Date of Award


Document Type


Degree Name

Master of Science


The C-5 consistently performs below its established mission capable rate of 75 percent. The purpose of this study was to investigate whether or not mission capable rates and maintenance costs can be improved by increased use of scheduled maintenance. Nine C-5 components were studied. Availability and cost were compared when scheduled replacement occurred at ten, twenty, and thirty percent before their respective mean time between failure and actual failure times. Actual failure times were not available so they were generated using simulation. The trade-off of using preventive maintenance is the decreased cost of sending fewer maintenance repair teams and increased C-5 availability, versus the increased cost of early component replacement. This study's findings suggest that the level of variance in the failure distribution of components will have an influence on the effectiveness of a preventive maintenance program. The use of preventive maintenance on components with a high variance in the failure distribution appears to have a negative effect on availability at a higher cost than with not using preventive maintenance. The use of preventive maintenance on components with a moderate or small amount of variance in its failure distribution appears to be effective up to a point of diminishing return.

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