsinsleeppropensity(theabilitytofallasleepandstayasleep),whichaffectrecovery.

2.2

Essentialsleep

science

There isawidespreadbelief that sleep time canbe

tradedoff to increase theamountof timeavailable

forwakingactivities inabusy lifestyle.Sleepscience

makes it very clear that sleep is not a tradable

commodity.

2.2.1 Whatishappeninginthebrainduringsleep

There are a variety of ways of looking at what is

happening in the sleeping brain, from reflecting on

dreams to using advanced medical imaging

techniques. Currently, the most common research

methodisknownaspolysomnography(seeAppendix

B for details). This involves sticking removable

electrodestothescalpandfaceandconnectingthem

to a recording device, to measure three different

types of electrical activity: 1) brainwaves

(electroencephalogram or EEG); 2) eye movements

(electroculogram or EOG); and 3) muscle tone

(electromyogram or EMG). Using polysomnography,

it is possible to identify two very different kinds of

sleep.

Nonrapideyemovementsleep

Compared to waking brain activity, nonRapid Eye

Movement sleep (nonREM sleep) involves gradual

slowingofthebrainwaves.Theamplitude(height)of

thebrainwavesalsobecomes largeras theelectrical

[Back to Contents] [Back to Overview]


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22 ScienceforFRMS

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activity of large numbers of brain cells (neurons)

becomes synchronized so that they fire in unison.

Heartrateandbreathingtendtobeslowandregular.

People woken from nonREM sleep do not usually

recall much mental activity. However, it is still

possible

for

the

body

to

move

in

response

to

instructions from the brain. Because of these

features,nonREMsleepissometimesdescribedasa

relativelyinactivebraininamovablebody.

NonREMsleepisusuallydividedinto4stages,based

onthecharacteristicsofthebrainwaves.

Stages1and2 represent lightersleep (it isnotvery

difficult to wake someone up). It is usual to enter

sleepthroughStage1andthenStage2nonREM.

Stages3and4representdeepersleep(itcanbevery

hard to wake someone up). Stages 3 and 4 are

characterized by high amplitude slow brainwaves,

andaretogetheroftendescribedasslowwavesleep

(ordeepsleep).

Slowwave sleep has a number of important

properties. Pressure for slowwave sleep builds up

acrosswaking anddischarges across sleep. In other

words:

thelongeryouareawake,themoreslowwavesleep

youwill

have

in

your

next

sleep

period;

and

acrossasleepperiod,theproportionoftimespentin

slowwavesleepdecreases.

Thisrisingandfallingofpressureforslowwavesleep

is sometimes called the sleep homeostatic process,

and it is a component in most of the bio

mathematical models that are used to predict

crewmemberfatiguelevels(seeChapter4).

Even inslowwavesleep,thebrain isstillabout80%

activatedandcapableofactivecognitiveprocessing.

There is growing evidence that slowwave sleep is

essential for the consolidation of some types of

memory, and is therefore necessary for learning.

OPERATIONALNOTE:

Mitigationstrategiesforsleepinertia

Operationally,slowwavesleepmaybe importantbecause thebraincanhavedifficulty transitioningoutof it

whensomeoneiswokenupsuddenly.Thisisknownassleepinertiafeelingsofgrogginessanddisorientation,

withimpairedshorttermmemoryanddecisionmaking.Sleepinertiacanoccurcomingoutoflightersleep,but

ittendstobelongerandmoredisorientingwhensomeoneiswokenabruptlyoutofslowwavesleep.

Thisissometimesusedasanargumentagainsttheuseofflightdecknappingorinflightsleep.Itwouldnotbe

desirable tohave a crewmemberwho iswokenupbecauseofan emergency,butwho is impairedby sleep

inertia.Thisargumentisbasedontheeffectsofsleepinertiaseeninlaboratorystudies.

