Mean Time To Repair (
MTTR) is a basic measure of the maintainability of
repairable items. It represents the
average time required to repair a failed component or device. Expressed mathematically, it is the total
corrective maintenance time for failures divided by the total number of corrective maintenance actions for failures during a given period of time. It generally does not include lead time for parts not readily available or other Administrative or Logistic
Downtime (ALDT).