Flying under IMC

[Peter Bauer]

Hi,
i'm asking myself to make an Instrument Rating or not.
There are some questions to IFR-Pilots :

... when flying under a flight plan (IFR) can i fly routes at my choice ?
e.g. take-off under IMC, enroute 10 min under IFR (clouds), 30 min VFR on
top, descending to my destination under IMC (through cloúds), landing
at destination under VMC (below the lower layer of clouds)

... when reaching IMC after 30 min. VMC ("round trip under VFR") do i have
to file a flight plan (IFR) or am i able to fly only by reference to the
instruments through an e.g. 300 ft Layer of clouds and after that, when
reaching "On Top" fly again under VFR ?

Peter

[Peter Duniho]

"Peter Bauer" > wrote in message
om...
> Hi,
> i'm asking myself to make an Instrument Rating or not.
> There are some questions to IFR-Pilots :
>
> [scenarios about flying in VMC under VFR between IFR segments snipped]

You can switch back and forth between IFR and VFR if you want but you may it
inconvenient, since every time you want to go back to IFR, you need to
obtain the necessary clearance from ATC (assuming not in Class G
airspace...in controlled airspace, you must have an ATC clearance and an IFR
flight plan in order to fly in IMC, even briefly). There is a way to file a
mixed IFR/VFR flight plan, but I've never heard of that being used when you
need IFR at both the departure and arrival ends of the flight.

Typically, if you're flying under IFR, find yourself in VMC and want to take
advantage of that to operate under the flexibility of VFR, you'd get a "VFR
on top" clearance. That's an IFR clearance, and you would still be
operating under IFR, but you usually would get the flexibility of choosing
your routing and altitude as if you were VFR (and in fact would have to fly
the +500' VFR cruising altitudes rather than the even thousands IFR cruising
altitudes).

For example, taking your first scenario, done this way, you'd take off in
IMC, arrive at VMC above the clouds, get a "VFR on top" clearance, fly in
VMC using VFR altitudes and procedures for 30 minutes, and then descend back
to your destination through IMC for the landing, possibly flying a full
instrument approach.

Your flight plan would be for the entire flight, you'd be flying under IFR
for the entire flight, but the time during which you were flying with a "VFR
on top" clearance, you'd be able to get most of the advantage you'd get had
you cancelled IFR and flown VFR for that period.

Something to keep in mind that some new instrument pilots forget: "VFR on
top" does not require that there be IMC below you. It can be used any time
you can maintain VMC. If you're cruising along IFR, but there's not a cloud
for 100 miles and ATC starts vectoring you around or slowing you down or
gives you a hold, often you can use the "VFR on top" clearance to resolve
whatever issue ATC had, and allow yourself to proceed directly to whereever
you were headed.

Basically, when IFR procedures become inconvenient and VMC prevails, "VFR on
top" allows you to practically fly VFR without giving up your IFR clearance.

Pete

[Andrew Gideon]

Peter Duniho wrote:

> the "VFR on top" clearance to resolve
> whatever issue ATC had, and allow yourself to proceed directly to
> whereever you were headed.

Is that likely to work? ATC may, after all, deny the "on top" clearance.

- Andrew

[Nathan Young]

On 28 Jun 2004 12:11:27 -0700, (Peter Bauer)
wrote:

>Hi,
>i'm asking myself to make an Instrument Rating or not.
>There are some questions to IFR-Pilots :
>
>.. when flying under a flight plan (IFR) can i fly routes at my choice ?

You have to submit a route when you file the IFR plan. In flight, you
can request changes to the route but it is nowhere the flexibility of
VFR.

> e.g. take-off under IMC, enroute 10 min under IFR (clouds), 30 min VFR on
> top, descending to my destination under IMC (through cloúds), landing
> at destination under VMC (below the lower layer of clouds)

This is very common and typically would be accomplished entirely on an
IFR flightplan. The exception would be if VMC conditions exist below
the cloud layer at the destination, which would allow a visual
approach, or cancel IFR and complete the flight as VFR.

