Date of Award


Document Type


Degree Name

Master of Science

First Advisor

V. Daniel R. Guide, Jr., PhD

Second Advisor

Mark E. Kraus, PhD


The Air Force currently uses an expected value model in the Aircraft Availability Model (AAM) to calculate aircraft availability. However, even with the application of Lean Logistics, the failure-demand rate and the depot repair time are not fixed and the mean value is still used in the model. This research looks at the effect of the magnitude of the variance of the distributions of failure-demand rate and depot repair time. Also, this research evaluates the effect of variable mean failure-demand rates on the variability of aircraft availability. A simulation model was developed which applied the variable failure-demand rates and depot repair times. Aircraft availabilities were calculated and the variances of the aircraft availabilities were computed. From this an ANOVA and paired t-tests were performed on the mean variances to test if the parameters significantly effected the variance of aircraft availability. From these tests, it was found that failure-demand rate variance and the failure-demand rate significantly effected the variance of aircraft availability with possible aircraft availabilities being +-- 10% in some cases.

AFIT Designator


DTIC Accession Number



The author's Vita page is omitted.

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