"VFR on top" clearance. . .

[mar]

Let me think...

If you are VFR on top how are you going to navigate with no VOR? Plus I thought once you accept a VFR on top clearance you could no longer fly in IMC conditions so you really aren't IFR persay. I just really don't understand the benefit, seems it would be better to either stay IFR or cancel completely and refile if needed to get down.

...ok, ok, I can see you're gonna make me work for this one. I was just hoping you'd take my word for it, but let me think of an example...

Let's say you're in a training situation and you want to do some airwork. The airport is IFR, so you file a flight plan from airport XYZ to ABC VOR, when you contact departure you explain you're in VMC and would like to manuever in a block of airspace and then return for the ILS at airport XYZ.

Since the primary purpose of ATC is to separate IFR aircraft from other IFR aircraft, you get *some* separation service (probably not in the "block" but at least that airspace is set aside and he knows about you) and then when you're ready to return all it takes is a call to report the latest ATIS and a request for the ILS. You already have a squawk, he already has a flight data strip, radar contact is already established. All you need is a vector.

In an enroute scenario, your airway might actually be defined by an NDB. Don't laugh. They're out there.

Or maybe there's icing at your assigned altitude and you want to climb out of it but you don't want to cancel your flight plan because you know you'll need it later on....

There are just dozens of scenarios that you can run into. It's worth knowing about it.

Good luck.

 

[A Squared]

Plus I thought once you accept a VFR on top clearance you could no longer fly in IMC conditions so you really aren't IFR persay.

If you're on a VFR on top clearence, you'd better believe that you are IFR, You are flying by Instrument Flight Rules (that's what IFR means, IFR isn't a weather condition) The only difference is, you can pick your own altitude, you fly at VFR altitudes and you must comply with VFR cloud clearences, other than that, *all* of the instrument flight rules are in effect and you are obligated to comply with them.

 

[Amish RakeFight]

AS I understand it, even though you're VFR-On-Top complying with IFR and VFR rules, ATC no longer provides the same traffic separation.

 

[A Squared]

AS I understand it, even though you're VFR-On-Top complying with IFR and VFR rules, ATC no longer provides the same traffic separation.

Correct. For purposes of traffic seperation see and avoid applies

 

[81Horse]

SilverFlyer, it seemed like the scenario you were asking about was something like: "Cleared to ABC, report reaching VFR conditions on top ... if not on top at/by xx00, maintain xx00 and advise ..."

In other words, a clearance designed to be cancelled as soon as you reach VFR conditions. So of course, the controllers are just waiting on you to break out and cancel.

And the others here are quite correct -- VFR-on-top is an IFR clearance, with instructions to maintain VFR conditions in lieu of a hard altitude.

 

[727gm]

You may also want to stay out of the clouds UNDER an overcast that the normal enroute clearance would put you in, if you are flying an aircraft without anti/de-icing equipment. Nothing about VFR-on-top says you have to be ABOVE the clouds. VFR-on top allows you to stay IFR, without trying to work out a new clearance while enroute.

 

[C-141/C-5]

WHY DON"T YOU JUST FILE A RADIAL DME OF A VORTAC?? You stay on an IFR flight plan and make your own straight line point. If you have an IFR rated GPS then i would just file direct.

VFR on top makes no sense to me. You don't have another set of eyes helping you clear and isn't VFR flying using pilotage and dead reckoning??? Kind of hard to do when you can't see the ground.

 

[81Horse]

VFR on top makes no sense to me.

VFR-on-top takes the place of a hard altitude -- what's the mystery? You retain your IFR clearance and routing, while maintaining a VFR altitude (and VMC). It can be a handy way to bypass or work around other IFR traffic -- which is no doubt the reason it came into being to start with.

 

[727gm]

WHY DON"T YOU JUST FILE A RADIAL DME OF A VORTAC??

Many light aircraft do not have DME installed(or GPS for that matter).

VFR-on-Top is an IFR clearance. No need to see the ground, and no need for dead reckoning, radio navigation is normally used.

 

[mar]

So don't use it.

VFR on top makes no sense to me.

I thought Asquared gave a good example of when it comes in handy.

Nobody is forcing you to request this service.

Just because you don't have a use for it doesn't make it senseless.