When the Calculate command is selected, the Calculate window opens. The Maintainability page specifies information about the maintainability calculations to perform. These calculations are described in Maintainability Calculations.

Repair level indicates the level at which to run calculations. It is critical that you select the appropriate repair level because the MTTR (mean time to repair) will be 0 if no replaceable items are defined at the level that you select. The levels available for selection are based on the list attached to Repair level. You select this list in the Project’s Data Definition file when Maintainability Definition is the table type. For more information, see Data Definition Files.

In a newly created System file, the Maintenance Levels list in the master Library file is attached to this field by default. The default repair level in this list is Intermediate. For more information, see List Library Files.

When you calculate maintainability results as described in Calculating Maintainability Results, system-level results are shown in the View Calculation Results window. You can then view the results calculated for any particular item in the System Tree as described in Viewing Calculation Results for a System Tree Item.