copyright 2008, ibr copyright 2010, ibr safte/fast evidence-based aviation fatigue risk management...
TRANSCRIPT
Copyright 2008, IBRCopyright 2010, IBR
SAFTE/FASTEvidence-based
Aviation Fatigue Risk Management
Steven R. Hursh, Ph.D.President, IBR and
Professor, Johns Hopkins University School of Medicine
September 1, 2011
Copyright 2008, IBR
Major Fatigue Factors●Time of Day: between midnight and
0600 hrs.●Recent Sleep: less than eight hours
in last 24 hrs. ●Continuous Hours Awake: more
than 17 hours since last major sleep period.
●Cumulative Sleep Debt: more than eight hours accumulation since last full night of sleep (includes disrupted sleep).
●Time on Task/Work Load: continuous work time without a break or intensity of work demands.
Copyright 2008, IBR
An Objective Fatigue Metric●No Blood Test for fatigue, yet●The conditions that lead to fatigue are
well known.● A fatigue model simulates the specific
conditions and determines if fatigue could be present.
●The model can estimate the level of degradation in performance and provide an estimate of schedule induced fatigue risk.
Copyright 2008, IBR
SAFTE
●The Sleep, Activity, Fatigue, and Task Effectiveness (SAFTE) Model is based on 12 years of fatigue modeling experience.
●Validated against laboratory and simulator measures of fatigue.
●Validated and calibrated to predict accident risk by the Department of Transportation.
●Peer reviewed and found to have the least error of any available fatigue model.
●Accepted by the US DOD (Air Force, Army, Navy, Marines) as the common warfighter fatigue model.
Copyright 2008, IBR
SAFTE Model Components
Copyright 2008, IBR
Least Error for Conditions of Sleep Restriction
2002 Seattle Fatigue & Performance Modeling Workshop, of all models tested against laboratory measurements:
●SAFTE had least error predicting objective vigilance performance.
●SAFTE had least error predicting subjective ratings of fatigue.
●Advances since 2002 have further validated the sleep and performance assumptions and prediction of accident risk and severity.
6Von Dongen, Aviation, Space, and Environmental Medicine, March, 2004, vol. 75, no. 3, section II
Copyright 2008, IBR
Accuracy of Predicting Sleep Pattern and Duration
7
Measure Signalman Maintenance of Way
Dispatchers(less night workers)
Train and Engine
Mean Agreement
92% 92% 90% 88%
Daily Sleep(Est.- Log)
-24 min -21 min -3 min - 10.8 min
Copyright 2008, IBR
516%
49%25%
142%
103%
70%
0
1
2
3
4
5
6
Less than or equal to 7777 to 90Greater than 90
Re
lati
ve R
isk
Crew Effectiveness Score
Economic Risk - Damage & Casualty Cost
Accident Risk
$
#$ $ #
#
1 = Unchanged relative risk
Economic Risk and Effectiveness
No Fatigue High Fatigue
Railroad Accident Relative Risk
Copyright 2008, IBR
SAFTE/FAST
Validated Fatigue Modeling Tools
Fatigue Science has the exclusive license from the US Army to commercialize SAFTE model.
Copyright 2008, IBR
Practical Software for Implementation
●Fatigue Avoidance Scheduling Tool (FAST) Fatigue assessment tool using the SAFTE
model Developed for the US Air Force and the
US Army DOT / FRA sponsored work has lead to
enhancements for transportation applications
●FAST Features Sleep estimation algorithm Graphical analysis tools Dashboard of fatigue factors Data based of all effectiveness
scores
Copyright 2008, IBR
FAST Aviation Sleep Estimation
●Accurate estimation of sleep is critical: Measure: actigraphy or log books Estimate: algorithm to simulate sleep
behavior
●Aviation specific estimates that can be refined with actrigraphic measurement.
●Considers time zone changes and is valid for any city pair.
