The current schedule selected for MQ-1B Medium Altitude, Long Endurance (MALE) UAS squadron tasks the crews with six continuous days of operation.  This requires the crew to work for 48 hours and, at a minimum, spend roughly 60 hours in work related activities.  This includes a minimum 30-minute commute, plus 1 hour of prep time before the shift.  The decision to expose the crews to this schedule is questionable as there are already reports of fatigue and inadequate sleep from the crew.  An initial recommendation to combat fatigue would be to decrease the shift frequency from 6 to 5 days, while maintaining two days off’ this is shown in Figure 1.  This decreases the total continuous operating time and provides for more frequent rest for the crews. A crew that is not experiencing fatigue can maintain the “operator involved in the crucial tasks to the extent that any task emergencies are recognized and acted on within a critical time envelope” (Barnes & Matz, 1998).  Reducing the total continuous days of work also reduces the level of social and water isolation experienced by the crews.
The cognitive load associated with operating an UAS, along with the level of stress from performing military operations, can be compared to stressors experienced by Air Traffic Controllers (ATC).  Both career fields expose the operators to long missions, high level of stress, and a high cognitive demand.  The FAA has commissioned studies on the effectiveness and effect of multiple shifts on stress and fatigue.  A commonly used shift is called the counterclockwise shift, which progressively moves the shift start date earlier with every shift.  This was ultimately found to be counterproductive as it reduced the hours and quality of sleep on the ATCs (Signal & Gander, 2007).  Applying this research to UAS crews provides insight on what can be recommended from a human factors perspective.  This first improvement would be the incorporation of short duration naps within the schedule.  “A daytime nap as short as 10-min can improve alertness and performance for about 2.5 h in the face of prior sleep loss, and for almost 4 h if preceded by normal sleep” (Ficca, Axelsson, Mollicone, Muto, & Vitiello, 2010).
A subsequent improvement to the UAS crew schedule would result in the implementation of a rotating clockwise schedule.  This type of schedule moves the start date to the right, later each shift, to provide additional opportunities for sleep.  The shifts would start one hour later each day for all teams; the progressive nature of the change provides more time to sleep in order for the crew to recover from compounded fatigue.  In addition to the progressive schedule, the crews would be required to participate in periodic stress and fatigue assessments for further adjustments.  Waiting for a crewmember to report symptoms is not conducive to safe operations.  The evaluations would include the requirement for all crewmembers to wear a sleep monitoring device to ensure accurate sleep tracking. 
The quality of sleep is a critical component of the health assessment of the crew.  Lack of sleep is a direct contributor to reduced cognitive function and poor performance from the crew. A progressive shift, naps, and sleep monitoring provide the best way to ensure proper crew rest and optimum operational capabilities from the crew.  In the same manner that an air vehicle undergoes preventive maintenance, the crew and operators require monitoring for optimum performance.


Figure 1.  Existing and Proposed shift scheduled for UAS operators.

References

Barnes, M. J., & Matz, M. F. (1998). Crew simulations for Unmanned Aerial Vehicle (UAV) applications: Sustained effects, shift factors, interface issues, and crew size. Proceedings of the Human Factors and Ergonomics Society 42nd Annual Meeting (pp. 143-147). Ft. Huachuca: ProQuest Central.
Ficca, G., Axelsson, J., Mollicone, D. J., Muto, V., & Vitiello, M. V. (2010). Naps, cognition and performance. Sleep Medicine Reviews, 14, 249-258.
Signal, T. L., & Gander, P. H. (2007, September). Rapid Counterclockwise Shift Rotation in Air Traffic Control: Effects on Sleep and Night Work. Aviation, Space, and Environmental Medicine, 78(9), 878-885.