>.. when reaching IMC after 30 min. VMC ("round trip under VFR") do i have
> to file a flight plan (IFR) or am i able to fly only by reference to the
> instruments through an e.g. 300 ft Layer of clouds and after that, when
> reaching "On Top" fly again under VFR ?

In the States, in class G airspace, you can fly IFR without a
clearance. Fortunately, class G is the exception, and pretty much
everywhere else, a clearance is required to fly IFR.

-Nathan

[Peter Bauer]

>
> You can switch back and forth between IFR and VFR if you want but you may it
> inconvenient, since every time you want to go back to IFR, you need to
> obtain the necessary clearance from ATC (assuming not in Class G
> airspace...in controlled airspace, you must have an ATC clearance and an IFR
> flight plan in order to fly in IMC, even briefly). There is a way to file a
> mixed IFR/VFR flight plan, but I've never heard of that being used when you
> need IFR at both the departure and arrival ends of the flight.


But what ...when descending under VMC into Class G Airspace and then
coming into IMC "wheather" (e.g. fog,..) then i can fly IFR without a
clearance ???
If a second pilot does the same "plan" .... very dangerous, isn't it ?
Nobody knows from each other flying in fog...


> Typically, if you're flying under IFR, find yourself in VMC and want to take
> advantage of that to operate under the flexibility of VFR, you'd get a "VFR
> on top" clearance. That's an IFR clearance, and you would still be
> operating under IFR, but you usually would get the flexibility of choosing
> your routing and altitude as if you were VFR (and in fact would have to fly
> the +500' VFR cruising altitudes rather than the even thousands IFR cruising
> altitudes).

i can really fly VFR under an IFR-Flight Plan ??
But probably with the same "squawk" as under IFR ?
...and then after getting "tired" flying VFR ..changing back to the
initial IFR Flight Plan ? (what is when too far away under VFR flying
from the "filed" Plan ???
Does ATC give me then another "Plan", an "abbreviated" Flight Plan ?


>
> For example, taking your first scenario, done this way, you'd take off in
> IMC, arrive at VMC above the clouds, get a "VFR on top" clearance, fly in
> VMC using VFR altitudes and procedures for 30 minutes, and then descend back
> to your destination through IMC for the landing, possibly flying a full
> instrument approach.
>
> Your flight plan would be for the entire flight, you'd be flying under IFR
> for the entire flight, but the time during which you were flying with a "VFR
> on top" clearance, you'd be able to get most of the advantage you'd get had
> you cancelled IFR and flown VFR for that period.
>
> Something to keep in mind that some new instrument pilots forget: "VFR on
> top" does not require that there be IMC below you. It can be used any time
> you can maintain VMC. If you're cruising along IFR, but there's not a cloud
> for 100 miles and ATC starts vectoring you around or slowing you down or
> gives you a hold, often you can use the "VFR on top" clearance to resolve
> whatever issue ATC had, and allow yourself to proceed directly to whereever
> you were headed.


Well, i haven't known about this......because i'm only an PP-ASEL
without
IFR-Privileges. But the described possibilitites makes it very
interesting getting an IFR-Pilot ;-)


>
> Basically, when IFR procedures become inconvenient and VMC prevails, "VFR on
> top" allows you to practically fly VFR without giving up your IFR clearance.
>
> Pete


Thanks to you...Pete


Peter

[Peter Bauer]

>
> You can switch back and forth between IFR and VFR if you want but you may it
> inconvenient, since every time you want to go back to IFR, you need to
> obtain the necessary clearance from ATC (assuming not in Class G
> airspace...in controlled airspace, you must have an ATC clearance and an IFR
> flight plan in order to fly in IMC, even briefly). There is a way to file a
> mixed IFR/VFR flight plan, but I've never heard of that being used when you
> need IFR at both the departure and arrival ends of the flight.


