flying in snow

In a typical spam can (say an archer), which has no deice at all (save pitot
heat), is it safe to fly in snow? More generally, of course the snow will
bounce off and not stick to the wings (right?) but what about the clouds that
are producing snow - will they also produce airframe ice? If it's above
freezing on the ground, and the clouds are very high, and it's snowing, then as
I climb I'll (yes?) climb above the freezing level - is there danger in that
transition when it's snowing? (I presume there's no freezing rain or sleet,
else I'd see it on the ground, no?)

Jose


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

"Teacherjh" wrote in message
...
In a typical spam can (say an archer), which has no deice at all (save
pitot
heat), is it safe to fly in snow?

It can be, yes. However, all of the usual caveats about flying in visible
moisture with freezing conditions apply.

Typically, in a cloud or not, you'll just get a light accumulation of snow
on forward surfaces of the airplane: leading edge of the wing, front of
tires (for fixed-gear airplanes), temperature probe, etc.

However, a heavy wet snow could result in significant rime ice accumulation,
and any kind of snow has the potential for blocking the air filter. It's
important to have all of the usual precautions that you'd have in any sort
of freezing/precip conditions, including a well-thought-out escape plan.

I can't think of any situation where precipitation that's freezing rain
aloft would show up as snow on the ground, but I think it would be unwise to
rule that possibility out. Weather does funny things some times.

Generally speaking though, when you see snow, things are cold enough that
all you'll get is plain old snow, and it will be too cold for it to produce
any significant accumulation.

Pete

On Thu, 18 Mar 2004 11:27:18 -0800, "Peter Duniho"
wrote in Message-Id:
:

any kind of snow has the potential for blocking the air filter.

I only see that as an issue if you are downwind of an active volcano,
and the ambient atmosphere is dust laden. It's my understanding that
most aircraft induction systems have a spring-loaded door that admits
air in the event of an interruption of flow through the filter
element.

"Larry Dighera" wrote in message
...
I only see that as an issue if you are downwind of an active volcano,
and the ambient atmosphere is dust laden. It's my understanding that
most aircraft induction systems have a spring-loaded door that admits
air in the event of an interruption of flow through the filter
element.

Huh? Many do not. All aircraft that I've flown DO have an alternate air
system; most of the C172-class planes I know of use carb heat as their
alternate air, not a spring-loaded door. My own airplane has a
spring-loaded door, but that's most likely because it's also fuel-injected,
so there's no carb heat installed.

But regardless of how the alternate air system works, it's still an issue to
be aware of. And in all cases I know of, the alternate air system means
unfiltered air. In cruise flight, not necessarily a problem, but if it also
means turning on the carb heat, it means a) you need to be aware of the
potential for the need to use carb heat, and b) you'll want to remind
yourself of the various implications of operating with the carb heat turned
on (like, need to readjust the mixture, fuel efficiency changes, maximum
power changes, that sort of thing).

You don't need to be downwind of an active volcano to care about the air
filter getting clogged.

Pete

On Thu, 18 Mar 2004 19:01:54 -0800, "Peter Duniho"
wrote in Message-Id:
:

"Larry Dighera" wrote in message
.. .
I only see that as an issue if you are downwind of an active volcano,
and the ambient atmosphere is dust laden. It's my understanding that
most aircraft induction systems have a spring-loaded door that admits
air in the event of an interruption of flow through the filter
element.

Huh? Many do not.

Of the 5 POHs I checked, only the Rockwell International 112A
mentioned using carb-heat as an alternate air source. Neither the
1974 Cessna Centurion, nor 1973 Cessna Cardinal RG, nor 1974 Cessna
Stationair, nor Piper Archer II, nor Bellanca Super Viking POH/Owner's
Manuals mention alternate air. Or, at least I couldn't find it.

All aircraft that I've flown DO have an alternate air
system; most of the C172-class planes I know of use carb heat as their
alternate air, not a spring-loaded door.

In the C-172S there is no carb-heat (it's injected).

My own airplane has a
spring-loaded door, but that's most likely because it's also fuel-injected,
so there's no carb heat installed.

But regardless of how the alternate air system works, it's still an issue to
be aware of. And in all cases I know of, the alternate air system means
unfiltered air. In cruise flight, not necessarily a problem, but if it also
means turning on the carb heat, it means a) you need to be aware of the
potential for the need to use carb heat, and b) you'll want to remind
yourself of the various implications of operating with the carb heat turned
on (like, need to readjust the mixture, fuel efficiency changes, maximum
power changes, that sort of thing).

You don't need to be downwind of an active volcano to care about the air
filter getting clogged.

