Why climb for ice?

[SkyHog]

This is something that I've wondered for a long time, but just now thought about. Why is it suggested that if one encounters ice, that person should climb to a higher altitude. I can understand the idea of "more altitude, more options," but it seems to me that in any case other than a temperature inversion, temperature reduces with altitude. Seems icing would be worse if you climb. Any moisture that has not become ice would freeze (at least in my mind).

What am I missing?

 

[Brian Austin]

What am I missing?

Think about the moisture content in the air at different altitudes.

Without moisture (or enough, anyway), ice can't form. I've heard (but can't quote from anywhere primarily because I'm too darn lazy at the moment) that the Arctic is actually as dry or drier than the Sahara. Even though it's obviously very cold there, relatively little snow or ice is formed except during its spring and autumn.

 

[Brian Austin]

That makes sense, Brian, but wouldn't it be better to descend and try to get the ice to melt off? While its drier up there, it's also colder, so I can't see the ice melting.

I'm not trying to challenge conventions here, just trying to get a good grasp on why.

Having never experienced icing, I'm going to let others comment on why. I don't even fly in those conditions (luxury of doing this as a hobby vs for work, etc.).

Challenge conventions whenever possible. It's what got us in the air in the first place.

 

[bbchien]

This is something that I've wondered for a long time, but just now thought about. Why is it suggested that if one encounters ice, that person should climb to a higher altitude. I can understand the idea of "more altitude, more options," but it seems to me that in any case other than a temperature inversion, temperature reduces with altitude. Seems icing would be worse if you climb. Any moisture that has not become ice would freeze (at least in my mind).

What am I missing?

Icing generally occurs because something IS inverted, such as a warm moist layer raised to be interspersed at a colder altitude. In the situtation of freezing rain, climbing is the ONLY way out, as supercooled drizzle drops at less than 32 degrees remain so until they collide with you- becoming ice.

The problem with climbing is that all the ice stops at the alititude with "lift" runs out- lift that supports the droplets in the atmosphere. At the very topmost such altitude, icing is always worst.

For much more, because I sold the copyright to a string of articles in Aviation Safety, to Aviation Safety when they were published, I can't post them here. But their website has 'em.

 

[Let'sgoflying!]

Sometimes going up means getting on top. No moisture = no chance of ice, that would be one situation where up is better.

If hemmed in by the MEA then up may be the only option.

A rule of thumb (means it is not always correct!) that you will often read is that if you can change altitude by 4000' then you might get out of icing conditions. So if you are less than 3000' abv MEA, climbing might be better because if we believe our RoT, down means you won't get out of it.

".. temperature reduces with altitude. Seems icing would be worse if you climb. "
Colder doesn't mean icing; colder can be better. If you are getting ice at m5C, climbing 4000' to say, m13C can put you outside the icing conditions. Not always away from the visible moisture, just away from where it will stick to you.

All the above is usually predicated on a stable atmosphere, non-convective. Near mountains for eg; all RoT's can go out the window.

Up vs Down: airplanes can always go down. (We haven't left one up there yet!) If you chose down, and it doesn't work out (still icing at mea), what option does that leave you? If you chose up, unless you leave the decision til very late you stand a chance of fixing the problem. If it doesn't work out then you are going down anyway and you will get to 'try' that option.

About moisture and altitude again:
Going higher may not get you into conditions of less moisture, I read that the upper levels of cloud layers have more moisture.

Not an icing expert; just a regurgitator of readings.
I have read others disagree with going up, too.

 

[Skip Miller]

Climbing to exit icing conditions is but one of your possible options. Know what they are BEFORE every flight where icing is a possibility.

Know where the cloud tops are. The cloud tops are the upper limit of ice. Beware of freezing rain coming from a higher cloud layer.

You should plan on getting out of ice as soon as you detect it. Climbing 4000 feet at Vy takes a long time, and frequently the ice is the worst at the top of the cloud. If your climb rate goes to zero while still in the ice, you are in very serious trouble indeed. A heavily laden plane, with experimental airfoils due to ice accretion, iced over windows, and now you must descend. Normally aspirated singles that most of us fly are poor performers with a little ice.

Climbing is a great option if you are near the tops, at a low altitude, and you are flying well below gross. But if you are in a C-152 at 10,000 and the tops are at 14,000 ... well, climbing had better not be your only plan.

