Unraveling the Mystery of General Aviation Controlled Flight into Terrain Accidents Using Hfacs

As part of the Federal Aviation Administration’s Safer Skies agenda, a Joint Safety Analysis Team (JSAT) was formed to review general aviation (GA) controlled flight into terrain (CFIT) accidents and recommend strategies to prevent their occurrence and/or mitigate their consequences. The JSAT reviewed 195 CFIT accidents occurring over a 2-year period between 1993 and 1994 and developed 55 interventions to address the causes. While a root cause analysis technique was employed during the review, the findings might have benefited from a more traditional human error analysis. In this study, the GA CFIT accidents reviewed by the JSAT were reexamined using the Human Factors Analysis and Classification System (HFACS) to determine if additional support for the identified interventions could be obtained and/or additional strategies identified. The causal factors associated with 164 fixed-wing GA CFIT accidents were classified using HFACS by 3 independent raters. Roughly 50% of the accidents examined were associated with decision errors, 45% with skill-based errors, 30% with violations, and 20% with perceptual errors. More important however, were the differences observed between fatal and non-fatal CFIT accidents. Significantly, more fatal than non-fatal accidents were associated with violations. In contrast, decision errors were more often associated with non-fatal CFIT accidents. When the NTSB considered weather a factor, significantly more CFIT accidents were associated with violations and decision errors. These findings support many of the interventions identified by the JSAT, including decision-making aides and recurrent pilot training. The information provided by the HFACS analysis will assist in the development, refinement, and more importantly, tracking the effectiveness of selected intervention strategies.