Ao

Operational Availability (Ao) (運用可用率)

Ao is a fundamental figure of merit (Run/Starting). If Ao is chosen as a target, the model will continue purchasing spares until the target rate has been achieved. Since each spare makes a discrete contribution to availability, the model cannot hit the target exactly in most cases. It will stop at the first availability that equals or exceeds the target, unless additional targets were specified and these targets have not been met yet. The following targets or stopping rules can be used in combination with Ao: budget, fill rate, average days delay/demand, and Slope of Availability vs. Cost Curve. The model will continue to purchase spares until the most difficult target is satisfied.

Operational availability is the product of supply availability and maintenance availability. Maintenance availability is the degradation in availability due to remove and replace times, independent of spares. It is not computed by TEMPO, but is an input variable by operating site. If the maintenance availability is not entered a default value of 1 is assumed, meaning that TEMPO is really computing supply availability (since it is possible to obtain an availability near one with sufficient spares).

« Back to Glossary Index