Copyright 2008, IBR
Sleep EstimatorTailored to Aviation Environment:
Copyright 2008, IBR
FAST Aviation Specific AutoSleep
●Mimics typical sleep patterns●Tailored to workgroup and schedule
demands●Considers total duty period and commuting●Naps prior to anticipated late starts ●Considers time zones●Slits sleep when appropriate●Automatically inserts in-flight sleep for
augmented crews. User defined parameters: amount of augmentation and quality of sleep environment
●Adjustable settings can be saved to file13
Copyright 2008, IBR
Fatigue Risk Management System
FRM Steering Committee
Involves all stakeholdersat each stage:
management, labor, aided by science
EnablersEmployee trainingMedical screening
Economic analysisTechnology aids
MeasureDefine the situationSchedule evaluationActigraph recordings
Model & AnalyzeModel the fatigue problem
Analyze sources and Fatigue factors
ManageCollaborate for solutionsObtain commitment to
solve problem
Modify/MitigateShared Responsibility
• Operating practices• Labor agreements• Individual “life style”
MonitorAssess operational indicators
Individual self-evaluationFeedback to process
Continuous Improvement Process
SAFTE/FAST
Copyright 2008, IBR
FAST Aviation Fatigue Assessment ProcessAirline Specific Schedule Database
XML formatCity-pairs/Trips or
30-day Bids
FAST AviationModeler
• Aviation AutoSleep• SAFTE Model• Output results to folder• Links to Manager
FAST Aviation Manager
• Sorts by Criterion• Displays results• Links to Analyzer• Fleet level reports
FAST AnalyzerIndividual Schedules
• Examine schedules• Effectiveness Graph• Fatigue Factors• “What-If” Drills• Individual reports
Modular Process for Speed and Flexibility
Standard FASTschedule is created by FAST Aviation Modeler
Translation Tools available for any scheduling system
Copyright 2008, IBR
FAST Aviation Modeler
Model the schedules: 1. Set AutoSleep parameters if necessary2. Name the Output folder a unique name3. Choose either a City Pairs file or a Bid
Schedules file for modeling
Airline Schedule DatabaseProcessed Schedules Modeling Results
Copyright 2008, IBR
FAST Aviation Manager
Sort by: Flight Time Below Criterion Level (FTBCL) Critical TBCL (30 min associated with takeoff/landing) Average Effectiveness Minimum Effectiveness overall Minimum Effectiveness during critical periods Maximum Workload (high workload score in schedule) Median Workload (central score across schedule)
Save table to text fileClick on any line in Aviation Manager and schedule opens in
FAST for detailed analysis.
Copyright 2008, IBR
If fatigue is present, what do you do about it?
●Modeling tools must do more than give you a fatigue score: It must estimate fatigue risk It must show detail of each schedule
It must calculate fatigue factors It must suggest conditions that lead to fatigue so mitigations can be implemented by an FRMS18
Copyright 2008, IBR
Detailed Analysis Results●Creates detailed database that shows:
All duty periods and estimated sleep intervals
Effectiveness in each half hour of each duty period
Effectiveness at each half hour of the clock Distribution of duty time in effectiveness
categories Allows results be sorted based on user
defined categories Individual ID reports with effectiveness at
the 1 min resolution19
Copyright 2008, IBR
FAST Aviation Analyzer
In-flight sleep
14.5 hr flight
Pre-flight napPre-flight nap
Sleep Timing based on both physiological and social cues
Dashboard with Fatigue Factors
Schedules in Aviation Manager link to FAST for detailed analysis.
San Francisco to Sydney Pairing
Copyright 2008, IBR
Dashboard Information
CriteriaValue at pointin schedule
Flags are fatigue indicators
Content based on fatigue analysis workshop hosted by NTSB and conducted by Drs. Mark Rosekind & David Dinges, funded by FRA Office of Safety.
Sleep (last 24 hrs) Chronic Sleep Debt Hours Awake Time of Day Out of Phase Performance Values
Effectiveness (vigilance) Mean Cognitive Lapse Index Reaction Time Reservoir
Copyright 2008, IBR
Schedule Files for Evaluation
● Translated the spread sheets using Access database into the required XML file structure.
● Batch processed through FAST Aviation● Used FAST Manager to rank order Pairings and Rosters● Used output spread sheet to rank order segments
22
A: 90 Short haul pairings, 1094 active flightsB: 56 Short haul monthly rosters, 3963 active flightsC: 47 Long haul pairings, 188 active flightsD: 64 Long haul monthly rosters, 1006 active flights
Copyright 2008, IBR
Fatigue Metrics●Typically, FAST is used to assess the “tail of
the distribution” – how much critical duty time is spent at low effectiveness.
●For this exercise, we were asked to rank order all segments and schedules, not just the extreme cases.
●We rank ordered segments by minimum effectiveness at critical times of flight – take-offs and landings.
●We rank ordered pairings and rosters by minimum effectiveness and “critical time below criterion” which is more useful for entire schedules.
