Sorry, maybe I was not exact enough.
When in LVO conditions RVR less than 400m, is it mandatory to call airborne after departure, as it is mandatory ( what I know for sure ) to make after landing a "runway vacated" call, when on the taxiway, behind the crossing lights..
Departure call is mandatory in Germany. But I mean a call to the tower before switching to Radar.
is it too special ? Maybe i should write an email to DFS about it
DFS = Deutsche Flugsicherung = ATC Germany