A Comprehensive Guide to Threat and Error Management (TEM)
- Mar 6
- 26 min read
Introduction to TEM
Threat and Error Management (TEM) is an aviation safety concept and practical methodology that helps pilots anticipate and manage operational hazards before they lead to incidents. It has been described as essentially an extension of good airmanship – a structured way of applying sound judgement and skill to maintain safety margins. In essence, TEM is the process of detecting and responding to threats (e.g. deteriorating weather or a congested circuit) and errors (e.g. mis-setting an instrument or mis-hearing a clearance) before they compromise the safety of the flight. If threats and errors are left unchecked, they can set the stage for an accident by creating an Undesired Aircraft State (UAS) – a situation where the aircraft is in a condition outside normal parameters, such as straying off altitude or on an unstable approach. Managing these UAS effectively is the last line of defence to avoid an unsafe outcome TEM is recognised globally as a foundational element of pilot training and flight operations. The International Civil Aviation Organization (ICAO) considers TEM a critical component of aviation safety training for pilots at all levels. In the UK and Europe, regulatory standards require the introduction of TEM and human factors principles into all pilot syllabi, from student pilots onward, emphasising that pilots must demonstrate the ability to recognise and manage potential threats and errors on every flight. The UK Civil Aviation Authority (CAA) also advocates TEM as a best practice approach, considering it an integral part of pre-flight planning and real-time decision-making during flight. By incorporating TEM into everyday flying, light aircraft pilots (whether student, private, or commercial) can systematically enhance situational awareness, decision-making, and ultimately flight safety.
Understanding Threats in Aviation
In TEM, a threat is any situation or event that has the potential to negatively affect flight safety or increase the likelihood of pilot error. Threats introduce additional complexity or risk into an operation, and they can originate from external factors or internal factors. Crucially, threats are considered beyond the pilot’s direct control – they are conditions we must react to or manage, rather than ones we create intentionally. Pilots cannot eliminate all threats, but by recognising them and preparing appropriate responses, they can prevent those threats from escalating into errors or undesired states.
External Threats: These come from the outside environment, technical issues, or interactions with others. Common external threats for light aircraft include adverse weather conditions (low visibility, thunderstorms, icing, strong winds), a congested or complex airspace/airport environment, terrain and obstacles (e.g. flying near high ground or wires), and aircraft malfunctions or system issues. Air traffic control can also present threats, such as late runway changes, complex clearances, or radio congestion and miscommunications. For example, weather is one of the most significant external threats – encountering unexpected fog or being forced lower by cloud can seriously challenge a VFR pilot’s safety. Aircraft issues like a faulty instrument or engine roughness likewise demand the pilot’s attention and management. Even other aircraft in the vicinity (traffic) or poor aerodrome signage could be considered threats; they complicate the situation and require heightened awareness. All these factors are not caused by the pilot, but the pilot must be ready to cope with them.
Internal Threats: These originate from the pilot or crew themselves – physical, physiological, or psychological factors that can undermine performance. For single-pilot general aviation flying, internal threats are just as critical to acknowledge. Fatigue is a prime example: an early start, a long flying day, or cumulative lack of sleep can markedly reduce a pilot’s alertness and reaction time. Distraction is another; whether it’s dealing with a cockpit technology issue (like a GPS unit acting up) or non-aviation concerns intruding on your focus, distraction can cause crucial items to be missed. Other internal threats include stress, illness, hunger or dehydration, complacency (becoming over-confident or letting routine lead to slack habits), and inexperience or lack of recent practice. Even emotional state or external pressures we impose on ourselves count as threats – for instance, feeling the need to “press on” to meet a personal schedule, which pilots colloquially dub “get-there-itis” or “press-on-itis,” is a hazardous mindset that can compromise decision-making. By recognising these internal factors, a pilot can take steps to mitigate them (for example, postponing a flight when excessively tired, or resolving to divide tasks and minimise distractions during critical phases like take-off and landing).
