I often see charts like the one above showing VFR cloud clearance minima. Since the regs list a minimum distance above clouds obviously VFR flights are allowed to fly over clouds. However, it's not clear what kind of clouds one can fly over: only individual smaller clouds, a broken layer or a solid layer. In the US does a pilot under VFR have to maintain a visual reference to the surface?
Yes, it's legal to operate under VFR without any visual reference to the surface. It's called operating VFR over-the-top, not to be confused with VFR-on-top which is an IFR clearance. Over-the-top is defined in 14 CFR 1.1:
Over-the-top means above the layer of clouds or other obscuring phenomena forming the ceiling.
There are some exceptions and restrictions, though (this list may not be complete):
- Recreational pilots must have visual reference to the surface (14 CFR 61.101)
- So must sport pilots (14 CFR 61.315)
- So must student pilots (14 CFR 61.89)
- If the pilot has a foreign-based private license then all restrictions on the foreign license apply, which could prevent VFR over-the-top (14 CFR 61.75)
- Large, turbine or fractionally owned aircraft must be equipped as for IFR (14 CFR 91.507)
- If flying for an airline or other operator, their OpSpecs must allow it