Is it possible to switch from VFR to IFR and back?

Ron Garret writes:

Because ATC only provides separation from other airplanes. It does not
provide separation from terrain.

If you know your position and altitude, charts will provide you with
separation from terrain. There are probably moving-map systems that
will do the same, although I'm not personally familiar with them (it's
certainly feasible to a large extent).

Also, with VFR into IMC situations you often don't have contact with ATC.

You call them when you see the clouds or fog coming.

So you have to get out your chart, try to figure out where you are
(not all planes have moving map GPS), find the right frequency,
dial it in, call them up, wait for a response ... and all the time
you have to fly the plane without being able to see where you're going.

If I'm flying the plane, I'll already know where I am based on
instruments, irrespective of weather conditions. I'm not going to
start looking at the chart and instruments only as I approach the IMC.

Additionally, I'll avoid aircraft that do not appear to have
instrumentation adequate to make IFR flight safe and reliable (in
addition to legal).

It's not so easy in real life as it might appear in a sim.

Maybe. How much of it have you done in a sim? I wouldn't call
instrument flight in a sim easy--most sim pilots don't know how to do
it.

And what will you do if your GPS fails?

Since I'll already know the nearest VORs and I'll be tuned to them, I
can go with that. I often do, anyway, as it's sometimes easier than
fooling with the GPS.

However, if all radio navaids fail, I'm in a bit more of a quandry, as
I have very little experience so far with dead reckoning.
Fortunately, it's relatively unlikely that I would have a total
failure of all navaids at the same time that I happen to get stuck in
IMC. And, by definition, if you have no instruments, you cannot fly
IFR.

No. ATC does not provide terrain separation.

I can provide terrain separation myself. In most cases I will already
be thousands of feet above the highest terrain in the area, out of
sheer prudence, and I have charts and navigational equipment to tell
me where I am and how high the terrain below happens to be. I only
need ATC for separation from other aircraft (TCAS helps in this
respect, but I'm assuming I wouldn't have that onboard, and it's not
100% reliable). Hopefully I'll have a radar altimeter, too, although
it's only useful in certain situations.

Those are all big IFs.

That depends on your personal policies as a pilot. If you routinely
make use of instruments to verify your position, you'll already know
where you are if you lose visual contact with the outside world.
You'll just have to be a bit more careful since you won't be able to
double-check anything visually. And you'll need ATC to help you stay
clear of other aircraft.

Sure. But you keep switching the topic back and forth between "when you
approach IMC" and when you are IN IMC. Those are two very different
circumstances.

Visually, yes. But depending on how much you routinely use your
instruments, it might not be that much different in other ways.

I might well look for landmarks out the window in good weather. But
that would not prevent me from keeping track of a VOR or two, and
looking at the GPS display or EHSI occasionally to make sure that all
information sources agree on my position. If I see unavoidable IMC
approaching, I call ATC for separation services, and I watch my
instruments more carefully.

One of the things I like about aviation is that it _is_ possible to
fly without any external visibility at all (excluding landing and
take-off, which are special circumstances). All you need is a few
instruments, a couple of charts, and knowledge of how to use them. I
find it fascinating that I can fly for hours with nothing but fog out
the window, then descend below the weather and see a runway directly
ahead of me, _exactly where the instruments and charts promised it
would be_. It is very reassuring. It proves that if you follow the
rules, and you are careful and diligent, and you know your procedures,
you can always find your way home. Ultimately the only thing you have
to worry about is other aircraft ... and that's where ATC comes into
play.

The major differences a 1) in IMC you cannot rely on your peripheral
vision.

If you are flying with instruments, you're not relying on peripheral
vision, either.

If you are flying with instruments, visual contact with the outside
world is only one of several sources of information. It helps you to
make sure that all is well, but if it abruptly becomes unavailable,
you still know exactly where you are, if you know how to use your
instruments.

In anything other than the severest of clear weather all the way to
the horizon, in the daytime, I'd be nervous relying on visual cues
alone. If it were required for a test, I could do it, but left to my
own devices, I'd look for confirmation from instruments and charts.
Mountains and rivers tend to look the same after a while; I want to
know if that twisty little river ahead really is the one that I think
it is before I try to follow it home.

