Fatigue risk assessment for flight crews flying across time zones in different directions to the east or west during the COVID-19 pandemic in China

There is a lack of data support and scientific validation of the Exemption Approach policy for responding to the COVID-19 pandemic, in terms of protecting the health of flight crews and meeting the requirements for passenger and cargo transportation in emergencies, in terms of its safety and the circumstances that contribute to pilots’ symptoms of jet lag and the risk of fatigue.

To assess pilots’ sleep issues related to jet lag symptoms and fatigue, this study evaluated an example of risk management for flight crews on flights across time zones during the COVID-19 pandemic. To evaluate the crew’s sleep status, variations in sleep index changes between before and after the flights, variations in sleepiness levels, and data on sleep indexes recorded by ActiGraph bracelets were collected from 146 crew members before and after flights eastward or westward across time zones. Sleepiness levels predicted by applying the SAFE model were also determined.

Whether flying east or west across time zones, the crew’s sleep indexes were relatively similar at the end of a flight during a layover. However, a comparison with the pre-flight period showed that the sleep indexes of the crew were slightly more disturbed after the eastward flight compared with those after the westward one. In addition, the SAFE model predicted a higher rate of change in crew mean sleepiness levels between before and after the flight for the eastward flight than for the westward one; however, the Karolinska Sleepiness Score (KSS) of the pilots on either eastward or westward flights did not exceed 5 (“not alert or sleepy”).

Flight crew adaptation to the Exemption Approach policy during the COVID-19 pandemic was assessed by evaluating the sleep problems of crews flying eastward or westward across time zones.