Fatigue and stress are major safety hazards for crews of long haul, manned aircraft as well as long endurance UAS. What is the relationship between fatigue and stress? How does one affect the other? What are the unique causes of fatigue and stress in UAS that are not present in manned aircraft? What do you think are the most effective fatigue and stress countermeasures that crews of both UAS and manned aircraft can use to mitigate the risk associated with these hazards?
When one reacts to physical, mental or emotional stimuli it can cause stressors that effect your health and functioning. Stress is defined as an organism’s total response to environmental demands or pressures (Medical dictionary, 2016). As a result, stress can either be short-term or long-term. One symptom of long-term stress is that of fatigue. Fatigue is defined as a state of diminished physical or mental efficiency (FAA, n.d.). Fatigue causes a dulling of senses, thought and reflexes (FAA, n.d.). Some of the unique causes of fatigue and stress in the UAS field have to do with duty periods. UAS crews typically work multiple, rotating, or both shift types unlike those crews who typically work day or irregular shifts (Thompson, 2006). Jansen, Van Amelsvoot, Kristensen, Van den Brandt and Kant (2003) noted the prevalence of fatigue in rotating shift workers was 24-29% compared to 18% for day workers and 19% for irregular shift workers. Therefore, due to the nature of UAS operations, chronic and periodic in nature, these crews are more susceptible to fatigue. The chronic and periodic nature can be explained by the split operations of the Predator series aircraft. The two crews split between the Middle East, the launch and recovery element (LRE) and the United States, the mission control element (MCE). Often, the LRE element is very sporadic in nature with launches and handoffs typically taking a couple to three hours then followed by complete boredom and downtime. The MCE phase of the operation can last for extensive periods then again followed by the recovery phase lasting another couple of hours.
Effective countermeasures to stress and fatigue can be implemented to help reduce the effects of these situations. Such countermeasures can be implementing a 12 hour duty period with more consecutive days off which should maintain operator peak performance (Thompson, 2006). More direct measures are medical evaluations to determine levels of shift-work disorders, development of a rest program, improved crew rest areas, exercise rooms and lighting and climate control improvements (Thorby, 2010).
References
Federal Aviation Administation Civil Aerospace Medical Institute. (n.d.). Physiology of flight: fatigue in aviation. Retrieved from https://archive.org/details/gov.faa.safety.3 (Links to an external site.)
Jansen, N. W. H., Van Amelsvoort, L. G. P. M., Kristensen, T. S., Van den Brandt, P. A., & Kant, I. J. (2003). Work schedules and fatigue: A prospective cohort study. Occupational and Environmental Medicine, 60(Suppl 1), i47-i53
Medical Dictionary. (2016). Stress. Retrieved from http://medical-dictionary.thefreedictionary.com/stress (Links to an external site.)
Thompson, W. (2006). Effects of shift work and sustained operations: operator performance in remotely piloted aircraft. Retrieved from http://www.wpafb.af.mil/shared/media/document/afd-090121-043.pdf (Links to an external site.)
Thorby, M. (2010). Shift Work Disorder. Retrieved from http://media.mycme.com/documents/29/culpepper_2010_swd_suppl_7021.pdf (Links to an external site.)