However,studiesofnappingon the flightdeckandofsleep inonboardcrewrest facilitiesshowthatsleep in

flightcontainsvery littleslowwavesleep. (It is lighterandmore fragmented thansleepon theground).This

meansthatsleepinertiaismuchlesslikelytooccurwakingupfromsleepinflightthanwouldbepredictedfrom

laboratorysleepstudies.Theriskofsleepinertiacanalsobereducedbyhavingaprotocolforreturningtoactive

dutythatallowstimeforsleepinertiatowearoff.

Overall,thedemonstratedbenefitsofcontrollednappingandinflightsleepgreatlyoutweighthepotentialrisks

associatedwithsleepinertia.Toreducetheriskofsleepinertiaafterflightdecknapping,therecommendationis

to limit the time available for the nap to 40 minutes. Given the time taken to fall asleep, a 40minute

opportunity is too short formostpeople toenter slowwave sleep.Refer toAppendixC for suggestedFlight

OperationsManualproceduresforcontrollednapping.


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ScienceforFRMS 23

Uneditedversion

Rapideyemovementsleep

DuringRapidEyeMovementsleep(REMsleep),brain

activitymeasuredbypolysomnography looks similar

to brain activity during waking. However in REM

sleep,fromtimetotimetheeyesmovearoundunder

the

closed

eyelids

the

socalled

rapid

eye

movements and this is often accompanied by

muscle twitches and irregular heart rate and

breathing.

People woken from REM sleep can typically recall

vivid dreaming.At the same time, the body cannot

moveinresponsetosignalsfromthebrainsodreams

cannot be acted out. (The signals effectively get

blocked inthebrainstemandcannotgetthroughto

the spinal cord.)People sometimesexperiencebrief

paralysiswhen theywakeupoutofadream,when

reversal of this REM block is slightly delayed.

Because of these features, REM sleep is sometimes

describedas ahighlyactivatedbrain inaparalysed

body.

Dreamshavealwaysbeenasourceoffascination,but

are difficult to study using quantitative scientific

methods. Theyhavebeen interpretedaseverything

from spiritual visitations to fulfillment of instinctual

drives, tobeingameaninglessbyproductofactivity

in variouspartsof thebrainduringREM sleep. The

currentneurocognitiveviewofdreamingarguesthatitresultsfrombriefmomentsofconsciousnesswhen

we become aware of all the processing that our

brainsnormally do offline, i.e. when they arenot

busy dealing with information coming in from the

environment through the senses,andarenotbeing

directed by our conscious control. This offline

processing includes reactivating memories and

emotionsfrompreviousexperiences,and integrating

them with experiences from the latest period of

waking.Dreams in thisviewareaglimpse intoyour

brainreshaping

itself

so

that

you

can

wake

up

in

the

morningstillyourself,butaslightlyrevisedversionas

aresultofyourexperiencesyesterday,andreadyto

startinteractingwiththeworldagain.

People vary greatly in their ability to recalldreams,

and we generally only recall them when we wake

spontaneously out of REM sleep (and then only

fleetinglyunlesswewrite themdownor talk about

them). Nevertheless, most adults normally spend

aboutaquarteroftheirsleeptimeinREMsleep.

NonREM/REMCycles

Across anormalnight of sleep, nonREM sleep and

REMsleep

alternate

in

acycle

that

lasts

roughly

90

minutes(butisveryvariableinlength,dependingon

a number of factors). Figure 2.1 is a diagram

describing the nonREM/REM cycle across the night

inahealthyyoungadult.Realsleep isnotas tidyas

this it includesmorearousals (transitionsto lighter

sleep) and brief awakenings. Sleep stages are

indicatedontheverticalaxisandtimeisrepresented

acrosshorizontalaxis1.

Figure2.1:

Diagram

of

the

non

REM/REM

cycle

across

thenightinayoungadult

Sleep isentered throughStage1nonREMand then

progressesdeeperanddeeper intononREM.About

8090minutesintosleep,thereisashiftoutofslow

wave sleep (nonREM stages 3 and 4). This is often

marked by body movements, as the sleeper

transitionsbrieflythroughStage2nonREMand into

the firstREMperiodof thenight. (REMperiodsare

indicatedas

shaded

boxes

in

Figure

2.1).

