Date of Award

3-21-2019

Document Type

Thesis

Degree Name

Master of Science in Operations Research

Department

Department of Operational Sciences

First Advisor

Raymond R. Hill, PhD

Abstract

Launched in 1996, EXPRESS (Execution and Prioritization of Repairs Support System) is a program integral to the Air Force reparable supply chain. Daily, EXPRESS relies on a number of data sources and individual modules like the Supportability Module to determine which necessary repairs can and should be made. The Supportability Module examines the prioritized list of repairs and checks four constraints in order to decide whether each repair can be made given current resources. According to the logic of the module, a single constraint failure means that subsequent resource checks are not made before evaluating the next repair. Unfortunately, this leads to missing observations in the EXPRESS data table, ultimately masking potential resource issues and possibly contributing to extended mission capability issues. In this study, a time series analysis via explanatory autoregressive distributed lag (ARDL) models was conducted using EXPRESS and MICAP (mission capability) data to examine possible connections between missing constraint values in the EXPRESS table and future MICAPs. These models suggested that up to 0.793 MICAP days are added for each additional parts failure missing in the EXPRESS table. Additionally, the presence of significant relationships between the EXPRESS and MICAP data over time suggest that maintainers examining trends in the EXPRESS data could feasibly reduce future MICAPs. As a byproduct of this study, the potential for the use of time series models with maintenance data was explored. Model diagnostics suggest that maintenance data is too volatile and noisy for regression-based methods and that stochastic methods or simulation may prove more useful.

AFIT Designator

AFIT-ENS-MS-19-M-151

DTIC Accession Number

AD1077564

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