This makes a much bigger difference than you might imagine (and
you can't experience it in simulation unless you have a lot of
monitors).

I can "turn my head" in a sim, but it is true that visibilty is in
most ways much more limited than in real life (although I can look
directly backwards in the sim, whereas the aircraft would block much
of my view in real life).

2) approach to landing must be done in a much more stylized
and pre-planned way in order to avoid terrain that you can't see.

That's how I land already. I consider a purely visual landing to be
sloppy. I always check the instruments to see if I'm really at the
altitude I appear to be at, if I'm really aligned as I should be, and
so on. Even in perfect weather, I may still be tuned to the ILS for a
straight-in approach, just to make sure that my glide path and
alignment agree with the instruments.

Additionally, I always try to navigate in a way and plan ahead in a
way that allows me a straight-in approach. I'll fly a pattern if I
have to, but otherwise straight in is preferable. Even for flying a
pattern, I'll check instruments.

3) if you don't have a moving-map GPS you have to twiddle a lot
of knobs in the right way at the right time, which adds to your
workload.

Yes, but planning ahead seems to help a little. It makes me nervous
if I don't have at least a VOR or beacon or something that I can use
to double-check that I really am where I think I am, no matter how
familiar the view out the window might be.

I like to be sure that the little airstrip I see up ahead really is
the airstrip I'm looking for. I'm especially vigilant about this
because I understand that airports are hard to recognize in real life,
even though they are already hard to recognize in the sim.

The combination of all three of these factors makes for a very different
experience.

If one flies purely visually and is suddenly thrust into a situation
where visual information is unavailable, I can see how panic would set
in. But if one is already scanning instruments with an awareness of
one's position derived therefrom, a sudden transition into low
visibility should be far less stressful.

Some pilots are willing to fly aircraft that don't provide the minimum
necessary for instrument flight, but I don't think I'd be very
sanguine about trying that myself, no matter how great the weather
might seem. I spend a lot of time thinking "what if?"

--
Transpose mxsmanic and gmail to reach me by e-mail.

"Mxsmanic" wrote

I can provide terrain separation myself.

You always have separation from terrain, as long as the legs on your desk don't
collapse.

You fly a computer, man. Get over yourself.
--
Jim in NC

In article ,
Mxsmanic wrote:

The major differences a 1) in IMC you cannot rely on your peripheral
vision.

If you are flying with instruments, you're not relying on peripheral
vision, either.

You'd be surprised.

This makes a much bigger difference than you might imagine (and
you can't experience it in simulation unless you have a lot of
monitors).

I can "turn my head" in a sim

Not the same thing at all I'm afraid.


Yes, but planning ahead seems to help a little.

Indeed.

The combination of all three of these factors makes for a very different
experience.

If one flies purely visually and is suddenly thrust into a situation
where visual information is unavailable, I can see how panic would set
in. But if one is already scanning instruments with an awareness of
one's position derived therefrom, a sudden transition into low
visibility should be far less stressful.

Less stressful to be sure. But you'd be amazed how different it can be
if you really can't see out the window and your (real not simulated)
life is on the line.

Some pilots are willing to fly aircraft that don't provide the minimum
necessary for instrument flight, but I don't think I'd be very
sanguine about trying that myself, no matter how great the weather
might seem. I spend a lot of time thinking "what if?"

Southern California in the summer is pretty safe for VFR flight.

rg

Ron Garret writes:

You'd be surprised.

I'd be in danger. If there's nothing but fog outside the windows, how
is peripheral vision going to help me with the instruments? Which
instruments are in my peripheral vision?

Less stressful to be sure. But you'd be amazed how different it can be
if you really can't see out the window and your (real not simulated)
life is on the line.

No, I would not be amazed. But I would try to be calm. Pilots die
when they cannot remain calm.

Sometimes, when listening to CVR recordings, I notice that the pilots
who ultimately survive sound a lot calmer than the ones who don't,
even in situations of equivalent risk. Transcripts show the same
thing.

Southern California in the summer is pretty safe for VFR flight.

That's one reason why I fly there in the sim, although much of it is
just the fact that I'm familiar with it. Arizona is similar. If I
need a challenge, I move up near Seattle. If I need a nap, I visit
the Great Plains in clear weather.