After

afairly

short period of REM, the sleeper progresses back

1GanderPH(2003)Sleepinthe24HourSociety.

Wellington,NewZealand:OpenMindPublishing.ISBN0

909009597


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24 ScienceforFRMS

Uneditedversion

downagain through lighternonREM sleepand into

slowwavesleep,andsothecyclerepeats.

The amount of slowwave sleep in each non

REM/REMcycledecreasesacrossthenight,andthere

maybenoneatallinthelatercycles.Incontrast,the

amount of REM sleep in each nonREM/REM cycle

increasesacross

the

night.

The

sleeper

depicted

in

Figure 2.1 wakes up directly out of the final REM

period of the night, and so would probably recall

dreaming.

Interestingly, slowwave sleep always predominates

atthebeginningofasleepperiod,regardlessofwhen

sleepoccursintheday/nightcycleorinthecircadian

body clock cycle. There seems to be a priority to

discharge the homeostatic sleep pressure first. In

contrast,thetime fromsleeponset to the firstbout

ofREM (theREM latency)and thedurationofeach

REMboutvariesmarkedlyacrossthecircadianbody

clock cycle. The circadian drive for REM sleep is

strongest a few hours before normal wakeup time.

Thesetwo

processes

the

homeostatic

sleep

process

and the circadian body clock are the main

componentsinmostofthebiomathematicalmodels

that areused topredict crewmember fatigue levels

(seeChapter4).

OperationalNote:

MitigationStrategiesforSleepLoss

RestorationofanormalnonREM/REM cycle isonemeasureof recovery from theeffectsof sleep loss. Lost

sleepisnotrecoveredhourforhour,althoughrecoverysleepmaybeslightlylongerthanusual.

On the firstrecoverynight, there ismoreslowwavesleep thanusual. Indeed, therecanbesomuchslow

wavesleepthatthereisnotenoughtimetomakeupREMsleep.

Onthesecondrecoverynight,thereisoftenmoreREMsleepthanusual.

Bythethirdrecoverynight,thenonREM/REMcycleisusuallybacktonormal.

Operationally,thismeansthatschedulesneedtoperiodicallyincludeanopportunityforatleasttwoconsecutive

nightsofunrestrictedsleep,toenablecrewmemberstorecoverfromtheeffectsofsleeploss.

Thisdoesnotequate to48hoursoff.Forexample,48hoursoffdutystartingat02:00wouldonlygivemost

peopletheopportunityforonefullnightofunrestrictedsleep.Ontheotherhand,40hoursoffstartingat21:00

wouldgivemostpeopletheopportunityfortwofullnightsofunrestrictedsleep.

Additionalnightsmaybeneededforrecoveryifacrewmemberscircadianbodyclockisnotalreadyadaptedto

thelocal

time

zone

(see

Section

2.3).


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ScienceforFRMS 25

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2.2.2 Theissueofsleepquality

Sleepquality(itsrestorativevalue)dependsongoing

through unbroken nonREM/REM cycles (which

suggests thatboth typesof sleeparenecessaryand

oneisnotmoreimportantthantheother).Themore

thenonREM/REMcycleisfragmentedbywakingup,

orbyarousalsthatmovethebraintoa lighterstage

of sleep without actually waking up, the less

restorativevaluesleephas in termsofhowyou feel

andfunctionthenextday.

OperationalNote:

MitigationStrategiestoMinimizeSleepInterruptions

Because uninterrupted nonREM/REM cycles are the key to good quality sleep, operators should develop

proceduresthatminimizeinterruptionstocrewmemberssleep.

Restperiods should includedefinedblocksof time (sleepopportunities)duringwhich crewmembersarenot

contactedexceptinemergencies.Theseprotectedsleepopportunitiesneedtobeknowntoflightcrewsandall

otherrelevant

personnel.

For

example,

calls

from

crew

scheduling

should

not

occur

during

arest

period

as

they

canbeextremelydisruptive.

