I bring you a weekly bite-sized chunk of the science behind helicopter human factors and CRM in practice, simplifying the complex and distilling a helicopter related study into a summary of less than 500 words.
TITLE:
Quantifying the impact of spatial disorientation on pilot mental workload and attentional focus.
WHAT?
Study examining how spatial disorientation (SD) affects helicopter pilots’ cognitive workload and attention, even when aircraft control is maintained. Rather than focusing on flight path errors, the researchers looked at how disorientation diverts attention or consumes mental capacity.
WHERE?
TU Delft, Netherlands.
WHEN?
Published 2025.
WHY?
SD is a known cause of helicopter accidents, especially in military and low-level operations. However, it often affects pilots before any obvious loss of control. The study aimed to objectively measure early attentional/cognitive effects to better understand risk and mission impact.
HOW?
Fourteen pilots flew a series of simulator scenarios. Each was flown twice: once with a SD stimulus and once without, allowing comparison within the same pilot. Six common disorientation stimuli were tested, including featureless terrain, brownout, the leans, false horizon, loss of horizon with NVG, and a vestibular yaw illusion.
To measure cognitive workload, pilots performed a simple mental arithmetic task over the intercom while flying. To measure attention, an eye-tracking system recorded where pilots looked, in particular, how much time they spent watching the attitude indicator (AI).
The rationale for these measures was the “orientation first” principle, which states that when a pilot’s sense of orientation is threatened or confused, the brain prioritises regaining or maintaining spatial orientation over all other tasks. Consequently, fewer mental resources remain available for other tasks such as communication, navigation, or mission management, even if the aircraft remains under control.
Pilots also provided subjective ratings after each scenario, self-reporting how disorienting the situation felt and how much it affected their thinking and task performance.
FINDINGS:
- SD significantly increased mental workload: pilots took longer and made more errors on the mental task, supporting the “orientation first” hypothesis.
- Pilots spent more time focused on the attitude indicator, indicating narrowed attention and reduced capacity to monitor other information.
- Featureless terrain, brownout, and the leans had the strongest effects.
- Some disorientation occurred without pilots realising they were disoriented, particularly over featureless terrain.
SO WHAT?
The study shows that SD can impact pilots’ cognitive capacity, even when the flight path appears unaffected. The pilot may still “fly the aircraft,” but at the cost of reduced ability to navigate, communicate, or process mission information.
This study demonstrates that simple, practical measures such as a short cognitive task and eye-tracking can reliably detect cognitive effects. This matters because helicopter pilots routinely operate in degraded visual environments where disorientation is likely. Combining simple cognitive tasks, eye-tracking, and potentially physiological measures (such as heart rate) could allow operators and researchers to identify high-risk flight scenarios & improve training to mitigate these.
Overall, the study supports a shift from viewing SD solely as a flight path control problem to recognising it as a cognitive workload and attention problem.
REFERENCE:
Evertsen, F. W., Landman, A., Groen, E. L., Houben, M. M. J., van Paassen, M. M., Stroosma, O., & Mulder, M. (2025). Quantifying the impact of spatial disorientation on pilot mental workload and attentional focus. Human Factors, 67(10), 997–1010. https://doi.org/10.1177/00187208251323116
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