operational availability
Type
term
Definition
The degree (expressed as a decimal between 0 and 1, or the percentage equivalent) to which one can expect a piece of equipment or weapon system to work properly when it is required, that is, the percent of time the equipment or weapon system is available for use. AO represents system “uptime” and considers the effect of reliability, maintainability, and Mean Logistics Delay Time (MLDT). AO may be calculated by dividing Mean Time Between Maintenance (MTBM) by the sum of the MTBM, Mean Maintenance Time (MMT), and MLDT, that is, AO = MTBM ÷ (MTBM + MMT + MLDT) It is the quantitative link between readiness objectives and supportability.