Behaviour and Motivation — Page 176, Lesson 275

I want to walk you through the next major topic in behaviour and motivation: the distinction between rule-based behaviour and knowledge-based behaviour, and the errors that can arise with each. Let’s start with a general principle about procedures. Generally speaking, procedures should be committed to documentation — that is, written down — unless they will need to be exercised under circumstances that might prohibit document consultation. A classic example of that exception is a rejected take-off, where time is so restricted that you cannot pause to read a checklist; you must have the procedure memorised and drilled. Now, rule-based behaviours. These are behaviours that follow a learned or documented procedure for a recognised situation. They are generally robust in practice and have many strengths. One key strength is that standardised procedures enable each crew member to know what other crew members should do in a selected situation, thereby acting as monitors of each other’s actions. So if I’m the pilot flying and I see the pilot monitoring start a sequence that doesn’t match the procedure, I can catch that error. Let’s look at the errors of rule-based behaviour. The first type is an error of commission. Error of commission is probably the most common error associated with rule-based behaviour. It is caused by the initial misidentification of a problem and engaging the wrong procedure entirely. For example, an auditory warning may cause the crew to action depressurisation drills when the action required is for propeller overspeed. Even when the identification of the problem is correct, it is still possible to apply an inappropriate rule — so you correctly identify the problem but pick the wrong procedure from memory or the wrong checklist. The second type of error is departure from the rules. Errors may also arise when the pilot believes it is safe to depart from the procedure. For example, aircraft have been flown into the ground when a GPWS warning — that’s Ground Proximity Warning System — has been ignored, even though many airlines make it mandatory to apply maximum pitch up and full power on receipt of this warning on all occasions. So the pilot departs from the mandatory procedure and the result can be catastrophic. The key takeaway here is: once a set of circumstances have been reliably identified, it is almost invariably advisable to complete the standard procedure if one is available. Now let’s move to knowledge-based behaviour. Knowledge-based behaviour is that for which no procedure has been learned. It requires the pilot to evaluate information, then use his knowledge and experience — what we call airmanship — to design a plan for dealing with the situation. Decision making is carried out by the central decision maker, which is shown in Figure 8.1 of the book, and requires all the information available to the pilot from his environment and memory. An important point here: automated controls for all stages of flight have now reached the stage where they perform better than the pilot under normal procedural conditions. But the pilot must remain, for the foreseeable future, to think, reason and evaluate the unexpected. So automation handles the routine, but the human is still essential for the non-routine. Knowledge-based behaviour requires an individual to draw on data stored in long-term memory to derive a course of action. It is affected by such factors as the completeness and accuracy of mental models. A mental model is your internal understanding of how a system works or how a situation unfolds. Knowledge-based behaviour enables a pilot to deal with non-routine or unfamiliar situations and problems. Now, errors of knowledge-based behaviour. Errors can take a wide variety of forms, none of which are necessarily predictable on the basis of the individual’s experience and knowledge level. So even an experienced pilot can make a knowledge-based error in a novel situation. However, some factors that may have a profound effect are listed here. First, incomplete or inaccurate mental models. This can be due either to ambiguous data or an incorrect association with incidents experienced in the past. So if your mental picture of how the aircraft’s systems work has a gap or a mistake, your reasoning will be flawed. Second, overconfidence. If you are too confident in your own assessment, you may not seek additional information or reconsider your plan. That figure shows the relationship between these behaviour types and the decision-making process. So to summarise: rule-based behaviour follows procedures and is strong for standard situations, but can suffer from misidentification or deliberate departure. Knowledge-based behaviour is your fallback for the unexpected, relying on your mental models and airmanship, but it is vulnerable to incomplete models and overconfidence.