--
Transpose mxsmanic and gmail to reach me by e-mail.

In article ,
Mxsmanic wrote:

Ron Garret writes:

You'd be surprised.

I'd be in danger. If there's nothing but fog outside the windows, how
is peripheral vision going to help me with the instruments? Which
instruments are in my peripheral vision?

You are cementing your reputation for being deliberately obtuse. I said
nothing about instruments being in your peripheral vision.

Less stressful to be sure. But you'd be amazed how different it can be
if you really can't see out the window and your (real not simulated)
life is on the line.

No, I would not be amazed.

Don't be so sure. If you are ever in Southern California look me up and
we can put it the test.

rg

Ron Garret writes:

You are cementing your reputation for being deliberately obtuse. I said
nothing about instruments being in your peripheral vision.

Well, then, explain how peripheral vision helps with instrument
flight. By definition, instrument flight involves only instruments.

Don't be so sure. If you are ever in Southern California look me up and
we can put it the test.

I've surprised people before. Most people assume that others are like
themselves, and that's a dangerous assumption.

--
Transpose mxsmanic and gmail to reach me by e-mail.

In article ,
Mxsmanic wrote:

Ron Garret writes:

You are cementing your reputation for being deliberately obtuse. I said
nothing about instruments being in your peripheral vision.

Well, then, explain how peripheral vision helps with instrument
flight. By definition, instrument flight involves only instruments.

You may define it that way, but reality is not bound by your definition.

But your real problem is that you have discarded the context of the
conversation. (You do this a lot, and it's very annoying.) The context
in this case was that you are flying by reference to instruments in
non-IMC conditions. In such cases you get a lot of information from
your peripheral vision. In particular, in VMC you can tell if the plane
is still right-side-up even if your gaze is fixed on the panel. More
precisely, in VMC you CAN'T NOT TELL (parse that carefully) if the plane
is right-side up even if your gaze is fixed on the panel. The
processing of the information in your peripheral vision is done
subconsciously. If the plane starts to bank you can't help but notice.
This is the reason hoods are used for instrument training. (BTW, even
under a hood there are subtle sensory cues when you are in VMC that go
away in real IMC, like the ambient lighting or shadows moving across
your lap, that give you clues about your orientation.)

In the clouds all that goes completely away. If the plane starts to
bank there are no sensory cues at all that this is happening until the
bank becomes extremely, often unrecoverably, severe.

"No problem" you say, "I just keep my wings level by looking at the AI."
And yes, that true. But the first thing you will notice in reality is
that the AI gives you much coarser information than your peripheral
vision does. Again, this is hard to appreciate unless you actually
experience it (and you cannot experience it in your typical sim because
there is no peripheral visual stimulation). So you will quickly realize
that you have to pay a lot more attention to keep the wings level using
the AI than you did using your peripheral vision. But now you have
other things to worry about. It is not enough to keep the wings level,
you have to also keep the plane heading in the right direction. So you
have to move your gaze from the AI to the DG. While your gaze is
averted you are flying totally blind. Your fovea is not large enough to
fixate simultaneously on the AI and the DG (at least not in a real
plane) so you have to remember to look back at the AI.

OK, still no problem. So you look at the DG briefly, then come back to
the AI. But now you have to call ATC. To do that you have to find the
frequency on your chart. To do that you have to look away from the AI
again and look at the chart. Once again you are flying blind. But
reading a chart is much harder than reading a DG. You have to hunt
around to find the right place. Maybe you have to refold it. Maybe you
have to get out a flashlight (because you've just flown into a cloud and
it's now much darker than it was when you began). Suddenly you realize
that you haven't looked at the AI in a while. You glance up and it's
flopped over onto its side. You move the yoke to level the wings, and
try to calm down because you have just come close to death. You look at
the DG and find that you are off course because of the inadvertent bank.
You correct. Then you look down at the chart again to try again to find
the right ATC frequency to call.

By now several minutes have elapsed and you are no longer sure exactly
where you are (assuming you don't have a moving map GPS -- those gadgets
make life a whole lot easier). You were flying on instruments before
you flew into the cloud so you've already got your VORs tuned in, but
now you have to twiddle the OBS to find your cross-radial. Once again
you have to take your eyes away from the AI. You twiddle the knob and
center the needle. Back to the AI, then you have to look down at your
chart again to figure out where you actually are based on that
information.

