Shappell & Wiegmann, 2002
THE HUMAN FACTORS ANALYSIS AND THE HUMAN FACTORS ANALYSIS AND CLASSIFICATION SYSTEM (HFACS)CLASSIFICATION SYSTEM (HFACS)
Scott Shappell, Ph.D.Civil Aerospace Medical Institute
Douglas Wiegmann, Ph.D.University of Illinois
Shappell & Wiegmann, 2002
Shappell & Wiegmann, 2002
Source: Boeing
0
10
20
30
40
50
1960
1970
1980
1990
Scheduled Air CarrierScheduled Air Carrier
0
10
20
30
40
50
1950
1960
1970
1980
1990
2000
Acc
iden
ts/1
00,0
00 fl
ight
hou
rs
U.S. General AviationU.S. General Aviation
Source: NTSB
0
10
20
30
40
1950
1960
1970
1980
1990
2000
Acc
iden
ts/1
00,0
00 fl
ight
hou
rs
U.S. Air ForceU.S. Air Force
Source: U.S. Air Force Safety Center
0
10
20
30
40
50
60
1950
1960
1970
1980
1990
2000
Acc
iden
ts/1
00,0
00 fl
ight
hou
rs
U.S. Navy/Marine CorpsU.S. Navy/Marine Corps
Source: U.S. Naval Safety Center
Shappell & Wiegmann, 2002
The rate of improvement has slowed significantly and substantially during the last 25 years.
This has led some to conclude that further reductions in accident rates are improbable, if not impossible.
REASONS FOR CONCERN
Shappell & Wiegmann, 2002
The rate of improvement has slowed significantly and substantially during the last 10 years.
This has led some to conclude that further reductions in accident rates are improbable, if not impossible.
REASONS FOR CONCERN
Still, aircraft are becoming increasingly expensive raising the cost of aviation accidents.
Total:$3.9 Billion
Aviation$3.3BAviation$3.3B
COST OF ACCIDENTSCOST OF ACCIDENTSCOST OF ACCIDENTSU.S. Navy and Marine CorpsU.S. Navy and Marine Corps
FY96FY96--0000
Shore/Ground$150M
Shore/Ground$150M
Shipboard$277M
ShipboardShipboard$277M$277M
PMV$129MPMV$129M
Recreation$67M
Recreation$67M
Source: U.S. Naval Safety CenterSource: U.S. Naval Safety CenterSource: U.S. Naval Safety CenterShappell & Wiegmann, 2000
Shappell & Wiegmann, 2002
U.S. Navy/Marine Corps (1950U.S. Navy/Marine Corps (1950--2000)2000)
0
10
20
30
40
50
60
1950
1960
1970
1980
1990
2000
Acc
iden
ts/1
00,0
00 fl
ight
hou
rs
Source: U.S. Naval Safety Center
Shappell & Wiegmann, 2002
All NAVY/MARINE Class A, B, & C MishapsAll NAVY/MARINE Class A, B, & C Mishaps
Cla
ss A
, B,&
C M
isha
ps/1
00,0
00 F
light
Hou
rsC
lass
A, B
,& C
Mis
haps
/100
,000
Flig
ht H
ours
00
22
44
66
88
1010
1212
1414
1616
1977
1977
1979
1979
1981
1981
1983
1983
1985
1985
1987
1987
1989
1989
1991
1991
YearYear
Mechanical
Human
Shappell, S. and Wiegmann, D. (1996). U.S. Naval aviation mishaps 1977-1992: Differences between single and dual-piloted aircraft. Aviation, Space, and Environmental Medicine, 67, 65-69.
Shappell & Wiegmann, 2002
Mechanical Failure
- Catastrophic failures are infrequent events
- When failures do occur, they are often less severe or hazardous due to effective intervention programs.
Data-DrivenResearch
Accident Investigation
- Highly sophisticated techniques and procedures
- Information is objective and quantifiable
- Effective at determining why the failure occurred
Database Analysis
- Traditional analyses are clearly outlined and readily performed.
- Frequent analyses help identify common mechanical and engineering safety issues.