Operatorsshouldalsodevelopprocedurestoprotectcrewmembersleepat layoverandnapping facilities.For

example,ifarestperiodoccursduringthedayatalayoverhotel,theoperatorcouldmakearrangementswith

thehotel to restrict access to the sectionof thehotelwhere crewmembers are trying to sleep (such asno

children, crewmembers only) and instruct their staff to honor the necessary quiet periods (for example, no

maintenanceworkorroutinecleaning).


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26 ScienceforFRMS

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Qualityofinflightsleep

Asmentionedabove,polysomnographystudiesshow

that crewmembers sleep in onboard crew rest

facilities is lighter and more fragmented than sleep

on theground2.Sleepduring flightdecknaps isalso

lighter

and

more

fragmented

than

would

be

predicted from laboratory studies3. Nevertheless,

there is good evidence that inflight sleep improves

subsequent alertness and reaction speed and is a

valuablemitigationstrategyinanFRMS.

Studiesof sleep inhypobaric chambersatpressures

equivalent to cabin pressure at cruising altitude

indicatethatthefragmentedqualityofinflightsleep

is not due to altitude4. Several studies have asked

crewmembers what disturbs their sleep on board.

The factors most commonly identified are random

noise, thoughts, not feeling tired, turbulence,

ambient aircraft noise, inadequate bedding, low

humidity,andgoingtothetoilet.

Sleepqualityandaging

Acrossadulthood,theproportionofsleeptimespent

inslowwavesleepdeclines,particularlyamongmen.

In addition, sleep becomes more fragmented. For

example,onestudywith2,685participantsaged37

92 yrs found that the average number of arousals

(transitions to lighter sleep and awakenings) rosefrom16perhourofsleep for3054yearolds to20

perhourofsleepfor6170yearolds5.

2Signal,T.L.,Gale,J.,andGander,P.H.(2005)Sleep

MeasurementinFlightCrew:ComparingActigraphicand

SubjectiveEstimatesofSleepwithPolysomnography.Aviation

SpaceandEnvironmentalMedicine76(11):105810633Rosekind,M.R.,Graeber,R.C.,Dinges,D.F.,etal.,(1994)

CrewFactorsinFlightOperationsIX:Effectsofplanned

cockpitrestoncrewperformanceandalertnessinlong

hauloperations.NASATechnicalMemorandum108839,MoffettField:NASAAmesResearchCenter.4Mumm,J.M.,Signal,T.L.,Rock,P.B.,Jones,S.P.,OKeeffe,K.M.,

Weaver,M.R.,Zhu,S.,Gander,P.H.,Belenky,G.(2009)Sleepat

simulated2438m:effectsonoxygenation,sleepquality,and

postsleepperformance.Aviation,Space,andEnvironmental

Medicine80(8):691697.5Redline,S.,Kirchner,H.L.,Quan,S.F.,Gottlieb,D.J.,Kapur,V.,

Newman,A.(2004).Theeffectsofage,sex,ethnicity,andsleep

disorderedbreathingonsleeparchitecture.ArchivesofInternal

Medicine164:406418.

These agerelated trends are seen in the sleep of

flight crewmembers,bothon thegroundand in the

air2,6.AstudyofinflightsleepondeliveryflightsofB

777 aircraft (from Seattle to Singapore or Kuala

Lumpur) found that age was the factor that most

consistentlypredicted

the

quality

and

duration

of

bunk sleep. Older pilots took longer to fall asleep,

obtainedlesssleepoverall,andhadmorefragmented

sleep.

It isnotyetclearwhethertheseagerelatedchanges

insleepreduce itseffectivenessforrestoringwaking

function. Laboratory studies that experimentally

fragment sleep are typically conducted with young

adults.Onthe flightdeck,experience (both interms

of flyingskillsandknowinghowtomanagesleepon

trips) could help reduce potential fatigue risk

associatedwithagerelatedchangesinsleep.

