How many of you non-FIKI aircraft choose never to penetrate a freezing cloud?

[RobertE]

I've always lived by the above rule in the subject line.  If the cloud is below freezing I stay above or below it but don't touch it.  But I'm questioning my judgment due to an upcoming flight.

I'm flying from Norcal to Bend, OR this weekend at it's likely that I'll get above an overcast cloud layer in CA without penetrating a cloud but will need to penetrate a solid layer somewhere over Oregon.  Now, if it's 1) just 1,000 feet thick at 5,000 AGL and 2) comfortably above freezing starting at several thousand feet AGL would you still not penetrate it?  Am I being overly sensitive to the fear of icing?  What if the facts are the same but it's a 3,000 foot thick layer?

Thanks for the practical advice.

[Oldguy]

While I have never had to make the call, my personal limits are no icing. Period. My dispatch rate is fairly high, I live south of I-20 and my destinations are usually south of my location, so I am fortunate in that way. That being said, I know several pilots around the area who will fly through an ice layer IFF (math term) it is relatively thin with above freezing temps at their destination altitude. As for me, I've done enough risky things in my earlier days to get my adrenaline fix for the next lifetime or two.

So I guess my advice is to question yourself as to why you would consider changing your personal limits in this situation. It may be time to upgrade them or some other underlying reason. Just make sure if you were to read an NTSB report about someone doing what you decide, you would not shake your head and think "why didn't they see this coming?"

[RobertGary1]

Realistically if you actually fly IFR you'll encounter some amount of icing at some point. I wouldn't go looking for it but what is important is that you have an out. Ice forecasts are probably the least reliable forecast put out. Anytime you will go IMC above the freezing level you need to have an out. Maybe warmer air below, easy U turn possible, etc. You can't rely on forecasts to avoid it. 

That is why there is no possible IFR over the Sierras here in California at any time. Summer has embedded TS, and winter has icing you'd have no chance of escaping. Fortunately the legs of a Mooney are long so you can navigate around weather systems. My dispatch rate is also much higher than the airlines. Just fly around it.

-Robert

[Marauder]

Icing is one of those beasts that will be unpredictable. I flew for years in western New York and found that even when you suspected a cloud to be in the freezing zone, an inversion can change all that. For me, making sure I had an out either above or below was what would make the decision for me. If the clouds are stacked and more than just a 1000' or 2000' thick, I wouldn't venture in them. Same with low ceilings. Nothing ruins your day more than being up in clear air then need to fly an approach in low clouds that may not only contain ice but also are pouring snow out of the bottoms and ruining any visibility on the approach.

 

PIREPS help but you need know the type of plane providing it. 

 

[thinwing]

Hello Robert ,having flown to Bend many times  I think your real issue will be when you depart Bend for home on Sunday.Checking the forecast for fri afternoon  at Bend shows clearing sky's,warmer temps so my opinion is an on top at say 13k is real doable and as long as any clouds you decend thru aren't painting green or better icing should be minimal.personally I think you will find broken to scattered conditions fri pm.Leaving Sunday...you are forced to climb from 4K to 11 k if IFR and that caused a few pilots to Scud run a few years back on a Mooney flyin to Sunriver.I typically have to use the tks in that area and again rate of accumulation is radar color dependent.Keep in mind my opinion on this flight is based on fiki Bravo performance.

[RobertE]

Thanks, everyone.  

Let me be clear.  No rain or snow expected.  No need to fly in the clouds while over the Sierras.  But a likely need to fly through a stratus layer that is colder than freezing into air below that is warm.  I've got Sirius XM onboard so there will be no question as to ground temps in near real time.  My question concerns how many would descend through a 1K thick layer in that instance?  How about a 3K thick layer?

Thanks again.  This is real world stuff that isn't really taught.

[RobertGary1]

I remember coming into the LA basin one time from Arizona and atc decended me to 10,000. I told him I couldn't do 10,000 because there could be ice but I'd do 8,000. At first he was confused but then kept me at 12,000 for a couple more miles and then gave me 8,000. 

-Robert

[DanM20C]

3K thick layer with potential icing conditions would make me nervous.  1K would depend on how much terrain clearance below the bases and the temps below. Here in the mid west I usually would try it if the Bases were at least 3.5k to 4K AGL.   Once I flew an approach though a 1K layer with the bases around 900ft.  I didn't get a lot of ice but enough to out pace my defroster.  It was night too.  Not my best moment. 

Dan

[Bartman]

I have flown thru clouds and layers when the OAT is less than freezing, but only a few times.  First time we had no ice on departure from 2,000 thru 5,000 but after lunch on the return trip we descended thru the SAME LAYER and picked up rime quickly.  I asked to remain above and set up for straight in ILS and descended at about 160 kts and picked up about 3/4 inch of rime on the leading edges quickly.  Broke out about 400ft, chop the power, no flaps, and landed uneventfully.  Just goes to show same day, no ice forecast, no ice on departure, then ice on return trip.  Other times it has been very cold and no ice forecasted or realized.

[thinwing]

Ok say bases are typically at 6-9 k msl....1 k stratus layer is a non event...maybe trace ice gone rapidly after breakout.3k..I would increase descent rate to 1500 /min and expect light to moderate with most of it gone by traffic pattern at 50 degree f.This advice apply only to east cascades valley airport,like bend,sun river,madras etc.

Edited March 8, 2017 by thinwing

[AH-1 Cobra Pilot]

No mention of what the FARs say?

[thinwing]

Edited to msl

[thinwing]

1 minute ago, Ah-1 Cobra Pilot said:

No mention of what the FARs say?

