What's the latest on "forecast icing = known icing"

I thought I'd try to make the discussion of flying into known ice more
concrete with a scenario. The following actually happened recently.
(Not to me of course ;-)

The leading edge of a cold front has moved in. Airmet for light to
occasional moderate rime and mixed ice in clouds and precip. Forecast
freezing level 8000 and above. Pirep of light ice at 8000. I've filed
for 6000. Field is at sea level. MOCA is 5000 due to a mountain range
that the airway crosses. My heading takes me through the leading edge
of the front and into VFR conditions beyond.

Can I legally launch?

Suppose I do launch. I enter the clouds at 3000. At 5500 climbing I
start picking up light ice. What should I do? Options include:

1. Do nothing. This is not an entirely unreasonable option in this
case becase a) the ice is light and b) I can reasonably expect to pop
out of the clouds in 10-15 minutes.

2. Climb. This takes me further into the forecast freezing conditions,
but buys me terrain clearance in case things get really dicey.

3. Descend. Seems like a bad plan because it may or may not get me out
of the ice by the time I hit the MOCA.

4. Go back. Also an unattractive option because I'm all but assured of
remaining in icing conditions while I maneuver to get set up for the
approach.

5. Declare an emergency and descend below the MOCA.

6. ???

rg

The leading edge of a cold front has moved in. Airmet for light to
occasional moderate rime and mixed ice in clouds and precip. Forecast
freezing level 8000 and above. Pirep of light ice at 8000. I've filed
for 6000. Field is at sea level. MOCA is 5000 due to a mountain range
that the airway crosses. My heading takes me through the leading edge
of the front and into VFR conditions beyond.

Can I legally launch?

Yes. It is not illegal to fly when there is an airmet for icing, it's
just illegal to fly into the airspace where this icing would occur (in
clouds and precip above the freezing level). You filed for (and
presumably got) clearance for below that. However, where I fly, under
these conditions I would not get a clearance for 5000, I'd get a
clearance for 9000. In those conditions, it still would not be illegal
for me to accept the clearance so long as I could stay out of clouds and
precip. Were it overcast at 8000 I could accept the clearance and
negotiate my way once I'm in the air, but I don't think that would be
legal - I'd be accepting a clearance into icing, even if I never
actually fly that clearance (what if I go NORDO).

Suppose I do launch. I enter the clouds at 3000. At 5500 climbing I
start picking up light ice. What should I do?

Each case is different. I have very little icing experience (and would
like to keep it that way without deice). I presume you are encountering
ice shortly after takeoff enroute to your cleared altitude of 6000.

10-15 minutes of light icing can be serious, depending on the aircraft.
Some airplanes are very sensitive to ice, some less so. I don't know
what you're flying. The most severe icing is at or near the tops of the
clouds, so the light icing may turn into moderate as you climb, and this
would be bad. Even if you popped out of the clouds, the ice might not
melt or sublimiate (my experience has been that it does not if the air
is below freezing). What are the cloud tops at? Could you top them?

The old adage "there's always warmer air above" may be true, but it
often requires a rocketship to get that high. In a spam can I would not
count on it (absent known weather to the contrary).

Other alternatives not listed include descending to VFR conditions
(could you fly VFR to your destination, even if the long way?) even if
that means shooting an approach and breaking it off when 500 feet below
the deck, changing course (say, away from the front to attack the
problem from a different angle). In your briefing you should have an
idea of where better weather is. Of course, the weather is not as
forecast so you have to take that into account.

If you get into ice, the object is to get out. Sometimes the best way
out is to keep going. What are the options (landing fields) ahead of
you should you decide to continue and find that wasn't so hot?

Declaring an emergency doesn't move granite, it just moves aluminum.
Descending below the MOCA may not be such a good idea. If you just
started picking up ice, you can probably get out of it fairly quickly by
turning around. How far away are the VFR conditions ahead? The
mountains (presumably ahead) may generate turbulence which, iced up, you
will be less able to handle.

Anyway, these are the things that go through my mind, along with turning
on pitot heat, the defroster, and anything else you've got. In any case
tell the controller you are picking up ice and would like to ...
whatever. Maybe there's another route that keeps you below the ice and
takes you around the mountain.

With what I'm reading so far, and assuming a cherokee, I'd probably tell
the controller I'm picking up ice and request 5000. If that doesn't get
me out of it, I'd probably turn around. If the cloud tops are low
enough, I might ask for higher and try to top them. (I'd guess 7000
would be too high for me to be comfortable trying that - that's 3-4
minutes of climbing in ice, and getting ice on the underside of the wings)

Jose

--
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In article ,
Jose wrote:

Each case is different. I have very little icing experience (and would
like to keep it that way without deice). I presume you are encountering
ice shortly after takeoff enroute to your cleared altitude of 6000.

Yep.

10-15 minutes of light icing can be serious, depending on the aircraft.
Some airplanes are very sensitive to ice, some less so. I don't know
what you're flying.

An SR22.

If you get into ice, the object is to get out. Sometimes the best way
out is to keep going. What are the options (landing fields) ahead of
you should you decide to continue and find that wasn't so hot?

Just FYI, this was on a trip from SJC to VNY. Lots of airports all over
the place. I decided to continue because I knew that this was the
leading edge of the front and I'd pop out of the clouds sooner if I
continued than if I decided to return to SJC (which would have required
shooting an approach at that point since I was already in the clouds).

I emerged five minutes or so later with what I would guess was 1/8 inch
of rime ice. (It was a little too cold to climb out into the wing and
measure it.) It didn't come off until I descended into VNY. It had a
small but noticeable effect on performance (cost me about 5 knots).