Sleepdisorders

Thequalityofsleepcanalsobedisruptedbyawide

varietyof sleepdisorders,whichmake it impossible

toobtainrestorativesleep,evenwhenpeoplespend

enough time trying to sleep. Sleepdisordersposea

particular risk for flight crewmembers because, in

addition,theyoftenhaverestrictedtimeavailablefor

sleep.ItisrecommendedthatFRMStraining(Chapter

6) should include basic information on sleepdisordersand their treatment,where toseekhelp if

needed,andany requirements relating to fitness to

fly.

2.2.3 Consequencesofnotgettingenoughsleep

Even for people who have good quality sleep, the

amount of sleep they obtain is very important for

restoring their waking function. An increasing

number of laboratory studies are looking at the

effectsof

trimming

sleep

at

night

by

an

hour

or

two

(known as sleep restriction). There are several key

findings from these studies that are important for

FRMS.

6Signal,T.L.,Gander,P.H.,vandenBerg,M.(2004)Sleepinflight

duringlongrestopportunities.InternalMedicineJournal34(3):

A38.


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ScienceforFRMS 27

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The effects of restricting sleep night after night

accumulate,sothatpeoplebecomeprogressivelyless

alert and less functional day after day. This is

sometimesdescribedasaccumulatinga sleepdebt.

This isacommonoccurrence forcrewmembers (see

below),forexamplewhenminimumrestperiodsare

scheduledfor

several

days

in

arow.

Theshorterthetimeallowedforsleepeachnight,the

faster alertness and performance decline. For

example,onelaboratorystudyfoundthatspending7

hoursinbedfor7consecutivenightswasnotenough

to prevent a progressive slowing down in reaction

time7. The decline was more rapid for a group of

participants who spent only 5 hours in bed each

night, and even more rapid for a group who spent

only3hoursinbedeachnight.Thisisdescribedasa

dosedependenteffectofsleeprestriction.

Thepressureforsleep increasesprogressivelyacross

successive days of sleep restriction. Eventually, it

becomes overwhelming and people begin falling

asleep uncontrollably for brief periods, known as

microsleeps. During a microsleep, the brain

disengagesfromtheenvironment(itstopsprocessing

visualinformationandsounds).Inthelaboratory,this

canresultinmissingastimulusinaperformancetest.

Drivingamotorvehicle,itcanresultinfailingtotake

a corner. Similareventshavebeen recordedon the

flightdeckduringdescentintomajorairports5.

Full recovery of waking function after sleep

restriction can take longer than two nights of

recovery sleep (i.e., longer than it takes the non

REM/REM cycle to recover). Indeed, chronic sleep

restriction may have effects on the brain that can

affect alertness and performance days to weeks

later8.

Forthe first fewdaysofseveresleeprestriction (for

example,3hoursinbed),peopleareawarethatthey

are getting progressively sleepier. However, after

7Belenky,G.,Wesensten,N.J.,Thorne,D.R.,etal.(2003).Patternsof

performancedegradationandrestorationduringsleeprestrictionand

subsequentrecovery:asleepdoseresponsestudy.JournalofSleep

Research12:112.8Rupp,T.L.,Wesensten,N.J,Bliese,P.D.etal.(2009).Banking

sleep:realizationofbenefitsduringsubsequentsleeprestriction

andrecovery.Sleep32(3):311321

severaldays theyno longernoticeanydifference in

themselves, even although their alertness and

performancecontinuestodecline.Inotherwords,as

sleep restriction continues, people become

increasingly unreliable at assessing their own

functionalstatus.Thisfindingraisesaquestionabout

thereliability

of

subjective

ratings

of

fatigue

and

sleepiness as measures of a crewmembers level of

fatiguerelatedimpairment(seeAppendixB).

At least in the laboratory, some people are more

resilient to the effects of sleep restriction than

others. Currently, there is a lot of research effort

aimedattryingtounderstandwhythisis,butitisstill

too early for this to be applied in an FRMS (for

example, by recommending different personal

mitigationstrategiesforpeoplewhoaremoreorless

affectedbysleeprestriction).

