The Use of Cost Estimating Relationships versus Accounting Models for Estimating Maintenance and Repair Costs: A Methodology Demonstration.

This thesis demonstrated a methodology of developing a Cost Estimating Relationship CER that is capable of generating nearly the same cost estimates as an accounting type of cost model. A cost model was first developed that estimated annual recurring maintenance and repair associated costs of a jet engine. This model used 51 input variables and 30 equations and represented an accounting approach to cost estimating with input requirements at low levels of detail. Using techniques of multiple linear regression, a CER was developed that used only seven aggregated variables to estimate the same cost at an acceptable level of accuracy. The emphasis in this thesis is on the demonstration of a methodology that can be used to develop CERs. Both the accounting type cost model and the CER in this thesis are exclusively for the validation of a methodology and were developed using an artificially generated data base. As such they are not valid for any cost estimation purposes. Keywords Life cycle costs Aircraft maintenance Cost analysis Regression analysis Theses.