Definition
In the PM component, you can create sub-operations for all the operations in a maintenance task list. Sub-operations represent an additional level of detail for an operation and are situated hierarchically below an operation. You can assign several sub-operations to one operation. This can be an advantage in the following scenarios:
Sub-operations may contain some of the same information as operations, for example,
Structure
There are two types of operations for maintenance task lists in the PM component:

You can divide the operation "Inspection" into two sub-operations:
You can also add a sub-operation to your operation if part of the task is to be processed externally. For example, the sub-operation "motor inspection" could be performed by a third party. In this case, the sub-operation will contain a purchase requisition for the external labor.
You can create different types of sub-operation for one operation. For example, you can create externally processed sub-operations for an internally processed operation and vice versa.
For more information on sub-operation, see
Features of the Sub-Operation.