UNCERTAINTY ASSESSMENT OF AIRCRAFT MAINTENANCE TIMES

Abstract

This thesis demonstrates the use of the Dempster-Shafer Theory of evidence as a decision aid to specify maintenance time during wartime operations, by the help of expert judgment elicitation. This more precise time estimation enables the decision maker to make more accurate decisions for Air Force’s wartime tactical operations allowing commanders to gain a decisive advantage. The major failures were modeled as assessments to investigate maintenance times. A questionnaire was tailored to elicit judgment from experts at the Aircraft Maintenance Facility (AMF). Through an application of the Dempster-Shafer Theory, expert judgment elicitation was determined to be the critical data. This approach was presented as a plausible evidence combination technique when uncertain, incomplete, and incorrect evidence must be assessed during wartime environment. Jet engine aircraft failures examples that met two classes of uncertainty, aleatory and epistemic, were presented to demonstrate possible maintenance time during wartime operations. A decision aid based on the Dempster-Shafer Theory was created and an uncertainty assessment is discussed. This decision aid allows a comparison of each expert’s assessment. The results of this methodology provide a useful and specific application area for the Dempster-Shafer Theory and the AMF in aiding a decision maker to assess the level of an expert’s uncertainty.

Keywords

• Evidence Theory
• Expert Judment Elicitation
• Uncertainty Assessment
• Risk Analysis
• Aircraft Maintenance