Multi-dimensional measurement of mental workload in industrial context: an experiment in the field of helicopter maintenance

Assessing mental workload is essential for optimizing the design of complex systems, particularly in aeronautical maintenance, where operators' activities serve as a crucial safety barrier to ensure optimal system safety levels. One of the roles of human factors in maintainability is, therefore, to anticipate maintenance activities and human behavior from the start of the design cycle. This study pursues a dual objective: firstly, to identify relevant for evaluating mental workload in an industrial maintenance environment, and secondly, to determine which of these indicators correlate with performance degradation. Ten participants performed five maintenance tasks of varying complexity on a helicopter, involving the removal, installation of components and a detailed inspection. Subjective measures (NASA-TLX), performance metrics (completion time), and cardiovascular data (heart rate, heart rate variability) were analyzed. We observed longer completion times and higher NASA-TLX scores for complex maintenance conditions. Regarding cardiovascular data, the results in the time domain of heart rate variability follow a similar trend compared to two other types of measurements. These results will be discussed in depth in this article. This study represents a further step in the multidimensional measurement of mental workload in maintenance within a realistic industrial context.