OK, so now how about ice?

[Dave Siciliano]

Dave,

Feb 19th? or 26th?

It would be the 19th.

 

[gismo]

Lance,

Dew point depression is the term used by forecasters to represent temperature-dew point spread. If you read my IFR magazine article, The Appleman Line this should explain the importance of dew point depression.[/quo'te]

That article has been in my "must read" pile but I haven't gotten a round tuit yet. I guess I better on it!

Given the temperature inversion and large dew point depression, flight at 10,000 feet should not only be ice-free, but also be cloud-free. This temperature inversion suppresses any lifting and knowing the synoptic picture helps you rule out the potential for vertically-developed clouds or convection.

That's one part of the Skew-T analysis I kinda remember from the days when I was into soaring and worked in the same building as the NWS MSP forecast office. Of course I wasn't all that interested or concerned with icing potential in those days as I didn't even have an instrument rating.

Soundings can be used at your destination, departure and alternate airports, but they can also be used to understand the potential for adverse weather along your route of flight. The best thing to do is use other products (too many to address in a post) to assess the big picture and then use the soundings to pinpoint the details that may have caught your attention.

Unfortunately AFaIK my main flight planning tool doesn't have any way to relate sounding locations with my route of flight nor any way to easily pull the Skew-Ts.

I normally spend about 4 hours in my weekend workshop teaching just the basics how to use this diagram in context of your route of flight to pinpoint the potential for turbulence, mountain waves, convection, non-convective low-level wind shear, icing, precipitation type, winds aloft, ceilings, fog potential, cloud tops, just to name a few. I am also teaching an introduction to the Skew-T diagram via an online seminar coming up in a couple days. See this post in the Classifieds forum for more details.

I already saw that post, but not until today which I assume is too late (the post stated March 1 as the date).

 

[gismo]

What would you have done had ATC refused clearance to descend due to traffic below?

Perhaps a safer method would be to request a 2000 ft block or request a PD descent to warmer air prior to reaching an icing altitude in the hold. An unusual request no doubt but something I suspect that ATC could live with. Either way you'd have a guaranteed out from the ice

You say you know what ice can do - but how can you justify that statement when, as far as I can tell, there isn't a reliable way to predict how quickly ice can form?

It is a fairly safe bet IME that accumulation rates in stratus clouds away from orthographic lifting and frontal zones will be low enough that you won't be in trouble with just a few minutes of exposure.

 

[Greebo]

Perhaps a safer method would be to request a 2000 ft block or request a PD descent to warmer air prior to reaching an icing altitude in the hold. An unusual request no doubt but something I suspect that ATC could live with. Either way you'd have a guaranteed out from the ice

Guaranteed? Suspecting ATC can live with it is hardly a guarantee.

It is a fairly safe bet IME that accumulation rates in stratus clouds away from orthographic lifting and frontal zones will be low enough that you won't be in trouble with just a few minutes of exposure.

I agree that its probably a fairly safe bet given those conditions, but the fact that it is a bet means that its still a gamble.

 

[gismo]

Guaranteed? Suspecting ATC can live with it is hardly a guarantee.

I didn't state this clearly, but what I had in mind was obtaining a clearance that included an escape to an ice free altitude before venturing into it. That way you aren't depending on ATC cooperation for your escape route.

I agree that its probably a fairly safe bet given those conditions, but the fact that it is a bet means that its still a gamble.

True, but life and especially flying is a gamble as well. The issue is are you comfortable with the odds.

 

[tonycondon]

The odds of getting that kind of clearance depend heavily on your geography. Out East, West or around Chicago would be no way, but around here, where you call MSP center, and get cleared as filed, whatever altitude you want, would probably be no problem.

 

[Dave Siciliano]

Dave,

Yes, I was actually capturing a bunch of data for earlier in the afternoon on this day right in the same area (Little Rock toward Tulsa). A pilot was forced to land at an airport just east of Tulsa after encountering icing conditions. Due to the snow on this runway, the airport was Notam'ed closed, however, him and his instructor still chose to land with some damage to the wheel pants on the plane. I'll post some more tomorrow, but there was a serious icing potential most of the morning and afternoon on the 19th with improving conditions into the evening.

