Principles and Guidelines.pdf (1.1 MB)Dinges, D. F., Graeber, R. C., Rosekind, M. R., Samuel, A., Wegmann, H. M. (1996). Principles and Guidelines for Duty and Rest Scheduling in Commercial Aviation (NASA Technical Memorandum 110404). Moffett Field, California: NASA Ames Research Center.
INTRODUCTION
Twenty-four Hour Requirements of the Aviation Industry
The aviation industry requires 24-hour activities to meet operational demands. Growth in global long-haul, regional, overnight cargo, and short-haul domestic operations will continue to increase these round-the-clock requirements. Flight crews must be available to support 24-hour-a-day operations to meet these industry demands. Both domestic and international aviation can also require crossing multiple time zones. Therefore, shift work, night work, irregular work schedules, unpredictable work schedules, and time zone changes will continue to be commonplace components of the aviation industry. These factors pose known challenges to human physiology, and because they result in performance-impairing fatigue, they pose a risk to safety. It is critical to acknowledge and, whenever possible, incorporate scientific information on fatigue, human sleep, and circadian physiology into 24-hour aviation operations. Utilization of such scientific information can help promote crew performance and alertness during flight operations and thereby maintain and improve the safety margin.
Challenges to Human Physiology
Throughout aviation history, operational capabilities and technology have evolved dramatically, while human physiological capabilities have not. Flight operations can engender fatigue, sleep loss, and circadian disruption and these physiological factors can result in decreased performance and reduced alertness during operations. Over the past 40 years, scientific knowledge about sleep, circadian physiology, sleepiness/alertness, and the performance decrements associated with these factors has increased significantly. Scientific research has extended its examination of these factors to operational environments, including field and simulator studies. These studies have confirmed the presence in aviators of performance-impairing fatigue resulting from the sleep loss, circadian disruption, and workload engendered by current flight and duty practices.
Humans are central to aviation operations and continue to perform critical functions to meet the 24-hour requirements of the industry. Therefore, human physiological capabilities, and limitations, remain crucial factors in maintaining safety and productivity in aviation.
Principles Based on Scientific Knowledge
Though research on fatigue, sleep and circadian physiology, and shift work schedules has generated an extensive body of scientific knowledge, the application of this information to the requirements of operational settings is relatively new. While acknowledgment of this scientific information is increasing, its transfer to operations (e.g., scheduling, regulatory considerations, personal strategies, countermeasures) offers the greatest potential for its benefit. Current federal regulations and industry scheduling practices rarely acknowledge or incorporate such knowledge. The primary purpose of this document is to outline scientifically-based principles that can be applied to the duty and rest scheduling requirements of the aviation industry.
Shared Responsibility
There is no one absolute or perfect solution to the demands of duty and rest scheduling in aviation. It is critical that safety be acknowledged as a shared responsibility among all the industry participants. Each component of the aviation system should be examined for avenues to incorporate scientific information and to apply guidelines and strategies that will maximize performance and alertness during flight operations. Regulatory considerations, scheduling practices, personal strategies, and technology design are specific components of the industry that could be subject to such an examination.
Each of these components is complex and presents unique challenges. This document is focused on scientifically-based principles and guidelines for duty and rest scheduling. However, it is acknowledged that regulatory action involves many considerations, such as legal, economic, and current practice. It is the intent of this document that relevant scientific information be considered in the regulatory domain.
"Safe" can be Difficult to Quantify
Determining a "safe" operation is a complex task. Aircraft accidents are such rare occurrences that they may not provide the best outcome variable to estimate safe operations. The aviation industry and flying public demand a high margin of safety and redundancy. Among modes of transportation, the aviation industry's reputation for safety is well-deserved. As many segments of the industry increase their activities, as technology enables longer flights, and as overall growth continues, the challenge will be to maintain, and where possible, improve the safety margin. The fatigue factors addressed in these principles can create a vulnerability for decrements in performance and alertness that can reduce the safety margin. Guidelines designed to specifically address these factors can help to minimize this vulnerability.
Objectives
The primary objective of this document is to provide empirically derived
principles and guidelines for duty and rest scheduling in commercial aviation.
In the first section, scientifically-based principles related to operational
issues posed by the aviation industry are outlined. In the second section,
the principles are applied to guidelines for duty and rest scheduling in
commercial aviation, with specifics provided where appropriate and available.
In the third section, a brief overview of other potential industry strategies
to address these issues is provided.
Principles and Guidelines.pdf (1.1 MB)