Description: Length of time that maintenance is performed on an object, including technical, logistical, and internal administrative delays; Name: time for maintenance 
Description: Time interval when maintenance is carried out on an item including technical, logistic and internal administrative delays; Name: Maintenance time
Description: Probability that an item is in a state to perform as required at a given instant, under given conditions, assuming that the necessary external resources are provided ; Name: Instantaneous availability