Another useful way to think about threats is by their predictability or visibility: anticipated, unanticipated, and latent. Anticipated threats are those you can foresee and plan for. Weather forecasts, NOTAMs, and thorough pre-flight planning help reveal many threats of this kind – such as expected turbulence en route, a short runway at your destination, or likely dense traffic around a fly-in event. Because they’re expected, you can brief and prepare countermeasures in advance (for example, briefing a diversion in case of forecast fog, or planning extra fuel in case of delays). Unanticipated threats are the opposite – they strike with little or no warning, like a sudden mechanical failure, an unforecast weather change, or an unexpected instruction from ATC that catches you off-guard. With these, your training, experience, and TEM mindset must kick in on the spot to handle the situation safely. Finally, latent threats are those hidden or dormant factors that aren’t obvious during the flight but can undermine safety. They might include organisational or systemic issues (for instance, an out-of-date chart or a maintenance error that wasn’t caught), or even aspects of aircraft design (such as two similar levers placed confusingly close together) that could lead to mistakes. Latent threats often lurk in the background until they combine with active conditions; pilots may need to rely on safety information, checklists, and standard procedures to uncover and address them. No matter the type, the key is that a pilot’s ability to manage threats is measured by detecting them early enough to prevent an undesired aircraft state. Good situational awareness – keeping a mental scan of what’s happening now and what might happen next – is crucial for staying ahead of threats.
Error Types and How They Manifest
Despite our best efforts to manage threats, human errors can and do occur. Pilots are human, and to err is human – but what TEM emphasises is catching and dealing with errors before they cascade into something worse. In the context of TEM, an error is broadly defined as any action or inaction by the pilot that leads to a deviation from intentions or expectations, reduces safety margins, or increases the probability of an adverse outcome. Errors in flight operations can take many forms. Some are obvious, like dialing in a wrong radio frequency, while others might be more subtle, like a slight misjudgment of altitude that goes unnoticed. It’s useful to break down errors into categories by type, because different types of errors have different causes and may require different responses. The major error types commonly discussed are slips, lapses, mistakes, and violations:
Slips: A slip is an action that did not go as intended – essentially a skill execution error. You had the right idea, but did the wrong thing. This often comes down to attention or motor control. For example, you mean to pull the carburettor heat in a Cessna, but accidentally grab the mixture knob – immediately the engine sputters because you briefly cut off fuel. That’s a slip. Or perhaps you dial 1013 into the altimeter instead of 1003; your mind was ahead of your hands, or distracted. Slips are usually unintentional “cockpit fumbles” – often caused by momentary lapses in concentration, multitasking, or operating in an unfamiliar cockpit layout. They tend to occur when a pilot is tired or task-saturated, and something as simple as bumping a switch or turning the knob the wrong way happens.
Lapses: A lapse is a memory failure – forgetting to carry out an intended action. These are also unintentional. A classic example is forgetting to lower the landing gear (a particularly dangerous lapse for retractable-gear pilots), or simply omitting a step on a checklist because you lost your place. Suppose you’re on downwind and get distracted by radio chatter; you might completely skip the pre-landing carb heat application because your routine was interrupted. Lapses are why checklists and cross-verifications are so important – they provide an external memory aid to catch what the human brain might miss, especially under stress or distraction.
Mistakes: A mistake is fundamentally a problem in the plan or decision – you did something wrong not because you executed it badly, but because your chosen plan or action was incorrect to begin with. In other words, the error was in your thought process or knowledge. Mistakes are sometimes divided into “rule-based” or “knowledge-based” errors. For instance, a pilot may calculate performance data incorrectly due to using the wrong chart or formula (a knowledge mistake), or apply an inappropriate procedure for the situation (a rule-based mistake). Even if carried out exactly as intended, the action won’t produce the desired result because the plan was flawed. An example might be misreading the wind and choosing the wrong runway for take-off, or deciding to scud-run beneath lowering clouds when the correct decision would be to turn around. The plan itself is erroneous. Mistakes often stem from insufficient knowledge, misinterpretation of information, or flawed decision-making. They highlight the importance of continual learning and prudent judgement.
Violations: A violation is an intentional deviation from rules or standard procedures. In this case, the pilot isn’t trying to do the right thing – they are consciously doing something they shouldn’t, or not doing something they should, often to save time or effort. This could be anything from skipping a pre-flight walkaround to pushing into a known icing area in a non-ice-certified aircraft, reasoning “it’ll be fine this once.” While some violations are flagrant (like deliberately flying aerobatics below a safe altitude), others might be seen as minor shortcuts (like routinely not bothering with the passenger safety brief or omitting an approach checklist). Any violation erodes safety margins and often reflects poor discipline or hazardous attitudes. In a training context, instructors work to correct any emerging habit of violating SOPs, because these deliberate omissions or “shortcuts” can easily set the stage for accidents. It’s worth noting that violations are different from slips/mistakes: they are deliberate – and thus within the pilot’s power to avoid by making the safer choice. TEM encourages a compliance mindset, where following standard procedures is seen as an essential defence against errors.
