IFR Clearance VFR-On-Top (several questions)

[jrh]

So tonight the weather sort of sucked, but at least it was warm enough to not worry about ice in the clouds. I was scheduled to do some instrument training with a student pilot, so I thought it would be a good situation to get an IFR to VFR-on-top clearance. Honestly, I've never used one of these clearances before, only read about them, but I thought I knew what I was doing.

I *thought* the main advantage to a VFR-on-top clearance was the ability to change altitudes and headings at the pilot's discretion, yet not have to get two seperate IFR clearances, one to climb and one to descend through clouds. Even though we were doing instrument training, I wanted the freedom to move around a lot without bugging the controller.

A few things confused me with this flight though. Let me list a few of the details:

Our clearance read:

Cleared to the Lincoln airport via radar vectors, maintain 4000, expect VFR-on-top 10 minutes after departure, departure frequency...blah blah blah

My question here is, shouldn't the clearance have contained a set of instructions for if we were not able to reach VFR conditions by 4000? In this case, what should I have done if I'd lost comms while in the clouds at 4000?


Next, another aircraft reported tops at 4300 during his descent. We heard this report just after being cleared for takeoff. The departure controller then instructed us to maintain 5000 and report reaching VFR.

We were in and out of the clouds at 5000, so he cleared us to 6000 and again told us to report reaching VFR. I took this to mean report when 1000 feet above the tops, as per the VFR cloud clearance criteria from 91.155 (1000 above, 500 below, etc.)

As we passed through 5,400 the controller queried us about if we'd reached VFR yet, since I'd told him we were in and out at 5k. It sounded as though he took "VFR" to mean "out of the clouds." Since the clouds were sloping down and away from us at that point, I told him we could maintain VFR at 6k. He told us to resume own navigation, remain within 20 miles of Lincoln, and maintain VFR-on-top at 6000.

Since I was a bit confused about the specifics at this point, I asked him to confirm we could operate VFR and change altitudes at our discretion, at or above 6000. He responded by saying he could give us a block altitude if we wanted, so I asked for 6000 block 8000, and he cleared us for that.

So my question here is, what does "VFR" mean to a controller versus a pilot in this case, and with regard to the altitude, was the controller confused about what I was allowed to do, or does a VFR-on-top clearance actually restrict the pilot to an assigned altitude unless otherwise cleared by the controller? The AIM says the pilot can fly any VFR altitude but should advise the controller prior to any altitude changes. After getting the block altitude we went up and down several times without advising the controller and he never seemed to care.

Finally, my last question is, how does a lost comm situation apply when operating VFR-on-top? The nearest hole in the clouds was about 100 or 150 miles away, so even though we had the fuel to get there, it would have been really inconvenient if we'd lost comms and had to go all the way out there to get back under the clouds, even though an ILS was directly underneath us. Had we lost comms, honestly I would have just squawked 7600 and shot the ILS, and it's a slow enough airport I doubt anyone would have cared, but I'm not sure what the technically, legally correct thing to do would have been.

Sorry for the long post. Just very curious after tonight. Learn something new every day, right?

 

[MidlifeFlyer]

Our clearance read:

Cleared to the Lincoln airport via radar vectors, maintain 4000, expect VFR-on-top 10 minutes after departure, departure frequency...blah blah blah

My question here is, shouldn't the clearance have contained a set of instructions for if we were not able to reach VFR conditions by 4000? In this case, what should I have done if I'd lost comms while in the clouds at 4000?

Not necessarily. The language you are looking for is part of the VFR On Top clearance. But at the point you are talking about, all you were told was to "expect" one. For lost comms, I'd say that your "expected" VFR On Top takes the same role as any other "expected" clearance, with two exceptions: if you reached VFR, you are supposed to stay VFR (part of the lost comm rules) and if you did not reach VFR, you are obviously unable to follow the expected clearance.

As we passed through 5,400 the controller queried us about if we'd reached VFR yet, since I'd told him we were in and out at 5k. It sounded as though he took "VFR" to mean "out of the clouds." Since the clouds were sloping down and away from us at that point, I told him we could maintain VFR at 6k. He told us to resume own navigation, remain within 20 miles of Lincoln, and maintain VFR-on-top at 6000.

Since I was a bit confused about the specifics at this point, I asked him to confirm we could operate VFR and change altitudes at our discretion, at or above 6000. He responded by saying he could give us a block altitude if we wanted, so I asked for 6000 block 8000, and he cleared us for that.

Given the in-and-out of the clouds nature of the communications, it sounds like the controller ultimately decided that VFR On-Top was not appropriate and that a block altitude clearance made more sense to ATC.

Also, assuming that the block was not as separate block altitude clearance negating the On-Top clearance (I can't tell), the AIM ATC Handbook descriptions of the clearance contemplate that there may be altitude restrictions involved.

So my question here is, what does "VFR" mean to a controller versus a pilot in this case, and with regard to the altitude, was the controller confused about what I was allowed to do, or does a VFR-on-top clearance actually restrict the pilot to an assigned altitude unless otherwise cleared by the controller?

