Aviation Safety Letter 3/2003

Short Take on Human Factors Basics

Approximately 80% of aviation accidents are primarily caused by a human error, while the remaining 20% almost always involve a human factors component. The following is the fourth, and last, of a series of short passages from TP 12863E, Human Factors for Aviation - Basic Handbook. We hope this encourages you to look further into this fascinating, and relevant, topic. - Ed.

The Importance of Judgement

Some writers see judgement as the process of choosing which alternative will give the safest outcome in a given situation. However it is defined, we need good judgement in order to fly safely. But there is much more to it than that.

Judgement and Regulations

In aviation, more than any other field we can think of, regulations are based on the assumption that practitioners will interpret them in accordance with their own skill. Though applying at face value to all pilots, the regulations are actually geared to the pilot who is extremely proficient, flying a well-equipped aircraft. Thus, whereas any pilot may be legally entitled to fly a cross-country flight in marginal VFR conditions, it is up to the individual pilot to judge whether such a situation exceeds his or her own personal limits, based on experience and currency.

Likewise, all performance data in the aircraft operating manual are derived from perfect situations. The take-off roll, for example, assumes a hard dry runway in a well functioning aircraft with an engine developing maximum horsepower. In real life, of course, any deviation from this ideal lengthens the required runway distance: if the engine is a little older, if the runway is contaminated with snow or water, or if the tires of the aeroplane are not at the correct pressure, then the numbers in the manuals are not accurate. So, once again, the individual pilot has to interpret the situation and apply judgement in determining what numbers to use. Using the data in the aircraft manual blindly, without interpretation, is likely to prove a bad judgement.

Judgement as the Basis of Aviation

Judgement is important in flying because the pilot is given a great deal of latitude in making decisions. The whole aviation system is based on the assumption that pilots will exercise good judgement in securing the safety of themselves and all others in the system. In other words, the aviation system is based on trust. Pilots are expected to honour the responsibility they have been given. Each time you exercise bad judgement, you are not only endangering yourself and others, but also undermining the very basis of aviation.

Good judgement, therefore, is much more than the means of safety. It is the cement that keeps all aspects of flying together.

Excerpt from TP 12863E Chapter 10, page 145. You can obtain your own copy of this publication by calling the TC Civil Aviation Communications Centre Services at 1-800-305-2059.

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