To put these error types in context, consider some typical errors in light aircraft operations: forgetting to switch fuel tanks (a lapse), inadvertently dialing the wrong transponder code (a slip), misjudging how much runway you’ll need on a hot day (a mistake in planning), or deciding not to bother with an engine run-up to “save time” (a violation). Each of these could have consequences – some minor, some severe – but all are preventable or manageable with proper TEM practices. The first step of error management is simply being aware that errors will happen, even to the best pilots. This mindset shift is important: rather than thinking “I must never make a mistake,” think “I might make mistakes, so I’ll plan to catch and correct them.” By acknowledging our human fallibility, we focus not just on error prevention but also on error recognition and recovery. The aim is that when an error does occur, it is detected and resolved quickly so that it remains inconsequential to safety. In other words, an error might happen, but it doesn’t have to lead to anything bad if managed properly.
Undesired Aircraft States (UAS) and Recovering from Them
An Undesired Aircraft State is exactly what it sounds like: the aircraft is in a condition that is not desired – specifically, a position, speed, attitude, or configuration that may reduce safety margins and require immediate correction. UAS are typically the result of one or more errors or threats that weren’t adequately managed. In the TEM framework, while threats and errors are part of everyday flying, an undesired aircraft state is a clear indication that safety is being compromised and that urgent action is needed to get back on track. Importantly, UAS are pilot-induced states – not that the pilot wants them, but they arise from pilot action or inaction (for example, mismanaging a descent such that you end up too low, or failing to notice your airspeed bleeding off until you’re close to stall).
Some examples of UAS in light aircraft flying include: altitude or course deviations (getting off assigned altitude or unintentionally wandering off your navigation track), unstable approaches (continuing an approach that is too high, too fast, or not properly configured), inadvertent flight into IMC while VFR (suddenly finding yourself in cloud, clearly an undesired and dangerous situation), or something like stalling or approaching a stall due to improper speed control. Even less dramatic states, like being on final approach not fully configured (say, flaps not set correctly) or finding yourself far off the centreline on landing, count as undesired states because they are deviations that increase risk. Another classic UAS example is a runway incursion – if you accidentally taxi onto a runway without clearance or when another aircraft is taking off, the aircraft is plainly somewhere it shouldn’t be, creating immediate risk. Essentially, a UAS is the last clear chance to break the accident chain: it’s a situation where if nothing is done, it could lead directly to harm (collision, loss of control, etc.), but if the pilot recognises it in time and takes corrective action, the situation can be saved.
Recognising a UAS is crucial. Sometimes it’s obvious (e.g. the wind has blown you well off the approach path and you realise you’re not stable), and sometimes it might be subtle (your altitude has drifted 300 feet off – an undesired state that could lead to airspace infringement or terrain risk if not corrected). Pilots must continuously monitor the aircraft’s flight path and energy state to catch these deviations early. Once a UAS is recognised, immediate recovery action is needed – this is where the old adage “first, fly the aircraft” comes into play. The TEM approach stresses not fixating on the error that led to the state, but rather taking action to correct the state itself. For instance, if you find yourself on an unstable approach (too high/fast), the correct response is to initiate a go-around (or other corrective manoeuvre) rather than pressing on or getting bogged down in why it happened in the first place. You can analyse the “why” later on the ground. At the moment a UAS is happening, recovery is the priority.
Common recovery techniques include: going around (for approach or landing issues), leveling off and sorting it out (if, say, you’ve gotten disoriented or off altitude, level the wings and hold altitude while you reorient, instead of continuing an unsafe trend), engaging autopilot (if available) to help stabilise the situation, or simply reducing workload (for example, if an instrument failure at night creates a high workload, you might consider asking ATC for a holding pattern or vectors, giving you time to troubleshoot in stable flight). In any UAS, the pilot should configure the aircraft and adjust the flight path to make it as safe as possible while correcting the situation. That may mean slowing down, climbing to a safer altitude, or disengaging an automation mode that is confusing things. An undesired state is often accompanied by a bit of startle or stress, so it’s critical to remember to aviate, navigate, communicate in that order. Control the aircraft (aviate) to get it back to a safe state, ascertain where you are and where you need to go (navigate), and only then communicate if needed (for example, inform ATC if you had to break off an approach). By swiftly managing UAS, pilots restore the safety margin and can then safely address any follow-up issues. TEM training puts a lot of emphasis on scenarios that induce undesired states and practicing the proper recovery, because this is truly the last barrier before an incident. If the UAS is not dealt with, it can quickly lead to outcomes like a loss of control or controlled flight into terrain – which are often fatal. Thus, UAS management is as vital as threat and error management itself in the TEM framework.