I'm not sure that it has to mean anything to specific to the controller, other than "the visibility and cloud clearances that apply to this pilot, whatever those are." Your request and acceptance of an On-Top clearance transfer responsibility for maintaining the proper visibility and cloud clearances to you. To the controller,

The AIM says the pilot can fly any VFR altitude but should advise the controller prior to any altitude changes. After getting the block altitude we went up and down several times without advising the controller and he never seemed to care.

If this was a block altitude assignment rather than an altitude restriction in the On-Top clearance, there would be no reporting requirement. If it was still in the context of the On-Top clearance, the requirement that you advise of the changes doesn't require ATC to care about them. How much they acre is probably related more to what other traffic is in the immediate area.

Finally, my last question is, how does a lost comm situation apply when operating VFR-on-top?

The lost comm rule is pretty specific on this: "If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable."

If you are in a scenario in which you can't - fuel doesn't allow for it, then I'd follow the same rules or procedures I'd follow if the loss occurred in IMC (which is, of course an entire topic onto itself).

 

[CoffeeIcePapers]

I have tried VFR on top to do manuevers and didn't have much luck either. The controllers didn't seem to like me doing it for manuevers and didn't seem very helpful. I think they prefer it just to go from point a to point b.

 

[nosehair]

Yep, VFR altitude A to B - that's what it means to a controller. You want to ask for a block altitude within a pie of radials, such as: 4,000 to 6,000 between the 270 and 330 radials from 5 to 15 miles. Then they know what you're talking about.

plus, you don't hafta watch out for cloud clearances. That airspace is yours.

 

[tgrayson]

You want to ask for a block altitude within a pie of radials, such as: 4,000 to 6,000 between the 270 and 330 radials from 5 to 15 miles. Then they know what you're talking about.

plus, you don't hafta watch out for cloud clearances. That airspace is yours.

That's what I do. Never been denied it, although they sometimes change the radials on me, as traffic necessitates.

 

[flyTotheSky]

jrh,

I'm curious, how did you indicate on your flight plan that you wanted VFR-on-top? Did you just throw that into your remarks section?

 

[PanJet]

Yep, VFR altitude A to B - that's what it means to a controller. You want to ask for a block altitude within a pie of radials, such as: 4,000 to 6,000 between the 270 and 330 radials from 5 to 15 miles. Then they know what you're talking about.

plus, you don't hafta watch out for cloud clearances. That airspace is yours.

That's what I've done as well. It really makes you good at situational awareness IMHO if you're in and out of the clouds and it's white all over and you're trying to keep yourself contained in a fairly small block.

 

[milski]

jrh,

I'm curious, how did you indicate on your flight plan that you wanted VFR-on-top? Did you just throw that into your remarks section?

You can also put OTP or OTP/55 (or any other appropriate altitude) in the altitude block of the flight plan. YMMV if you're trying to do that when filing with FSS.

DUAT used to have some help on all the things that you can enter in the altitude field but I cannot find it right now.

Edit: It was duats, actually. I cannot get the link but here is the text:


Enter cruising altitude as a 2 or 3 digit number representing hundreds of feet, with a minimum altitude of 1,000 feet. For example, enter 10 for 1,000 feet, 120 for 12,000 feet, 390 for FL390.
You may also use one of the following additional formats:

• OTP (for an IFR flight operating VFR on top)
• OTP followed by a slash and a 2 or 3 digit number (i.e., OTP/120)
• ABV followed by a slash and a 2 or 3 digit number (i.e., ABV/120)
• VFR (for a VFR flight, no specified altitude)
• VFR followed by a slash and a 2 or 3 digit number (i.e., VFR/125)
• A block altitude may be entered using a low limit 2 or 3 digit number followed by a B, followed by a high limit 2 or 3 digit number. The low limit must be lower than the high limit. For example, enter 120B160 for 12,000 through 16,000 feet.

 

[jrh]

Yep, VFR altitude A to B - that's what it means to a controller. You want to ask for a block altitude within a pie of radials, such as: 4,000 to 6,000 between the 270 and 330 radials from 5 to 15 miles. Then they know what you're talking about.

plus, you don't hafta watch out for cloud clearances. That airspace is yours.

Good call. That's what I'll do in the future I think.

Now my question though, is when would a VFR-on-top clearance be to my advantage? When would it be in my best interest to use a VFR-on-top clearance instead of a standard IFR clearance? It seems as though having to maintain VFR only adds restrictions to the flight, not freedom.

 

[jrh]

jrh,

I'm curious, how did you indicate on your flight plan that you wanted VFR-on-top? Did you just throw that into your remarks section?

I never filed a flight plan. I just called Clearance Delivery and told them that I'd like an IFR clearance to VFR-on-top for a training flight and we could use whatever altitude and sector of their airspace they wanted, wherever would be easiest for them.

 

[milski]

Good call. That's what I'll do in the future I think.

Now my question though, is when would a VFR-on-top clearance be to my advantage? When would it be in my best interest to use a VFR-on-top clearance instead of a standard IFR clearance? It seems as though having to maintain VFR only adds restrictions to the flight, not freedom.

