Greg Goodknight wrote:

"MC" wrote in message
...
Australia is changing/rearranging its' airspace model to more closely
line-up with ICAO and also to be a _very_ close copy of the current
USA system.

Basically there will be a heck of a lot of class-E. (usually bottomed
at FL180, but in some areas down to A085).
Our radar coverage won't change much beyond the current (roughly) 200nm
band along the east and south coasts.


One of the new procedures is called 'VFR on top', whereby an IFR aircraft
can go into VMC at VFR levels and still receive traffic advisories
(but no seperation) from IFR or observed VFR traffic.

As I see it, the procedure seems odd to me, because the requesting IFR
aircraft loses the safety of being seperated by ATC.

But you will be told about that traffic, and because the IFR separation is
not required (it's visual separation!) the airspace is much more flexible.
And you remain in the system as IFR with all those advantages (like not
being dropped when things get busy) and can always request a clearance back
to an IFR altitude.

I've not used it as much as I should. I can think of a couple of times I
should have asked for it when someone's departure was waiting until I
cleared the area. Had I been asked for VFR-on-top the next guy could have
beparted as soon as I got on top of the low stratus....

-Greg

So my questions are ;
Is 'VFR on top' used a lot in the USA ? In the rest of the world ?
What practical advantages are there from a pilots' POV ?


Thanks for all the replies folks.
In Oz we don't have quite the same volume of traffic
(or radar coverage) as that in the USA, and it's
usually not a problem getting the altitude or track
you want.