Implementing TEM in Flight Operations
Threat and Error Management isn’t a one-time task; it’s a continuous, structured practice throughout a flight. For a light aircraft pilot, implementing TEM can be thought of as adding an extra layer of planning and mindfulness at each phase of the flight: pre-flight, in-flight, and post-flight. Below, we break down practical strategies for each phase, illustrating how to recognise and respond to threats and errors in a structured way.
Pre-Flight Planning (Anticipation): TEM begins before take-off, with thorough planning and briefing. A pilot should systematically review the upcoming flight for potential threats and think through “what if” scenarios. This means doing a careful weather analysis (Are there fronts or storm cells on route? Is there a risk of fog at my destination? What is the freezing level?) and considering alternates in case conditions change. It also means examining NOTAMs for airspace restrictions or navaids outages that could pose problems. As you plan, explicitly ask yourself: “What could make this flight challenging today?” If, for example, you note that the only available runway at your destination is short and has trees at the end, that’s an anticipated threat – you might decide to take an extra 30 minutes of fuel in case a go-around and diversion is needed, or brief a firm go/no-go decision height on final. If flying with passengers, think about how you’ll manage them – could they be a distraction during critical moments? Maybe brief them to minimize conversation during take-off and landing (passenger distraction is a threat you can mitigate by setting expectations). By identifying threats in advance, you can put countermeasures in place. Countermeasures in planning might include simple things like rescheduling the flight to avoid forecast thunderstorms, or arranging for a refuelling stop to reduce the risk of low fuel later. The UK CAA recommends using a TEM approach to pre-flight by mentally briefing for specific threats and errors at each stage of flight and having a contingency ready. A memory aid some pilots use is the PAVE checklist (Pilot, Aircraft, enVironment, External pressures) to cover personal and external risk factors during planning. Ultimately, a well-prepared pilot will have a “game plan” for how to avoid or deal with the most significant threats of the day.
Pre-Flight Checks and Briefing: Before engine start and take-off, incorporate TEM into your routine by doing a structured self-briefing. Airlines have formal briefings; solo GA pilots can still brief themselves aloud. For example: “Departure runway 24, left-hand circuit. Key threats: birds reported in the area, and there’s terrain to the west I must avoid on climb-out. If engine fails after take-off, I have a field about 2 o’clock position I can glide to.” By verbalising this, you’re priming yourself to handle those situations if they arise. Include potential errors in your brief: “I need to remember to reset the altimeter to QNH before departure – easy to forget since I was playing with it earlier.” That way you’ve brought a possible slip to conscious attention. If flying with an instructor or another pilot, discuss the threats and allocate tasks (for instance, “There’s a lot of traffic today – I’ll focus on flying, you help me watch for traffic”). Good TEM practice also involves using checklists diligently at this stage, because many errors can originate on the ground (like setting the wrong frequency or improper weight and balance entry). A take-off briefing that covers the plan and alternatives acts as a mental rehearsal, so if something unexpected happens, you’re not starting from zero.
In-Flight: Active Management: During the flight, TEM becomes a cycle of monitoring, evaluating, and correcting. Maintain a high level of situational awareness by continuously scanning instruments and the outside environment (traffic, weather) to detect any deviations or emerging threats. For example, as you cruise, keep an eye on heading and altitude to catch any deviations (small errors) early – this prevents a minor wander from turning into an airspace bust or getting lost. Workload management is another TEM strategy: aviate, navigate, communicate – in that priority. If tasks start to overload you (perhaps ATC is giving a lot of instructions while you’re trying to navigate around weather), consciously prioritise what must be done now versus what can wait. It’s not a failure to ask ATC for a delay or hold if you need time to regroup – that’s good TEM, recognising your human limits.