But what ...when descending under VMC into Class G Airspace and then
coming into IMC "wheather" (e.g. fog,..) then i can fly IFR without a
clearance ???
If a second pilot does the same "plan" .... very dangerous, isn't it ?
Nobody knows from each other flying in fog...


> Typically, if you're flying under IFR, find yourself in VMC and want to take
> advantage of that to operate under the flexibility of VFR, you'd get a "VFR
> on top" clearance. That's an IFR clearance, and you would still be
> operating under IFR, but you usually would get the flexibility of choosing
> your routing and altitude as if you were VFR (and in fact would have to fly
> the +500' VFR cruising altitudes rather than the even thousands IFR cruising
> altitudes).

i can really fly VFR under an IFR-Flight Plan ??
But probably with the same "squawk" as under IFR ?
...and then after getting "tired" flying VFR ..changing back to the
initial IFR Flight Plan ? (what is when too far away under VFR flying
from the "filed" Plan ???
Does ATC give me then another "Plan", an "abbreviated" Flight Plan ?


>
> For example, taking your first scenario, done this way, you'd take off in
> IMC, arrive at VMC above the clouds, get a "VFR on top" clearance, fly in
> VMC using VFR altitudes and procedures for 30 minutes, and then descend back
> to your destination through IMC for the landing, possibly flying a full
> instrument approach.
>
> Your flight plan would be for the entire flight, you'd be flying under IFR
> for the entire flight, but the time during which you were flying with a "VFR
> on top" clearance, you'd be able to get most of the advantage you'd get had
> you cancelled IFR and flown VFR for that period.
>
> Something to keep in mind that some new instrument pilots forget: "VFR on
> top" does not require that there be IMC below you. It can be used any time
> you can maintain VMC. If you're cruising along IFR, but there's not a cloud
> for 100 miles and ATC starts vectoring you around or slowing you down or
> gives you a hold, often you can use the "VFR on top" clearance to resolve
> whatever issue ATC had, and allow yourself to proceed directly to whereever
> you were headed.


Well, i haven't known about this......because i'm only an PP-ASEL
without
IFR-Privileges. But the described possibilitites makes it very
interesting getting an IFR-Pilot ;-)


>
> Basically, when IFR procedures become inconvenient and VMC prevails, "VFR on
> top" allows you to practically fly VFR without giving up your IFR clearance.
>
> Pete


Thanks to you...Pete


Peter

[Teacherjh]

>>
If a second pilot does the same "plan" .... very dangerous, isn't it ?
Nobody knows from each other flying in fog...
<<

Yes. That is the purpose of controlled airspace - to prevent such things by
ensuring that everyone in there under IFR is being separated. Flying IFR in
uncontrolled airspace is not all that prudent, and fortunately not necessary in
most of the US.

Most airports have controlled airspace surrounding them to the ground for the
purpose of instrument approaches.

Jose




--
(for Email, make the obvious changes in my address)

[Ditch]

>Is that likely to work?

I fly IFR into Ontario, California IFR on my run and do it VFR on top as much
as possible. It cuts down on our run time as we fly a more direct route, and
since we are on a schedule it helps a lot.

>ATC may, after all, deny the "on top" clearance.

They can, but unlikely. It frees up the controller to focus on other things.





-John
*You are nothing until you have flown a Douglas, Lockheed, Grumman or North
American*

[Julian Scarfe]

"Peter Bauer" > wrote in message
om...

> .. when flying under a flight plan (IFR) can i fly routes at my choice ?
> e.g. take-off under IMC, enroute 10 min under IFR (clouds), 30 min VFR
on
> top, descending to my destination under IMC (through cloúds),
landing
> at destination under VMC (below the lower layer of clouds)
>
> .. when reaching IMC after 30 min. VMC ("round trip under VFR") do i have
> to file a flight plan (IFR) or am i able to fly only by reference to
the
> instruments through an e.g. 300 ft Layer of clouds and after that,
when
> reaching "On Top" fly again under VFR ?

