I was flying VFR yesterday in the area. The ground fog was only a few hundred feet thick in the valleys with full blue sky/CAVOK above.
In places the High Power lines poles and windmills tops were sticking out the fog base on some hills.
As Annex 14 correctly and wisely said earlier , there were plenty on airfields open in full sunshine on the high terrain, all around Trier. Attempting yesterday to go inside the Mosel valley with this weather ( plus the fog was in icing conditions as well ) on a strip with no Nav aids is not understandable for me.
Brings another question, how can you cancel IFR, ( they had to at some point for destination Trier ) and then enter known IMC ?
Pressure of the guy in the back paying for the trip ?
An accident that should not have happenned.