So as to the suggestion you have been given to climb when encountering ice: "It depends".

-Skip

 

[Ed Guthrie]

Without moisture (or enough, anyway), ice can't form. I've heard (but can't quote from anywhere primarily because I'm too darn lazy at the moment) that the Arctic is actually as dry or drier than the Sahara.

The reason for the above is that "moisture" by definition is liquid water. While ice is a form of water it is not moisture. The Artic is so cold that there is virutally no liquid water, ergo no moisture, ergo the Artic is "drier" than the Sahara.

BTW, this happens to be related to one of the great misnomers in aviation. You'll find a goodly collection of foot stompers who will insist that all clouds consitute "visible moisture", which is related to the FAA definiition of known icing conditions. The fact is that clouds may be composed of liquid water, ice crystals, or both. Those clouds composed of ice crystals are not "visible moisture" as they contain no moisture (liquid water) at all.

 

[The Old Man]

Bottom line, get to where the OAT is below the dew point.

 

[AirBaker]

As a side note, don't forget that an MEA isn't necessarily the lowest altitude you can fly at.

My guess would be that you would want to know where you were in the icing. Is it 500' up to non icing and 3000' back down through it.

 

[poadeleted20]

In stratus clouds, this is good advice. If you climb a couple of thousand feet, you will probably be out of it, either on top or in warmer air aloft in a warm front or inversion situation. In cumulus clouds, it isn't, as the icing gets worse as you get near the top and the tops of cumulus clouds may be WAY higher than where you are.

As with all other ROT's, you must understand the context and the background for the information to be used correctly.

 

[Toby]

Those clouds composed of ice crystals are not "visible moisture" as they contain no moisture (liquid water) at all.

I didn't know that!

 

[Skip Miller]

Ok, so I get it...once you start to collect ice then, you don't try to get the ice to melt, you are more concerned with not picking up more of it.

Correct. Once out of icing conditions, the ice you do have will ablate (go from a solid state to a gaseous state without having to melt) and if you are up there long enough, no more ice.

You go higher so that worse case scenario, maybe you can get to an airport somewhere and scrape the ice off.

Remember please that going higher may be the wrong direction to exit icing conditions. And don't scrape the stuff off! Can you say scratches in the paint? Unless its a rental of course! LOL! NOT!

-Skip

 

[wsuffa]

Correct. Once out of icing conditions, the ice you do have will ablate (go from a solid state to a gaseous state without having to melt) and if you are up there long enough, no more ice.

Remember please that going higher may be the wrong direction to exit icing conditions. And don't scrape the stuff off! Can you say scratches in the paint? Unless its a rental of course! LOL! NOT!

-Skip

"Long enough" may be too long under certain conditions. Don't expect sublimation in all conditions - though it will be helpful if you've got sunshine beating down on it. It can take hours for ice to work its way off....

As others have noted, know the conditions. Going higher may make things worse if you're in the tops or you can't bust out of the top. And yes, you can pick up ice in the summertime - I hit a layer at 16,000 one August day outside of Dallas and started to immediately pick up rime. The right choice there was to go lower.....

 

[poadeleted20]

Ok, so I get it...once you start to collect ice then, you don't try to get the ice to melt, you are more concerned with not picking up more of it. You go higher so that worse case scenario, maybe you can get to an airport somewhere and scrape the ice off.

I think you're overgeneralizing. Yes, you are concerned with not picking up more ice, but you do also want to get the ice to melt. Ideally, you'd want to do both, but in a not-so-ideal situation, you may have to choose between the two, and the better choice will be situationally-dependent -- there's no one, clear-cut answer.

So if you know you're close to the top of a stratus, and there's sunshine up there, you might try to drag your ice up there, picking up a bit more in the process but knowing that it will all sublimate off once you get there. OTOH, if you're in a cumulus cloud, you can probably get out faster by a horizontal move than a vertical one, and that means ending the accumulation but not necessarily melting off what you've already got.

Doesn't sound too promising, but I guess neither does flying into ice in the first place.

Amen. Just remember the priorities -- Avoid, Survive, Escape. Avoid getting into it in the first place, know how to Survive if you get in it, and know how to Escape the situation you got into.

 

[Let'sgoflying!]

once you start to collect ice then, you don't try to get the ice to melt,

well if you can get into sunshine on top it will disappear (not 'melt' though)

you are more concerned with not picking up more of it.

