Reliability Predictions and System Support Costs

A case study demonstrates that spares requirements based on operational reliability predictions result in the system being undersupported during its burn-in and useful-life phases by average factors of 42.2 and 4.22, respectively. However, systems spares requirements based on logistics estimates result in the system being oversupported during its burn-in phase by an average factor of 4.26 with this factor probably increasing as the system enters the useful-life phase of its life cycle. Adequate system support within predetermined cost estimates will be achieved only when reliability predictions are accurate and when systems spares requirements are computed separately for the equipment burn-in phase and useful-life phase.