Miti
gatio
n
Prev
entio
n
EffectiveIntervention
and Prevention Programs
- Designed around traditional categories
- Variables are well-defined and causally related
- Organization and structure facilitate access and use
Accident Database
Feedback
Research Sponsors
- FAA, DoD, NASA, & airplane manufacturers provide research funding.
- Research programs are needs-based and data-driven. Interventions are therefore very effective.
Wiegmann, D. & Shappell, S. (2001). Human error analysis of commercial aviation accidents: Application of the Human Factors Analysis and Classification System (HFACS). Aviation, Space, and Environmental Medicine,72, 1006-1016.
Shappell & Wiegmann, 2002
Feedback
Human Error
- Errors occur frequently and are the major cause of accidents.
- Few safety programs are effective at preventing the occurrence or consequences of these errors.
Research Sponsors
- FAA, DoD, NASA, & Airlines provide funding for safety research programs.
- Lack of good data leads to research programs based primarily on interests and intuitions. Interventions are therefore less effective.
Fad-DrivenResearch
Miti
gatio
n
Prev
entio
n
IneffectiveIntervention
and Prevention Programs
Accident Investigation
- Less sophisticated techniques and procedures
- Information is qualitative and illusive
- Focus on “what” happened but not “why” it happened
Accident Database
- Not designed around any particular human error framework
- Variables often ill-defined
- Organization and structure difficult to understand
Database Analysis
- Traditional human factors analyses are onerous due to ill-defined variables and database structures.
- Few analyses have been performed to identify underlying human factors safety issues.
Wiegmann, D. & Shappell, S. (2001). Human error analysis of commercial aviation accidents: Application of the Human Factors Analysis and Classification System (HFACS). Aviation, Space, and Environmental Medicine,72, 1006-1016.
Shappell & Wiegmann, 2002
Shappell, S. and Wiegmann, D. Controlled flight into terrain: The utility of an information processing approach to mishap causal factors. Proceedings of the Eighth Symposium for Aviation Psychology, Ohio State University, 1300-1306, 1995.
Wiegmann, D and Shappell, S. Human factors in U.S. Naval aviation mishaps: An information processing approach. Proceedings of the Eighth Symposium for Aviation Psychology, Ohio State University, 1995.
Wiegmann, D. and Shappell, S. Human factors analyses of post-accident data: Applying theoretical taxonomies of human error. International Journal of Aviation Psychology, 7, 67-81, 1997.
Wiegmann, D. and Shappell, S. Human error perspectives in aviation. International Journal of Aviation Psychology, 11, 341-357, 2001.
What was required, therefore, was a general human error framework around which accident investigation and prevention programs can be developed.
We explored several approaches and “off-the-shelf” frameworks
ADDRESSING THE PROBLEMADDRESSING THE PROBLEM
CognitiveErgonomics AeromedicalPsychosocialOrganizational
Shappell & Wiegmann, 2002
The Human Factors Analysis and Classification The Human Factors Analysis and Classification System (HFACS)System (HFACS)
Shappell, S. and Wiegmann, D. A human error approach to accident investigation: The Taxonomy of Unsafe Operations. International Journal of Aviation Psychology, 7, 269-291, 1998.
Shappell, S. and Wiegmann, D. Human factors analysis of aviation accident data: Developing a needs-based, data-driven, safety program. Proceedings of the HESSD, Brussels, Belgium, 1999.
Shappell, S. and Wiegmann, D. The Human Factors Analysis and Classification System – HFACS. Office of Aviation Medicine Technical Report No. DOT/FAA/AM-00/7. Civil Aeromedical Institute, Oklahoma City, OK 73125, 2000.
Shappell, S. and Wiegmann, D. Beyond Reason: Defining the holes in the Swiss Cheese. Human Factors in Aviation Safety, (in press), 2000.
