Break rate: a reliability parameter for surge operations

A method for measuring the break rate (BR) of an individual avionics system is described. The method is convenient early in the design process and accounts for item criticality, redundancy, task deferrability, and when deferred tasks are repaired. Also introduced is a new criterion of effectiveness, sortie loss rate, as an alternative to BR. Sortie loss rate has the benefit of measuring the total number of potential military sorties missed due to unscheduled maintenance. BR is calculated as the number of sorties missed divided by the number of sorties attempted. An alternative way to compute BR is one minus the ratio of actual sorties launched to attempted sorties