Abstract: In order to quantify the effect of fatigue on controllers' cognitive behavior,32 on-the-job controllers were selected as testees to conduct experiments at 12:00 and 00:00 when the fatigue was cumulated to the maximum.EEG signals of the testees were recorded both before doing the experiments and during the time when they were doing radar simulator task involving large number of traffic and abnormal situations.A fatigue index was calculated based on EEG data .The reaction time of controllers to abnormal situations was used as an index of cognitive ability.The results show that the fatigue level at 00:00 is significantly higher than that at 12:00,and the fatigue index increases sharply after completing task at 00:00 with bigger fatigue risk.There is a linear relationship between the fatigue index before work and the reaction time to abnormal situations when working,and that the detection of fatigue before work can be used as a measure for managing controller fatigue risks.

Key words: civil aviation safety, controller, fatigue index, electroencephalogram (EEG) signal, cognitive behavior, reaction time to abnormal situations