Icing Airmets

I've been watching the icing airmets for some time now, and it seems
to be getting more and more conservative to the point of being
unrealistic. For example, right now the freezing level is at 5000 ft,
MEA is at 2500 ft, yet we have an airmet Z that goes all way from SFC
to 18k. How could you possibly justify such an airmet? Even though the
conditions appear to be quite good for an IFR training flight, we
still have to cancel the flight because we don't want to teach the
students that airmets can be ignored. Yet I am at a loss to explain to
them why there is an airmet when the ingredients for icing is just not
there.

The ADDS icing potential charts appear to be more realistic, but they
warn you that it supplements the Airmet and should not be used as a
substitute for icing intensity.


Any thoughts?

On 26 Jan 2004 10:08:44 -0800, (Andrew
Sarangan) wrote:

For example, right now the freezing level is at 5000 ft,
MEA is at 2500 ft, yet we have an airmet Z that goes all way from SFC
to 18k.

Since the published icing conditions occur from +5 to -20 C, a
freezing level at 5000 would mean icing potentially below 3000 feet.
The MEA may be 2500 but the normal minimum IFR altitudes would be
either 3000 or 4000 feet depending on direction and that is known
icing conditions. I am sorry this frustrates you but depending on
where you live a big chunk of winter is off limits to small GA
aircraft trying to fly IFR.

I'd like to know how you get in icing when the temperature is +5. I have
never seen ice until the the gauge reads 0 or below.




"ArtP" wrote in message
...
On 26 Jan 2004 10:08:44 -0800, (Andrew
Sarangan) wrote:

For example, right now the freezing level is at 5000 ft,
MEA is at 2500 ft, yet we have an airmet Z that goes all way from SFC
to 18k.

Since the published icing conditions occur from +5 to -20 C, a
freezing level at 5000 would mean icing potentially below 3000 feet.
The MEA may be 2500 but the normal minimum IFR altitudes would be
either 3000 or 4000 feet depending on direction and that is known
icing conditions. I am sorry this frustrates you but depending on
where you live a big chunk of winter is off limits to small GA
aircraft trying to fly IFR.

Dave ) wrote:

I'd like to know how you get in icing when the temperature is +5. I have
never seen ice until the the gauge reads 0 or below.

I have picked up ice when the digital thermometer on an '02 C172 read +3c.

--
Peter












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How do you know your guage wasn't wrong?


"Peter R." wrote in message
...
Dave ) wrote:

I'd like to know how you get in icing when the temperature is +5. I have
never seen ice until the the gauge reads 0 or below.

I have picked up ice when the digital thermometer on an '02 C172 read +3c.

--
Peter












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Dave ) wrote:

How do you know your guage wasn't wrong?

The digital gauge was calibrated when new and the aircraft is about one and
one half years old. Is it possible that it slipped out of calibration a
degree or two? I suppose.

But since every icing article I have ever read states that icing can occur
at temperatures higher than 0c, I have no trouble believing that my icing
encounters above 0c actually did occur one to three degrees above 0c.



--
Peter












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Dave ) wrote:

How do you know your guage wasn't wrong?

I forgot to include the point of my adding to this thread: I use these
experiences (granted that they are somewhat limited to two winters of IFR
flying downwind of the Great Lakes, US) of encountering ice above 0c when
flight planning a cruise altitude, as well as when making a go/no decision
due to ice.

Are you implying that you are comfortable that ice will *not* occur above
0c and therefore plan accordingly?

--
Peter












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You can't unless your thermometer is wrong.

Mike
MU-2

"Dave" wrote in message
ink.net...
I'd like to know how you get in icing when the temperature is +5. I have
never seen ice until the the gauge reads 0 or below.




"ArtP" wrote in message
...
On 26 Jan 2004 10:08:44 -0800, (Andrew
Sarangan) wrote:

For example, right now the freezing level is at 5000 ft,
MEA is at 2500 ft, yet we have an airmet Z that goes all way from SFC
to 18k.

Since the published icing conditions occur from +5 to -20 C, a
freezing level at 5000 would mean icing potentially below 3000 feet.
The MEA may be 2500 but the normal minimum IFR altitudes would be
either 3000 or 4000 feet depending on direction and that is known
icing conditions. I am sorry this frustrates you but depending on
where you live a big chunk of winter is off limits to small GA
aircraft trying to fly IFR.

Mike Rapoport ) wrote:

You can't unless your thermometer is wrong.

Are you replying to Dave's first sentence, which is:

I'd like to know how you get in icing when the temperature is +5.

Or his second:

I have never seen ice until the the gauge reads 0 or below.

Or both?

If you are replying to his second sentence, this is contradictory to my
understanding that the temperature right at the leading edge of an airfoil
could be up to a few degrees colder than the surrounding air, which is why
I learned that airframe icing (excluding freezing rain) can occur in air
temperatures above freezing.

I should point out here that I am simply seeking clarification of your
comment, not challenging it (as I look to you as one of the more
experienced in these groups).

--
Peter












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In article , Peter R.
writes:

I'd like to know how you get in icing when the temperature is +5. I have
never seen ice until the the gauge reads 0 or below.

I have picked up ice when the digital thermometer on an '02 C172 read +3c.


I picked up ice when my digital theromometer indicated +2 deg F. I brought it
home to calibrate it and found that it read 2 deg high at 25, 45, and 65 deg.
Pretty consistent in its error. Spec on the thermometer was plus/minus 0.5
deg. Know your own thermometer but you won't pick up ice much above 32 deg F.

Chuck