That's why I'm interested Scott. I analysed that and flew threw it. It would be interested to see how you would have looked at it to see if you would have picked up anything materiel that I didn't see. I flew right through that area at 12,000 feet. Be interesting to see if you thought one should give that a go or not, and what altitude appeared to be the best to penetrate it. There were very strong southwesterly winds which was my direction of flight. They made flying higher very slow going. I stayed about 50 miles east of Tulsa as I headed south to Addison.

Dave

 

[AirBaker]

The odds of getting that kind of clearance depend heavily on your geography. Out East, West or around Chicago would be no way, but around here, where you call MSP center, and get cleared as filed, whatever altitude you want, would probably be no problem.

If you weren't granted the clearance... You don't have to do it.

There's just too many variables here.

 

[Dave Siciliano]

That's what we thought Scott, but couldn't piece it together as well as you. Any chance you can explain that chart a little? For your info, it was actually about -2C at 12,000. Reported colder below. The Nexrad showed a system of visible moisture and radar showed light returns. To the west toward Tulsa, the radar returns were much stronger: yellow up to some red.

The outs we planed were to climb or do a 180: definitely not to descend.

Sound like we were on target with you?

Dave

 

[Doug R]

Great thread gang. Ice should command as much respect as a level 5 thunderstorm. Visit the links section on POA and take the NASA online Ice course. Excellent information. Please invest the time to take this course.
fly safe,
Doug

 

[Dave Siciliano]

We went right over Springfield, Mo. That's where the V-tail Bo reported moderate ice at 5,000. Passed just east of Little Rock on the way to Addison.

 

[Henning]

Apparently I've hit a sore spot in many of you.

Yeah, because it doesn't make sense. First off, every time you Ice, you will be playing test pilot with a new and different airfoil, so the "Learn how it is" analogy is inappropriate because it's never exactly the same, and because it was like this and ok last time, doesn't mean it will be next. Advocating the experience for no good purpose is not good. It is better to follow a basic escape proceedure and preferably out the bottom with an AOA to keep the ice on the top of leading edge area. There is no reason to flirt with icing unless you are in it through no misscalculation of your own. If you fly a non K-Ice plane purposely into Icing and get killed, that is on par with running out fuel on the inexcusable ways to die. When you do encounter it, you make your calculations on the spot to match the situation. There is no graph or correction formula in the POH for ICED UP PERFORMANCE. You have to look and see what is required for each individual circumstance.

 

[Henning]

No offense Chuck, but the problem with this statement is that it has been done. It just isn't approved in the POH. True, the icing potential is an unknown, but the knowledge would still be helpful.

My guess is that my airplane has had ice on it before, I just haven't been around to see it. Maybe I just need a video of it.

The problem is while yes, the plane will fly with some ice on it, how do you know it will fly with the load you pick up this time? That's the whole problem with flying IMC in icing conditions, you don't know what you're going to get, that's why you don't purposely go there. If you even think you might possibly get there, but not likely, you don't go unless you always have down as an out, and realistically, if down is an out, why the heck you up in it, save fuel? The risk benefit equation on this one just never works out in favor of flying a non K-Ice plane into icing. Icing can get severe enough to bring down big K-Ice planes, and has. Even the heavy iron routes around the bad cells. If you get some, you get some and deal with it (or die as does happen) as the situation requires. To fly into it for no good reason is unacceptable.

 

[Henning]

Ed, I think what you've said is good advice. My answer to the above is... I would not fly in IFR conditions even CLOSE to possible icing if my aircraft could only handle (figureatively) 1/4" of ice versus the 5"...

Knowing that I can handle 1/4" safely, gives me that chance to make the 180, ascend/descend, to get out of the ice. And to do so by choice.

Right, the forcast has some icing in it, but you know you're plane will haul a bit of Ice, so when you get in it, you can just turn or whatever and get out right? So as you bump along through the soup you see the 1/4" and rightly decide to get out now. Since you're in IMC in a small plane, you have no idea where the moisture concentrations and convections are. Turning that left turn turned you into the edge of the supercooled water drops, you picked up a bunch of Ice on the top, and now you are full power engine about to break the mount from the shaking of prop because the ice only broke off one blade because there is no system to ensure it'll be symetrical, can't read the instruments either the plane is shaking so hard, luckily the other blade slings some ice and it evens out, even if you survive, you've got a major tear down inspection to do after that before next flight, especially if you have the floating counterweights in your engine. Now you're losing altitude and start pitching up because there's hills in these clouds. Now you're building ice up on the bottom of the wing, and you're still not out of it. You just died executing a proper exit strategy.

