Aircrew Actual vs. Prescriptive Sleep Schedules and Resulting Fatigue Estimates.

BACKGROUND: Fatigue is an insidious and costly occurrence in the aviation community, commonly a consequence of insufficient sleep. Some organizations use scheduling tools to generate prescriptive sleep schedules to help aircrew manage their fatigue. It is important to examine whether aircrew follow these prescriptive schedules, especially in very dynamic environments. The current study compares aircrew sleep during missions to prescriptive sleep schedules generated by a mission scheduling tool. METHODS: Participating in the study were 44 volunteers (Mage= 28.23, SDage= 4.23; Proportionmale= 77.27%) from a C-17 mobility squadron providing 25 instances of sleep and mission data (80 flights total). Aircrew wore actigraph watches to measure sleep during missions and prescriptive sleep schedules were collected. Actual and prescriptive sleep was compared with calculated performance effectiveness values per minute across mission flights. RESULTS: Prescriptive schedules generally overestimated effectiveness during missions relative to estimated actual sleep, potentially causing shifts in effectiveness to ranges of increased risk requiring elevated fatigue mitigation efforts. Actual and prescriptive effectiveness estimates tended to increasingly diverge over the course of missions, which magnifies differences on longer missions. DISCUSSION: The current study suggests that aircrew sleep during missions often does not align with prescriptive sleep schedules generated by mission planning software, resulting in effectiveness estimates that are generally lower than predicted. This might discourage aircrew from using mission effectiveness graphs as a fatigue mitigation tool. Additionally, because fatigue estimates factor into overall operational risk management processes, these schedules might underestimate risks to safety, performance, and health. Morris MB, Veksler BZ, Krusmark MA, Gaines AR, Jantscher HL, Gunzelmann G. Aircrew actual vs. prescriptive sleep schedules and resulting fatigue estimates. Aerosp Med Hum Perform. 2021; 92(10):806814.

Fatigue-Related Aviation Mishaps.

INTRODUCTION: Fatigue is a critical safety issue to U.S. Air Force (USAF) flight and ground crew. Nearly 15 yr of mishap reports were analyzed to determine how fatigue affects USAF operations with the goal of improving fatigue risk management policies and tools.METHODS: Summary data for 19,920 aviation mishap reports dating back to 2003 were collected from the Air Force Safety Automated System (AFSAS). Fatigue-related mishaps were identified based on designations provided within AFSAS. Other metrics examined were characteristics such as timing, cost, and aircraft metrics, among others. Contingency tables built from these metrics were used to assess fatigue-related trends across the aviation community.RESULTS: While only 3.88% of all mishaps were identified as fatigue-related, they are associated with 2.1 billion of medical expenses and property damage, or 18% of the 11.7 billion total cost of all mishaps included in the study. Nearly a quarter of the fatigue-related mishaps fall into the most severe mishap category and more than half occurred between 0100 and 0700, local time. Fatigue-related mishaps tended to be more common for Remotely Piloted Aircraft (RPA) and ground operations.DISCUSSION: Fatigue is very costly to the USAF despite the relatively low incidence rate of fatigue-related mishaps. This is because larger proportions of severe mishaps were found to be fatigue-related. RPA and ground maintenance operators might be especially susceptible to fatigue and potentially lack adequate fatigue mitigation support and training tailored to their unique operational environment, suggesting a need to improve upon fatigue mitigation tools and strategies.Gaines AR, Morris MB, Gunzelmann G. Fatigue-related aviation mishaps. Aerosp Med Hum Perform. 2020; 91(5):440447.