Use this activity to define maintenance groups. A maintenance group is one of the basic maintenance objects with a connection to operational parameters, maintenance plans, and interval maintenance. Maintenance groups are defined per serial part, where one serial part can have one or several maintenance groups.
Maintenance groups are tightly connected to operational parameters. For each maintenance group, several operational parameters can be defined. When a maintenance group is defined for serial parts, a control is executed to determine if serials exist with operational data from operational measurements for the maintenance group. When entering a new operational parameter, the parameter is automatically assigned to all serials in the selected maintenance group. When a maintenance group is changed, the operational parameters are changed according to the new maintenance group.
This activity is done using Maintenance Group tab in Serial Part page. You can select between Manual Average, Planned Average or Historical Average in the Average Value Rule field. The value is used for the due calculation. If you enabaled the Preferred Maint Group option, the maintenance group is always used if nothing else is specified.
The following table shows the valid average value rules:
| Average Value Rule | Description |
| Manual Average Value Rule | A monthly average for the operational value is manually defined in Maintenance Plan. |
| Planned Average Value Rule | Monthly planned operational values are retrieved from the operational budget (defined in IFS/VIM Forecasting). |
| Historical Average Value Rule | Average historical operational values for the last twelve months. |
A primary operational parameter must exist for the serial part.