I'm testing this very nice piece of the software - for more info check https://play.google.com/store/apps/deta ... cs.Horizon
It has integration with Flightgear. I was very curious and made test low level flight from Samedan to Aosta in CAT III limited visibility. I was able perform that flight without any trouble, syntetic rendered terrain was absolutly perfect. And virtual tunnel in the sky guided me direct to runway.
Conclusion - very good app. But some expensive You can use it without payment, but some features will not work. Free use is limited to 60 days.