I would say this is the most important thing (besides avoiding accumulation to begin with through adequate planning)

You go higher so that worse case scenario, maybe you can get to an airport somewhere and scrape the ice off.

you go higher as a technique to stop the accumulation, and as you say, so you can get to an airport. More on scraping it off later.

Doesn't sound too promising, but I guess neither does flying into ice in the first place.

that's the thing - ice in an airplane not equipped for it boxes you in rapidly - I was surprised to learn how fast (seconds to a few minutes in some cases) and is not too promising as you say.


Scraping it off:
-if you are scraping ice off you are removing finish. Not encouraged. Warm water from the fbo, poured into a pail, then into trash bags which are held on the leading edge is the poor man's way. A heated hangar while you have lunch in town is 00x better!
BUT why are you doing it? Planning to go back up and get some more?!
Might be a good day to stay vfr. I know a guy who took a 182 into ice over New Mexico a while back. He couldn't climb out of it and discovered an uncommanded descent... he steered away from the mountains and exited the clouds still in control, way below MEA (yes AB is right MEA is not the endpoint of safe descent sometimes) where it melted off. Continued to destination. Climbed back up into it (atc actually held his clearance open) and landed with another 1 & 1/2". THEN he melted/pounded the ice off and went back home in it AGAIN!
I'd never get away with that!

 

[bbchien]

I'm not at home right now. But I'll try to remember to post a copy of Dr. Bruce's Op Specs for opeartion of Non Deiced Singles in winter. ALWAYS HAVE A CERTAIN OUT!

 

[Dave Siciliano]

Just to add to the above, on several occassions I've flown my A-36TN through cloud layers well below freezing and got an accumulation of light ice crystals on the front of the wings: the water in the air was frozen. This has generally been at -10C or colder. It's just been a light coating that doesn't accumulate and quickly clears off when I'm out of the clouds. On several occassions, I've climbed through cirrus clouds to clear conditions on top where the it was -10 C or colder in the clouds. So, one out in an aircraft that will go high, is to get up where it's too cold to accumulate. That being said, one has to get up there and back down. When I fly on long cross country flights, I can often climb and descend in acceptable conditions.

One of the most fun things I did once was depart Wisconson in VMC conditions. As I climbed through 12,000 feet, I got into cirrus clouds (and knew the tops were about 13,000). Came out on top with white whiskers on the front of the wings and tip tanks. At 14,000 the flying was clear and smooth all the way to Oklahoma where the clouds broke up and it was VMC again. This is an instance where the turbo make a huge difference. The FSS brief was also fun as the briefer gave an icing SIGMET from Illinois to Oklahoma (of course in visible moisture) up to 12,000 feet. I asked where the cloud tops were (12 to 13,000) and where it was -10C. He was a little befuddled, but said it was -10 and 9,000 feet. So, I knew if I could get above 9,000 feet before entering the clouds, the moisture would be frozen and I could easily climb on top.

Best,

Dave
A-36TN ADS

Best,

Dave
A-36TN ADS

 

[grattonja]

Think seriously about IFR in the winter months, particularly in the Northeast, before you do it. A broad generalization, but it does come from some experience.

In a light single, depending on how fast the ice is coming on, you may soon find yourself not able to climb, even if you want to. Two things to consider as you slowly become an ice cube. First, that ice adds a ton of drag. Second, the prop becomes unbalanced in a hurry if there is no heat for it. Then the ride becomes slow and rough.

I won't belabor you all with my story, as I have posted it elsewhere in the past. I will only say that airmets for icing are not always accurate, New England on a cold, damp winter's day can be a dangerous place to be IFR, and a skyhawk with more than an inch and a half of rime ice on it would not go above 5500 feet on a November day.

Climb if you can, but make sure you have some room for error below you. We did, with at 4400 foot ceiling to get down below as soon as we were West of the mountains. Darned glad to see the ground and positive temps that day

Jim G

 

[bbchien]

For what it's worth:

"Flying a non-deiced single, hopefully WITH a turbocharger, in clouds when the surface temperature is below freezing is possible but requires careful planning with continuous updating.

