Failure rates within the RIAC NPRD-2011 databook are based on the number of cumulative operating hours for a given component and the number of failures of that component that are experienced during those cumulative operating hours. These failure rates are not a function of component type. A motor that experiences 5 failures in 2.5 million operating hours will have the same failure rate as a computer hard drive that experiences 5 failures in 2.5 million operating hours (or some approximate multiple that results in an identical/similar failure rate). Also, two dissimilar components, each of which experiences 0 failures in 200,000 operating hours will have the same lower-bound failure rate.
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