Right. What I was attempting to imply was that at cruise altitude the
air is generally free of impurities normally filtered unless there is
a source of such impurities upwind spewing to significant heights.

Larry Dighera wrote:

Of the 5 POHs I checked, only the Rockwell International 112A
mentioned using carb-heat as an alternate air source.

My understanding from the old Jeppesen-Sandersen PP manual was that this is
standard; IOW, if your plane has carb heat, that's the alternate air source.
I would assume that most POHs would not mention something that they feel to be
obvious.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

"Larry Dighera" wrote in message
...
Of the 5 POHs I checked, only the Rockwell International 112A
mentioned using carb-heat as an alternate air source.

See George's post. If there's carb heat, there's usually alternate air,
even if the manual doesn't say so.

All aircraft that I've flown DO have an alternate air
system; most of the C172-class planes I know of use carb heat as their
alternate air, not a spring-loaded door.

In the C-172S there is no carb-heat (it's injected).

So? What's your point? Are you claiming the 172S has no alternate air
source?

Right. What I was attempting to imply was that at cruise altitude the
air is generally free of impurities normally filtered unless there is
a source of such impurities upwind spewing to significant heights.

I understand what you were trying to imply. But the point here is that
filtration is not the only concern with many alternate air systems, since
they combine two completely different functions (carb heat and alternate
air).

Pete

The snow itself will not stick but you will find ice in the snow producing
clouds, particularly if the snow falling out of them is the "little
styrofoam balls" type. Sometimes there are no clouds when it is snowing the
flake type. The flake type is formed by moisture going directly from vapor
to crystal whereas the ball type is a collection of supercooled cloud
droplets frozen together.

So the bottom line is that you will not get airframe ice if you can see
where you are going.

Mike
MU-2


"Teacherjh" wrote in message
...
In a typical spam can (say an archer), which has no deice at all (save
pitot
heat), is it safe to fly in snow? More generally, of course the snow will
bounce off and not stick to the wings (right?) but what about the clouds
that
are producing snow - will they also produce airframe ice? If it's above
freezing on the ground, and the clouds are very high, and it's snowing,
then as
I climb I'll (yes?) climb above the freezing level - is there danger in
that
transition when it's snowing? (I presume there's no freezing rain or
sleet,
else I'd see it on the ground, no?)

Jose


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

Oh good Mike, you're alive!


(see related thread on R.A.S)

"Mike Rapoport" wrote in message
hlink.net...
The snow itself will not stick but you will find ice in the snow producing
clouds, particularly if the snow falling out of them is the "little
styrofoam balls" type. Sometimes there are no clouds when it is snowing
the
flake type. The flake type is formed by moisture going directly from
vapor
to crystal whereas the ball type is a collection of supercooled cloud
droplets frozen together.

So the bottom line is that you will not get airframe ice if you can see
where you are going.

Mike
MU-2


"Teacherjh" wrote in message
...
In a typical spam can (say an archer), which has no deice at all (save
pitot
heat), is it safe to fly in snow? More generally, of course the snow
will
bounce off and not stick to the wings (right?) but what about the clouds
that
are producing snow - will they also produce airframe ice? If it's above
freezing on the ground, and the clouds are very high, and it's snowing,
then as
I climb I'll (yes?) climb above the freezing level - is there danger in
that
transition when it's snowing? (I presume there's no freezing rain or
sleet,
else I'd see it on the ground, no?)

Jose


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

And it feels good!...

966MA was owned by a doctor who I met a couple of times. He and his wife
were nice people.

Mike
MU-2

"Brad Z" wrote in message
newslp6c.36349$1p.545565@attbi_s54...
Oh good Mike, you're alive!


(see related thread on R.A.S)

"Mike Rapoport" wrote in message
hlink.net...
The snow itself will not stick but you will find ice in the snow
producing
clouds, particularly if the snow falling out of them is the "little
styrofoam balls" type. Sometimes there are no clouds when it is snowing
the
flake type. The flake type is formed by moisture going directly from
vapor
to crystal whereas the ball type is a collection of supercooled cloud
droplets frozen together.

So the bottom line is that you will not get airframe ice if you can see
where you are going.

Mike
MU-2


"Teacherjh" wrote in message
...
In a typical spam can (say an archer), which has no deice at all
(save
pitot
heat), is it safe to fly in snow? More generally, of course the snow
will
bounce off and not stick to the wings (right?) but what about the
clouds
that
are producing snow - will they also produce airframe ice? If it's
above
freezing on the ground, and the clouds are very high, and it's
snowing,
then as
I climb I'll (yes?) climb above the freezing level - is there danger
in
that
transition when it's snowing? (I presume there's no freezing rain or
sleet,
else I'd see it on the ground, no?)

Jose


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