The University of Texas at Austin
Threat and Error Management
Model
Robert Helmreich
University of Texas
Capt. Bruce Tesmer
Continental Airlines
ATA CRM Conference
Comair, Cincinnati
September 21,1999
The University of Texas at Austin
Applying TEMM to a ‘pilot error’ incident:
Landing at the wrong airport
Aerospace Crew Research Project
Aerospace Crew Research Project
Aerospace Crew Research Project
The Flight Scenario
 Houston to Corpus Christi second leg of the first day
of a trip that began in Newark
 Captain was PF from Newark, FO to CRP
 Captain was highly experienced check airman
conducting IOE
 CRP ATIS “..good, 6,000 broken 10 miles, wind 010,
10kts. Expect loc app to Rwy 31.”
 Descent started early expecting VORTAC vectors to
Rwy 31 localizer. ….. On autopilot until intercepting
final approach course
 After CRP Vortac, App Cont. gives vectors to, and
clearance for intercepting localizer and “Cleared
Approach.Rwy 31 Localizer”
Aerospace Crew Research Project
The Scenario – continued
 Turning final, the Capt sees the airport and reports to
tower “Runway in sight.”
 Crew has slowed and configured early to allow time
to reach landing configuration and be stable by 500’
AGL. They are surprised runway so close.
 A normal landing was completed but runway shorter
than expected. Landing completed with 500’
remaining
 There was no terminal, only hangers. Crew taxis off
Rwy and realizes they are not at CRP
 The call Tower which knows they have landed at
Cabaniss
External
Threats
Known
Threats
•First day as crew
•IOE being given
•1st leg in 737-300 round
dial, 2nd in 737-500 EFIS
•1st EFIS leg for FO
•FO only exposure to
EFIS in Level 5 device
•FO’s 1st trip to CRP
•Capt had not been to
CRP in 3 years & had
never landed to North at
CRP
Unexpected Threats
•ATIS doesn’t mention
2000’ scattered cloud layer.
Doesn’t warn about
location of Cabaniss Field
•A/C on autopilot, has
problem intercepting
localizer
•Scattered 2,000’ cloud
layer blocks fwd vision but
allows ground contact for
5 miles
External
Error
•ATC had localizer set to
Rwy 13 for previous A/C
doing training
Aerospace Crew Research Project
Latent Systemic Threats
Regulatory: Cabniss Field located 6nm
on Corpus localizer
Regulatory: no ATIS warning about
Cabaniss on weekend
Regulatory: chart depiction hard to
read
Regulatory: Cabaniss field layout looks
like CRP
Regulatory: MSAW warning for Cabniss
disabled
Regulatory: runway alignment (31)
same as Corpus
Navy: allows racing events except
special days (Mothers’ Day)
System: information on other near
approaches to Cabaniss existed, but
not available
Organizational: no mention of Cabaniss
on10-7 page in manual
Professional: operational and
professional pressure to make landing
Crew Error
Proficiency
Error
Types
Error Responses
Crew lacked knowledge
about Cabaniss location
Fail to Respond
Undesired State
Error
Outcomes
Additional Error
Procedural
Error
Types
Error Responses
Crew briefed and were
flying ILS approach, did
not check DME to confirm
FAF
Fail to Respond
Undesired State
Error
Outcomes
Additional Error
Error
Types
Error Responses
Error
Outcomes
Decision Error
Crew high & fast when
lined up for Cabaniss but
stable at 500’ chose riskier
decision
Fail to Respond
Undesired State
Approach tp
wrong airport
Fail to Respond
Undesired
Aircraft State
Outcomes
Incident
The University of Texas at Austin
Threat and Error Totals
System -- Organizational -- Professional
Latent Systemic Threats
External
Threats
Actions
External
Threats
Threat Recognition and Error Avoidance Behaviors Intentional Noncompliance
-Procedural
Communication
Proficiency
Operational Decision
Error
Action
Outcomes
Fail to Respond
Inconsequential
Undesired Aircraft State
Additional Error
Mitigate
Exacerbate
Fail to Respond
Actions
Final
Outcome
External Error
•Expected
•Unknown
Recovery
Additional Error
Incident
Aerospace
Research--Project
System --Crew
Organizational
Professional
10 Latent Systemic Threats
External
Threats
Actions
External
Threats
•Expected -6
•Unknown -3
Threat Recognition and Error Avoidance Behaviors - 2
Intentional Noncompliance
1 -Procedural
Communication
1 Proficiency
1- Operational Decision
Error
Action
Outcomes
3- Fail to Respond
Inconsequential
Undesired Aircraft State
Additional Error
Mitigate
Exacerbate
1 Fail to Respond
Actions
Final
Outcome
External Error
1
Recovery
Additional Error
1
Incident
Aerospace Crew Research Project
Conclusion
 A short flight with a highly competent captain became
very complex because of numerous latent systemic
threats
 These were compounded by external threat and error
and crew errors
 Any of a number of actions could have broken the
incident sequence
Aerospace Crew Research Project
About Latent Threats
 Latent threats are highly variable. They can
–
–
–
–
exist for a long time
be based on tradition ‘We’ve always done it this way.’
be associated with new technology
fail to appear as threats or seem to be based on good
decisions
– be difficult to resolve because corrective actions cross too
many jurisdictions and no entity takes responsibility for
corrective action
– are often known by some but not communicated to others
– frequently involve ‘local knowledge’
 Latent threats don’t show up in training
Aerospace Crew Research Project
The Future
 The identification of Latent Systemic Threats is
essential to safety
 Application of the model points to training needs and
to latent threats that need to be modified
 Safety, CRM, Training and Flight Ops need to
coordinate to address threat and error management
The University of Texas at Austin
CRM Countermeasures
Aerospace Crew Research Project
CRM Countermeasures Possible
Situation was high threat but not fully recognized
 External Threat and error
 Mental models
 Mental model check
 Cockpit Communication error
Aerospace Crew Research Project
Conclusions
 Crew faced a variety of external threats and error
 Crew recognized and managed several threats
 Latent Systemic Threats played a critical role
– They can be addressed in CRM if identified
 CRM countermeasures were available for error management
 Mental models of ATC and Crew were understandable but led to
misinterpretation of actions
– A ‘Mental Model Check’ could have served as the critical
countermeasure