It represents the average time required to repair a failed component or device.
[1] 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.
[2] It generally does not include lead time for parts not readily available or other Administrative or Logistic Downtime (ALDT).
If a latent fault goes undetected until an independent failure occurs, the system may not be able to recover.
For example, a system with a service contract guaranteeing a mean time to "repair" of 24 hours, but with additional part lead times, administrative delays, and technician transportation delays adding up to a mean of 6 days, would not be any more attractive than another system with a service contract guaranteeing a mean time to "recovery" of 7 days.