Divergence between Human State Assumption and Actual Aircraft System State

One of my Graduate Resident Tutors (GRTs), Sathya Silva, gave her thesis defense yesterday on the topic of divergence between human assumptions and actual state in aircraft. In short, the divergence framework she built examines how differences between pilots’ mental models of the state of the aircraft they are flying (i.e. throttle setting, landing gear position, etc.) and the actual state contribute to accidents and postulates mitigations for these divergence events. Her presentation (slides here) drew on a variety of sources, including previous research and aircraft incident reports. I’d like to focus on slide 33 in particular:


This slide comes after more detailed analysis of a number of incidents during flight and shows visually timing information for each incident in the divergence framework. The use of lines that split and come together again, with visual markers for recovery time, loss of control time, and impact times, highlight the extent of divergence in each case, any subsequent re-convergence, and the relative timing in events. One of the main takeaways from this aggregate view is that in many cases the difference between fatal and non-fatal incidents was not that convergence did not happen, but that it it happened without enough time left for a full recovery, proving insight into a possible mitigation strategy.

The audience for this defense was her thesis committee, as well as friends and family attending the defense. In addition to Sathya’s main goal of passing the defense, the presentation was meant to lay out the concepts behind divergence to provide evidence for the thesis; slide 33 in particular highlights patterns in these incidents in the context of the divergence framework. The presentation overall was effective in achieving its goals; the novel divergence visualizations provide at-a-glance comprehension in the divergence framework and demonstrate its effectiveness in highlight patterns. The thesis committee agreed that this was a great presentation – congratulations Dr. Silva on passing your thesis defense!