During each phase of flight (climb, cruise, approach, etc.), quickly reassess threats. For instance, approaching the destination: are winds stronger than expected? Is the sun low on the horizon causing glare on final approach? By thinking ahead, you might decide to adjust (maybe brief a different runway or prepare for a possible go-around if the approach is too challenging). This kind of real-time threat update ensures you’re not caught by surprise. Importantly, if confronted with an unanticipated threat – say a random avionics failure or an unexpected aircraft in your vicinity – take appropriate action calmly. Training and checklist discipline pay off here: follow memory items or checklists for malfunctions, and apply see-and-avoid or traffic advisories for traffic conflicts.
One formal TEM tool is using “countermeasures.” In practice, countermeasures are simply the tactics or resources you use to manage threats/errors. These fall into three groups: Planning countermeasures (things like briefings and fuel planning done pre-flight), Execution countermeasures (like keeping a sterile cockpit during take-off, or cross-checking navigation data en route), and Review countermeasures (updating plans as conditions change, and being willing to speak up or make adjustments as needed). For a GA pilot flying solo, it might be as straightforward as doing regular FREDA checks (Fuel, Radio, Engine, Direction, Altitude) to catch any emerging issues, or consciously deciding “If I don’t have the field in sight by 5 miles on final, I will go around” – and sticking to that decision. The key is to actively manage the flight, rather than passively letting things happen to you.
Another critical in-flight TEM practice is avoiding fixation. If an error happens – e.g. you realise you’ve been off course for a few minutes – it’s easy to get drawn into solving that and forget to fly the airplane. TEM reminds us to correct the unsafe condition first (in this case, navigate back on course or climb to safe altitude), then sort out the details. A classic training scenario is the distraction of a minor equipment problem leading to loss of control; for example, a pilot fixated on why the GPS is not working might accidentally let airspeed decay. Don’t let managing a threat or error itself become a new threat (through distraction). Good cockpit resource management, even in single-pilot ops, means using all available resources – your checklists, autopilot (if you have one), ATC services (don’t hesitate to ask for help or information), and even your passengers (a right-seat passenger can help look for traffic or hold a chart).
If an undesired aircraft state does occur despite prevention efforts, react immediately and appropriately. This might mean disconnecting autopilot if it’s inducing a wrong flight path, or conversely, engaging it if you are disoriented. If you catch yourself in a dangerous attitude, apply your upset recovery training: unload, roll wings level, etc. Should you find that a situation is deteriorating (for example, weather getting much worse ahead), TEM encourages early intervention – turning around or diverting before you are truly in extremis. Many accident scenarios show a chain of small errors leading to a crisis; TEM’s goal is to break that chain early. For instance, if you become unsure of your position (a navigation error), the TEM approach is to immediately take action: admit you’re unsure (“lost”), and execute a lost procedure or ask for help. This proactive step keeps an error from worsening into a full-blown emergency. In summary, during flight, keep scanning for threats/errors, fly proactively, and don’t hesitate to correct your plan as needed.
Post-Flight (Learning and Improvement): TEM doesn’t stop when the engine shuts down. A hallmark of airmanship is to reflect on the flight and learn from it. After landing, take a moment during your shutdown or while tying down the aircraft to debrief yourself on threats and errors you encountered. Ask: “What caught me off guard today? How did I handle it? Did I miss any threats that only became obvious later? What errors did I make, and how were they resolved? What could I do better next time?” This self-reflection is invaluable, especially for student and newly qualified pilots, as it cements lessons learned. For example, you might realise: “I became distracted looking for a landmark and missed a radio call – next time I’ll make sure to divide my attention more evenly.” Or perhaps: “I didn’t anticipate how the late-day sun would affect my landing – in future, I’ll consider sun angle as a threat in my approach briefing.” Some pilots keep a personal log of lessons or discuss their experiences with an instructor or mentor. The UK’s general aviation community often emphasises a culture of openly sharing near-misses and lessons, so others can learn collectively. By analysing our own flights, we become better at TEM the next time. The TEM model even provides a simple tool for post-flight analysis: sketch out the timeline of Threats, Errors, and UAS during the flight, along with how you responded and what the outcome was. If the outcome was inconsequential – great, your management was effective. If it was consequential (maybe an undesired state or a scare), figure out where an earlier intervention could have prevented it. This deliberate debrief habit helps pilots continuously improve their threat recognition and error management skills. Remember, every flight – even the routine ones – can offer insights to sharpen your airmanship.
