This paper presents an analysis of an unexpected failure during vibration and shock life test of an electronic circuit board that has been in use for more than 15 years. During testing, an aluminum bracket used to mount a transistor and provide a path for heat transfer was damaged. Prognostic methods were employed to determine whether the bracket failure could have been predicted prior to the life test. Details of the analytical calculations and modeling results are described in this paper. Results show that the failure could have been predicted before actual testing.