The 'small print' for my UK Permit to Fly aeroplane contains the words:
The Aircraft shall be flown by day and under Visual Flight Rules
The rules are contained in
this handy document for those who have forgotten, or never bothered to learn it in the first place.
Clear of cloud & in sight of the surface - It doesn't specify how far away that surface has to be though, especially if it's the Matterhorn poking through in the distance..