You do not say where you are flying, Peter. Others have answered on the
assumption that you are flying in the US, I'll give you an answer for
Germany.

The airspace system in Germany is not very different to that in the US, but
there are a couple of differences. Controlled airspace generally starts at
2500 ft agl rather than 1200 ft agl. Flying under IFR in class G is
forbidden in Germany. Thus for an IFR flight, if your destination is not an
IFR airport surrounded by controlled (or class F) airspace, you usually need
to be able to cancel IFR by the minimum instrument altitude which is not
below 2500 ft. This makes IFR flights to VFR airports fairly painful.

To fly under IFR you need a clearance. Pop-up IFR clearances (if you find
IMC on a VFR flight like your second scenario) are troublesome. I've had to
dictate an entire flight plan (including the colour of the dinghy cover) to
a FIS controller to get an IFR pop-up, despite having filed a VFR plan with
almost exactly the same info.

"VFR on top" clearances, as Pete described are not used in Germany (in fact
they're not used outside the US). But you will find that practical IFR
clearances tend to include long direct legs, so it's unusual to be in a
situation where a VFR routing will save you a lot over an IFR one.

So where are you based?

Hope that helps

Julian Scarfe

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
> Is that likely to work? ATC may, after all, deny the "on top" clearance.

As Ditch says, ATC has the authority to deny the clearance, of course. But
since it makes their life easier, I don't know why they would. I have never
been denied a request for a "VFR on top" clearance. Granted, I fly VFR much
more often than IFR, but I just can't see why ATC would ever deny a "VFR on
top" clearance.

Pete

[Peter Duniho]

"Peter Bauer" > wrote in message
om...
> But what ...when descending under VMC into Class G Airspace and then
> coming into IMC "wheather" (e.g. fog,..) then i can fly IFR without a
> clearance ???
> If a second pilot does the same "plan" .... very dangerous, isn't it ?

As Jose says, you can easily avoid other pilots flying IFR in Class G by not
doing it yourself. Airports with instrument approaches also have Class E
surface areas, preventing anyone from flying IFR without a clearance and
flight plan in IMC at those airports. So as long as YOU stick to making
arrivals only through published instrument approaches, you'll avoid any
nut-case trying to do it on their own.

(No offense intended to any nut-cases out there that actually go around
flying IFR without a clearance or flight plan in IMC while in Class G :) ).

> i can really fly VFR under an IFR-Flight Plan ??

Well, sort of. You are still flying IFR (that is, under "instrument flight
rules") while on a "VFR on top" clearance. So you have to comply with
applicable IFR rules, *and* applicable VFR rules. Notably, your cruising
altitude changes to the +500' altitudes, and you are required to maintain
the proper cloud clearances and visibility. But other IFR rules still
apply, like proper notification to ATC of equipment failures, airspeed
changes, reporting points, that sort of thing.

> But probably with the same "squawk" as under IFR ?

Yes...you are still flying IFR, on an IFR flight plan, and maintain the same
squawk code you'd have without the "VFR on top" clearance.

> ..and then after getting "tired" flying VFR ..changing back to the
> initial IFR Flight Plan ? (what is when too far away under VFR flying
> from the "filed" Plan ???

In order to quit the "VFR on top" clearance, if you have left your original
route, you won't get a clearance to return to normal IFR flight until ATC
can arrange a new routing for you from your position. Generally, it's
advisable to stay reasonably close to your planned route, since off-airways
can be challenging to plan for IMC while you're busy actually flying the
plane.

Personally, I make sure I'm back on my planned route before going back to
non-"VFR on top" flight.

> Does ATC give me then another "Plan", an "abbreviated" Flight Plan ?