Now... how long has it been since you looked at the altimeter? Oh ****,
in all this time you suddenly realize you've lost 2000 feet! The threat
of actual real-life death looms again as you realize that you are no
longer above the terrain. Where exactly are you? You still haven't
figured that out yet. OK, no problem, just push in the throttle and
climb. Look at the chart again...

Now you're starting to get a little freaked out because in this game if
you lose you can't just hit the reset button. Have you remembered to
apply right rudder? Are you watching your airspeed? Where the hell are
you? And you still haven't found the frequency to contact ATC. And you
haven't looked at the turn coordinator even once, so if your AI flopped
over because your vacuum pump failed and you were following the scenario
above then you're dead. Real-life dead, not simulator dead.

And then there's turbulence. And there are a couple of other things
I've left out too because this post is already way too long.

When the stakes are high things are different.

Don't be so sure. If you are ever in Southern California look me up and
we can put it the test.

I've surprised people before. Most people assume that others are like
themselves, and that's a dangerous assumption.

Come to LA and we will see.

rg

Ron Garret wrote in
:

More precisely, in VMC you CAN'T NOT TELL (parse
that carefully) if the plane is right-side up even if your gaze is
fixed on the panel.

Hey Ron,

Did you mean IMC in the above sentence?

"No problem" you say, "I just keep my wings level by looking at the
AI." And yes, that true. But the first thing you will notice in
reality is that the AI gives you much coarser information than your
peripheral vision does. Again, this is hard to appreciate unless you
actually experience it (and you cannot experience it in your typical
sim because there is no peripheral visual stimulation).

You are wasting your time Ron.

I have been this route with Mx. Look me up in Google with the buzz word of
leans. According to Mx, he suffers leans looking at a screen of a
computer.

So needless to say, it would be better served if you reply to those that
really do appreciate the value of your time.

Allen

Ron Garret writes:

OK, still no problem. So you look at the DG briefly, then come back to
the AI. But now you have to call ATC. To do that you have to find the
frequency on your chart. To do that you have to look away from the AI
again and look at the chart. Once again you are flying blind. But
reading a chart is much harder than reading a DG. You have to hunt
around to find the right place. Maybe you have to refold it. Maybe you
have to get out a flashlight (because you've just flown into a cloud and
it's now much darker than it was when you began). Suddenly you realize
that you haven't looked at the AI in a while. You glance up and it's
flopped over onto its side. You move the yoke to level the wings, and
try to calm down because you have just come close to death. You look at
the DG and find that you are off course because of the inadvertent bank.
You correct. Then you look down at the chart again to try again to find
the right ATC frequency to call.

Now, why would the aircraft flop over on its side while you are
looking at the chart? Aren't you in straight and level flight? I
thought aircraft tended to stay in straight and level flight once
established there. So you might be in a lazy bank to one side or the
other, but you should be able to just correct it the next time you
look at the AI.

I share your reservations about the chart, which I have expressed here
before. But then I was told that it was no big deal to look at a
chart while flying. Now I'm being told the opposite. Which is right?

Supposedly some GPS units will provide the right frequencies.
Unfortunately, it seems to require so much knob twisting and button
pressing that I'm not sure it's more practical than a chart.

One option is to write down frequencies in advance. Center
frequencies don't change often, and Center could give you any other
frequencies you need, I presume.

By now several minutes have elapsed and you are no longer sure exactly
where you are (assuming you don't have a moving map GPS -- those gadgets
make life a whole lot easier). You were flying on instruments before
you flew into the cloud so you've already got your VORs tuned in, but
now you have to twiddle the OBS to find your cross-radial. Once again
you have to take your eyes away from the AI. You twiddle the knob and
center the needle. Back to the AI, then you have to look down at your
chart again to figure out where you actually are based on that
information.

Yes, it's a lot of work, especially without the moving map. Seems
like instrument flight might be a good time to have a copilot (who
need not actually be a pilot, as long as he or she can read charts,
tune and talk on radios, etc.).

Now... how long has it been since you looked at the altimeter? Oh ****,
in all this time you suddenly realize you've lost 2000 feet!

