4 min read

Threat and Error Management (TEM) is not a term you hear much in general aviation circles, but it is widely adopted among airlines and is taking hold in corporate operators as well.

I am exposed to TEM through my employer who does Part 121 training under-pinned with the Threat and Error Management philosophy.

TEM is the brainchild of human factors researchers from the University of Texas and in a way it is not new, it is rather a modernized form of risk mitigation that accounts for the human(s) that are in the loop. With so many accidents attributed to pilot error and with modern airplane reliability it makes sense that we focus on the human part of the equation.

According to Dr. Helmreich: “The easiest way to understand Threat and Error Management is to liken it to defensive driving for motorists. The purpose of defensive driving is not to teach people how to drive a vehicle (e.g., how to shift a manual transmission) but to emphasize driving techniques that people can use to minimize safety risks (e.g., techniques to control rear-wheel skids). Similarly, TEM does not teach pilots how to technically fly an airplane; instead, it promotes a proactive philosophy and provides techniques for maximizing safety margins despite the complexity of one’s flying environment. In this sense, TEM training can be framed as defensive driving for pilots.”

Threat and Error Management

This diagram illustrates what Threat and Error Management is and what it is trying to achieve.


Threats are anything that alone, or combined with something else, can have an adverse effect on the outcome of the flight. Threats occur outside the influence of the pilot, like weather, terrain, a complex procedure, or an aircraft malfunction. Threats require your attention and management if safety is to be maintained.


Errors are pilot actions or inactions that lead to a deviation of some kind. You are likely familiar with the myriad of pilot errors that occur.

TEM accepts that human error will occur — this is a shift from previous airline safety dogma. And you can see this in the amount of human factors engineering being used by manufacturers, operators, and training organizations that have adopted these techniques.

Undesired Aircraft State

In simple terms, the goal is to avoid an Undesired Aircraft State. Keep the airplane’s vertical and horizontal flight path under our control and safe at all times.

Reason model

The famous Reason model describes the error chain with a Swiss cheese illustration.

The Reason’s Model

Physiologist James T. Reason’s 1990 Swiss cheese model is a famous threat/error chain illustration. If the issue is allowed to get through all the barriers the outcome is usually not good. The idea is to place more barriers, and with fewer holes, in front of the problem.

How can it help me?

In an airline environment TEM involves scenario-based simulator training, Crew Resource Management, specialized line-checks, and incident reporting; none of which we have in our flying. Although it is not specifically designed for general aviation, there are certainly things we can do to apply it to our everyday flying. 

TEM Philosophy

So you try to do everything right and something still goes wrong — now what?

There are three basic concepts you need to adopt: anticipation, recognition, and recovery.

  • Anticipation: Staying alert, knowing that you can’t possible predict everything that can go wrong. Maintaining a state of vigilance and avoiding complacency.
  • Recognition: The sooner you recognize that something is not right, the faster you can act to mitigate that threat or error. Early recognition obviously aids recovery.
  • Recovery: This is you intervening in what will soon become, or has already become, an undesired aircraft state.
The cycle of threat and error management

Threat and Error Management is an ongoing process.

Here’s a short list of techniques you are probably already using today.

Threat Management Techniques:

  • Personal weather minimums
  • Self-imposed proficiency requirements
  • Proper aircraft maintenance
  • Severe weather avoidance

Error Management Techniques:

  • Checklist discipline
  • Proper use of automation
  • Managing your resources (ground or flight)
  • Fatigue recognition
  • Distraction mitigation

Although we didn’t dive deep into the details of Threat and Error Management, this article should provide an adequate introduction and hopefully provoke some thought about risk management in your flying.

Brent Owens
Latest posts by Brent Owens (see all)
15 replies
  1. Stephen Gray
    Stephen Gray says:

    It is always difficult to argue with a Human Factors discussion – it seems to make so much sense. But like all these discussions the suggested actions always leave out one thing, ability to fly the plane.
    Here the author suggests pre flight planning, checklists and resource management but leaves out becoming competent at handling the machinery so that when a problem arises we can prevent it from becoming an accident. “I was too busy reading the checklist to recognize that we were upside down”!! Maybe that is what “self imposed proficiency requirements” means, I am not sure.
    Back home when they first introduced “human factors” training at the expense of some stick and rudder time, the accident rate increased so the CAA in their wisdom said we obviously need more human factors.
    I am sure that it makes a difference, and an awareness of what causes risky situations is a great thing, but “human factors” are no substitute for handling skills and the rapidly diminishing art of actually being able to fly a plane.

    • Brent
      Brent says:

      Well said Stephen! Flying the airplane comes first. The article assumes that, but you know what they say about the word assume…

      I agree that the threshold of competency should not be taken for granted, especially in this age of technically advanced aircraft.

      Thanks for your feedback!

  2. Steve Phoenix
    Steve Phoenix says:

    I kind of have a hard time relating TEM and other similar programs to GA. The implication here is that TEM useage is a reason that the airlines are safer than GA and thus should be trickled down. Perhaps, but I think more likely it has to do with:
    Redundant crews flying (practicing) daily.
    Redundant airplane systems of the highest quality, maintained regularily.
    Good performing airplanes that stay above the weather and are fast enough to go around weather they can’t fly through.
    Familiar practiced departures, routes and destinations and rigid procedures for each segment.
    Regular simulator practice for the unusual occurrences.
    TEM type programs that can be discussed regularily while somebody is paying you.

