Note---A Note on Computing Periodic Inspection Policies

Certain systems must be inspected in order to discover failures that would otherwise go undetected. Periodic inspection is the most commonly used inspection policy and is the optimal policy form for some inspection models. Determining the optimal periodic inspection interval, however, would involve a numerical search and require knowledge of the underlying failure distribution. This note examines the cost performance of an existing simple approximation of the optimal inspection interval and presents a new approximation. The new approximation is computationally simple, and outperforms the existing approximation. The new approximation yields expected total costs that are typically well within one percent of optimal.