Thanks Pablo.
In the Stay Alert crew fix mod I adjusted the distances for this exact scenario:
In perfect conditions (clear unfogged day) the small airplanes will be detected 3km away and the big ones 8km away. But with fog (the majority of the time in game) this distance will be reduced for 2/3 or a half. This is yet far better than stock but not uber!
Don't forget that this is for 8km version, using the Stay Alert crew fix.
The 16 km have these values far large: crew detect a Hurricane 5km away in a fogged day!!! I guess that this is a bit uber ,no?