"Andrew Gideon" wrote in message
online.com...
Ah, I'd not thought about it that way. It's not a comforting thought:
that
I could be above a ceiling and unable to return to full IFR. There's no
regulatory requirement that would force a controller to let a
VFR-on-top-er
back into the system?

Not as far as I know. But, it's not an issue of the controller "letting you
back in the system". You ARE "in the system". You've just chosen to apply
VFR rules to your IFR flight, in addition to the usual IFR rules.

Also, remember that the previous concern was regarding when you fly way off
your route using the "VFR on top" rules. I wouldn't say that's an advisable
use of "VFR on top", for the very reason that it might be more difficult to
get back on route.

Now, all that said, just as I've never had any trouble asking for "VFR on
top", I've also never had any trouble cancelling "VFR on top". I stay
reasonably close to my originally filed route, or I plan my deviation so
that I have a good nav signal back to my route, and acceptable terrain
clearance.

I suppose it's possible you could ask for "VFR on top" to a particular
waypoint, giving ATC some prior notice of where you plan to return to
conventional IFR flight. That might give you some reassurance that you
wouldn't lose your status as a non-"VFR on top" flight.

But honestly, I can't think of any reason ATC wouldn't cancel "VFR on top"
for you. You never lose your status as an IFR flight, so it seems to me
that the worst that could happen is that a) you remain responsible for your
own off-airway navigation for some time (if you're out of radar coverage,
for example) or b) ATC vectors you in an inconvenient way for a little
while, as they work you back into their normal traffic flow. You still have
a valid IFR clearance and are still "in the system".

I didn't mean to scare anyone off of "VFR on top" by my comment. It was
more along the lines of "I'm not aware of any regulatory requirement that
ATC grant ANY request by a pilot". ATC won't grant a request that they
cannot accomodate with respect to the other traffic, but otherwise they
generally allow pretty much whatever you ask for.

Pete