23
Copyright 2008, IBR
24
RankA SH Pairings Start End Min Critical Time Minimum E Rank
1 A10040 LAX ATL 5/15/2010 5:55 5/15/2010 10:08 70.84 32 A10002 LPB IQQ 2/4/2011 8:15 2/4/2011 9:19 74.64 73 A10045 ATL SEA 5/14/2010 1:30 5/14/2010 6:57 74.8 84 A10002 VVI LPB 2/4/2011 6:30 2/4/2011 7:44 74.99 95 A10002 IQQ SCL 2/4/2011 10:10 2/4/2011 12:24 75.65 10
C LH Pairings
1 C10027 ANC LAX 9/16/2010 15:05 9/16/2010 20:09 70.32 12 C10014 PDX NRT 5/17/2010 21:10 5/18/2010 7:59 70.45 23 C10033 DFW BRU 9/23/2010 18:15 9/24/2010 3:34 72.06 44 C10025 BRU SHJ 9/27/2010 16:40 9/27/2010 23:09 73.62 55 C10030 LAX AMS 9/16/2010 23:10 9/17/2010 9:49 73.81 6
B SH Rosters
1 B10049 ARI SCL 12/22/2010 5:45 12/22/2010 8:09 72.59 62 B10046 IQQ SCL 1/10/2011 5:30 1/10/2011 7:44 72.84 73 B10052 ANF SCL 1/8/2011 3:40 1/8/2011 5:29 73.66 84 B10049 ARI SCL 1/16/2011 2:55 1/16/2011 5:19 74.17 95 B10044 IQQ SCL 1/10/2011 4:25 1/10/2011 6:39 74.39 10
D LH Rosters1 D10029 GUM NRT 5/26/2010 5:00 5/26/2010 8:54 66.82 12 D10032 LIM SCL 1/4/2011 6:15 1/4/2011 9:34 67.76 23 D10024 SLC ANC 5/18/2010 3:35 5/18/2010 8:29 67.78 34 D10052 HKG HEL 11/17/2010 17:15 11/18/2010 4:19 68.59 45 D10024 SLC ANC 6/2/2010 3:35 6/2/2010 8:29 68.88 5
SAFTE/FAST - Segment Analysis
Copyright 2008, IBR
25
RankA SH Pairings
Critical TBCL (77) TBCL Overall Rank Minimum E Rank
1 A10002 149 2 2
2 A10001 88 4 4
3 A10008 61 6 5
4 A10040 53 9 1
5 A10000 41 10 8
C LH Pairings1 C10014 182 1 3
2 C10033 143 3 4
3 C10019 77 5 7
4 C10038 61 6 1
5 C10027 61 6 2
B SH Rosters1 B10049 201 1 1
2 B10050 194 2 6
3 B10046 126 4 2
4 B10045 124 5 8
5 B10047 123 6 5
D LH Rosters1 D10024 180 3 3
2 D10043 111 7 9
3 D10044 91 8 6
4 D10022 85 9 16
5 D10029 79 10 1
SAFTE/FAST - Roster Analysis
Copyright 2008, IBR
SEGMENTSMinimum Critical Time Effectiveness
26
Copyright 2008, IBR
Short Haul PairingA 10040 LAX to ATL Segment
27
Early Start Daytime Rest
Night flight
Copyright 2008, IBR
LH Pairing - C 10027 Anchorage-LAX Segment
28
5 hrs
86% reservoir
Copyright 2008, IBR
LH Pairing - C 10014 – Narita Segment
29
Narita
Copyright 2008, IBR
Short Haul Pairing - A 10002 Santa Cruz, Bolivia – Santiago,
Chile
30
1.5 hr Nap
Copyright 2008, IBR
A 10002, continued Santa Cruz, Bolivia – Santiago,
ChilePossible Mitigation
313 hr Nap
Copyright 2008, IBR
Long Haul Pairing - C 10014 Honolulu to Salt Lake
32
93% Res
3:15 Base
Narita Honolulu Salt Lake
Copyright 2008, IBR
C 10014 Honolulu to Salt Lake
Altered Sleep Pattern
33
Altered Sleep Pattern
Copyright 2008, IBR
Long Haul PairingC 10033 Kuala Lumpur Based
Pilot
34
Copyright 2008, IBR
ROSTERSGreatest Time Below Criterion
35
Copyright 2008, IBR
Long Haul Roster - D 10029
36
11 Day - Closer Examination
Copyright 2008, IBR
D 10029 Detroit– Narita- Guam Segment
37
Copyright 2008, IBR
Long Haul RosterD 10029 Guam – Narita
Segment
38
Copyright 2008, IBR
39
Short Haul Roster - B 10049 92 Segments in 57 Days
25th Ranking Workload of 56
Copyright 2008, IBR
B 10049Early Start on 12/19
40
Copyright 2008, IBR
B 10049 Multiple Segments at Night
on 12/21 starting 1730 to 0510
41
Copyright 2008, IBR
B 10049Multiple Segments at Night
42
Copyright 2008, IBR
Long Haul Roster - D 10024 Salt Lake-Anchorage-Minn
43
Copyright 2008, IBR
D 10024 Six Day SeriesSalt Lake-Anchorage-Minn
44
Copyright 2008, IBR
Two Early Starts (0700 and 0500) Two Consecutive Night Flights (2235 and 0020)
Daytime Recovery
D 10024 Salt Lake-Anchorage-Minn
Explanation
45
6 hrs 5 hrs
Copyright 2008, IBR
Workload Factor
●According to the NTSB: “One factor that contributes to self-reported pilot fatigue, especially in short-haul flight operations, is the number of legs flown in a duty period.”*
●The highest workload in a flight occurs at take-off and landing; increasing segments multiplies these high stress periods.