Shappell & Wiegmann, 2002
Active ConditionsFailed to scan instruments
Penetrated IMC when VFR only
UnsafeActs
Adapted from Reason (1990)
Failed orAbsent Defenses
Breakdown of a Productive SystemBreakdown of a Productive System
Shappell & Wiegmann, 2002
Active and Latent ConditionsPoor CRM
Loss of situational awareness
Failed orAbsent Defenses
Preconditionsfor
Unsafe Acts
UnsafeActs
Adapted from Reason (1990)
Active ConditionsFailed to scan instruments
Penetrated IMC when VFR only
Breakdown of a Productive SystemBreakdown of a Productive System
Shappell & Wiegmann, 2002
Latent ConditionsDeficient training program
Improper crew pairing
Active and Latent ConditionsPoor CRM
Loss of situational awareness
Failed orAbsent Defenses
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Adapted from Reason (1990)
Active ConditionsFailed to scan instruments
Penetrated IMC when VFR only
Breakdown of a Productive SystemBreakdown of a Productive System
Shappell & Wiegmann, 2002
Latent ConditionsExcessive cost cutting
Inadequate promotion policies
Latent ConditionsDeficient training program
Improper crew pairing
Active and Latent ConditionsPoor CRM
Loss of situational awareness
Failed orAbsent Defenses
OrganizationalFactors
InputsEconomic inflation
Few qualified pilots
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Adapted from Reason (1990)
Accident & InjuryCrashed into side ofmountain
Active ConditionsFailed to scan instruments
Penetrated IMC when VFR only
Breakdown of a Productive SystemBreakdown of a Productive System
Shappell & Wiegmann, 2002
UNSAFEACTS
UNSAFEACTS
ViolationsErrorsErrors
ExceptionalRoutinePerceptualErrors
DecisionErrors
Skill-BasedErrors
UnsafeActs
Shappell & Wiegmann, 2002
Violations
ExceptionalRoutine
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
DecisionErrors
DECISION ERRORSRule-based Decisions
- If X, then do Y- Highly Procedural
Choice Decisions- Knowledge-based
Ill-Structured Decisions- Problem solving
UnsafeActs
Shappell & Wiegmann, 2002
Violations
ExceptionalRoutine
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
Skill-BasedErrors
SKILL-BASEDERRORS
Attention Failures- Breakdown in visual scan- Inadvertent operation of control
Memory Failure- Omitted item in checklist- Omitted step in procedureStick-and-Rudder Skills
UnsafeActs
Shappell & Wiegmann, 2002
Violations
ExceptionalRoutine
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
PerceptualErrors
ErrorsErrors
PERCEPTUALERRORS(due to)
Misjudge Distance,Altitude, AirspeedSpatial DisorientationVisual Illusions
UnsafeActs
Shappell & Wiegmann, 2002
Exceptional
Violations
Routine
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
Violations
Routine
ROUTINE (INFRACTIONS)(Habitual departures from rules condoned by management)
VFR Flight into IMCElected to File VFR in Marginal Weather ConditionsFailed to Use Radar Advisories from ATCInadequate Brief and Limits on MissionIFR Procedure Not FollowedWeight and Balance ExceededProcedure/Directives Not FollowedOperating With Known DeficienciesMin. Descent Altitude not Complied with
UnsafeActs
Shappell & Wiegmann, 2002
Routine
Violations
Exceptional
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors Exceptional
UNSAFEACTS
UNSAFEACTS
Violations
Exceptional
EXCEPTIONAL(Isolated departures from the rules not condoned
by management)
Violated NATOPS/Regulations/SOP- Performed Unauthorized Acrobatic Maneuver- Canyon Running- Failed to Complete Performance Computations for Flight- Failed to Obtain Valid Weather Brief
Accepted Unnecessary HazardNot Current/Qualified for MissionExceeded Limits of Aircraft
UnsafeActs
Shappell & Wiegmann, 2002
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
PRECONDITIONSFOR
UNSAFE ACTS
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
ADVERSE MENTAL STATE
Adverse Mental States
Loss of Situational AwarenessCircadian dysrhythmiaAlertness (Drowsiness)OverconfidenceComplacencyTask Fixation
Condition of Operators
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
Adverse Physiological
States
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Adverse Physiological
States
Condition of Operators
ADVERSE PHYSIOLOGICALSTATES
Spatial DisorientationVisual IllusionsG-induced Loss of ConsciousnessHypoxiaMedical Illness
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Condition of Operators
Physical/Mental
Limitations
PHYSICAL/MENTALLIMITATIONS
Lack of Sensory InputLimited Reaction TimeIncompatible Physical CapabilitiesIncompatible Intelligence/Aptitude
