When creating a utility node, gravity fittings are not available in this interface however you can create a place holder node and change to a gravity node after the fact. I think this is maybe an oversight. Gravity fittings are very common in services; bends, wyes, null nodes, etc.
There is a work around; create a place holder, select this place holder and then change the site improvement type to the desired node but this adds some steps, especially when in a hurry.
Thank you for the consideration!