What is the reason that the object type Pipe cannot be selected in the Route Navigator?

The subtypes for the cable protection pipes are taken from the table ELES_KABELSCHUTZ_ROHR.

In the column USE_IN_ROUTENAV, it can be defined which subtypes should be displayed. These contain the value 1.
If the value 1 is not set for any entry, the object type Pipe is not available as a selection in the Route Navigator.