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Personnel Factors
Crew Resource Management
CREW RESOURCEMANAGEMENT
Not Working as a TeamPoor Aircrew CoordinationImproper Briefing Before a MissionInadequate Coordination of Flight
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Personnel Factors
Personal Readiness
PERSONAL READINESSReadiness Violations
Crew Rest RequirementsBottle-to-Brief RulesSelf-Medicating
Poor JudgementPoor Dietary PracticesOverexertion While Off Duty
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Environmental Factors
Physical Environment
PHYSICAL ENVIRONMENT
WeatherLightingNoiseHeatAccelerationVibrationPollutants
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Environmental Factors
Technological Environment
TECHNOLOGICAL ENVIRONMENT
Equipment and controlsAutomation reliability/complexityTask and Procedure DesignManuals and Checklist DesignInterfaces and Displays
Shappell & Wiegmann, 2002
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
UNSAFESUPERVISION
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
UNSAFESUPERVISION
UNSAFESUPERVISION
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
UNSAFESUPERVISION
InadequateSupervision
INADEQUATE SUPERVISIONFailure to Administer Proper TrainingLack of Professional Guidance
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
UNSAFESUPERVISION
UNSAFESUPERVISION
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
UNSAFESUPERVISION
PlannedInappropriate
Operations
PLANNED INAPPROPRIATEOPERATIONS
Mission Risk without BenefitImproper Work TempoPoor Crew Pairing
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
UNSAFESUPERVISION
UNSAFESUPERVISION
UNSAFESUPERVISION
Failed toCorrectProblem
FAILED TO CORRECT AKNOWN PROBLEM
Failure to Correct Inappropriate BehaviorFailure to Correct a Safety Hazard
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
UNSAFESUPERVISION
UNSAFESUPERVISION
UNSAFESUPERVISION
SupervisoryViolations
SUPERVISORY VIOLATIONSNot Adhering to Rules and RegulationsWillful Disregard for Authority by
Supervisors
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
OrganizationalInfluences
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
OrganizationalClimate
ResourceManagement
ResourceManagement
OperationalProcess
ORGANIZATIONALINFLUENCES
Shappell & Wiegmann, 2002
OrganizationalClimate
ResourceManagement
ResourceManagement
OperationalProcess
ORGANIZATIONALINFLUENCES
ResourceManagement
ResourceManagement
ORGANIZATIONALINFLUENCES
RESOURCE MANAGEMENTHumanMonetaryEquipment/Facility
OrganizationalInfluences
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
OrganizationalClimate
ResourceManagement
ResourceManagement
OperationalProcess
ORGANIZATIONALINFLUENCES
ORGANIZATIONALINFLUENCES
OrganizationalClimate
ORGANIZATIONALCLIMATE
StructurePoliciesCulture
OrganizationalInfluences
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
OrganizationalClimate
ResourceManagement
ResourceManagement
OperationalProcess
ORGANIZATIONALINFLUENCES
ORGANIZATIONALINFLUENCES
OperationalProcess
OPERATIONALPROCESSOperationsProceduresOversight
OrganizationalInfluences
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Shappell & Wiegmann, 2002
Errors
UNSAFEACTS
Errors
PerceptualErrors
Skill-BasedErrors
DecisionErrors ExceptionalRoutine
Violations
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
ResourceManagement
OrganizationalClimate
OrganizationalProcess
ORGANIZATIONALINFLUENCES
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Shappell & Wiegmann, 2002
Shappell & Wiegmann, 2002
OrganizationalFactors
UnsafeSupervision
Preconditionsfor
Unsafe Acts
UnsafeActs
Intervention: Filling the Holes in the Cheese
SafeSupervision
Preconditionsfor
Safe Acts
SafeDecisions
SafeActs
Shappell & Wiegmann, 2002
U.S. NAVY/MARINE CORPSU.S. NAVY/MARINE CORPS
AVIATION ACCIDENT DATAAVIATION ACCIDENT DATAShappell, S. and Wiegmann, D. Is proficiency eroding among U.S. Shappell, S. and Wiegmann, D. Is proficiency eroding among U.S. Naval aircrews? A quantitative analysis using the Naval aircrews? A quantitative analysis using the
Human Factors Analysis and Classification System. Proceedings ofHuman Factors Analysis and Classification System. Proceedings of the the 4444thth Annual Meeting of the Human Factors Annual Meeting of the Human Factors and Ergonomics Societyand Ergonomics Society, San Diego, California, 2000., San Diego, California, 2000.