Oh you mean known ice forecast 

[201er]

If there is no icing forecast or reported and I have a good out, I'll consider going through a thin cloud layer (2000ft thick or less) in winter as long as I know I won't be stuck in it for long. If the layer is thick or I could be spending a lot of time in it, I want to be certain of an inversion layer through skew-t, pireps, etc. One time I flew from Linden to Charleston in winter as the sun was setting. Temps on the ground were just a bit over freezing and temps aloft were essentially the same. No icing forecast, warming air to the south, good pireps so I went for it. I was in the soup most of the way with OAT around 0-2C at 6000ft. Night was coming in but being offset by getting more South so temps stayed the same the whole way. No ice the entire way. 

[thinwing]

What was your out if you started picking up significant ice while at 6000,oat 0-2c?

[Moonbat]

Good question. Bear in mind, I live on the east coast. Here is what I think. If it is a thin layer (<1000’) AND it is warm below AND there is enough room between the bottom of the layer and the tops of the terrain AND I am 95% certain that air traffic control won’t park me inside the layer but rather will ascend or descend me through it promptly (remember, you can always say “unable”), THEN I’d launch. Unfortunately here in the east, the cloud layers are often several thousand feet thick AND the freezing level is so often close to the ground, the decision is pretty easy. Fuhgetaboutit.  Remember that web site (https://rucsoundings.noaa.gov/) I showed you that tells you the thickness of the cloud layer? This trip might be a good time to use it.

[201er]

Just now, thinwing said:

What was your out if you started picking up significant ice while at 6000,oat 0-2c?

It was above freezing all the way to the ground and ceilings were a few thousand. I honestly don't recall exactly how much but manageable to get vectored below and go VMC yet low enough not be a comfortable VFR flight beneath. I just remember that it was an interesting lesson. Coming back was a bit different. That flight had me climb above the layer in warmer weather down south and stay above it all the way back. It was forecast to open up by south Jersey for an easy VFR approach toward the end. Unfortunately it didn't play out as forecast and I had to descend through it. Fortunately it wasn't thick so I only picked up a little ice.

[kortopates]

No mention of what the FARs say?

Ah, you mean 91.527? At first it may seem pretty clear, till you look for a definition of known ice or icing conditions. But you'll find the FARs are pretty silent on that. That came from their legal council in a Info interpretation letter a few years back.


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[thinwing]

I remember that letter Paul,It was so full of legalese ,that what I got out of it was that if the possibility of icing existed and later the hapless pilot iced up and had an accident.Than the fact that he actually iced up proved the possibility of ice in the first place ,and hence ,hang the pilot!

[kortopates]

I remember that letter Paul,It was so full of legalese ,that what I got out of it was that if the possibility of icing existed and later the hapless pilot iced up and had an accident.Than the fact that he actually iced up proved the possibility of ice in the first place ,and hence ,hang the pilot!

It is full of legalese but their intent is right on. It's written in a sense to throw lots of caution to an inexperienced pilots. But it also gives lots of flexibility to an experienced pilot that doesn't simple stay in icing till it's an emergency and always has planned to give themselves a realistic out never has to worry about being violated. I.e. If the planning and decision making where prudent one shouldn't have to worry if things should go upside down.


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[RobertGary1]

Yea, legally its very not clear. The FAA says "known icing conditions". What does that mean? "Known" because of a PIREP? "known" because of a possibility stated in a sigmet? "Known" as in you should have known because of the meteorology training we receive as pilots??

Clear as mud???

Remember that the only official determination can come from the office of the chief council. Everything else is just opinion at the FAA. 

-Robert

[carusoam]

The thickness of the cloud layer is part of the equation.  The density of the moisture can add to the complexity...

And of course, if you find the cloud full of super cooled water droplets that freeze on impact as they run back...

Be aware of how quickly you are accumulating ice as you are moving on to plan B... climb above, descend below, go around....

Ice tends to accumulate pretty quickly in some environments.

Best regards,

-a-

[jlunseth]

It would depend.  I would likely go if the deck is 1,000 and I am sure of that, but 3,000 would be unlikely.  I would want to look at the icing forecast and a SkewT.  I would also take a look at the clouds with my MKI eyeball before I leave.  Lots of times a 1,000 deck is not very "thick," I mean the clouds are not dense.  If the clouds are not dense there won't be ice.  If they are wet clouds even a thousand feet would be worrisome.  I would also want to see what the temp is doing in that layer. Very often, if the temp at the base of the layer is just marginal freezing, say a degree or two C above freezing, it won't decrease in going through the layer, and you probably will find that temps actually increase above the layer before they start to fall again in the climb.  Sometimes they go just the other way.  But if it is a stratus layer there is a reason why it is capped at the thousand foot thickness.  The temps are too warm above the layer for the air to rise.  

Edited March 9, 2017 by jlunseth

[peevee]

As I think you're finding out its completely situational. As with the others if it's a thin layer and I can get through it I'll consider it as long as the bases are high enough that I'm not flying the approach in it. I'll also pop through it if it's extremely cold. I live out west where the terrain limits options below and it's freezing at the surface all winter. There are areas like the Cascades where I wouldn't even consider trying it.

My training (part 141) was to interpret k own icing as visible moisture and below freezing temps. Very safe but not very practical, though I guess I do basically still treat it that way.

[jlunseth]

There was one thing that I definitely should have mentioned.  WIth stratus layers in the winter, it is rarely the ascent through that concerns me.  It would be less than a minute through a 1,000 foot layer, and if there is ice you will pick up so little it won't matter. It is the descent at my destination.  You can usually negotiate with ATC and that helps some.  But what if you just have to stay in the layer to fly an entire instrument approach?  There are times that just can't be avoided if you want to get down.  Enroute also.  Often there will be some kind of frontal passage to make and the clouds may be quite a lot higher and denser.  As I said, I worry more about those than a thin ascent layer.