In general, more complex mental tasks such as

decision making and communication seem to be

more severely affected by sleep loss than simpler

tasks. Brain imaging studies also suggest that the

brainregionsinvolvedinmorecomplexmentaltasks

arethemostaffectedbysleepdeprivationandhave

the greatestneed for sleep to recover theirnormal

function.

Laboratorysleeprestrictionstudiesarecurrentlythe

main source of information on the effects of sleeprestriction. However, they have some obvious

limitations. The consequences of reduced alertness

andpoortaskperformancearequitedifferent inthe

laboratory than for crewmembers on duty.

Laboratory studies usually look at the effects of

restricting sleep atnight andparticipants sleep in a

dark, quiet bedroom. This may mean that current

understanding is based on a best case scenario.

Moreresearchisneededontheeffectsofrestricting

sleep during the day, and on the combination of

restrictedsleep

and

poor

quality

sleep.

Laboratory

studiesalsofocusontheperformanceof individuals,

notpeopleworkingtogetherasacrew.

Onesimulationstudywith67experiencedB747400

crewshasdemonstratedthatsleeplossincreasedthe


23/150

28 ScienceforFRMS

Uneditedversion

totalnumberoferrorsmadebythecrew9.Thestudy

designwassetupsothatthepilot incommandwas

always the pilot flying. Paradoxically, greater sleep

loss among first officers improved the rate of error

detection. On the other hand, greater sleep loss

amongpilotsincommandledtoahigherlikelihoodof

failureto

resolve

errors

that

had

been

detected.

Greater sleep losswasalsoassociatedwith changes

in decision making, including a tendency to choose

lower risk options, which would help mitigate the

potential fatigue risk. Simulator studies like this are

expensive and logistically complex to conduct

properly,but theyprovidevital insightson the links

betweencrewmembersleepandoperational fatigue

risk.

Sleeprestrictioninflightoperations

The ideaofsleeprestriction impliesthat there isan

optimumamountofsleepthatpeopleneedtoobtain

eachnight.Theconceptofindividualsleepneedisan

areaofactivedebate insleep research.Oneway to

measuresleeprestrictionthatavoidsthisproblem is

to look at how much sleep crewmembers obtain

when theyareathomebetween trips,compared to

howmuchsleeptheyobtainduringtrips.

Table2.1summarizesdataonsleeprestrictionacross

different flight operations that were monitored by

theNASA FatigueProgram in the 1980s. 10 In thesestudies, crewmembers completed sleep and duty

diaries before, during, and after a scheduled

commercial trip.Foreach crewmember,hisaverage

sleepdurationper24hoursathomebeforethe trip

wascomparedwithhisaveragesleepdurationper24

hourson thestudytrip.Duringnightcargoand long

haul trips,crewmembersoftenhadsplitsleep (slept

morethanoncein24hours).

Scheduling has undoubtedly changed since these

studies,so

the

data

in

Table

2.1

are

likely

to

be

9 Thomas, M.J.W., Petrilli, R.M., Lamond, N.A., et al. (2006).

Australian Long Haul Fatigue Study. In: Enhancing Safety

Worldwide: Proceedings of the 59th Annual International Air

SafetySeminar.Alexandria,USA,FlightSafetyFoundation.10

Gander, P.H., Rosekind, M.R., and Gregory, K.B. (1998) Flight

crew fatigue VI: an integrated overview. Aviation, Space, and

EnvironmentalMedicine69:B49B60

unrepresentative of the current situation in many

cases.However,theyindicatethatsleeprestrictionis

very common across different types of flight

operations.

Short

Haul

Night

Cargo

Long

Haul

crewmembers

averagingatleast1

hourofsleep

restrictionpertrip

day

67% 54% 43%

crewmembers

averagingatleast2

hoursofsleep

restrictionpertrip

day

30% 29% 21%

lengthoftrip34

days

8

days

49

days

timezonescrossed

perday01 01 08

numberof

crewmembers

studied

44 34 28

Note: the night cargo trips included a 12 night break in the

sequence of night shifts. Splitting long haul trips into 24 hours

daysisratherarbitrarybecausetheaveragedutydaylasted10.2

hoursand

the

average

layover

lasted

24.3

hours.