Shappell, S.,Shappell, S., SquierSquier, H.,, H., AbadAbad, G., and Wiegmann, D. An analysis of U.S. Navy and Marine Corps, G., and Wiegmann, D. An analysis of U.S. Navy and Marine Corps mishaps using the mishaps using the failure analysis classification system: Implications for preventfailure analysis classification system: Implications for prevention. ion. 69th Annual Meeting of the Aerospace Medical 69th Annual Meeting of the Aerospace Medical AssociationAssociation, 1998., 1998.
Shappell, S., Wiegmann, D., Fraser, J., Gregory, G., Kinsey, P.,Shappell, S., Wiegmann, D., Fraser, J., Gregory, G., Kinsey, P., andand SquierSquier, H. Beyond mishap rates: A human factors , H. Beyond mishap rates: A human factors analysis of U.S. Navy/Marine Corps TACAIR and Rotary Wing mishapanalysis of U.S. Navy/Marine Corps TACAIR and Rotary Wing mishaps using HFACS. 70s using HFACS. 70th Annual Meeting of the th Annual Meeting of the Aerospace Medical AssociationAerospace Medical Association, 1999., 1999.
Shappell, S., Wiegmann, D., Fraser, J., Tanner, G., Kinsey, P., Shappell, S., Wiegmann, D., Fraser, J., Tanner, G., Kinsey, P., andand ReddixReddix, M. Tracking aircrew error trends in Naval , M. Tracking aircrew error trends in Naval aviation mishaps using HFACS. aviation mishaps using HFACS. 71st Annual Meeting of the Aerospace Medical Association71st Annual Meeting of the Aerospace Medical Association, 2000., 2000.
Shappell & Wiegmann, 2002
Aircraft Control Not MaintainedProcedures/Directives Not FollowedAbort DelayedAirspeed (VREF) Not MaintainedAPU SelectedProper Touchdown Point MisjudgedAbort Above V1 ImproperAirspeed (VMC) Not MaintainedAutopilot Improper Use OfComplacencyControl Interference InadvertentCrew/Group Coordination Not MaintainedProper Touchdown Point Not AttainedAirspeed Not MaintainedAirspeed (VR) ImproperAutopilot Inadvertent DeactivationCircuit Breaker SelectedCompensation for Wind Conditions Not PossibleFlare ImproperUnsafe/Hazardous Condition Not IdentifiedVFR Flight Into IMC AttemptedFlight Into Adverse Weather ContinuedHydraulic System Not SelectedInadequate Surveillance of OperationProper Touchdown Point Not PossibleAborted Takeoff DelayedAirspeed (VLOF) Not AttainedAirspeed ExcessiveAltimeter Setting Not ObtainedAltitude Not MaintainedBecame Lost/DisorientedChecklist Not Complied WithCrew/Group Coordination Not PerformedFlaps Improper Use OfFlare ExcessiveFlight into Known Adverse Weather InitialedGo-Around Not PerformedIdentification of Aircraft Visually DelayedInadequate Substantiation ProcessVisual Separation Not MaintainedMinimum Descent Altitude Not MaintainedWheels Up Landing InadvertentAircraft Preflight Not PerformedAircraft Weight and Balance MisjudgedAltimeter Not UsedChecklist Inaccurate
Compensation For Wind Conditions InadequateDescent ExcessiveDistance MisjudgedFlare DelayedGround Loop/Swerve IntentionalRemedial Action DelayedVFR Flight Into IMP InitiatedVisual Lookout Not MaintainedAbort Above V1 PerformedCompensation for Wind Conditions ImproperDirectional Control Not MaintainedDiverted AttentionIce/Frost Removal From Aircraft InadequateIFR Procedure ImproperAircraft Control Not PossibleStall InadvertentInadequate Visual LookoutLack of Familiarity With AircraftLack of Total Experience in Type of AircraftLowering of Flaps