Availability based Optimal Maintenance Policies in Military Aviation

Aviation components are considered repairable and subjected to maintenance actions at various levels. The paper discusses general renewal process for an aero engine as repairable component. Reliability parameters are estimated using Generalized Renewal process (GRP) Maximum Likelihood Estimators (MLEs), by collecting field data from three producers of the aero engine. The current practice designates repairable components, as high failure rate components (HFRC) based on the number of unscheduled failures at Repair depots. A methodology is developed to designate HFRC based on Availability. Further, decisions for review of maintenance policies are presented by formulating a maintenance model based on HFRC declaration. The overall capabilities of GRP model, HFRC model and Maintenance models have been evaluated through numerical examples and validated with the existing field conditions.