Experts are not immune to making mistakes, which sometimes arise from the way an expert draws upon knowledge of familiar problems and responds to them using familiar solutions. [Figure 3-21] Mistakes can occur when the expert categorizes a particular case incorrectly. For example, an experienced pilot may become accustomed to ignoring nuisance alerts issued by his traffic alerting system when approaching his home airport, as many aircraft on the ground turn on their transponders prior to takeoff. One night, he ignores an alert that was generated not by an aircraft on the ground, but rather by another aircraft that has turned in front of him on final approach.

Although it is impossible to eliminate errors entirely, there are ways to reduce them, as described in the following paragraphs.

The first line of defense against errors is learning and practice. Higher levels of knowledge and skill are associated with a lower frequency and magnitude of error.

Errors can often be reduced by working deliberately at a comfortable pace. Hurrying does not achieve the same results as faster performance that is gained by increasing one’s skill through continued practice.

Another way to help avoid errors is to look actively for evidence of them. Many tasks in aviation offer a means of checking work. Learners should be encouraged to look for new ways of checking their work.

Errors are reduced when visible reminders are present and actively used. Checklists and other published procedures are examples of reminders. Many aircraft instruments such as heading indicators offer bugs that can be used to remind the pilot about assigned headings and courses and some may also prompt altitudes and airspeeds. Mechanics and pilots alike can use notepads to jot down reminders or information that should otherwise be committed to memory.

The use of standardized procedures for routine tasks is widely known to help reduce error. Even when a checklist procedure is unavailable or impractical, learners can help reduce the occurrence of error by adopting standardized procedures.

Another line of defense against errors is to raise one’s awareness when operating in conditions under which errors are known to happen (e.g., changes in routine, time pressure), or in conditions under which defenses against errors have been compromised (e.g., fatigue, lack of recent practice).

Given that the occasional error is inevitable, it is a worthwhile exercise to practice recovering from commonly made errors, or those that pose serious consequences. All flight learners need to learn and practice a lost procedure to ensure that they can recover from the situation in which they have lost their way. It is useful to devote the same sort of preparation to other common learner errors.

Error can be a valuable learning resource. Learners naturally make errors, which instructors can utilize in training to help while being careful not to let the individual practice doing the wrong thing. When a learner makes an error, it is useful to ask them to consider why the error happened, and what could be done differently to prevent the error from happening again in the future. In some cases, errors are slips that simply reveal the need for more practice. In other cases, errors point to aspects of learner methods or habits that might be improved. For example, beginning instrument flight learners commonly make errors when managing two communications radios, each with an active and standby frequency. When the same learners understand each radio’s specific purpose (e.g., ATIS, ground, tower frequencies), error rates often drop quickly.