The weather report from flight watch made is sound like all hell was
breaking lose. Severe turbulence, thunderstorms, the works. But I
ended up having a perfectly smooth flight with VMC the entire way. Go
figure.

I've had one other icing encounter. The first thing I noticed was the
air from the vents not blowing as hard as it was. At that point I had
about 1/4 inch or so on the leading edges. OAT read +3C (which is the
reason I wasn't on the lookout for ice). Called ATC and got a reroute
so I could descend into VMC, where the ice immediately came off.

rg

An SR22.

Did the parachute figure into your decision making at all? (if it did,
would you admit it? I've never flown one, but my understanding is
that it has plenty of power (which is good) but a laminar wing (which is
sensitive to ice).

this was on a trip from SJC to VNY.

I know those ridges... flown over them many times (VFR) from STS to EMT.
VFR down the highway (past Q99) might have also been an option and
kept you down low, if you are used to low level VFR. But with strong
winds that might not be a good idea.

I decided to continue because I knew that this was the
leading edge of the front and I'd pop out of the clouds sooner if I
continued than if I decided to return

Probably a good choice, although returning you could have descended too.

I emerged five minutes or so later with what I would guess was 1/8 inch
of rime ice.

That's a lot of ice to pick up in five minutes. Had it been fifteen,
the outcome might have been different.

The weather report from flight watch made is sound like all hell was
breaking lose.

It probably was, somewhere. But sometimes the weather guessers get it
wrong.

Jose
--
Nothing takes longer than a shortcut.
for Email, make the obvious change in the address.

Ron Garret wrote:

snip
I've had one other icing encounter. The first thing I noticed was the
air from the vents not blowing as hard as it was. At that point I had
about 1/4 inch or so on the leading edges. OAT read +3C (which is the
reason I wasn't on the lookout for ice). Called ATC and got a reroute
so I could descend into VMC, where the ice immediately came off.

Your SR22 is not equipped with the TKS system? I thought that feature was
standard on the SR22.

--
Peter

In article ,
"Peter R." wrote:

Ron Garret wrote:

snip
I've had one other icing encounter. The first thing I noticed was the
air from the vents not blowing as hard as it was. At that point I had
about 1/4 inch or so on the leading edges. OAT read +3C (which is the
reason I wasn't on the lookout for ice). Called ATC and got a reroute
so I could descend into VMC, where the ice immediately came off.

Your SR22 is not equipped with the TKS system? I thought that feature was
standard on the SR22.

No, it's an option. And they (meaning OurPlane) decided not to get it
on this particular plane. After all, ice is NEVER a problem in
California, right?

rg

In article ,
Jose wrote:

An SR22.

Did the parachute figure into your decision making at all?

I never seriously considered deploying it if that's what you mean.

(if it did, would you admit it?

Sure. The fact that it's there is always in the back of my mind.

I've never flown one, but my understanding is
that it has plenty of power (which is good) but a laminar wing (which is
sensitive to ice).

Yeah, it has gobs of power, especially with only one person and fuel to
the tabs :-) It climbs like a banshee. And it's the only plane I've
ever had ice on, so I have nothing to compare it to in that regard.


this was on a trip from SJC to VNY.

I know those ridges... flown over them many times (VFR) from STS to EMT.
VFR down the highway (past Q99) might have also been an option and
kept you down low, if you are used to low level VFR. But with strong
winds that might not be a good idea.

I thought the whole point of getting an instrument ticket was so that I
wouldn't have to scud-run any more! Besides, it was dark. Scud-running
at night seemed like a bad plan.

I decided to continue because I knew that this was the
leading edge of the front and I'd pop out of the clouds sooner if I
continued than if I decided to return

Probably a good choice, although returning you could have descended too.

Without declaring an emergency? I don't think so. Wouldn't I have to
stay above the MVA as long as I'm in the soup?

rg

In article ,
Jose wrote:

Oh, one more thing...

I emerged five minutes or so later with what I would guess was 1/8 inch
of rime ice.

That's a lot of ice to pick up in five minutes. Had it been fifteen,
the outcome might have been different.

Yeah, I think I pushed my luck about as far as I ever want to that night.

rg

: I emerged five minutes or so later with what I would guess was 1/8 inch
: of rime ice.
:
: That's a lot of ice to pick up in five minutes. Had it been fifteen,
: the outcome might have been different.

: Yeah, I think I pushed my luck about as far as I ever want to that night.

I would argue that 1/8" in 5 minutes is pretty heavy icing in a "spam-can"
(even in your can is made out of sand and plastic). (Un)fortunately, slippery,
high-performance singles like that make light icing a "perceived manageable risk."
Much moreso than in my Cherokee which climbs like a tub no matter what you do. In
reality, many people take the power to be an "out," but to me it seems pretty iffy to
do that. On a nice laminar wing, really strange things can happen that robs you of
lift/power very fast.

To each their own. Risk management is a personal thing.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Did the parachute figure into your decision making at all?
I never seriously considered deploying it if that's what you mean.

No, I meant did the presence of that additional out make it easier for
you to decide to continue on rather than turn back (did it influence
your decision to do so)?

I thought the whole point of getting an instrument ticket was so that I
wouldn't have to scud-run any more!

Well, sorta. It just lets you fly with your head in the clouds.

Besides, it was dark. Scud-running
at night seemed like a bad plan.

Agreed.

Probably a good choice, although returning you could have descended too.

Without declaring an emergency? I don't think so. Wouldn't I have to
stay above the MVA as long as I'm in the soup?

Yes, you'd need to stay above the MVA, but that probably decreases as
you return (after all, you came from there and were climbing out)

Jose
--
Nothing takes longer than a shortcut.
for Email, make the obvious change in the address.