I have flown VFR Over the top many times on longer nav trips from and to Belgium. It's only a term, no need for a license. VFR rules state a vertical and/or horizontal clearance from clouds and a visibility. Only G airspace below 3000ft needs you to have ground surface in sight.
So imagine taking off from EBAW with no clouds and great visibility; you climb south to FL65, and abeam the french border the clouds are building in an overcast layer between 2000 and 3000ft. You loose sight of ground, but when preparing your nav, you found that the destination aerodrome was cavok and you know the cloud layer will dissappear again going further south towards the destination. You did a takeoff in VFR conditions, and you can land in VFR conditions. The flight itself above the clouds is also in legal VFR conditions. Technically of course there was no way to navigate with your visual charts since you had no sight of ground marks. This is VFR OTT. No problem to fly this with GPS and VOR, but one can ask the question, what in case of engine failure during cruise over the overcast layer?
VFR on top is not the same as VFR over the top. An aircraft flying IFR in VMC conditions can in certain airspaces request VFR on top, so they can choose altitudes themselves according to VFR rules, and navigate as a VFR aircraft, thus avoiding IFR routings. If you are a PPL without IFR license, you cannot fly VFR on top.
Last edited by Piper19; 21st Jul 2013 at 23:14.