See, the problem with IMC especially when there's convective activity is you don't know where the moisture is unless you have a radar (and know how to operate and interpret it). Most radar equipped planes are K-Ice, although I do know a few that aren't. The one that sticks in my head is an Alaska Airlines captain with a Bonanza as his commuter from Big Bear to LGB. Know why he put it in? To help him avoid icing in IMC. I used to fly a Cherokee 6 that had one and There was a P-210 on our ramp that had one.

 

[flyingcheesehead]

My learning encounter with ice

Might as well throw one more in the mix.

MSN to DBQ and back, IFR training flight. No ice forecast, and none encountered on the outbound trip. Ceilings ~600 feet. After a Localizer backcourse approach to near mins in DBQ, we taxied back, copied our clearance back to MSN, and took off again.

At 5,000 we were in and out of the tops, very pretty. MSN approach brought us down to 4,000 and we began to pick up light rime. It probably was only 3/4" or so in the end, but enough to get my attention! The problem was that Approach was busy and I couldn't get a word in edgewise at first. I wanted to start descending right away anyway, CFII wouldn't let me.

Finally, I heard a break and squeaked out "Approach, 27M picking up light rime at 4,000, request immediate descent." They brought us down to 2,700 which is the initial altitude on the ILS 18.

I was surprised how quickly the ice shed off when we descended into warmer air (still solid IMC). I also didn't notice a significant difference in performance, but this was a while ago (ie not as much IR training as I have now).

Put me in the "Glad I had some icing experience with a CFII aboard but won't touch the stuff on purpose" category.

 

[Richard]

It probably was only 3/4" or so in the end, but enough to get my attention!

Kent, that has to be the understatement of the year! (bold highlight is mine) "only", indeed.

Put me in the "Glad I had some icing experience with a CFII aboard but won't touch the stuff on purpose" category.

So they would find two bodies not just one? I imagine very few go looking for it on purpose but I have heard folks say what they would do if encountered but then later say they were slow to respond or did the wrong thing, as determined by hindsight and review of wx charts. That is a scenario just like what Henning said.

This thread makes me recall Langewieschie Jr's story of purposely seeking out bad wx to fly into. I think it would be highly instructional to make such a flight with an experienced pilot in a capable bird but the risk would be through the roof. And your ins co would probably drop you if they ever found out what you were doing.

 

[poadeleted20]

The problem was that Approach was busy and I couldn't get a word in edgewise at first. I wanted to start descending right away anyway, CFII wouldn't let me.

Bad lesson -- you had the better idea. In a non-KI airplane, any ice encountered unexpectedly is an emergency. If I "couldn't get a word in edgewise" to request lower, I'd have squawked 7700 and started down to the warmer air on my 91.3(b) authority long before I had 3/4-inch of ice (a potentially lethal dose) on the plane.

 

[Dave Siciliano]

We went right over Springfield, Mo. That's where the V-tail Bo reported moderate ice at 5,000. Passed just east of Little Rock on the way to Addison.

Sorry;

I've got a heck of a head cold! We flew just west of Little Rock.

 

[flyingcheesehead]

Bad lesson -- you had the better idea. In a non-KI airplane, any ice encountered unexpectedly is an emergency. If I "couldn't get a word in edgewise" to request lower, I'd have squawked 7700 and started down to the warmer air on my 91.3(b) authority long before I had 3/4-inch of ice (a potentially lethal dose) on the plane.

My perspective may be colored a bit because of my lack of experience at the time. "Couldn't get a word in edgewise" probably only lasted for 20 seconds, and it was 3/4" or less (didn't have my ruler mounted on the wing at the time ). That CFI had quite a bit of KI Seneca time and probably just enough icing experience to be dangerously comfortable with it.

I'll ask my current CFII (who also has lots of KI multi hours, both Seneca and Aztruck, but mostly for himself rather than instruction) what he would do in a non-KI single. Either way, Ron, I'm with you. Get the heck out!

