ForeFlight claim that you can enter UTM coordinates into ForeFlight: https://support.fore...PS-coordinates-
In my experience, this is not the case, as ForeFlight only support MGRS and it's very frustrating, as many clients I work with use UTM coordinates rather than Lat/Lon.
I, therefore, created an iPhone/iPad app, that converts UTM into Lat/Lon and then exports them directly into ForeFlight.
It can be purchased in the app store: https://itunes.apple...01167?ls=1&mt=8
Demo of the app in action can be seen In this YouTube video:
Also, see brief feature animation below: