Date of Award


Document Type


Degree Name

Master of Science


This study examined the effects of converting a large USAF aircraft maintenance squadron from an 8- hour shift system to a 12-hour shift system. In 1996, the squadron converted its 24-hour operations from three 8-hour work shifts, to two 12-hour work shifts with compressed work weeks. The squadron maintained 12-hour shifts for 19 consecutive months. A comparison was made of organizational performance, worker health and safety measures before, during and after 12-hour shift implementation. Findings indicated that changing from 8- to 12-hour shifts resulted in a slight increase in aircraft Mission Capability rates. However, this benefit appears to have come at the expense of worker health, as evidenced by a ten-fold increase in worker sick-call visits to the base hospital. Additionally, the squadron expended a higher proportion of direct labor hours in support of the flying schedule. There were no significant differences in any other aircraft reliability, maintenance repair or deferred maintenance indicators. On- and off-duty accident rates were also examined. There were no significant differences noted between mean 8- and 12-hour shift accident rates. The decision to implement 12-hour shifts is one that must be made with careful consideration of the costs and benefits identified in this study.

AFIT Designator


DTIC Accession Number



Presented to the Faculty of the Graduate School of Logistics and Acquisition Management of the Air Force Institute of Technology