●FAST Aviation is the first fatigue assessment tool to provide an automated method to assess this source of fatigue.
*NTSB Safety Recommendation, A-09-61 through -66, August 7, 2009
Copyright 2008, IBR
0
2
4
6
8
10
12
14
87654321
Num
ber o
r Fac
tor
Days from Start of Schedule
Workload Calculation
Workload
Segments
Sample Workload Pattern
Median
Workload incre
ases with
segmentsW
orkload dissipates over time
Maximum
Copyright 2008, IBR
B 10007Top Ranking Workload
58 Segments in 12 Days
48
Copyright 2008, IBR
Advantages of Modeling Approach
●Validated model with history of outstanding performance under independent review.
●Explicit Sleep Estimator (AutoSleep) tailored to habits and policies of the airline.
●Aviation specific drivers of fatigue. Cognitive fatigue Workload related fatigue
●Analysis tools that lead to specific fatigue factors and mitigation approaches.
●Modular design can be tailored to customers needs.
Copyright 2008, IBR
Summary
Copyright 2008, IBR
Fatigue Risk Management System
Involves all stakeholdersat each stage:
management, labor, aided by science
EnablersEmployee trainingMedical screening
Economic analysisTechnology aids
MeasureDefine the situationSchedule evaluationActigraph recordings
Model & AnalyzeModel the fatigue problem
Analyze sources and Fatigue factors
ManageCollaborate for solutionsObtain commitment to
solve problem
Modify/MitigateShared Responsibility
• Operating practices• Labor agreements• Individual “life style”
MonitorAssess operational indicators
Individual self-evaluationFeedback to process
Continuous Improvement Process
Mitigations are Proportional to the RiskEvolutionary, Incremental ImprovementResponsive to Changing Circumstances
Copyright 2008, IBR
Fatigue Risk Pyramid
Mea
sure
s & B
arrie
rs
Fatigu
e M
odeli
ng
Mea
sure
s & B
arrie
rs
Mea
sure
s & B
arrie
rs
Fatigu
e M
odeli
ng
Mea
sure
s & B
arrie
rs
Fatigu
e M
odeli
ng
Diagno
sis
Fatigu
e M
odeli
ng
Job Performance ChangesSubjective Awareness
Even
t Seq
uenc
e
Employee sleep habits, traits, & conditions
Work demands, schedules, and sleep opportunities
Fatigue Related Errors
Accidents& Incidents
Based on James Reason, “Managing the Risks of Organizational Accidents”, Figure 1.6, Stages in the development and investigation of an organizational accident.
Level 1 Defense
Level 2 Defense
Level 3 Defense
Copyright 2008, IBR
If fatigue is present, what do you do about it?
●Modeling tools must do more than give you a fatigue score: It must estimate fatigue risk It must show detail of each schedule
It must calculate fatigue factors It must provide context of conditions that lead to fatigue so mitigations can be implemented by an FRMS
53
Copyright 2008, IBR
Steven R. Hursh, PhD and Reid BlankInstitutes for Behavior Resources
2104 Maryland AvenueBaltimore, MD 21218
(410) [email protected]@ibrinc.org
Chris HallmanBaines Simmons America
17 Greenville St., Suite 221Newnan, GA 30263
(678) 343-1635 Office(770) 251-5654 Fax
54
Questions:
Copyright 2008, IBR
Wrist movements are recorded 24/7 and downloaded over the internet
Downloaded data are converted to daily sleep/wake/work timesDaily sleep/wake/work times are
fed into the SAFTE risk evaluation model
SAFTE evaluates the fatigue risk and effectiveness of each individualdriver
Individual fatigue risk levels are amalgamated into a group report
FS Actigraph Data ProcessingPersonnel wear the actigraph that measures wrist movements