Yes, basically. If you're not on your planned route, you'll probably get a
vector or "direct" to a navaid to get you back to some place where ATC can
get you back into their system. In my experience, this has always been some
waypoint already on my IFR flight plan...ATC basically just looks to bring
you back to your filed plan, unless you request otherwise.

> Well, i haven't known about this......because i'm only an PP-ASEL
> withoutIFR-Privileges. But the described possibilitites makes it very
> interesting getting an IFR-Pilot ;-)

For what it's worth, there's also a rec.aviation.ifr newsgroup. I don't
follow it because frankly I read too many newsgroups as it is. There are
probably others here who are instrument rated and who don't follow that
newsgroup, but that's really the place to go to find people who are not just
willing, but who are eager to talk about instrument flying.

Pete

[Peter Bauer]

Hi,

i'm based in Germany with a FAA-PPL ASEL.
It's very interesting to read the differences in IFR-Flying in the
States and in Germany. Although the two countries are "ICAO-countries"
they are not
participating in same air work to each other.
Well, i think ...when learning for an IFR-Rating you should know
before what you are allowed to do with it or not after passing it.
I think most "VFR"-Pilots only know about the new ability to fly in
clouds without reference of the ground surface.
It's very interesting for me to know how the real IFR-flight is
working, what problems with ATC you have when flying under IFR, the
change IFR-VFR, and a lot of other things....and that....before
"doing" the Rating.

Thank you all for asking my questions....

Peter

[Newps]

"Andrew Gideon" > wrote in message
online.com...
> Peter Duniho wrote:
>
> > the "VFR on top" clearance to resolve
> > whatever issue ATC had, and allow yourself to proceed directly to
> > whereever you were headed.
>
> Is that likely to work? ATC may, after all, deny the "on top" clearance.

They might in very busy terminal airspace that you are inbound to. They
will be gleeful that you want to remove yourself from the separation pool
otherwise.

[Andrew Gideon]

Ditch wrote:

>>Is that likely to work?
>
> I fly IFR into Ontario, California IFR on my run and do it VFR on top as
> much as possible. It cuts down on our run time as we fly a more direct
> route, and since we are on a schedule it helps a lot.
>
>>ATC may, after all, deny the "on top" clearance.
>
> They can, but unlikely. It frees up the controller to focus on other
> things.
>

That certainly makes sense. But what about when I want to return to (let's
call it) "full IFR". I could be well off my flight plan at that point,
right? It may mean less work in the short term, but possibly more work
long term (for the controller).

Of course, perhaps the controller can hope that this'll be the next guy's
problem <laugh>.

- Andrew

[Julian Scarfe]

"Peter Bauer" > wrote in message
om...

> i'm based in Germany with a FAA-PPL ASEL.
> It's very interesting to read the differences in IFR-Flying in the
> States and in Germany. Although the two countries are "ICAO-countries"
> they are not
> participating in same air work to each other.

If you think Germany and the US are different, try crossing the border into
other European countries. Of all of them the airspace system in Germany is
most like the US, and the UK is probably at the opposite extreme. Here we
have mostly class A and class G, with little between. IFR flight in class G
is something we do every day -- there's not a lot of choice.

Good luck if you choose to do the IR.

Julian

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
> That certainly makes sense. But what about when I want to return to
(let's
> call it) "full IFR". I could be well off my flight plan at that point,
> right? It may mean less work in the short term, but possibly more work
> long term (for the controller).

It's more of a problem for you than the controller. The controller will
only provide a clearance that he is able to provide. If you put yourself
into a position where he's unable to provide you with a new clearance,
that's your problem, not his. He's not obligated to cancel the "VFR on top"
clearance, as far as I know.

In other words, it's more work for YOU, if you make it more work for anyone.
Personally, I recognize the issues of getting back on a non-"VFR on top"
clearance and make sure that when it's time to get back to regular IFR, it's
easy to do.