    The above things would also improve GA safety, at the expense of flexibility. I’m sure you may disagree, but that’s how I see it.

    • Brent
      Brent says:

      Good points Steve!
      It is an apples to oranges comparison when you look at it that way. TEM came into the airlines because accident rates were spiking and they needed to do something about it.
      As for GA, it would be impossible to adopt it lock, stock, and barrel – no infrastructure, although some of the Red Bird stuff is interesting for those with the money and time.

      In the end, hopefully some of the human-factors concepts provide value to our everyday flying even if only partially applicable.

      Good discussion.

      • Allen Benzing
        Allen Benzing says:

        Brent – Regarding Steve’s comment and your reply. It is certainly true that the GA environment is quite different from the structure and infrastructure of Airline flying – but there are still Threats coming at you and Errors made that need to be managed. We just need to approach these from the standpoint of resources available. Much like CRM – Single Pilot flying doesn’t seem to lend itself to the situation, but the reality is we are not without resources – ATC, FSS, data fm our shiny new iPad, etc.

        You provided a good presentation of the TEM principles.

        • Brent Owens
          Brent Owens says:

          Thanks for the kind words. It is true that we should use everything at our disposal. I guess that’s when CRM goes from Crew Resource Management to Cockpit Resource Management.


  3. Cameron Fraser
    Cameron Fraser says:

    Over the last 10 years I have been involved in developing, refining, facilitating, and providing training in risk-based decision-making processes for both government and industry including aviation regulators in Canada and aircraft manufacturers in the United States. The processes were originally intended for large-scale corporate decisions but, over time, as the organizations saw the value in deliberately considering risks when making decisions, they began to ask how the processes could be applied on a more operational level… By the individual pilot or maintainer.

    After a period of reflection, and through discussions with my clients, I was able to distil the essence of the big process into five questions. These are:

    1. What could go wrong?

    2. How could it happen?

    3. How would it affect me?

    4. How can I prevent it happening, or reduce the impacts if it does?

    5. What do I need to do next?

    The key here is to recognize that virtually any change in flight condition involves the pilot making a decision. These five questions have you consider the threats and errors each decision may expose you to, the probability and severity of unintended consequences, and possible mitigating actions. Quickly running through the questions in your head prior to implementing a change in your plans or approach to the situation can potentially save you a great deal of grief.

    Certainly I have found them useful in my personal flying and can think of at least one situation in my younger days where having these in hand could have prevented what turned out to be a very close call. Like all models it is not perfect but I hope you find it helpful.

    • Brent
      Brent says:

      Well said Cameron! When you break it down, it really makes sense and as you state, it can be applicable outside of flying as well.

  4. Charles Lloyd
    Charles Lloyd says:

    I have worked with Brent on a number of projects and am glad he is joining Air Facts to share his wisdom and experience.

    Questions to ask yourself is do you fly a long cross country after working all day? Did you have adequate rest before the flight. Airlines and fractional operations have hard and fast length of duty days. I adapted this as part of my personal operations manual for GA flying and do not fly longer than 12 hours past the start of the day.

    This is one way I plug the holes in the cheese.


    • Brent
      Brent says:

      Good to hear from your my friend and thanks for the props!

      Sage words. This is probably the most insidous and overlooked issue we face – fatigue. I know you and I could write volumes on the subject.

      Good advice indeed!

  5. Bob Gould
    Bob Gould says:

    I too teach human factors and risk management. General aviation pilots unfortunately do not have the training resources available to them as in the airlines, corporate, or military environments. Most of our flying is really SPRM (single pilot resource management). To add to the great suggestions of Cameron Fraser, AFTER you have completed a flight, take some time to debrief yourself with asking questions such as “Did I encounter and threats, planned or unplanned?” or “Did I make any errors and why?” or “What could I do better?”. Be critical of yourself and you will find yourself beginning to understand TEM, and become a better pilot.

  6. Charles Lloyd
    Charles Lloyd says:

    There are some CRM techniques that I have adopted from flying crew aircraft.

    The first is to call out to myself when passing 1,000 and 300 feet to assigned altitude when flying solo.

    Next, you don’t have to have a rated pilot in the right seat to use crew CRM. My wife makes altitude call outs. We brief the approach and she announces the 500 and 200 foot to minimums call outs. She also announces at 200 feet that she is outside looking for the runway. Then, calls direction when she sees it or when I call minimums then she can make the missed approach call with no runway in sight.

    Single pilot piston engine aircraft flying is in some aspects more complex that crew type turbine flying. Get creative and train you own first officer. It works for me.


    • Allen Benzing
      Allen Benzing says:

      Excellent techniques Charles… Single pilot ops require all the help you can find. It’s just too easy to make an undetected error.


  7. JACK
    JACK says:

    I think it’s important to always keep the “basics” in mind
    that’s why I made a little website resuming them :principles and factors,human factors and now 19 events as illustration!!

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