In general, it is better if you can plan your mid flight on top, rather than in the middle and using descent as your out from ice. You simply have more options. For years, I flew a turbo Mooney to Colorado in the wintertime and would go if all of the following were true:

1) No icing predicted on climbout, as compiled by compositing the UCAR website experimental models of moisture content/icing, and Federal Weather and pireps, or : Light icing possible on climbout, but climb rate expected in excess of 800 fpm through the top, and departure airport or nearby airport supports criteria (3,5) continuously.
2) Ability to continue ON TOP for the entirety of the enroute trip.
3) Descent through a potential icing layer (3 minute maximum exposure), only if the surface temperature is above 35 deg F and the IFR weather is a pretty certain "make", e.g, ILS with 600-2.
4) No flying into the warmfont side (all the moisture is there, in nice wet/cold layers!). OK to fly away from it.
5) Weather at all enroute airports with ILSs is a "make" rather than a "shoot" or "break".
6) Enough fuel to fly to VFR descent if absolutely required.

Enroute, continuously update the current local surface conditions by listening into ATISs along the way; they have to continue to satisfy (5) above. The terminal weather per FSS enroute must not deteriorate below (3). If they do, execute plan (6), and plan better next time.

The inability to climb through the top at 800 fpm is a red flag (see your POH). If you have to hold Vy to climb 500 fpm, you may be in the top, where all majority of big water particles hang out, for a long time. Climb degrades very quickly with any ice, and takes a long time to sublimate off in the on-top winter cold, when you're running wide open throttle and getting only Vy+10."

The key, is always have an option. Now, Ed Guthrie and I have discussed this multiple times over the years. He had an experience in which his cold soaked Mooney (fuel against the skins!) did not shed in 38 degree temps. He regards that or 40F to be his minimum for temperature below. One has to set his personal operations specs to one's own personal level of comfort. His is a VALID opinion. This is just what I use.

Currently I am flying a turbocharged Known Ice Twin. The only thing different is in such planning, I can generally count on making it out on top. And "On Top" is subject to 3, and 5 above if the TOP is above my Single engine Service ceiling. For example, if I am blowing over on top at FL 21, I am still constantly checking ATISs below because I won't be able to maintain by 13,500 on a single blower.

 

[Ed Guthrie]

For what it's worth:

1) No icing predicted on climbout, as compiled by compositing the UCAR website experimental models of moisture content/icing, and Federal Weather and pireps, or : Light icing possible on climbout, but climb rate expected in excess of 800 fpm through the top, and departure airport or nearby airport supports criteria (3,5) continuously.

3) Descent through a potential icing layer (3 minute maximum exposure), only if the surface temperature is above 35 deg F and the IFR weather is a pretty certain "make", e.g, ILS with 600-2.

5) Weather at all enroute airports with ILSs is a "make" rather than a "shoot" or "break".

Now, Ed Guthrie and I have discussed this multiple times over the years. He had an experience in which his cold soaked Mooney (fuel against the skins!) did not shed in 38 degree temps. He regards that or 40F to be his minimum for temperature below. One has to set his personal operations specs to one's own personal level of comfort. His is a VALID opinion. This is just what I use.

I really appreciate that Bruce posts this advice and that he acknowledges that it is all about choices. At one time my personal icing avoidance rules pretty much matched what Bruce advises above. Strangely, I developed those rules while flying a Mooney as Bruce did. Then I managed to test the envelope once too often.

FWIW, I have problems regarding #1, (because it links to) #3, and #5.

#3--I once had a ~15 second encounter with icing one April day over Arizona. In the few secons of that brief time I turned a Mooney into a brick. One minute I'm cruising west bound at 16,000' truing 150 kts, but a few seconds later I'm piloting a brick descending at better than 1000 fpm while trying to guess what the new airfoil's Vy might be. Bet my butt that I'll survive a 3 minute icing encounter? No way!

#5--Commit the following firmly to memory: There is no guarantee that an iced aircraft will be able to maintain an ILS GS. None what-so-ever. The aircraft may very well plummet right through GS intercept. I have inadvertently flown a brick more than once; holding a standard 3 degree GS was totally out of the question. If the surface temperature is a mere 35 degrees F the aircraft may very well carry the ice load all the way to impact. I once carried a significant but lesser ice load down the ILS and the full taxi distance to the FBO ramp at AGC. Surface temps were above freezing. Welcome to test pilot school. An ILS is not an icing encounter "out"--it is wishful thinking.

As a result of some inadvetent encounters my icing planning rules list is much simpler than Bruce's: Don't plan on it--ever. Ice can accumulate faster than you would ever imagine--even in your worst nightmare. Don't flirt with icing at all--ever. Don't tell yourself that there is such a thing as a controlled icing encounter--ever.