 

[Dave Siciliano]

More perspective on ice. Here's a post from a fella that encountered ice on the west coast over the mountains that had a TKS system.

Dave
=====================================================
Monday, I had to use the TKS system in “anger” for the first time since I had it installed last October.

I have to say that it didn’t perform up to my expectations. So, I’m wondering why. Expectation too high? Didn’t operate the system as I should?

Scenario:

Flight back to Bremerton from the Bay Area. Filed for 10K as the ADDS FPT said there shouldn’t be any ice up there (too cold). ATC routed me as I filed but didn’t let me climb to altitude for a very long time. I was sitting in IMC at 8K and at about -10C outside. I had the anti-ice (low-flow setting) on. Up around Northern California, I picked up a trace of rime and it stayed there. Kinda streaky along the chord of the wing; stayed on in some areas and came off in others. I finally got 10K after a while but it was still building. By the time I got to 12K I was in and out of the clouds so was able to work with what I had built up and wasn’t getting any more.

As I saw that the anti-ice setting wasn’t keeping up with the buildup, I switched to de-ice (high-flow setting). That kept it from getting any worse but didn’t get off what had already built up. There was a foot and a half section, about two-thirds of the way out from the fuselage on both sides, that didn’t seem to be getting any protection at all. The ice just built up and stayed. That ice looked more like clear than rime but it was hard to see. It built up about ½ to ¾ inch and didn’t melt off until I descended into warm air. The rest of the wing was reacting to the de-ice setting eventually. The windshield was loaded and occasional bursts of fluid didn’t do very much. That stuff came off over time with the fluid that was coming off the prop. The windshield fluid bar did some good but not as fast as I had expected.

I spoke to Dave Van Horn who lives up here in Washington State, deals with this stuff regularly and has the TKS system on his A36. I also chatted with the folks at AS&T who make and install the system. It seems that you can get “behind” the situation easily. The TKS system is only effective if you are early and aggressive with it. I also should have started working with ATC to get the higher altitude sooner but I wanted to see how the system worked in actual conditions – something you can’t easily orchestrate.

The “new” procedure is now to:

Slather the airframe using the de-ice (high) setting for three to five minutes if it looks like an encounter is imminent but well before entering IMC. Switch to anti-ice if the wing is free of ANY ice and watch. At the first sign of ice sticking, switch back to de-ice to clear it. Once clear – if that happens – you can go back to anti-ice.

All the while, aggressively work with ATC to get to a new situation (higher/lower/turn back/land/whatever).

Switching between de-ice and anti-ice is how you manage the total fluid you have available. The high setting throws out fluid at twice the rate as the low setting. In my case, the low setting gets me about three hours out of the seven gallons, the high setting takes that down to about an hour and a half.

 

[poadeleted20]

Dave's post is just what I was worried about when I made that post elsewhere about the Columbia (Lancair) ad -- this guy stayed in icing conditions in a non-KI airplane because he figured the TKS system would prevent things from becoming lethal. Note the statement "I wanted to see how the system worked in actual conditions." Scary, huh?

 

[wsuffa]

Dave's post is just what I was worried about when I made that post elsewhere about the Columbia (Lancair) ad -- this guy stayed in icing conditions in a non-KI airplane because he figured the TKS system would prevent things from becoming lethal. Note the statement "I wanted to see how the system worked in actual conditions." Scary, huh?

Ron, are you sure that this plane was NON-KI?

The advice in that post is excellent, in terms of getting out of conditions, even with deicing equipment. However, the plane MAY have been K-Ice because AS&T produces a K-Ice certified version of TKS for the A36, I'd want the facts for this situation before I judge:

 

[Chas]

In re: Experimental investigations of the effects of icing on the airworthiness of my aircraft, and of my skills in handling the situation.

Me, I restrict my investigations of hypotheses to controlled laboratory conditions, where the worst thing that can happen is that I dump the hypothesis in favor of a new and better one (never run out of them !) and a few million tumor cells die on a dish. The process is usually repeated a short time later .....

Airframe icing investigations are best left to those approved by FAA to carry them out.

