This study provides a systematic analysis of the types of human
error occurring in Australian civil aviation accidents. It also
compares these results against a larger sample of accidents
occurring in the United States. Inevitably, all humans make errors.
But safety can be enhanced when the number and consequences of
these errors are reduced. This paper aims to enhance aviation
safety through extending our knowledge of aircrew errors.
While the types of accidents and flying operations varied
slightly between Australia and the US, the pattern of aircrew
errors were remarkably similar. Skill-based errors were the most
prevalent type of aircrew unsafe act, followed by decision errors,
violations and perceptual errors in both Australian and US
accidents. Skill-based errors were also the most common error type
irrespective of the severity of the accident. In Australia,
decision errors and violations were more common in fatal
accidents.
The trend data indicated that the proportion of accidents
associated with skill-based errors did not change over the period
studied, but decision errors decreased.
The distribution of unsafe acts across flying operation type
indicated that skill-based errors were disproportionately higher in
both general aviation and agricultural operations. Charter
operations (called on-demand in the US) had a high proportion of
violations and decision errors. The pattern of unsafe acts within
each type of flying operation was broadly similar for Australian
and US accidents.
The study demonstrated that the greatest gains in reducing
aviation accidents could be achieved by reducing skill-based
errors. Moreover, improvements in aeronautical decision making and
the modification of risk-taking behaviour could reduce aviation
fatalities. Further study is needed to both identify which
particular skills need improving, and to investigate the importance
of interactions between the error categories.