Fatigue Exposure in the Context of Nighttime Airline Operations

Introduction: A. Introduction Managing crew fatigue is a critical aspect of aviation safety, particularly in the context of night duties. Following changes in fatigue risk requirements (EU2023/023/R) by the European Aviation Safety Agency (EASA), a leading airline operating medium- and long-haul flights conducted scientific research investigating its crews' exposure to fatigue risk. A key component of this regulation is the classification of nighttime flight duty periods (FDPs) based on their potential to induce fatigue. EASA distinguishes three subtypes: FDPs starting between 02:00 and 04:59, FDPs starting before 02:00 and ending between 02:00 and 05:59, and FDPs starting before 02:00 and ending after 05:59. The effects of these nighttime FDPs on fatigue levels among crews were analyzed. By assessing fatigue exposure and identifying contributing factors, the study aimed at supporting regulatory compliant fatigue risk management. The objectives were 3-fold: - To identify currently implemented fatigue risk management measures; - To diagnose fatigue risk exposure levels among crews; - To support the airline in managing fatigue risk.