Date of Award


Document Type


Degree Name

Master of Science


This study examined the effects of converting a large aircraft maintenance squadron from 8-hour shifts to 12-hour shifts. The squadron studied converted its 24- hour maintenance work force from three 8-hour work shifts to two 12-hour work shifts incrementally, with one section converting to 12-hour shifts in January, 1996, and the remaining section converting in July, 1996. Both sections remained on 12-hour shifts until September, 1997, when both sections converted back to a three shift 8-hour operation. Health and well being, on- and off-duty accident rates, day shift vs. night shift accident rates, and the effects of stress and fatigue on specific satisfactions, job dissatisfaction, and reenlistment intentions were examined. Results showed an increase in hospital visits when 12-hour shifts were employed, as well as an increase in hospital visits immediately following all schedule changes. There were no significant differences in 8-hour and 12-hour shifts on and off-duty accident rates or day and night shift accident rates. Reported levels of fatigue were significantly greater when 12-hour shifts were used. Tension was greater while on 12-hour shifts, but did not decrease significantly until a few months after the conversion back to 8-hour shifts.

AFIT Designator


DTIC Accession Number



Thesis presented to the Faculty of the Graduate School of Logistics and Acquisitions Management.