If you fly IMC/IFR in the winter you will sooner or later create enough inadvertent icing encounters to last your lifetime. Don't add to the collection by deliberately flirting with icing.

Just my opinion. YMMV. I wish I had Bruce's k-ice bird.

 

[gismo]

#3--I once had a ~15 second encounter with icing one April day over Arizona. In the few secons of that brief time I turned a Mooney into a brick. One minute I'm cruising west bound at 16,000' truing 150 kts, but a few seconds later I'm piloting a brick descending at better than 1000 fpm while trying to guess what the new airfoil's Vy might be. Bet my butt that I'll survive a 3 minute icing encounter? No way!

#5--Commit the following firmly to memory: There is no guarantee that an iced aircraft will be able to maintain an ILS GS. None what-so-ever. The aircraft may very well plummet right through GS intercept. I have inadvertently flown a brick more than once; holding a standard 3 degree GS was totally out of the question. If the surface temperature is a mere 35 degrees F the aircraft may very well carry the ice load all the way to impact. I once carried a significant but lesser ice load down the ILS and the full taxi distance to the FBO ramp at AGC. Surface temps were above freezing. Welcome to test pilot school. An ILS is not an icing encounter "out"--it is wishful thinking.

As a result of some inadvetent encounters my icing planning rules list is much simpler than Bruce's: Don't plan on it--ever. Ice can accumulate faster than you would ever imagine--even in your worst nightmare. Don't flirt with icing at all--ever. Don't tell yourself that there is such a thing as a controlled icing encounter--ever.

Just my opinion. YMMV. I wish I had Bruce's k-ice bird.

One of the biggest problems with ice is that there's so much variance left to chance between one instance and another. And IME the vast majority of icing encounters are relatively benign, leading one to belive that escape is always possible. Then along comes the time like Ed's example where things get really bad really quick. I don't preach that you should ground all non KI aircraft for half the year, but anyone flying in the upper half of the country during the winter months in anything but CAVU conditions is taking on additional risk. I also think that this extra risk must be fairly small given the small percentage of accidents blamed on airframe ice vs the large number of flights conducted in potential icing conditions.

Also FWIW (Ed you already know this, but your comment might mislead others) KI only decreases the risk, it doesn't come anywhere near to eliminating it. It seems that a significant fraction of the few icing accidents occur on KI airplanes that were overwhelmed by conditions, and/or mishandled by the pilot.

 

[gismo]

I didn't know that!

If you ever got your tongue stuck to a too cold ice cream treat, you would know first hand that ice isn't the slightest bit moist.

 

[wsuffa]

Also FWIW (Ed you already know this, but your comment might mislead others) KI only decreases the risk, it doesn't come anywhere near to eliminating it. It seems that a significant fraction of the few icing accidents occur on KI airplanes that were overwhelmed by conditions, and/or mishandled by the pilot.

And to top it off, the KIND of deicing system and TYPE of icing makes a huge difference, too. Roselawn is the poster child for a K-Ice plane becoming overwhelmed by SLD ice. OTOH, slow-forming rime is usually a different story if you have boots.

According to folks that have flown both boots and TKS, the TKS system is far superior for preventing icing in the first place. It does cost in terms of chemicals, but from everything I've heard my preference would be for TKS.

 

[gismo]

And to top it off, the KIND of deicing system and TYPE of icing makes a huge difference, too. Roselawn is the poster child for a K-Ice plane becoming overwhelmed by SLD ice. OTOH, slow-forming rime is usually a different story if you have boots.

According to folks that have flown both boots and TKS, the TKS system is far superior for preventing icing in the first place. It does cost in terms of chemicals, but from everything I've heard my preference would be for TKS.

On the plus side for TKS:

Just turn it on and it works.

Can prevent (and sometimes remove) ice from the whole airplane (except the spinner), antennas and all.

No bridging or runback issues (theoretically).

More resistant to careless line crews.

Short individual sections are replaceable.

Doesn't kill vacuum pumps.

Entire weight is carried winter and summer.

The negatives:

Operation time is limited by fluid capacity.

Line crew may fill fluid tank with avgas.

Usage cost of $10-20/hr (when you need it you won't care).

 

[wsuffa]

Lance, that's exactly my point.

