Cost of specifying maintenance/failure free operating periods for Royal Air Force aircraft

In an effort to increase the availability of RAF aircraft and thus increase their effectiveness, a method of specifying reliability has been increasingly adopted that looks for success rather than the previous philosophy which accepted that failure was inevitable. Maintenance/failure free operating periods (M/F-FOP) measures the probability that a mission or series of missions can be successfully completed without failure or without maintenance degrading the ability to conduct the next mission or series of missions. However, the M/F-FOP philosophy is still relatively immature and not been applied to much equipment so far delivered to service. M/F-FOP assumes that success is attainable and that the probability of that success can be accurately applied from entry into service; moreover, it specifies needs in unambiguous terms. That it is advantageous to aircraft systems has been shown in the civil aircraft field with aircraft like Boeing 777 and the Airbus family already in service. This paper identifies and examines the cost drivers of M/F-FOP and develops them into a metric to inform the R&M community of the financial and nonfinancial cost/value benefits and penalties of M/F-FOP. A method by which qualitative data could be resolved into quantitative data was developed in order to produce the metrics. Analysis of these metrics provided the following: purchase cost benefits < purchase cost penalties; operating cost benefits > operating cost penalties; and nonfinancial positive impacts > negative impacts.