===== Downtime =====
[[ddsf:public:guidebook:06_append:glossary:start| Return to Glossary ]]

**Downtime (T<sub>d</sub>)** is the Mission Duration times the sum of all of the different kinds of time required to transition from being down to the time to be fully operational divided by the Mean Time Between Failure.

  * [[ddsf:public:guidebook:06_append:glossary:m:mttr]] is time required to restore operations the level defined in the system specification
  * [[ddsf:public:guidebook:06_append:glossary:m:mldt]] is time required to obtain parts from the part depot or from the manufacturer including transportation to the site
  * [[ddsf:public:guidebook:06_append:glossary:m:mamdt]] is average time required to perform diagnostics and replace parts 

Source: [[https://en.wikipedia.org/wiki/Availability_(system) | Downtime ]]