What Crews Do: Context and Concepts of Threat and Error Management TEM

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What Crews Do Context and Concepts of Threat
and Error Management (TEM)

• Robert L. Helmreich, Ph.D. FRAes
• The University of Texas
• Human Factors Research Project
• LOSA WEEK
• Kuala Lumpur
• September 13, 2005

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Goals

• Define threat and error management concepts
• Demonstrate threat and error findings from Line
  Operations Safety Audits (LOSA)
• Clarify relationship between CRM and TEM
• Place threat and error management in the context
  of flight operations

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Threat, Error, andUndesired Aircraft State

• Definitions

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Threat

• Event or error that occurs outside the
  influence of the flight crew, but which requires
  crew attention and management if safety margins
  are to be maintained. Mismanaged Threat A
  threat that is linked to or induces flight crew
  error. 

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Types of Threats

• Observable Threats
• Known
• Hurricane
• Unexpected
• Engine failure on take off
• Latent Threats factors residing in the system,
  organization or individual that increase risk.
• Latent threats are not directly observable at the
  sharp end of operations. Usually uncovered by
  analysis of aggregate data such as confidential
  incident reports
• Equipment design issues
• Optical illusions
• Air traffic system design
• Training philosophy and practices
• Organizational culture (positive or negative)

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Error

• Action or inaction that leads to a deviation from
  crew or organizational intentions or expectations

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Communications
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Crew-linked Undesired Aircraft State

• An aircraft deviation or incorrect configuration
  associated with a clear reduction in safety
  margins

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Undesired Aircraft States

• Position wrong
• Speed wrong
• Heading wrong
• Configuration wrong

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Threat and Error Management is the Conceptual
Framework for LOSA
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Some Representative Datafrom 4,800 flights
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Carving the data

• Data can be examined in several ways
• of all threats or errors of a particular type
• of all flights with a specific threat or error
• Average number of threats or errors encountered

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Variability of threat

• Range of threats/flight 0 - 19
• Average number of threats/flight 3.7

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Sources of Threat

• 2/3 of threats are environmental (wx, airport
  conditions, ATC, terrain)
• 43 of environmental threats occur during
  descent/approach/landing
• 1/3 are airline (ground, ramp, dispatch, cabin,
  operational pressure, mx)
• 75 of airline threats occur during pre-departure

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The Top Three Threats

• 54 of all flights encountered one or more
  weather threats
• 54 faced one or more ATC threats
• 32 had aircraft malfunction/MEL threats with
  operational implications

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29 of flights had a threat that was mismanaged
and led to some form of crew error
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Mismanaged Threats

• Challenging clearance from ATC
• Thunderstorms with turbulence/icing
• Aircraft malfunction unexpected by crew
• MEL item with operational implications
• Operational time pressure

• 15 of all mismanaged threats
• 9 of all mismanaged threats
• 6 of all mismanaged threats
• 5 of all mismanaged threats
• 5 of all mismanaged threats

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ATC Threats by Phase of Flight

• 50 of ATC threats during descent/approach/landing
  
• 22 pre-departure
• 15 during takeoff
• 9 during cruise
• 50 of mismanaged ATC threats occur during
  descent/approach/landing

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Variability of Error

• Range of errors per flight 0 - 24
• Average number of errors per flight 2.6

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Errors Undesired Aircraft States

• 75 of flights had 1 or more errors
• 35 of flights had a mismanaged error
• 3 of flights had additional error
• 32 of flights had an undesired aircraft state
  (UAS)
• 6 of flights had a mismanaged UAS

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Type of Error

• Handling errors 36 of all errors
• Most common unintentional speed deviation
• Procedural errors 52 of all errors
• Most common checklist from memory
• Communications errors 12 of all errors
• Most common missed ATC call

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Most Common Errors

• 25 of all flights had manual handling/flight
  control errors
• 23 had automation errors
• 21 had checklist errors
• 20 had SOP cross-verification errors

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When Crews Err of Errors by Phase of Flight

• Pre-departure/taxi 26
• Take-off 20
• Cruise 6
• Descent/approach/landing 42
• Taxi in 6

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Other Applications of TEM
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Using TEM

• Conceptual framework for flight crew training
• Template for assessing threats during line checks
• Basis for accident and incident analysis

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TEM and CRM Bobs Error

• In describing the evolution of CRM from its roots
  in executive management training to its current
  focus on cockpit behaviors, the sixth generation
  was described as threat and error management
• Some airlines substituted TEM for CRM in training

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Human Factors/CRM TEM

• CRM provides countermeasures against threat and
  error as well as supporting basic aspects of
  effective teamwork and leadership
• TEM serves as a critical component of Human
  Factors/CRM training
• CRM is not forever
• Awareness and acceptance decay and need refresher
  reinforcement

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Threat and Error CountermeasuresCRM 101

• Planning
• Share plan
• Develop contingencies
• Execution
• Monitor and cross-check
• Manage workload
• Manage automation
• Review
• Inquire
• Modify course of action

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The Context of Threat and Error Management

• TEM is an essential component of flight
• It is influenced by system factors, the culture
  and characteristics of an organization, and its
  pilots

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Conclusion

• Threat and Error Management is a useful
  organizing concept for classification and
  understanding of crew performance in normal
  operations
• TEM helps organizations to integrate data from
  different sources such as maintenance, dispatch,
  pilot reports, etc.

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• The University of Texas
• Human Factors Research Project
• www.psy.utexas.edu/HumanFactors