Seasonal variation in fatigue indicators in Brazilian civil aviation crew rosters.

Abstract

Analyzing, understanding and managing fatigue risk in aviation is relevant for flight safety and to reduce human error. To analyze probable levels of fatigue among a convenience sample of Brazilian civil aviation pilots and flight attendants and to develop appropriate methods and indicators to quantify potential fatigue risk in critical phases of flight (landings and takeoffs). Data were obtained from flight rosters voluntarily and anonymously fed to a digital platform. Rosters were analyzed with software SAFTE-FAST, which considers homeostatic process and circadian cycles related to attention and wakefulness and sleep inertia. The rosters for January (n=248), May (n=259) and July (n=261) 2018 were associated with incidence of 77, 54 and 77% respectively of least one event of minimal effectiveness (<77%) during critical phases of flight. The distribution of minimal effectiveness and hazard area during critical phases of flight exhibited significant seasonal oscillation upon comparing the results for January and July relative to May 2018 (p<0.001). Relative likelihood of fatigue was high in the crew rosters, with significant seasonal oscillation of minimal effectiveness and hazard area in critical phases of flight. These results point to the need for improved roster management since prescriptive rules were insufficient to mitigate risk.