Coaching Corner… Threats and errors – can we manage them?

Heard about Threat and Error Management, but don’t think it’s for you? As Head of Coaching David Cockburn suggests,

time to pay some more attention…

Threat and Error Management (TEM) is a hot topic for aviation safety regulators. Instructors are encouraged to discuss the subject whenever they fly with another pilot, whether they’re a student or a qualified pilot, and it also features in aviation theory exam questions. There are, however, differing definitions of the terms used, and these can make the subject seem overly complex. Humans have a natural tendency to defer complicated subjects until they become clearer, and that is bad news for pilots, because a number of useful documents exist on the subject which can help you manage threats and errors during flight.

TEM is all about reducing the risk of potential problems causing accidents. It is a large part of what we would consider ‘airmanship’. We, as pilots, have been doing this in the past, but as with many aspects of life, regulators have decided to categorise the subject.

While exact definitions may be subject to discussion, we can probably get away with considering a ‘threat’ as a hazard which is outside the control of the pilot. The expression ‘error’ sounds reasonably self-explanatory, but can more broadly be defined as a hazard that falls within the control of the pilot. It is not necessarily restricted to mistakes made by the pilot; it includes hazards for which the pilot has not been trained, and maybe could not be expected to be trained. To fly safely, we need to be able to ‘manage’ these threats and errors.

Threats

If threats are outside the control of the pilot, knowledge can improve our chances of managing them. The more understanding we can gather about situations which might catch us out, the better we can be prepared to cope with them if they occur.

In the UK, the weather poses probably the most likely threat. Modern forecasts are more accurate than ever, but pilots can still be wrong-footed by variations that occur on the day. For example, winds of higher speed, or differing directions, and clouds that form with bases below that forecast, then remain low when they are forecast to rise. Other threats can be found in engine or system failures, as well as the threat of collision.

We can manage these by minimising either their likelihood or their consequences. That unforecast weather? We could decide only to fly if the forecast allows a greater margin of safety than we really need. Unfortunately that would prevent us flying on days when the weather actually turned out better than forecast, and there are few enough flyable days in the UK. I suggest it is better to just always anticipate that the forecast has underestimated the hazard and have a fallback plan which we can use when the forecast turns out to be over-optimistic. We could also reduce the likelihood of being caught out if we obtain actual reports from our route (and upwind of it) and compare these with the forecast; although sadly the UK has a shrinking number of reporting stations that can provide such warning. We also need to be able to recognise when to adopt that fallback plan before we run out of fuel or daylight, and be prepared to make alternative arrangements when we divert.

Engines and systems failures can be reduced by carrying out the required maintenance properly, and exercising care in handling them, monitoring gauges for abnormal indications and being alert to unusual sounds. Odd noises may provide enough early warning to allow a safe landing before serious damage results.

We can also attempt to reduce the effects of any threats we fail to avoid. The consequences of encountering bad weather can be serious, but the skills and knowledge we have built up during training can save us. Some of us with instrument qualifications may be able to climb and reach a safe aerodrome if we can avoid icing and invisible high ground, but we should all have been trained to make a precautionary landing. If we can do the latter before it is too late, we can avoid becoming a fatal accident statistic.

We can reduce the consequences of an engine failure by keeping in practice with forced landing techniques and always staying within reach of a safe landing area. That suggests we should aim to fly at suitable cruising altitudes, and always be aware of the surface conditions and the wind direction for landing. As for system failures, do you know how to lower the gear in an emergency, or make a safe flapless or brakeless landing? An ASI failure can be frightening even in good visibility. Knowing how your aircraft ‘feels’ as it approaches the stall will help, as will flying an approach without reference to the ASI with a coach or other instructor. Again we should consider a suitable diversion; a long runway gives a considerable margin for error.