PerformedPressureVFR Flight Into IMC InadvertentAborted Takeoff PerformedCommunications Not UnderstoodEmergency Procedure Not FollowedInadequate Weather EvaluationNosewheel Steering ExcessiveProcedure InadequateRotation ExcessiveVFR Flight into IMC ContinuedEmergency Procedure Not PerformedLack of Familiarity with Geographic AreaLevel Off Not AttainedMaintenance, Adjustment ImproperMonitoring InadequatePropeller Feathering Not PerformedRemedial Action Not PossibleVisual/Aural PerceptionPreflight Planning/Preparation InadequateAircraft Handling ImproperCrew/Group Coordination InadequateSpoiler Extension Not PerformedStall/Spin InadvertentAirspeed (VREF) Not AttainedAirspeed (VS) Not MaintainedGo-Around Delayed
Fatigue (Flight and Ground Schedule)Flight to Alternation Not PerformedOperation with Known Deficiencies in EquipmentSpoiler Extension Inadvertent ActivationSupervision InadequatePlanning/Decision improperRaising of Flaps ImproperIn-Flight Planning/Decision ImproperOverconfidence in Personal AbilityParking Brake Not SetExpectancyFlight Manuals Improper Use OfWrong Taxi Route SelectedGear Extension Not PerformedWeather Evaluation InadequateStall/Mush EncounteredParking Brakes Inadvertent DeactivationIn-Flight Planning/Decision PoorProper Glidepath Not MaintainedAltitude InadequateConditions/Steps Insufficiently DefinedEvacuation ImproperPassenger Briefing InadequateSpatial DisorientationThrottle/Power Control Improper Use OfWeather Evaluation InaccurateWrong Runway SelectedIce/Frost Removal From Aircraft Not IdentifiedPlanned Approach PoorRecovery from Bounced Landing ImproperPlanning/Decision InadequateAircraft Preflight InadequateChecklist InadequateDescent InadvertentGenerator Inadvertent DeactivationTouchdown InadvertentPreflight Planning/Preparation ImproperCompensation for Wind Conditions MisjudgedVisual IllusionUncontrolled DescentProper Descent Rate Not MaintainedChecklist Not UsedAnti-Ice/Deice System Not UsedInadequate MonitoringPowerplant Controls Inadvertent ActivationTraffic Advisory Not Identified
Clearance MisjudgedIFR Procedure Not FollowedInattentiveRemedial Action AttemptedSomeone GoofedImproper Use of Preflight Briefing ServiceDescent PrematureProper Descent Rate Not AttainedAirspeed Not Maintained (generic)Inadvertent StallVisual Lookout InadequateIce/Frost Removal From Aircraft Nor PerformedInformation InsufficientSelf-Induced PressureTrim Setting ImproperFlight Controls Improper Use OfAltitude/Clearance Not MaintainedManeuver PerformedPreflight Planning/Preparation PoorProper Altitude Not MaintainedFlare InitiatedFlight Advisories Not FollowedAltitude/Clearance InadequateDistance/Altitude MisjudgedInadequate TrainingRotation ImproperUnsuitable Terrain or Takeoff/Landing/Taxi AreaVFR Procedures InadequateProper Alignment Not PossibleRemedial Action ImproperFlare MisjudgedProper Alignment DelayedMissed Approach Not PerformedProper Alignment Not AttainedLack of Total Experience in Type OperationMinimum Descent Altitude BelowMiscellaneous Equipment InitiatedProper Alignment Not MaintainedSupervision ImproperGear Down and Locked Not VerifiedWind Information MisjudgedAircraft Weight and Balance ExceededAircraft Control-UncontrolledCrew/Group Coordination Not AttainedChecklist Not FollowedClearance Not Maintained
