Measurement And Analysis Of Primary-task And Secondary-task In The Landing Of Carrier-based Aircraft

In the modern complex system of man- machine- environment- tasks, all kinds of advanced airborne equipment provide pilots with flight parameters and information, which makes pilots operate more simply. However, the occurrence of large amounts of information at the same time makes pilots’ mental workload higher. Especially, in some flight phase such as the landing of carrier aircraft, high instantaneous information needs to be timely processed in unconventional way, which leads to the high mental workload of pilots. The landing of carrier aircraft imposes a higher requirement of response, decision-making and operation on pilots, which could be a heavy high mental workload of them. The instantaneously increased mental workload has negative influences on the pilots’ cognition and operation, which is a threat to the flight safety. Therefore, it is significant to evaluate the pilots’ mental workload at the time of landing of carrier aircraft. In the work, we meant to evaluate the mental workload in the tasks to simulate characteristics of carrier aircraft landing or continuous touch-and-go of carrier aircraft byanalyzing changes of mental workload indexes. This project constituted of the following two parts:Part one: The effects of reverse operation on mental workloadObjective: By comparing the scores in reverse target tracking task and ordinary target tracking task based on national aeronautics and space administration-task load index(NASA-TLX), electrocardiogram(ECG) and index of performance, we investigated the effect of reverse operation on mental workload and the contributing factors.Methods: Twenty-five young male subjects accomplished the ordinary target tracking task and the reverse target tracking task, with two degrees of difficulty in each direction. ECG signals were recorded during the resting period before the task, periods of each task and the resting period after the task. Each subjects filled in NASA-TLX scale after completing each task. Each task had a score as feedback. The scores of NASA-TLX and the indexes of performance were assayed by analysis of variance(ANOVA) in 2×2 factorial design. The indexes of ECG were analyzed by Friedman M test and the multiple comparisons were carried out by LSD-t test.Results: The score of NASA-TLX(F=39.19, P<0.05) and the average tracing distance(F=16.14,P<0.05) of the reverse target tracking task were higher than those of the ordinary target tracking task with the highest indexes in the dual reverse target tracking task. Heart rate(HR) also had the same change(2=34.87,P<0.05), but the indexes of heart rate variability(HRV) had no significant differences between the two tasks.Conclusions: Mental workload of the reverse operation task is higher than that of the ordinary operation task if the other conditions are the same. The reverse operation’s impact on mental workload is greater when more information is needed to be dealt with. Mental demand, physical demand and frustration level are the major influence factors of high mental workload during reverse operation.Part two: The research on the changes of heart rate and heart rate variability in different stages of simulated carrier aircraft landing flightObjective: To analyze the changes of heart rate and heart rate variability in different stages of simulated carrier aircraft landing flight and to explore the differences of mental workload of pilots in different stages.Methods: Five pilots carried on the simulated carrier aircraft landing flight which included four touch-and-go. We recorded each pilot’s ECG signals during the flight and investigated the changes of them in different flight stages and different period. The ECG data was assayed by analysis of variance analysis(ANOVA) in two factor repeated measures design and the multiple comparisons were carried out by LSD-t test. The correlation of different indicators was analyzed by linear correlation analysis and the correlation coefficient was compared by Z test.Results: Pilots’ HR and low frequency norm(LFnu) kept increasing from the cruise stage to the turning stage then to the landing stage while root mean square of successive difference of the RR intervals(RMSSD), low frequency(LF), high frequency(HF) and high frequency norm(HFnu) kept decreasing. There were significant differences in HR, RMSSD, HF and LF/HF among different flight stages(F=5.74~29.01,P<0.05). Pilots had a higher HR, LFnu and LF/HF and a lower RMSSD, LF, HF and HFnu in the fourth take-off and landing flight. The time effect of HR was statistically significant(F=4.31,P<0.05). The correlations between HR and HRV were statistically significant. The correlation between HF or LF and RMSSD was better than that between HFnu or LFnu and RMSSD(Z=4.72~4.87,P<0.05).Conclusions: As compared with the cruise stage and the turning stage, pilots had a higher mental workload at the landing stage. Hooking the arrester wires aggravated the mental workload of pilots. The sensitivity of HR and HRV in assessing mental workload was related to the nature of the task.