A Conceptual Fatigue Risk Management Model for Short-Haul Duty Cycles in Urban Air Mobility Operations

Purpose: Urban Air Mobility (UAM) operations are characterized by repetitive short-haul missions, high-frequency duty cycles, and increasing automation dependency, which may generate fatigue patterns distinct from those observed in conventional aviation.This study aimed to propose a UAM-specific fatigue risk management conceptual framework based on cumulative exposure and duty cycle characteristics.Methods: This study reviewed International Civil Aviation Organization fatigue risk management system (FRMS) principles, Federal Aviation Administration operational guidance, and prior fatigue studies related to short-haul operations and human factors.Based on these findings, a conceptual UAM-FRMS framework reflecting repetitive duty cycles, monitoring fatigue, and automation-based operational environments was developed.Results: The proposed UAM-FRMS consists of four major components: fatigue risk indicator setting, cumulative exposure-based fatigue assessment, Alert Level based operational control, and data-driven feedback and adaptation.The framework incorporates sector count, duty length, turnaround time, monitoring duration, and recovery status as key fatigue indicators.In particular, the model emphasizes cumulative exposure-based fatigue management rather than conventional total flighttime limitations and introduces a staged operational control structure using Alert Levels.Conclusion: The proposed UAM-FRMS suggests that repetitive duty cycle exposure and automation monitoring environments should be considered key fatigue risk factors in future UAM operations.The study provides a conceptual basis for expanding conventional FRMS toward a cumulative exposure-based and human centered fatigue risk management framework suitable for emerging UAM operational environments.