Table2.1:Sleeprestrictionduring

commercialflightoperations

Agrowingamountofevidence,frombothlaboratory

studies and from epidemiological studies that track

the sleep and health of large numbers of people

across time, indicates that chronic short sleep may

havenegativeeffectsonhealthinthelongterm.This

research suggests that short sleepers areat greater

risk

of

becoming

obese

and

developing

type2

diabetes and cardiovascular disease. There is still

debate about whether habitual short sleep actually

contributes to these health problems, or is just

associated with them. In addition, flight

crewmembers as a group are exceptionally healthy

comparedtothegeneralpopulation.Whatisclear is

thatgoodhealthdependsnotonlyongooddietand


24/150

ScienceforFRMS 29

Uneditedversion

regularexercise,butalsoongettingenoughsleepon

a regular basis. Sleep is definitely not a tradable

commodity.

OperationalNote:

MitigationStrategiesforManagingSleepDebt

Sleeprestriction iscommonacrossdifferenttypesofflightoperations.Becausetheeffectsofsleeprestriction

are cumulative, schedules must be designed to allow periodic opportunities for recovery. Recovery

opportunitiesneedtooccurmorefrequentlywhendailysleeprestrictionisgreater,becauseofthemorerapid

accumulationoffatigue.

The usual recommendation for a recovery opportunity is for a minimum of two consecutive nights of

unrestrictedsleep.Somerecent laboratorystudiesofsleeprestrictionsuggestthatthismaynotbeenoughto

bring crewmembersbackup to theiroptimal levelof functioning.There isevidence that the sleeprestricted

braincanstabilizeatalowerleveloffunctioningforlongperiodsoftime(daystoweeks).

Especiallyin

irregular

operations,

procedures

that

allow

acrewmember

to

continue

sleeping

until

needed

can

reducetherateofaccumulationofsleepdebt.Forexample,ifanaircraftwithananticipatedrepairtimeof0730

will not actually be ready until 11:30, then a reliable procedure that allows the crew member to continue

sleepingwouldbebeneficial.Oneairlinehasasystemwheretheoperatorcontactsthelayoverhoteltoupdate

thereporttimebyslippingamessageunderthecrewmembersdoor.Thehotelprovidesawakeupcallonehour

beforepickuptime.

2.3 Introductiontocircadianrhythms

Sleepingatnight isnotjustasocialconvention. It is

programmedinto

the

brain

by

the

circadian

body

clock, which is an ancient adaptation to life on our

24hour rotating planet. Even very ancient types of

living organisms have something equivalent, which

means that circadian biological clocks have been

aroundforseveralbillionyears.

A feature of circadian clocks is that they are light

sensitive. The human circadian clock monitors light

intensity through a special network of cells in the

retinaoftheeye (thisspecial light inputpathway to

thecircadianclockisnotinvolvedinvision).Theclock

itselfresidesinafairlysmallclusterofcells(neurons)

deeper in the brain (in the suprachiasmatic nuclei

(SCN)of thehypothalamus).The cells thatmakeup

the clock are intrinsically rhythmic, generating

electricalsignalsfasterduringthedaythanduringthe

night.However,theyhaveatendencytoproducean

overallcyclethat isabitslow formostpeoplethe

biologicaldaygeneratedbythecircadianbodyclock

isslightlylongerthan24hours.Thesensitivityofthe

circadianbodyclocktolightenablesittostayinstep

with the day/night cycle. However, that same

sensitivity to light also creates problems for

crewmemberswhohavetosleepoutofstepwiththe

day/nightcycle(forexampleondomesticnightcargo

operations),orwhohavetoflyacrosstimezonesand

experiencesuddenshiftsintheday/nightcycle.