Why are you in a 1000 fpm descent? What happened to straight and
level?

The threat of actual real-life death looms again as you realize
that you are no longer above the terrain.

You were flying at only 2000 feet AGL, in an untrimmed aircraft making
a descent of 1000 fpm?

In this case, the first job would be to stabilize the aircraft in
straight and level flight at a constant, safe altitude. Once it's
willing to hold that, you can start looking at your chart and working
the radios. If the aircraft is in the middle of a change in heading
or altitude when you enter IMC, you need to finish the maneuver and
resume straight and level flight before you try to read charts.
Presumably you have some idea of the height of terrain in the area,
and you make sure you're a few thousand feet above it, at an
appropriate VFR altitude for your heading (IFR altitude would place
you even with IFR traffic, which should probably be avoided until you
have ATC to provide separation).

Where exactly are you? You still haven't figured that out yet.

Presumably you knew where you were before you entered IMC. At small
place speeds, you can't be too far away. If you were straight and
level when you entered IMC, you can estimate your position by dead
reckoning, and if your altitude is sufficient, you're clear of
terrain. Then you can look at the chart to see where you probably
are. Once you contact ATC, they can give you a pretty good fix as
well.

OK, no problem, just push in the throttle and climb. Look at
the chart again...

I wouldn't _just_ climb. I'd climb to what I know to be a safe
altitude in the area, and then stabilize the aircraft again. If there
were no mountains at 7500 feet before you entered IMC, there probably
still aren't even though you're in a cloud.

Now you're starting to get a little freaked out because in this game if
you lose you can't just hit the reset button.

You can't just do that in a sim, either.

Have you remembered to apply right rudder?

Aren't you trimmed?

Are you watching your airspeed?

Aren't you straight and level at a stable airspeed?

Where the hell are you?

Didn't you know before you entered IMC? You probably are fairly close
to your previous position. Unless there's a mountain range nearby, or
a lot of IFR traffic, the skies should be safe, even if they are no
longer clear.

And you still haven't found the frequency to contact ATC.

Personally, I'd already have the radios tuned to ATC, so that I could
just key the microphone and talk.

Some of what you are postulating assumes a fairly primitive
instrumentation on the aircraft and very little preparedness for the
possibility of low visibility. Keeping the radios appropriately tuned
whenever you have a spare moment in VMC would be a good idea, even if
you aren't in radio contact. Likewise, you need to know where you
are, even in VMC. Likewise, you need to keep your aircraft stable so
that it doesn't require constant attention just to maintain a heading,
altitude, and speed. And, finally, you need enough instruments to
allow you to control the situation less stressfully in IMC. The two
that spring immediately to mind are an autopilot and RNAV with a
moving map. These may be luxuries in the eyes of a VFR pilot, but
they are simple tools of the trade if you have to fly IFR.

And you haven't looked at the turn coordinator even once,
so if your AI flopped over because your vacuum pump failed
and you were following the scenario above then you're dead.
Real-life dead, not simulator dead.

The same thing will happen if the wings snap off. But neither a wing
nor an instrument failure are likely at the precise time that you just
happen to find yourself in IMC (although icing conditions could change
this). Pilots who die in IMC usually have fully functional
instruments.

And then there's turbulence. And there are a couple of other things
I've left out too because this post is already way too long.

Turbulence is a problem in itself, even in clear air.

When the stakes are high things are different.

Agreed. But I do notice that much of what you are talking about here
can be avoided if you just prepare in advance. If you have complete
control of the situation before you find yourself stuck in poor
visibility, you're much more likely to retain control when IMC comes.

And above all, you must remain calm. Pilots die because they panic.
The workload may be heavy and unfamiliar, but it's a lot easier to
address with a cool head than it is when one is yielding to one's
darkest fears. Some people are better at staying calm than others.

Come to LA and we will see.

Is LA often fogged in? That's a bad place to get stuck in IMC if
you're not used to it. Not only because of those mountains looming in
several directions, but simply because of the amount of traffic out
and about.

Nevertheless, Van Nuys is said to be the busiest GA airport in the
United States.

--
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Ron,

nice description.

--
Thomas Borchert (EDDH)