Pete

[Kai Glaesner]

Julian,

> most like the US, and the UK is probably at the opposite extreme. Here we
> have mostly class A and class G, with little between. IFR flight in class
G
> is something we do every day -- there's not a lot of choice.

IIRC in the UK you have some sort of "poor-mans-IFR" (no pun intended ;-)
called the "IMC" rating, giving you the right to fly under IMC without being
"in-the-system".

Does that thing make it to JAR-FCL?

Best Regards

Kai Glaesner

[Julian Scarfe]

"Kai Glaesner" > wrote in message
...

> IIRC in the UK you have some sort of "poor-mans-IFR" (no pun intended ;-)
> called the "IMC" rating, giving you the right to fly under IMC without
being
> "in-the-system".
>
> Does that thing make it to JAR-FCL?

Still available as a national rating valid for IFR only in the UK. The only
difference from the way it used to be is that it no longer gives credit
towards an IR. However, an FAA IR gives credit towards a JAA IR, and the
instrument time for an IMC rating counts for the time required for an FAA
IR. So we have the screwy situation that the usual "upgrade" path is IMC
rating -> FAA IR -> JAA IR.

Julian Scarfe

[Kai Glaesner]

Julian,

> IR. So we have the screwy situation that the usual "upgrade" path is IMC
> rating -> FAA IR -> JAA IR.

That's what I call "european harmonization".... ;-)

Any estimates available what to spend on an IR (starting from a national
PPL) in the UK? Here in germany they charge you around 13.000 EUR for that.

Best regards

Kai

[Andrew Gideon]

Peter Duniho wrote:

> He's not obligated to cancel the "VFR on
> top" clearance, as far as I know.

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?

- Andrew

[Peter Duniho]

"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

[S Green]

"Ross Younger" > wrote in message
...
> * Kai Glaesner >:
> >IIRC in the UK you have some sort of "poor-mans-IFR" (no pun intended ;-)
> >called the "IMC" rating, giving you the right to fly under IMC without
being
> >"in-the-system".
>
> Yes, it relaxes certain rules from the basic PPL/CPL (minimum flight
> visibility and the requirement to remain in sight of the surface at all
> times), as well as allowing flight under IFR in class D and E airspace.
> (The basic PPL may fly IFR in class F/G; it's just that one must remain
> in flight conditions which are essentially VMC.) However, it doesn't
> change any of the rules about filing flight plans.
>
> >Does that thing make it to JAR-FCL?
>
> It would be nice if it would be recognised...

To be more precise the IMC rating allows the following:-

1. Valid in the UK (and Channel Islands):

o In Classes F and G, to fly VFR in visibility less than 3km (down to
1500m, but 1800m for runway use)

o In Classes D, E, F and G, to fly IFR down to zero visibility,
providing the aircraft is 'legal' for it, in or out of sight of the surface.

o For Controlled Airspace, (including Class A designated as a ConTRol
Zone), to fly Special VFR down to 3km visibility.

[Julian Scarfe]

"Kai Glaesner" > wrote in message
...

> Any estimates available what to spend on an IR (starting from a national
> PPL) in the UK? Here in germany they charge you around 13.000 EUR for
that.

Yes, about EUR 15,000 for a SEP-IR and about EUR 20,000 for an MEP-IR (55
hours training, not including the mandatory ground school). The problem is
that while ICAO specifies 40 hours "instrument time", JAA-FCL specifies 55
hours instrument training by an approved training facility.

I did mine 10 years ago under rules that allowed me to do just 28 hours
(with credit for the IMC rating) in my own aircraft.

Julian

[Frank Ch. Eigler]

duniho wrote:

> [...]
> 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.
> [...]

This has been confusing me since the thread a few weeks ago. I looked through
several reference sources, and cannot find an explanation of the "vfr-on-top"
IFR clearance that implies authorization to depart from the route one was
earlier cleared via. Where may one find this?


- FChE