Investigation of the methods and their effectiveness used in determining the mental workload occurring in aircraft maintenance technicians

In this study, it has been investigated how the performance of aircraft maintenance technicians working under stress and time pressure changes and how their mental workload is affected in increasing task difficulties. For the experimental studies carried out, scenarios with easy, medium and hard difficulty levels were prepared using fuzzy logic. fNIRS and NASA–TLX methods were used to measure the mental workload of experienced and inexperienced aircraft maintenance technicians while performing maintenance tasks of different difficulty levels. Moreover, the performance scores of the participants were measured. The effects of experience and scenario difficulty level on mental workload were investigated in the analyses. Statistically significant differences were found between inexperienced and experienced groups in at least one scenario difficulty level for each measurement method. It was seen that the experienced group had lower NASA–TLX results, had less difficulty in the tasks; had higher performance scores, showed higher performance in the tasks; had lower oxyhemoglobin concentrations, had less cognitive difficulty, and the effect and importance of the experience were revealed. Statistically significant differences were found for mean NASA–TLX results, performance scores and fNIRS results from easy to hard scenario for inexperienced and experienced groups. As the scenario difficulty increased it was observed that, there was an increase in NASA–TLX results, the participants had more difficulty in the tasks; there was a decrease in performance scores, the participants showed lower performance in the tasks; there was an increase in oxyhemoglobin concentrations and the mental workload of the participants increased.