Human Factors

Human Factors

Human Factors is a wide and complex domain. Its importance in aviation is indeniable, especially in today’s world. With technology and human-machine interaction more present than ever, it is essential to consider the role of human factors in the present and future operational environments. Special emphasis will need to be directed to the human factors issues that may influence the design, transition and in-service use of the future CNS/ATM systems.

Human Factors also play a significant role in improving safety in aviation, by making States and organisations more aware and responsive to the importance of the role of the human in civil aviation operations in general, through the provision of practical human factors material and measures developed on the basis of experience (ICAO, 2020). IFATCA has been at the forefront of these initatives, as it can be seen by the numerous policies the Federation has developed on the topic over the years.



According to Doc 9683 (ICAO, 1998), Human Factors has to be clearly defined because these words can easily be misued in common language and are also sometimes applied to any factor related to humans. The human element is the most flexible, adaptable and valuable part of the aviation system, but it is also the most vulnerable to influences which can adversely affect its performance. Throughout the years, some three out of four accidents have resulted from less than optimum human performance. This has commonly been classified as human error.

However, the term “human error” is of no help in accident prevention because although it may indicate WHERE in the system a breakdown occurs, it provides no guidance as to WHY it occurs. An error attributed to humans in the system may have been design-induced or stimulated by inadequate training, badly designed procedures or the poor concept or layout of checklists or manuals. Further, using the term “human error” can have consequences, such as hiding (voluntarily or not) the underlying factors which must be identified, if accidents are to be prevented.

Contemporary safety-thinking argues that there are many possible starting points and angles that can be used to examinate human factors, such as the linear and the systemic approaches to safety. For more information on these two models, please refer to the pages proposed below.

According to ICAO:

“an understanding of the predictable human capabilities and limitations and the application of this understanding are the primary concerns of Human Factors. Human Factors has been progressively developed, refined and institutionalized since the end of the last century, and is now backed by a vast store of knowledge which can be used by those concerned with enhancing the safety of the complex system which is today’s civil aviation.”


What falls under Human Factors?

As said previously, the domain of Human Factors is vast. As regards air traffic control, it encompasses inter alia the following aspects:

  • Human Factors management and organization;
  • Human Factors issues in the development and implementation of Communications Navigation and Surveillance/Air Traffic Management (CNS/ATM) systems;
  • Ergonomics;
  • Human Factors within systems;
  • Automation in air traffic control;
  • Selection and training of air traffic controllers;
  • The human element  and its specific attributes.

To illustrate the complexity of Human Factors, it can be useful to use a model to facilitate the understanding. An easy and practical model was developed by Edwards in 1972, later on modified by Hawkins in 1975, with a diagram to illustrate the model. The SHEL conceptual model uses blocks to represent the different components of Human Factors. The model can then be built up one block at a time, with a pictorial impression being
given of the need for matching the components (the edges of the blocks are embedded within each other, as seen below). The name SHEL is derived from the initial letters of its components:

  • Software,
  • Hardware,
  • Environment,
  • Liveware.

Where the Liveware refers to the human, the hardware refers to the machine, the software refers to either the procedures, the symbology, etc., and the environment refers to the situation in which the Liveware/ Software/ Hardware system must function. This building block diagram does not cover the interfaces which are outside Human Factors (hardware-hardware; hardware-environment; software-hardware) and is only intended as a basic aid to understanding Human Factors.

For more information, visit one of the following WIKIFATCA pages:

Human Factors


Last Update: May 9, 2020  

October 27, 2019   92   superman    WIKI  

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