This study employed the taxonomy of human factors presented in the Department of Defense Human Factors and Analysis and Classification System (based largely on the previous HFACS model developed by Wiegmann and Shappell, and Reason's "Swiss cheese" model) model to analyze and compare the human causes resident in failures of single- and multiple-operator human-machine systems functioning in a dynamic, mission-oriented environment. Specifically, the human factors involved in flight-related mishaps generated by single-piloted and multi-crewed U.S. Navy and Marine Corps tactical jet aviation platforms between fiscal years 1997 and 2007 were examined. The method applied to this study began with the construction of a previously undeveloped data set containing the mishap human causal factors cataloged in accordance with the DoD HFACS followed by a quantitative evaluation of this data set to determine the mean mishap rate and human causal factor occurrence (by number and type) between the two system configurations. In all, data from 497 total mishap reports were evaluated resulting in 1,421 total human factors analyzed.The results of this investigation revealed a generally higher overall mean failure rate in the multiple-operator human-machine system. However, when the data was sorted by failure severity, the failure rates in the most severe (Class A) mishaps were nearly identical between the two systems, while failure rates in the least severe (Class C) mishaps diverged and were significantly higher for the multiple-operator system. The second analysis in this study examined the mean number of factors resident in each mishap and revealed a generally higher overall mean in the single-operator system than the multiple-operator system. Evaluation of the data sorted by failure severity revealed a similar mean between the two systems in Class C mishaps and a greater distinction in Class A mishaps. The final analysis of the data explored differences in the types of factors produced by each system and showed Cognitive Factors, Decision Errors, and Communication, Coordination, and Planning to be the most common for both system configurations. Overall, the single-operator system incurred significantly higher Cognitive Factors, Adverse Physiological State factors, and Skill-Based Errors.
|In Administrative Set: