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  • Santiago Garcia

Human Factors: A Telltale Sign of Aviation Safety

In order to gain a better understanding of aviation safety, I analyzed Mr. Alan Hobbs' article (attached below) on the importance of identifying human factors as the leading cause of in-flight aviation related mishaps and incidents.


Human factors emerged as a significant challenge to aviation safety only after the reliability of avionics stabilized and mishaps could no longer be primarily attributed to a hardware, software, or mechanical malfunction. As time passes and technology advances, it is widely accepted that the frequency of technical malfunctions decreases and the prevalence of human factors errors increases. The research conducted in this article provides insight on the relationship between aviation mishaps occurring in the early 1900s and human factors errors. Specifically, this investigation looks for evidence to suggest that human factors errors have been, are, and will continue to be the underlying cause of most aviation related incidents.


It was not until research performed in the last two decades that the aviation administration was able to confidently identify human factors as “broadly contributing to most aircraft accidents” (Hobbs). A formerly agreed upon perspective that was widely accepted by the safety sector, is that human factors has not always had a prominent place in accident causation. Rather, human factors was restrained to being a secondary or tertiary cause of in-flight failure until aircraft became more mechanically reliable and technologically consistent (International Civil Aviation Organization, 1984).


The author hypothesizes that human factors has been the leading and most influential flight safety issue since the beginning of aviation. Despite the general increase in the amount of system accidents attributed to human error, Mr. Hobbs considers the possibility that the increase in mechanical reliability and avionics improvements have made human factors errors more visible and shifted the focus of accident investigations.


The author conducted 100 independent aircraft accident analyses that resulted in death or injury from the years 1921-1932. These were the first ten years the Australian Transport Safety Bureau (ATSB) existed, thus representing the earliest possible records of aviation mishaps. In each aircraft analyses, a narrative of the accident summarized the important points and contributing factors.


These contributing factors were categorized by: pilot (human factors), airframe (including flight controls), engine, terrain, other personnel (passengers and people on the ground), and weather. It was possible for more than one factor to contribute to the accident. To ensure validity, factors were assigned to the accidents using Cohen’s kappa. This was a simply designed investigation as it relied solely on records and accounts from the past.


In this investigation the experimenter controlled the categories for which the accident analysis could fall into. The six factors (pilot, airframe, engine, terrain, personnel, and weather) did not change during the investigation analysis. The independent variable was the accident report (i.e., accident analysis #1 resulted in two deaths), and the dependent variable was the category the cause of the accident fell into (i.e., cause of the two deaths was weather related).


I expect that the results of this investigation will describe a similar pattern to those found in current aviation times (with the majority of mishaps being attributed to human error). Additionally, this approach was only limited by the accuracy and detail of the accident reports and does not present a significant source of error that jeopardizes the overall validity. Further, for five of the contributing factors, good to excellent levels of inter-rater agreement were obtained (Fleiss 1981).


In 68% of the accident analyses, the cause of accident resulted from pilot (human) factors. These accident reports contained statements such as, “poor judgement” and “loss of situational awareness.” In more specific cases, the nature of the accident involved poor decision making and showboating (flying excessively low, attempting to take off toward obstructions, exceeding the performance parameters of the aircraft).

The results of this investigation support the research hypothesis; the majority of the accidents from the years 1921-1932 were a direct result of human factors related errors.


In this investigation there were no relevant alternative explanations. The nature of the research did not allow for any feasible extraneous explanations as all data (quantitative and qualitative) came from the accident reports and observations.


Mr. Hobbs concludes that the results of this study support the idea that human factors as a primary cause of aviation mishaps has always existed. Just as in modern time, accidents of the early 1900s were attributed to pilot factors with more frequency than aircraft and extraneous factors. Regardless of technological state, reliability, and prevalence, human factors is the leading cause of aviation related mishaps and incidents. An additional study suggests that 90% British aviators who died in the first year of airborne conflict did so due to “individual deficiencies” (Wilmer 1935).


While human factors as the leading cause of in-flight error is consistent across time, engine and airframe failures did contribute to a greater proportion of accidents compared to modern-day accidents (a higher quantity of in-flight emergencies resulted from mechanical or technological failures in the past). The author acknowledges that human factors in itself is not adequate to fully explain a mishap or incident. While a human factors error (i.e., loss of situational awareness, poor judgement, fatigue, boredom, physiological deficiencies, etc.) can be the immediate cause of an accident, there are always several contributing factors to a single mishap. A combination of leadership, task, equipment, and environmental factors always play a role in the incident, no matter how significant of an error the user made.


The findings of this investigation justify the following claim: while the nature of aviation technology has improved dramatically, the human element as a determinant of flight safety remains consistent. As technology improves and pilots begin to rely more and more on their aircraft’s systems, there ought to be heightened emphasis placed on human performance as a measure of safety. As technological reliability begins to stabilize, the cause of error will be placed more and more on the human.


This contributes directly to the aviation community because it places a heightened emphasis on the notion that training and preparing our pilots is the most important indicator of flight safety. In the majority of circumstances, if pilots are trained and prepared to handle the rigors of aviation there is a low chance that their aircraft will malfunction. Thus, a low chance of mishap or incident.


Additional studies on this area of research could focus on the correlation between human factors related errors and technological reliability. Is there any evidence that suggests humans are more likely to fail when the technology is less or more reliable? Will the human be more likely to fail when more cognitive dependence is placed on the aircraft? Gaining a greater understanding of how the human mind performs (focus, attention, trust in automation, etc.) with various degrees of aviation technology would be the primary focus of my desired follow-up study.

Relevant Media:

Hobbs, A. (2009). Human Factors: The Last Frontier of Aviation Safety?, The International Journal of Aviation Psychology, 14 (4), 331-345. DOI: 10.1207/s15327108ijap1404 1

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