Darren Smith, Flight Instructor
  Home | Login | Schedule | Pilot Store | 7-Day IFR | IFR Adventure | Trip Reports | Blog | Fun | Reviews | Weather | Articles | Links | Helicopter | Download | Bio

Site Map


Private Pilot
  Learn to Fly

Instrument Pilot
  7 day IFR Rating
  IFR Adventure

Commercial Pilot

Multi-Engine Pilot

Human Factors/CRM

Recurrent Training

Ground Schools


Privacy Policy
About Me


Support this Website

Introduction to Threat & Error Mgmt

by Darren Smith, CFII/MEI
General Aviation Human Factors, May, 2007
Navigation:  Fundamentals of CRM | Resolving Conflict | Workload Management | Checklist Usage | Briefings & Callouts | Training CRM | Threats to Safety | Intro to TEMError Management | Integrating Threat & Error Management | TEM Countermeasures | FOTA | What are you doing over there? | New Captain Series

TEM Series:  Threats to Safety | Unsafe Acts | Intro to TEM | Error Management | Integrating TEM | Countermeasures

Let’s talk about Threat & Error Management (TEM) in depth.  TEM is a conceptual model to help you understand the relationship between safety, human performance, and flight operations. 

The focus is on Human Performance and System Performance. Human Performance is important because pilots under stress or task saturated (high threat level) do not perform   at their best.  We know this from the Yerkes-Dodson curve (see graphic below to the right).    At a given level of stress, you’ll get a level of performance.  There’s a breaking point, however, where further increasing stress affects human performance.

Threat & Error Management is an important conceptual framework because:
  • it can be used to describe cause & effect relationships,
  • it can be used to analyze failures of the system (accidents), 
  • it can be used to alter and improve pilot training,
  • it can be used to predict human performance,
  • it can be used as an audit tool in flight operations, and
  • it can be used as a reporting tool when errors have occurred.

The three components of TEM are:  threats, errors, and undesired aircraft states.  In it’s simplest form, it describes a relationship where “A” leads to “B” which leads to “C”.

Think of the TEM model (depicted to the right) as a funnel.  Whatever we allow to be poured into the top will get to the bottom if we don’t do something to resist the flow.  If you avoid the threat, it usually doesn't occur.  In other words, the threat doesn't even get into the funnel.  Your avoidance activities will go a long way to minimizing a threat but if it does occur, it means easier threat management.

This means we can spend our time resisting threats or we can spend our time resisting the errors.  Because of the cause & effect relationship between threat & error, we can consider that resisting threats is managing the future while resisting error is managing the past.  In our flight operations, we always have a choice:  proactive or reactive.  Proactive increases our margin of safety while reactive consumes our margin of safety.

Some threats can be anticipated.  Weather briefings, security briefings, quality of VHF / HF communications with ATC, cockpit workload.  Preparing for the most conservative outcome is a way of managing and anticipating threats.

Some threats can’t be anticipated.  Missing radio calls, unforecast weather, last minute runway changes, traffic flow restrictions, and other such gotchas.  There are some real challenges in today’s aviation system and these complexities increase your workload as a pilot.  Your deployment of TEM Countermeasures will increase your margin of safety regardless of whether the threat was anticipated or unanticipated.

The key thing to remember is that the threats are there and you aren’t likely to avoid them.  Threats are unavoidable components of our complex operating environment.  Managing these threats, or resisting threats is a way to mitigate the consequence.  Fail to manage the threat, error is the result.  When you’re managing and responding to errors, you’ll completely forget about new incoming threats.  This nasty scenario sets you up for an undesired aircraft state because as threats stack up, more errors occur and there is a higher chance one of those errors is going to slip by you.  Mismanaged threats lead to flight crew errors.

There are always exceptions to the rules.  There are times when threats can lead directly to undesired aircraft states without the flight crew ever making an error.  There are also occasions when flight crews can make errors when no threats are known to exist.  Both scenarios could present flight crews with no conceivable way to manage the undesired aircraft state or the threat.  Building predictability between flight crew members (pilot monitoring) and TEM Countermeasures offer a robust toolkit for mitigating these potentials.

In the next article, I’ll define Errors and provide examples & case study information to help you identify and manage Errors.

NEXT: Error Management>>

Your Thoughts...

Name: (Anonymous posts deleted)

E-mail: (if you want a reply)

How did you hear
of this website?
Message:  (What should I write?)
Business Card
News Group
Safety Seminar
Word of Mouth
(Required) Enter number from image to send:


Check this out...
  Home | Login | Schedule | Pilot Store | 7-Day IFR | IFR Adventure | Trip Reports | Blog | Fun | Reviews | Weather | Articles | Links | Helicopter | Download | Bio
All content is Copyright 2002-2010 by Darren Smith. All rights reserved. Subject to change without notice. This website is not a substitute for competent flight instruction. There are no representations or warranties of any kind made pertaining to this service/information and any warranty, express or implied, is excluded and disclaimed including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose. Under no circumstances or theories of liability, including without limitation the negligence of any party, contract, warranty or strict liability in tort, shall the website creator/author or any of its affiliated or related organizations be liable for any direct, indirect, incidental, special, consequential or punitive damages as a result of the use of, or the inability to use, any information provided through this service even if advised of the possibility of such damages. For more information about this website, including the privacy policy, see about this website.