This is a familiar quote in many subsequent boards of enquiry or investigations concerning fatal and non-fatal events. Indeed, they are found in almost all high-risk endeavours, whether it be with nuclear, medicine, emergency personnel, military or transport operators. In the aviation system, people are both the source of some of the risks and an integral part of identifying and managing all risks.

To deal with a system as if it were a group of unrelated individual systems is, on the one hand, the method that saves the most thinking time, but on the other hand, it is the method that guarantees neglect of the side effects and therefore guarantees failure to achieve a full understanding. If we have no idea how the variables in the system influence one another, we cannot take these influences into account. Often when researching the network of interactions following an adverse event, it can be traced back to a single point; that of one of the many human influences. However, it becomes clear, when following these network influences, that a person’s ability to adapt means that the system is more likely to recover from unexpected disturbances, resulting in increased resilience.

Historically, thinking about the human contribution to the aviation system has largely focused on the errors and violations people make that adversely affect safety. Barriers were erected and they worked pretty well. More recently, there has been a shift in focus to the positive contribution to safety, resilience, and efficiency made by people in the system. This focus recognizes the value in assessing and understanding, not only when things go wrong, but also when things much more often go right. Understanding this is a vital precursor to designing safer automatic systems.

Human Factors (HF) encompasses knowledge from a range of scientific disciplines that support human performance (HP) through the design and evaluation of equipment, environments, and work, in order to improve complex system performance. It is uniquely the human contribution that often provides the important safety barriers and sources of recovery.

Managers and Decision Makers should not underestimate this influence on systems safety.

References:

• Managing The Unexpected – Karl Weick and Kathleen Sutcliffe
• Manual on Human Performance [HP] for Regulators – ICAO [Doc 10151, Advanced Unedited]
• The Human Contribution- James Reason
• The Logic of Failure – Dietrich Dorner
• To Engineer is Human – Henry Petroski