Human Systems Integration Division @ NASA Ames

"Analyses of incident reports, jumpseat observations of line operations and task analyses were performed to better understand the causes of pilot error and develop defenses against consequential errors. Between 60 and 80% of aviation accidents and incidents can be attributed, at least in part, to human error. Most incident reports submitted to the Aviation Safety Reporting System are written by experienced, skilled, well-trained and conscientious pilots. Sheer probability could block such incidents from evolving into accidents since performance errors occur on a daily basis in the course of everyday flight operations. Our effort is to move beyond the traditional view of errors as a source of failure toward a better understanding the root causes of system failures. Pilot errors are naturally and predictably occurring events often attributable to many opportunities in the operating environment and to human cognitive vulnerabilities. On the operational side, interruptions and distractions are opportunities for error that are unpredictable in source, timing, and nature. They are the norm in everyday operations. Consequently, their impact is highly underestimated. To respond to distractions, pilots interleave novel activities with habitual, wellpracticed sequences of actions, continuously making decisions about adding, shedding, and/or rescheduling actions. On the human side, error vulnerability arises from cognitive limitations. Memory (particularly for deferred actions), sidetracking and preoccupation with interrupting events, automaticity, assumptions and expectations based on habit make pilots particularly vulnerable to the demands of intrusive events. Thus, interruptions and distractions pose significant threats to pilots during seemingly routine flight operations.

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