Validation of Flight Crew Rest Period Adequacy Using Bio-mathematical Model

Fatigue is a critical factor that can significantly impair the alertness and operational performance of flight crew members, thereby increasing the risk of aviation accidents. To mitigate this risk, regulatory authorities have established Flight Time Limitations (FTL) to manage crew work hours and ensure adequate rest periods. However, the adequacy of these rest periods is often based on empirical data and requires scientific validation. This study proposes a method to validate the adequacy of flight crew rest periods using bio-mathematical models, specifically the Fatigue Audit InterDyne (FAID) model. By comparing fatigue levels under different scheduling scenarios, this study demonstrates the effectiveness of rest periods in mitigating fatigue for ultra-long-haul flights. The results indicate that the rest periods, as defined by a specific airline, are sufficient to restore crew alertness to acceptable levels, thereby supporting the application of these regulations in operational contexts.