Attentional Characteristics of Pilots for International Exempting Flights Based on Signal Detection Theory

Exempting flights are those without providing overnight rest to the pilots, which follow the policy: Implementation Measures for Exempting Crew Members from Duty Period and Flight Time Requirements during COVID-19.Pilots of exempting flights should have a high level of ability to detect various signals The signal detection ability represents the accuracy and efficiency of the crew's information processing and decision making, which are effective in ensuring flight safety. A high level of selective attention, tonic alertness and phasic alertness of pilots are of great importance for flight safety. Based on the principle of signal detection, a test method is designed to assess pilot's sensitivity(d') and bias(β) of the 3 types of signals. The results of 18 pilots' in-flight judgement outcomes of three types of signals are collected, pilots are all on domestic exempting and non-exempting flights to North America. Three types of signals' sensitivity and bias are calculated, receiver operating characteristic curves(ROC) are drawn. Finally, the following conclusions are conducted. The difference of self-reported fatigue degree between exempting and non-exempting flights is most significant after the outbound flight landing(karolinska sleepiness scale's difference = 2.333, samn perelli scale's difference = 1.222). Sensitivity and bias regarding selective signal show no significant difference between exempting and non-exempting pilots(sig =0.337, sig =0.200). The sensitivity to tonic signal of exempting pilots(d'=4.149) is higher than that of non-exempting pilots(d'=3.137), and bias of tonic signal of exempting pilots(β =0.616) is lower than that of non-exempting(β =0.629). The sensitivity to phasic signal of exempting pilots(d'=3.916) is higher than that of non-exempting pilots(d'=2.994), while bias has no significantly different(sig =0.262). Overall, exempting pilots have higher ability to perceive the three signals than non-exempting pilots, while their bias and average reaction time show no significant difference between the two flight modes. The signal detection ability of pilots on exempting flights does not negatively affect flight safety.