Sample of the Types of Human Error Typically FoundSample of the Types of Human Error Typically Found
Shappell & Wiegmann, 2002
Count (%) Count (%)
USMCn=73
USNn=105
Organizational InfluencesResource ManagementOrganizational ClimateOrganizational Process
Unsafe SupervisionInadequate SupervisionPlanned Inappropriate OperationsFailed to Correct a Known ProblemSupervisory Violations
Preconditions for Unsafe ActsAdverse Mental StatesAdverse Physiological StatesPhysical/Mental LimitationsCrew Resource MismanagementPersonal Readiness
Unsafe ActsDecision ErrorsSkill-based ErrorsPerceptual ErrorsViolations
170
19
18948
57187
402
36382322
(23)(0)(26)
(25)(12)(5)(11)
(78)(25)(10)(55)(3)
(49)(52)(32)(30)
32139
27111011
792711695
64572833
(30)(1)
(37)
(26)(10)(10)(10)
(75)(26)(10)(66)(5)
(61)(54)(27)(31)
Number and Percentage of Mishaps Associated with EachHFACS Causal Category (FY 91-99)
Number and Percentage of Mishaps Associated with EachHFACS Causal Category (FY 91-99)
Shappell & Wiegmann, 2002
Violations
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
VIOLATIONS
Violation of Orders/Regulations/SOP- Failed to Inspect ACFT after In-Flight Caution Light- Violated Squadron SOP Restricting Flight Below 500’- Failed to Comply with NATOPS During Streaming- Conducted Night Training and Ops Mission with PAX- Elected to File VFR in Marginal Weather Conditions- Failed to Use Radar Advisories from ATC- Inadequate Brief and Limits on Mission- HAC Knowingly Accepted Non-Current Crew
Failed to Adhere to BriefNot Current/Qualified for MissionImproper Procedure
Shappell & Wiegmann, 2002
0
10
20
30
40
50
91 92 93 94 95 96 97 98 99Fiscal Year
Perc
enta
g e
Percentage of Human Error Mishaps Associated with Violations (FY 91-97)Percentage of Human Error Mishaps Associated with Violations (FY 91-97)
ρρ==--.487, ns.487, ns
Shappell & Wiegmann, 2002
Intervention StrategyIntervention Strategy
ProfessionalismProfessionalismAccountabilityAccountabilityEnforcing the RulesEnforcing the Rules
Shappell & Wiegmann, 2002
0
10
20
30
40
50
91 92 93 94 95 96 97 98 99Fiscal Year
Perc
enta
g e
Percentage of Human Error Mishaps Associated with Violations (FY 91-99)
Percentage of Human Error Mishaps Associated with Violations (FY 91-99)
Shappell & Wiegmann, 2002
UnsafeActs
Violations
ExceptionalRoutine
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
PerceptualErrors
DecisionErrors
Skill-BasedErrors
UNSAFEACTS
UNSAFEACTS
ErrorsErrors
Skill-BasedErrors
SKILL-BASED ERRORSBreakdown in Visual ScanFailed to See and AvoidPoor TechniqueOmitted Checklist ItemInadvertent Operation of ControlImproper Use of Flight Controls
Shappell & Wiegmann, 2002
Percentage of Human Error Mishaps Associated withSkill-based Errors (FY 91-99)
Percentage of Human Error Mishaps Associated withSkill-based Errors (FY 91-99)
0
10
20
30
40
50
60
70
80
91 92 93 94 95 96 97 98 99Fiscal Year
Perc
enta
g e
ρρ=.832, p<.01=.832, p<.01
Shappell & Wiegmann, 2002
Preliminary Intervention StrategyPreliminary Intervention Strategy
Improve instrument scanImprove instrument scanPrioritizing attentionPrioritizing attentionRecognizing extremis situationsRecognizing extremis situationsRefine basic flight skills (StickRefine basic flight skills (Stick--andand--Rudder)Rudder)Practice proceduresPractice proceduresReview the mishap database!Review the mishap database!
