Periodic Checkout and Associated Errors

Periodic checkout of space or weapon systems is investigated to determine the probability of no undetected defects (or failures) as a mathematical function of various parameters related to checkout equipment design criteria and checkout techniques. This probability is treated (1) when the checkout is complete and therefore tests for all possible failures and (2) when the checkout is not complete and does not test for all possible failures. One of the parameters affecting the probability of no undetected defects is the frequency of checkout. Special attention is paid to this parameter as it affects the system failure rate, as opposed to its effect on the probability of no undetected defects. The probability of a checkout erroneously determining that a failure exists (a false alarm) is treated as a matter of considerable importance because it results in unnecessary mission delays and money expenditures. This probability is also shown as a mathematical function of the various checkout equipment design and checkout techniques.