Effectively utilizing existing on-board and atwing data that encompasses environmental, built-in-test (BIT), vibration, and maintenance test results, can realize improved maintenance, survivability and critical failure rates via the identification of degrading components prior to critical failure. The authors have developed software to show the feasibility of onboard and at-wing prognostics using field data from an Army aircraft platform as a multifaceted case study for predicting and diagnosing the health of a mission-critical targeting subsystem.