Shappell & Wiegmann, 2002
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Preconditionsfor
Unsafe Acts
UnsafeActs
Personnel Factors
Crew Resource Management
CREW RESOURCEMANAGEMENT
Not Working as a TeamPoor Aircrew CoordinationImproper Briefing Before a MissionInadequate Coordination of Flight
Shappell & Wiegmann, 2002
0
10
20
30
40
50
60
70
80
91 92 93 94 95 96 97 98 99Fiscal Year
Perc
enta
g e
Percentage of Human Error Mishaps Associated withCrew Resource Management Failures (FY 91-98)
Percentage of Human Error Mishaps Associated withCrew Resource Management Failures (FY 91-98)
ρρ=.551, ns=.551, ns
Percentages do not add up to 100%
Shappell & Wiegmann, 2002
Platform specific trainingPlatform specific trainingUse of video feedbackUse of video feedbackRestructure tasks (i.e., EP’s)Restructure tasks (i.e., EP’s)
Preliminary Intervention StrategyPreliminary Intervention Strategy
Change group compositionChange group compositionAttempt to change attitudesAttempt to change attitudesAdditional research...Additional research...
Shappell & Wiegmann, 2002
0
10
20
30
40
50
60
70
80
91 92 93 94 95 96 97 98 99Fiscal Year
Perc
enta
g e
Percentage of Human Error Mishaps Associated withCrew Resource Management Failures (FY 91-99)
Percentage of Human Error Mishaps Associated withCrew Resource Management Failures (FY 91-99)
Percentages do not add up to 100%
Shappell & Wiegmann, 2002
Feedback
Human Error
- Errors occur frequently and are the major cause of accidents.
- Few safety programs are effective at preventing the occurrence or consequences of these errors.
Research Sponsors
- FAA, DoD, NASA, & Airlines provide funding for safety research programs.
- Lack of good data leads to research programs based primarily on interests and intuitions. Interventions are therefore less effective.
Fad-DrivenResearch
Miti
gatio
n
Prev
entio
n
IneffectiveIntervention
and Prevention Programs
Accident Investigation
- Less sophisticated techniques and procedures
- Information is qualitative and illusive
- Focus on “what” happened but not “why” it happened
Accident Database
- Not designed around any particular human error framework
- Variables often ill-defined
- Organization and structure difficult to understand
Database Analysis
- Traditional human factors analyses are onerous due to ill-defined variables and database structures.
- Few analyses have been performed to identify underlying human factors safety issues.
Accident Investigation
- Sophisticated techniques and procedures
- Information is qualitative and quantitative
- Focus on both “what” happened and “why”
Accident Database
- Designed around a well-known human error framework
- Well-defined variables
- Organization and structure easy to understand
FeedbackFeedback
Human Error
- Errors occur less frequently.
- Safety programs are effective at preventing the occurrence or consequences of these errors.
- FAA, DoD, NASA, & Airlines provide funding for safety research programs.
- Research programs are needs-based and data-driven. Interventions are therefore very effective.
Research Sponsors
Fad-DrivenResearch
Data-DrivenResearch
EffectiveIntervention
and Prevention Programs
Database Analysis
- Traditional human factors analyses are much less onerous due to well-defined variables and error database
- Analyses can now be performed to identify human factors safety issuesHFACSHFACS
Shappell & Wiegmann, 2002
Errors
UNSAFEACTS
Errors
PerceptualErrors
Skill-BasedErrors
DecisionErrors ExceptionalRoutine
Violations
InadequateSupervision
PlannedInappropriate
Operations
Failed toCorrectProblem
SupervisoryViolations
UNSAFESUPERVISION
ResourceManagement
OrganizationalClimate
OrganizationalProcess
ORGANIZATIONALINFLUENCES
PRECONDITIONSFOR
UNSAFE ACTS
Condition of Operators
Physical/Mental
Limitations
Adverse Mental States
Technological Environment
Physical Environment
Personal Readiness
Crew Resource Management
Personnel Factors
Adverse Physiological
States
Environmental Factors
Shappell & Wiegmann, 2002
HFACS can be applied anywhere! HFACS can be applied anywhere!
FlightdeckFlightdeck(HFACS)(HFACS)
MaintenanceMaintenance(HFACS(HFACS--ME)ME)
ATCATC(HFACS(HFACS--ATC)ATC)??
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