A two-phase inspection policy for a single component, preparedness system is investigated. Inspections or tests are considered to be imperfect; that is, false positives and false negatives can occur. We further suppose that a component may be weak or strong, with a lifetime distribution that follows a mixture. In these circumstances, the long-run cost and availability of the policy are
... [Show full abstract] determined. The policy appears to behave sensibly; when the false alarm probability is high, less testing should be carried out; when the false positive probability is high the converse is true, provided the cost of testing is not too high. The policy is illustrated using a valve in a gas supply network.