Altitude is at your discretion, so you may be able to get something that the controller would not give to you. Although I'm not sure how realistic or safe that would be. I've seen it used here in the west to fly below the MEA when there's a possibility of icing at MEA or above but that's not legal.
I use it when I have to do VFR work but there is a think layer over the airport - I just ask CD for a climb to VFR-on-top and cancel once I'm high enough above the clouds.

 

[MidlifeFlyer]

Altitude is at your discretion, so you may be able to get something that the controller would not give to you.

That's really the only advantage over straigh IFR I could think of also. The controller might be unwilling to give you an IFR block altitude where the controller remains responsible for such things as separation, but perfectly willing to give you a VFR On-Top clearance where he can effectively treat you as a VFR aircraft for airspace and separation purposes.

The other advantage I can think of is an advantage over being VFR. If you are VFR over the top and clouds increase around you or it's overcast at your destination, you need to negotiate an IFR clearance. VFR on-top, you are already on an IFR clearance, so it just takes saying you can no longer maintain VFR on-top conditions to get fully back in the system.

 

[milski]

The other advantage I can think of is an advantage over being VFR. If you are VFR over the top and clouds increase around you or it's overcast at your destination, you need to negotiate an IFR clearance. VFR on-top, you are already on an IFR clearance, so it just takes saying you can no longer maintain VFR on-top conditions to get fully back in the system.

I think we completely agree on that one, but that just brings us back to the question why would you want to be VFR instead of IFR? The usual reasons like not waiting for clearance/release don't really apply since you are waiting for the OTP clearance.

 

[Flyin_bryan]

.... you need to negotiate an IFR clearance....

hahah if you ever want to fly around phoenix IFR you will definately need negotiation skills.

here is what the FAA tells controllers to do Vfr ON TOP! it is recent as of feb 2008!
http://www2.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/ATC/Chp7/atc0703.html

I dont see any use of vfr on top....

maybe the controller is more apt to issue a direct clearance if you are vfr on top? just throwing that out there...

 

[MidlifeFlyer]

hahah if you ever want to fly around phoenix IFR you will definately need negotiation skills.

. That's not the only place. But there's a difference between negotiating the contents of a clearance and whether ATC can just say, "Sorry. Go away." Hard for them to do that VFR On-Top since you are already on an IFR clearance.

 

[MidlifeFlyer]

I think we completely agree on that one, but that just brings us back to the question why would you want to be VFR instead of IFR? The usual reasons like not waiting for clearance/release don't really apply since you are waiting for the OTP clearance.

Maybe for some of the same reasons why some people like to be VFR on a long cross country with no flight following, listening to an mp3 player with the comm on 121.5 just in case.

Severe clear enroute. More leeway in altitude, maybe more leeway in heading (I'd ask, but ATC probably would care - you're at a VFR altitude at least 500' above/below IFR traffic). Maybe a small diversion for sightseeing.

But IMC at the destination - a busy place where you might not be able to get that pop-up.

I could see it.

 

[aerospacepilot]

I just want to clarify.

I am from California where we often get a fog layer from about 1,000 to 2,000ft, and it is severe clear above. My options are to get an IFR clearance and cancel when VFR, get an IFR to VFR on top clearance and cancel when VFR, or keep the IFR to VFR on top clearance while VFR on top.

My questions are about keeping the IFR to VFR on top clearance while VFR on top. If you are VFR on top, can you just maneuver as you please, or is this clearance designed for you to stay on an IFR airway?

If I can't maneuver as I please, can I just ask for a block of airspace (say 270 to 320 radial at 5 to 15nm, or something like that)?

Also, Nosehair mentioned "you don't have to worry about cloud clearance, that airpsace is yours", Is he referring to a block of airspace when VFR on top, or when strictly IFR and you get a block of airspace?

Finally, when I am on an IFR to VFR on top clearance, do I have to stay clear of bravo airspace? My home airport is about 6 miles from SFO, so I am surrounded by bravo airspace. If I take off, get VFR on top, and the airway I am on at the altitude I select goes through bravo airspace, is this legal? Or do I specifically have to request, and hear "Cleared through class bravo airspace" like when I am normally VFR.

Thanks.

 

[milski]

VFR-on-top is closer to normal IFR than being VFR. You get to chose your altitude and you don't get traffic separation services but that's about it. You're still required to comply with IFR rules like following your assigned route, heading etc.

If you need to do some airwork on top: getting an IFR clearance or VFR-on-top is about the same, VFR-on-top around here is a bit easier since you don't have to file but can just call CD and ask for it. I'm not sure if that's a local thing or not. Once above the clouds, IFR or VFR-on-top, you need to ask for a block of airspace which is what nosehair describes (between radials, etc.). When you're done, just ask for your approach clearance. If you cancel, you'll need either to get a pop-up to get back or have another flight plan on file and get the clearance in the air.

Getting a clearance in the air can be slow sometimes, if approach is busy but if they're busy enough for that they probably will be busy enough to give you a block of airspace too.

I would try each option a few times or ask someone with more experience in your local area what works best with this particular controllers.