2.3.1 Examplesofcircadianrhythm

It is not possible to directly measure the electrical

activityofthecircadianbodyclock inhumanbeings.

However,almosteveryaspectofhuman functioning

(physicalormental)undergoesdaily cycles that are

influenced by the circadian body clock. Measuringovert rhythms in physiology and behaviour is like

watchingthehandsofan(analogue)wristwatch.The

handsmovearoundthewatchfacebecausetheyare

driven by the timekeeping mechanism inside the

watch, but they are not part of the timekeeping

mechanism itself. Similarly, most circadian rhythms

thatcanbemeasured,suchasrhythms incorebody


25/150

210 ScienceforFRMS

Uneditedversion

temperatureor selfrated fatigue, aredrivenby the

circadian body clock, but they are not part of the

biologicaltimekeepingmechanism.

Figure2.2showsanexampleofcircadianrhythms in

corebodytemperatureandselfratedfatigueofa46

yearold

short

haul

crewmember

monitored

before,

during,andaftera3daypatternofflyingontheeast

coastof theUSA (staying in the same time zone)11.

The crewmember had his core temperature

monitored continuously and kept a sleep and duty

diary,inwhichhenotedhissleeptimesandratedthe

qualityofhissleep,aswellasratinghisfatigueevery

2hourswhilehewasawake(onascalefrom0=most

alertto100=mostdrowsy).

Corebody temperature typically fluctuatesbyabout

1 C across the 24hour day. Note that the

crewmember's core temperature starts to rise each

morning before he wakes up. In effect, his body is

beginning to prepare aheadof time for the greater

energydemandsofbeingmorephysically active. (If

bodytemperatureonlybegantoriseafterhestarted

tobemorephysicallyactive,itwouldbealotharder

togetupinthemorning).

Lookingathisselfratedfatigue,thiscrewmemberdid

not feel at his best first thing in the morning. He

tendedtofeelleastfatiguedabout24hoursafterhe

woke up, after which his fatigue climbed steadilyacross the day. The dashed line across the sleep

period indicates that he was not asked to wake up

every2hourstoratehisfatigueacrossthistime.

Core body temperature is often use as a marker

rhythmtotrackthecycleofthecircadianbodyclock

because it is relatively stable and easy to monitor.

However,nomeasurablerhythm isaperfectmarker

of the circadian body clock cycle. For example,

changes in the level of physical activity also cause

changesin

core

temperature,

which

explains

the

smallpeaksanddipsintemperatureinFigure2.2.

11Gander,P.H.,Graeber,R.C.,Foushee,H.C.,Lauber,J.K.,

Connell,L.J.(1994).CrewFactorsinFlightOperationsII:

PsychophysiologicalResponsestoShortHaulAirTransport

Operations.NASATechnicalMemorandum#108856.Moffett

Field:NASAAmesResearchCenter.

The daily minimum in core body temperature

corresponds to the time in the circadianbody clock

cyclewhenpeoplegenerallyfeelmostsleepyandare

leastabletoperformmentalandphysicaltasks.This

issometimesdescribedas theWindowofCircadian

Low(WOCL).

Figure2.2:Circadianrhythmsofashorthaulpilot

2.3.2 Thecircadianbodyclockandsleep

AsmentionedinSection2.2,thecircadianbodyclock

influences sleep in a number of ways. (It has

connections to centers in the brain that promote

wakefulness and to opposing centers that promote

sleep, as well as to the system that controls REM

sleep.) Figure2.3 isadiagram thatsummarizes the

effectsofthecircadianclockonsleep. It isbasedon

data collected from 18 night cargo pilots on their

daysoff,i.e.,whentheyweresleepingatnight12.Like

the crewmember in Figure 2.2, they also had their

core temperaturemonitored continuously,and kept

sleepanddutydiaries.

12Gander,P.H.,Rosekind,M.R.,andGregory,K.B.

(1998)FlightcrewfatigueVI:anintegratedoverview.

Aviation,Space,andEnvironmentalMedicine69:B49

B60


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