But this thread is giving me ideas. Maybe I should fly below one of the fire suppression "bombers" on a mission out of Ramona, just as it is releasing its load over the conflagration. This would simulate: 1) flight into very heavy precip. beneath a massive TS, 2) accidental flight into a thermonuclear exposion. Experimental findings will be presented on the local news, with film at 11.

 

[Pilawt]

My curiosity about ice was satisfied one December, enroute from Portland to Medford in IMC, about -2C. Descending was not an option. I could see a buildup of about an inch on the leading edge of an antenna, which started whipping back and forth like a happy greyhound's tail, so wildly I thought it would break off ...

... so I pulled over at the next rest area and scraped the ice off the radio antenna, as well as the rest of the front of the car.

(The "IMC" was freezing ground fog, and this was in a Ford Explorer on Interstate 5.)

I'm cured, thank you very much.

-- Pilawt

 

[Dave Krall CFII]

I spoke to Dave Van Horn who lives up here in Washington State, deals with this stuff regularly and has the TKS system on his A36. I also chatted with the folks at AS&T who make and install the system. It seems that you can get “behind” the situation easily. The TKS system is only effective if you are early and aggressive with it. I also should have started working with ATC to get the higher altitude sooner but I wanted to see how the system worked in actual conditions – something you can’t easily orchestrate.

The “new” procedure is now to:

Slather the airframe using the de-ice (high) setting for three to five minutes if it looks like an encounter is imminent but well before entering IMC. Switch to anti-ice if the wing is free of ANY ice and watch. At the first sign of ice sticking, switch back to de-ice to clear it. Once clear – if that happens – you can go back to anti-ice.

All the while, aggressively work with ATC to get to a new situation (higher/lower/turn back/land/whatever).

Cold ice is fairly sticky stuff on an almost equally cold surface that hasn't been adequately pre-lubricated.

source: Winter 101

 

[poadeleted20]

Ron, are you sure that this plane was NON-KI?

No, now that you mention it. For some reason, I got the idea this was an SR22, which is not KI-certified. In any event, if the system is not effectively removing the ice (and the post suggests it was not), one should not remain in the icing conditions, even in a KI-certified aircraft.

 

[Dave Siciliano]

A little more insight:


I find if the system has not been used for a while i.e. 3 weeks or so, you
need to turn the system on before you fly. Then once it starts to come out
you rub your hand along the wing and make sure to smear the fluid on all
parts of the tks panel. This tends to prime the system and makes it flow
even across the panel. Really makes a big difference.
I agree with what he is saying about staying ahead, I rarely need to use
the system on high, but my flow rate on low may be set higher.
As a result I only have one hr of protection on low setting.

 

[ejensen]

What kind of planes are these, Bo's?

 

[AirBaker]

No, now that you mention it. For some reason, I got the idea this was an SR22, which is not KI-certified. In any event, if the system is not effectively removing the ice (and the post suggests it was not), one should not remain in the icing conditions, even in a KI-certified aircraft.

The writeup by Dave S is in regards to a 1992 F33A Bonanza. The A36 mentioned is owned by anothed 'Dave' and is a 1993 Turbo Normalized model.

 

[Dave Siciliano]

The writeup by Dave S is in regards to a 1992 F33A Bonanza. The A36 mentioned is owned by anothed 'Dave' and is a 1993 Turbo Normalized model.

Thanks for clarifying Chris. I asked the owner which TKS system he purchased: the K-ice or basic system. Many folks smooth over the difference saying the K-ice system is more back up systems only, but, it's not K-ice for a reason.

Dave

 

[AirBaker]

No problem. Just as a point of reference, I've met both of them last year at the B2osh training. Dave VH was the only guy from the Northwest to make it down. He came from Washington, and the others in Oregon had to cancel due to the weather. Dave's TN and TKS got him through.

 

[spiderweb]

Thanks for that, Dave. If the high setting still gets 1.5 hours, I would just ALWAYS use high. I should be able to get out of icing ASAP, and I certainly don't want to be sitting in it as long as 1.5 hours! So, if you figure you had to climb out of and later back down into an icing area, even if you had to spend 30 minutes total, you'd still have lots of time to use the full amount!

 

[spiderweb]

This is a very valuable thread. I'd even suggest making it a sticky. But if "unregistered" man had his way, this thread wouldn't have even existed. I'm sure he knows all of this stuff, though. . . .