Real-World Example: Breaking the Error Chain
To illustrate how TEM principles can make a difference, let’s examine a real-world incident scenario and see how better threat and error management might have changed the outcome. Consider the case of a Cessna 210 pilot who experienced a gear-up landing accident. In this scenario, multiple threats and errors compounded, resulting in an undesired aircraft state (the aircraft not properly configured for landing) and ultimately an accident. Here’s a simplified reconstruction of events:
Scenario: A pilot was returning home after a long cross-country flight. It had been a full day of flying and he was feeling fatigued – an internal threat that was already degrading his alertness. As he approached his home aerodrome, air traffic control threw an external threat at him: they changed the landing runway at the last minute due to shifting winds. He had been planning for Runway 36, but now had to switch to Runway 27 on the fly. This unexpected change upset his routine and created time pressure. Additionally, Runway 27 came with a significant crosswind component that day, and the pilot privately worried that his crosswind landing skills were a bit rusty. So now we have at least three threats in play: fatigue, a late runway change (which can induce confusion and haste), and challenging wind conditions.
Under stress from these threats, the pilot began to commit errors. During the descent, he was interrupted (perhaps by ATC instructions or simply distraction from re-planning the circuit) and failed to complete the descent checklist. This was an error of omission (a lapse). As a result, he didn’t configure the aircraft as he normally would: notably, he didn’t open the cowl flaps or enrich the mixture, so the engine started running hot – an undesired state that he did notice (one cue being the engine temperatures rising). Now dealing with that, he became further distracted. Entering the circuit for Runway 27, he struggled with the crosswind corrections – a handling challenge that took a lot of his attention (a potential slip or at least a high workload task). In the rush and confusion, he never got to the “before-landing” checklist either. Two critical items on that list: lowering the landing gear and setting flaps for landing, were never accomplished – major errors. As he turned final, he was “behind the aircraft,” barely managing to keep it aligned (and in fact it was not well aligned – another undesired state). No one (neither the pilot nor ATC) noticed the gear was still up, and the gear warning horn, though sounding, went unnoticed in the chaos. The pilot attempted to land. The aircraft, not being configured, touched down with the wheels up. The result: a belly landing, causing significant damage to the airplane (propeller and engine destroyed on contact with the runway, airframe scraped up). Fortunately, nobody was hurt, but it was a costly accident and a clear case of an error chain spiraling into an accident.
Now, let’s apply TEM thinking to see how this chain could have been broken. Several opportunities stand out. Threat recognition and management: The pilot knew he was fatigued; acknowledging that and perhaps deciding on an alternate plan (like postponing the flight, or being extra cautious to use checklists and perhaps even informing ATC he might need a bit more spacing due to being fatigued) could have helped. When ATC changed the runway – a classic unanticipated threat – a good TEM response would be to take a moment (if fuel and conditions permit) to orbit or extend downwind to gather oneself, or explicitly tell ATC “standby” to have time to re-brief the new approach. Rushing is dangerous; here it directly contributed to skipped procedures. The crosswind was an anticipated threat (the winds were known); the pilot might have prepared by recalling crosswind techniques or deciding in advance that if not comfortable, he’d go around rather than force the landing. Error management: Missing the checklist items was the crucial error. A possible TEM countermeasure is an “immediate actions” flow or a mnemonic that even if a checklist is interrupted, critical items (landing gear!) are verified. If flying solo, saying out loud “landing gear down, three greens” on base leg could jog memory. In this case, none of that happened. The pilot also became fixated on trying to salvage the landing, rather than recognising the approach was unstable and the aircraft not configured – a textbook undesired state. The proper action at that point (and the last chance to avoid the accident) was a go-around. A go-around would have given him time to reconfigure (gear and flaps up for climb, then re-attempt with gear down next approach) or even divert if needed. Post-accident, the pilot himself noted that a go-around was the correct response that he failed to execute. This scenario underlines how multiple smaller failures lined up: fatigue -> checklist omitted -> aircraft not configured -> undesired state not recognized -> accident. It’s reminiscent of the “Swiss cheese model” of accidents, where each layer of defence (in this case, checklist procedure, gear warning horn, personal limitations) had a hole in it, and those holes aligned to let the accident happen.