Errors

There is a danger that use of the word ‘error’ in published reports might encourage people to apportion blame on the pilot after every incident report which contained the expression. Indeed, that is probably a major factor in pilots’ reluctance to report incidents in which they have been involved. Flying is a stressful business with many opportunities to become distracted from the primary task. Human factors affect us and we have limitations. Omitting to select the ignition switch(es) on for start (yes, I’ve done it!) may not affect safety, but taking off with the wrong flap or carburettor heat setting certainly could.

As mentioned earlier, any hazard which is under the control of the crew can be regarded as an ‘error’. For example, a simple case of a patch of cloud appearing ahead of us on our flight path at our level. That cloud is a threat, and if we have anticipated it and considered how to manage it, the decision should, in theory, be easy. However, we are likely to be presented with a variety of possible courses of action. Do we climb above it, descend, alter track or turn back? Of these options, one will undoubtedly turn out to produce the best result, but at the time we make the decision we are unlikely to know which one. After that initial decision, our subsequent actions and decisions will continue to affect the outcome of the flight, but any decision which turns out to be less than the best one possible is effectively an ‘error’ when we are considering how to manage it.

Like threats, we cannot remove errors, but we can try to manage them by reducing their likelihood and / or their consequences. One way of reducing errors on the ground would be to use a checklist, just be wary of its completion being interrupted.

Making critical switches (such as undercarriage and flaps) unique and more obvious, both to the eye and the touch, can reduce the likelihood of incorrect switch selection, and we can go further to reduce the consequences of say raising the gear on the ground by fitting an electrical or mechanical device, which prevents the gear moving if the aircraft’s weight is on the wheels.

Standard procedures reduce not only the likelihood of making errors, but also their effects. For example, if we never move an electrical switch in flight below a certain height, then even if we switch off the ignition instead of the landing light there should be time to restart the engine before we crash. Many professional pilots go through a

‘reds, blues, greens, clear to land’ check just before touchdown – and others have invented their own. If we develop the habit of always waiting until we have rolled to a halt after landing before selecting flap, we are less likely to raise the gear by mistake.

Management

Good pre-flight preparation can reduce the chances of making errors when we have to react to perceived threats, and the sooner we realise that a threat is present the more time we have to make decisions and the better our chances of making the best one. However, we must not waste the time available by continuing towards a hazard while we think about what we are going to do about it. It is usually better to make a bad decision early than no decision at all –unless we have already backed ourselves into a corner, we should be able to change that decision later.

Avoiding that cloud by climbing might seem the best option, but if we then find it extends over a large area we might not be able to descend again safely. Descending below it might be an error if the ground rises and the base lowers. Turning to avoid may infringe notified airspace, and even turning back might take us into deteriorating weather. Before committing ourselves to action, we should ideally consider the likelihood and possible effects of that action and what we could do to manage those risks. What was a good decision when we were presented with the problem may subsequently turn out less than ideal, so once we dealt with the initial problem, we should consider whether what we are doing is still the best course of action. If it appears that we need to change our actions or decisions, and if it is safe to do so, we should not be afraid to change them. As with the flight itself, managing threats and errors does not stop until the engine has shut down and the occupants have left the aircraft.

We shall never be able to avoid every threat that may present itself, or avoid all the errors, but we can manage them. By identifying and considering as many as we can, not only will there be fewer unexpected ones to deal with, but we should hopefully have some spare capacity to handle them, following the list of priorities – aviate, navigate, and communicate.

As GASCo reminds us, every take-off is the start of a unique flight. We can all benefit from taking time during our pre-flight planning to think whether there are any specific threats or errors likely on this particular flight, and what we can do to mitigate them.

This is especially important if we are doing something we consider ‘adventurous’. Flying will never be 100% safe, but we have all discovered how rewarding it can be. Managing threats and errors involves assessing the risks of what we are about to do and balancing those against the rewards we feel we would gain from doing it. Each of us has to make our own judgement of risk versus gain, but the more we can anticipate and avoid or mitigate these risks, the safer our flying will be.

Just remember that our passengers may be keen to enjoy the rewards, but they are not familiar with the risks! ■

The

latest LAA Engineering topics and investigations. Compiled by

Jerry Parr