Thursday, November 20, 2014

Does Shift Work Matter? A look into UAS Shift work schedules

UAS Shift Work Schedule
            Shift work is commonly used among UAS operators and other pilots in the United States Air Force (USAF).  For this particular review, the author will analyze a current hypothetical shift work schedule and make recommendations to improve pilot conditions.  For the purposes of this analysis the original schedule for an MQ-1B Medium Altitude, Long Endurance (MALE) UAS squadron will be comprised of active missions that take place 24/7, 365 days a year.  The current shift rotation follows a continuous shift work schedule of 6 days on, 2 days off for 4 teams as indicated by Figure 1. However, there are several issues with this schedule.
 According to the report, the current schedule resulted in many pilot complaints.  The primary complaint is that the UAS crews have been reporting many instances of extreme fatigue while on the job.  Further, there have been several complaints of inadequate sleep directly as a result from the current shift schedule.  For this reason, an alternative schedule has been mapped out in order to alleviate some of these stressors resulting in fatigue.


Figure 1. Original schedule.  This image depicts the original schedule of 6 days on 2 days off ratio.  Team 1 follows 6 day, 2 off, 6 Swing, 2 off, 6 night, 2 off pattern.  Team 2 follows 2 off, 6 swing, 2 off, 6 night, 2 off, and 6 days pattern.  Team 3 follows 4 night, 2 off, 6 day, 2 off, 6 swing, 2 off, 2 night pattern.  Team 4 follows 2 swing, 2 off, 6 night, 2 off, 6 day, 2 off, and 4 swing. 

            A common issue with the current schedule is the rotation from different shifts.  Moving from a day shift, to a swing shift, then a night shift disrupts an individual’s natural biological rhythm or circadian rhythm.   Studies indicate that the circadian rhythm regulates many body functions such as body temperature, blood pressure and certain hormone excretions; as such, circadian rhythms often directly influence whether or not an individual, such as a pilot, is sleepy or alert (Costa, 1996).  Additional studies found that weekly rotation schedules tend to perpetuate disturbed circadian rhythms; therefore it is better to incorporate monthly rotation schedules (Tvaryanas, Platte, Swigart, Colebank & Miller, 2008).  In Figure 2, a new schedule is proposed in order to help alleviate the circadian rhythm disruptions the UAV pilots are currently suffering.  This new schedule takes into consideration the negative impact of weekly rotations and eliminates it for the most part.



Figure 2.  Proposed schedule.  This image depicts the proposed schedule that aims to eliminate most of the weekly shift rotation.  Team 1 follows all day shifts with 6 days, 1 off, 6 days, 2 off, 5 days, 2 off, and 2 days.  Team 2 follows 1 night shift and the rest swing shifts with 1 night, 3 off, 6 swing, 1 off, 6 swing, 1 off, 5 swing, and 1 off.  Team 3 follows all night shift with 1 off, 6 night, 2 off, 6 night, 1 off, 6 night, 1 off and 1 night.  Lastly Team 4 serves as the ‘floater’ and fills in the gaps of the schedule with 4 swing, 2 off, 1 day, 2 night, 1 off, 1 swing, 2 off, 2 day, 1 night, 1 off, 1 swing, 2 off, 2 day, 1 night and 1 swing.  Team 4 is given extra off days to help offset the changes in shifts.

There are both benefits and drawbacks to the new proposed schedule.  For the most part, it addresses the primary issue of rotating shifts.  Originally, the main UAS pilot complaint was fatigue due to the schedule rotation.  However, with the new schedule, teams 1, 2 and 3 all have a relatively set schedule.  Team 1 always works days, team 2 works 1 night and the rest swings, and team 3 works all night shifts.  The drawback comes with team 4, which is the ‘floater’ team.  This team serves to ‘plug the holes’ in the schedule, filling in wherever there is a schedule gap.  Although this means that team 4 will have a more irregular schedule, the team is compensated with the additional days off to help recoup sleep and help readjust their circadian rhythms.  
Further, with the proposed new schedule, each team would be assigned to their shift for a month, at which point they would then rotate to the next shift.  For example, team 1 would now become team 2, team 2 would become team 3, team 3 would become team 4 and team 4 would become team 1.  This allows for a more gradual shift change (over a period of a month rather than a week) and makes it easier to reduce fatigue due to circadian rhythm disruptions.  Additionally, this also makes it so that each team is assigned to the more difficult ‘floater’ shift only once per month with plenty of recoup time in the following regular shifts.
Conclusively, the move from the original schedule to the proposed schedule is one that would very likely allow the squadron to optimize operations while simultaneously improving the fatigue issues suffered by the crewmembers.  Although the original schedule allows for more regular shifts for team 4, having the ‘floater’ team 4 in the proposed schedule helps alleviate fatigue for teams 1-3.  Further, as this is a monthly schedule, the team assigned to the ‘floater’ position would only need to do so once every four months due to the nature of the monthly rotation.  Therefore, it is a practical solution that would ultimately yield positive results.

References
Costa, G. (1996). The impact of shift and night work on health. Applied Ergonomics 27(1):9-16.
Tyvaryanas, A., Platte, W., Swigart, C., Colebank, J. and Miller N. (March 2008).  A resurvey of

shift work-related fatigue in MQ-1 predator unmanned aircraft system crewmembers.  Naval Postgraduate School. 1-37.

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