James Reason’s famous “Swiss cheese” model illustrates how an accident can occur when multiple safety defences are breached or bypassed. Each slice of cheese is a layer of defence (such as technology, procedures, training, or human vigilance). The holes represent weaknesses or errors. In this diagram, three hazard vectors (red arrows) are stopped by different layers, but one arrow passes through all the aligned holes – meaning none of the barriers caught it, resulting in an accident. TEM works by adding and strengthening layers of defence (anticipating threats, catching errors, managing undesired states) so that even if some holes exist, it’s very unlikely they’ll all line up.
The gear-up landing example reinforces why a proactive TEM approach is so important. Had the pilot managed the threats (acknowledged fatigue, anticipated the runway switch or at least responded to it methodically) or trapped the errors (used his checklist despite the curveballs, or heeded the warning horn), the outcome could have been just a go-around and an embarrassing missed approach, nothing more. Many general aviation incidents and accidents have similar chains: often weather-related (continued VFR flight into IMC), or navigation-related (getting lost or infringing controlled airspace), or fuel-related (mismanagement leading to exhaustion). In each case, there are threats (e.g. bad weather ahead, or ambiguous terrain features, or time pressure to “just get there”), and there are errors (pressing on into deteriorating weather, misreading the map, not checking fuel levels properly). If not managed, these lead to UAS (like spatial disorientation in cloud, or flying well off-course, or engine sputtering from fuel starvation). The goal of TEM is to give pilots the tools to cut off the chain early. For instance, many VFR into IMC accidents could be prevented by the pilot making an earlier decision to turn around or land when weather started to worsen – that’s threat recognition and a timely response. Or consider a pilot who became unsure of his position: calling ATC for help or climbing to safe altitude are TEM actions that prevent the situation from becoming dangerous. Every pilot can probably recall a flight where things didn’t go perfectly – those are moments to analyse and ask “What can I learn, and how would I handle that better next time?” By studying incidents (whether our own or others’), we improve our ability to foresee and manage risk. This is why safety publications and accident reports often highlight the chain of events – to train our TEM mindset.
Assessing and Improving Your TEM Skills
Threat and Error Management is not a one-and-done checklist item; it’s a set of behaviours and habits that a pilot develops over time. As a student or private pilot, how can you gauge your TEM performance and work on improving it? Here are some tips and guidance:
Use Flight Debriefs: As mentioned, after each flight, debrief yourself (and with your instructor if you have one). Did you identify key threats before the flight? How did the flight actually go – were there surprises you hadn’t considered? List any errors you noticed – even small ones like forgetting to turn the landing light on – and think about why they happened. This reflection should be done constructively, not to beat yourself up, but to build awareness. Over time, you’ll start noticing patterns. For example, maybe you realise you often get distracted by passengers during approach – so next time, brief them to keep quiet at that time. Or you find that almost every flight, you forget something minor like switching fuel tanks on time – that’s a cue to maybe add a prominent reminder in your cockpit flow or a sticker on the panel. Writing down your personal “gotchas” helps. Some pilots even use a formal TEM log: noting Threats, Errors, UAS, and how they were managed (T-E-U log) as suggested by TEM frameworks. This can reveal if, say, navigation errors are a common theme for you versus communication errors, etc., and you can target training to those areas.
Seek Feedback: If you fly with instructors or more experienced pilots, ask them to critique your TEM. Instructors naturally teach aspects of TEM (even if not calling it that) by quizzing you “what if the engine fails now?” or pointing out missed checklist items. After a flight, ask your instructor or safety pilot: “Did you spot any threats I missed or errors I didn’t catch quickly?” You might be surprised – perhaps you never even noticed you busted your altitude by 200 ft at one point, because you were heads-down. That’s an error that went unrecognized. Feedback brings those blind spots to light. Similarly, participate in safety seminars or online forums where scenarios are discussed. The UK’s General Aviation Safety Council (GASCo) and CAA safety evenings often discuss real incident case studies – hearing those can sharpen your threat awareness.
Scenario-Based Practice: One of the best ways to improve TEM is to practice it in low-risk environments. This could be in a simulator or during dual flights with an instructor who can introduce random issues. For instance, an instructor might quietly pull a circuit breaker to simulate an instrument failure, or ask unexpectedly for a diversion to a different airfield. These scenarios force you to think on your feet and apply TEM: identify the emergent threat or error, manage it, and still fly safely. Even in solo practice, you can do mental what-ifs: occasionally ask, “What would I do if X happened now?” This keeps you alert. Importantly, when practicing, emphasise the process – don’t rush to solve everything at once, but go through Aviate-Navigate-Communicate and use checklists. Over time you’ll react to surprises more calmly and methodically.
Integrate TEM into Checklists and SOPs: You can modify your personal checklists to include TEM reminders. For example, many pilots add a line in pre-flight like “IMSAFE check completed” (Illness, Medication, Stress, Alcohol, Fatigue, Emotion) to remind checking internal threat factors. Another line could be “Threats reviewed” as part of pre-take-off checks, prompting you to recall the main threats (like “weather moving in from west” or “temporary tower closed, so watch out for NORDO traffic”). If you always fly from the same airfield, you might know the common threats (e.g. “bird activity near threshold of runway 20” or “glider site 5 miles south”), so bake those into your routine scan. The idea is to make threat anticipation and error trapping a normal part of your flying workflow.
Stay Informed and Learn from Others: Read accident reports (the AAIB reports for the UK are a great resource) and look for the threats and errors in each story. Ask yourself what you would have done or what TEM techniques would have helped. Publications like CAA Safety Sense leaflets, General Aviation Safety newsletters, or Skybrary articles often contain TEM principles applied to GA scenarios. For instance, the CAA has published guidance on using TEM to avoid airspace infringements – reading such material can give you new strategies, like doing a “TEM briefing” focusing specifically on navigation and airspace before a flight near complex airspace. Similarly, attend workshops or online courses on human factors; many cover decision-making and TEM skills. The more tools and knowledge you have, the more refined your TEM process will be.
Attitude and Discipline: Ultimately, improving TEM performance comes down to consistently exercising a questioning, proactive attitude about safety, and maintaining discipline in following good practices. It means always asking “What if…?” and not becoming complacent. It also means being honest about your own performance and limitations. Pilots who cultivate humility – recognising that anyone can make mistakes – tend to be better at TEM because they remain vigilant and are not too proud to double-check or take corrective action. If you catch yourself thinking “I’ve got this wired, nothing will catch me out today,” that’s a red flag to consciously re-engage your TEM mindset! Conversely, confidence is important – confidence that you can handle threats as they come – but it should be grounded in preparation and knowledge, not optimism alone.
Conclusion
Threat and Error Management is about building multiple layers of defence into your flying and staying one step ahead of trouble. For UK light aircraft pilots, adopting TEM principles means combining classic airmanship with modern human factors knowledge to fly safer and smarter. By thoroughly planning for threats, conscientiously avoiding and trapping errors, and being ready to recognise and recover from undesired states, pilots can significantly reduce the likelihood that a benign flight will escalate into a dangerous situation. TEM isn’t extra work as much as it is a mindset – once it becomes second nature, you’ll find you are more alert to potential problems and more adept at handling them calmly. Aviation safety is built on the idea of anticipation, recognition, and recovery: anticipate what can go wrong, recognise quickly when something’s not right, and recover or adapt to keep the flight safe.
Especially for student and general aviation pilots, developing TEM skills early on will pay dividends throughout your flying career. It will help you make better decisions, whether it’s choosing not to launch into marginal weather, or double-checking that “odd feeling” that something in the cockpit isn’t configured correctly. As the saying goes, “Learn from the mistakes of others; you won’t live long enough to make them all yourself.” TEM is the practical application of that wisdom on each flight. It encourages you to learn, to stay curious about safety, and to never stop improving your personal minimums and procedures. In the UK, where flying can involve dynamic weather, busy mixed-use airspace, and a variety of aerodrome types, having a strong TEM approach is an invaluable asset for every pilot. By incorporating the concepts discussed – from identifying internal and external threats, understanding the kinds of errors and why we make them, to practicing swift recovery from upsets – pilots can build a robust safety net.
In summary, Threat and Error Management is about being proactive rather than reactive. It’s a commitment to professionalism, whether you fly an airliner or a humble Cessna on weekends. It’s knowing that while you cannot eliminate all risks from flying, you can certainly manage them to keep your flight well within the envelope of safety. With a TEM-focused outlook, you’ll be better equipped to handle whatever challenges the day’s flight might bring, ensuring that you and your passengers fly safely and confidently. Safe flying!
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