I'd spend the money on the TKS over boots for the better deicing. The only real issue seems to be that there are a limited number of airports that carry the fluid. Call ahead - or carry some in your baggage.

Even with TKS, you want to stay out of the ice as much as possible.

 

[gismo]

TKS vs Boots

Lance, that's exactly my point.

I'd spend the money on the TKS over boots for the better deicing. The only real issue seems to be that there are a limited number of airports that carry the fluid. Call ahead - or carry some in your baggage./QUOTE]

Oh, I wasn't disagreeing. If I had the choice between TKS and boots, I'd take TKS. Availability of the fluid is one downside I'd forgotten about (cause I don't have that worry now).

 

[poadeleted20]

The only real issue seems to be that there are a limited number of airports that carry the fluid. Call ahead - or carry some in your baggage.

Before you carry that fluid anywhere in your plane other than the place in which it's supposed to go, check the label to see whether you want it in the cabin. We've had this debate over carrying TCP (used as a fuel additive to reduce lead fouling by folks who don't religiously follow Lycoming's recommendations in their Service Letters 185B, 192B, and 197A which pretty well take care of the problem if you follow their advice) in the Grumman world, and when it comes up, I always point folks to this fatal accident:

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001211X12083&key=1

Now, I don't know how flammable that de-ice stuff is, but y'all oughta check before you carry it, and if it is, make sure the container is approved for occupied space carriage in aircraft.

 

[wsuffa]

Now, I don't know how flammable that de-ice stuff is, but y'all oughta check before you carry it, and if it is, make sure the container is approved for occupied space carriage in aircraft.

Good advice, Ron. TKS fluid is essentially glycol with about 5% isopropyl and 10% water. It is generally considered to be of low flammibility. I think booze is more flammable....

 

[Dave Siciliano]

What I didn't see in the above comparison is initial cost and maintenance:

I'm told that installation of TKS on my A-36 TN with tips for K-ice (still in cert. process) will be about $40,000. The non-certified version is about $28,000. I'm also told that the fluid on one's hanger floor is a bit messy in addition to the issues above.

Don't know the acquisition price of boots, but K-ice with boots wouldn't be available for my plane. Several Barons I've looked at already have boots. So if I was to sell my plane and purchase another, it would be much more cost effective to purchase a plane with boots. Maintenance of boots is an issue I'd love perspective on.

Best,

Dave

 

[poadeleted20]

I'm also told that the fluid on one's hanger floor is a bit messy in addition to the issues above.

Not only messy, but a HazMat issue -- spilled deicing fluid attracts the EPA like ants to a picnic. You can't just hose it down out of the hangar without violating the Clean Water Act.

 

[Walt]

In reply to Dave Siciliano question about boot maintenance. I owned a booted T-210 for 15 years and found the maintenance needs to be continuous but not arduous. I replaced one pump after 1350 hrs. and at least annually thoroughly cleaned the boots and checked for pinhole leaks. Repair of leaks was not much work. The valves do need cleaning and inspection every five years or so and the plumbing needs to be leak checked every several years. The most continuous maintenance is applying ICEX all the time so the ice will release from the boot. The boots were 25 years old when I sold the plane and were still in good shape.

I now have a TKS equipped Mooney (K ice). I have found the maintenance to be less, but still have found several items to repair and more than a few leaks to stop. The fluid does leak on the floor but will evaporate after a few days. If you have pets best to wipe it up. Works better than a mousetrap on mice. I have not found the fluid hard to find, although I buy 5 gals at a time and do not use it that rapidly.

From the perspective of ice removal, I like the TKS better than boots. Boots hardly ever remove all the ice, the TKS does. The TKS takes several minutes for the fluid to flow so it does have to play catchup for 10-15 minutes. Often I am out of the ice before the fluid reaches the wing. The windshield spray bar puts so much fluid on the window so cannot see out for at least a minute. Inside the FAF you had better not use the windshield spray.

Either system works effectively both have pluses and minuses.

 

[Dave Siciliano]

Thanks Walt for your detailed answer. And Ron for the heads up on the HAZMET side.


Dave

 

[gismo]

AFaIK the initial cost of boots is pretty close to the uncertified TKS price. As to recurring costs, the biggest is replacement of the boots themselves. On my plane that would run clost to $15K I think and I'm told this will be needed about every 20 years if the plane is hangared (sunlight is bad for boots). There are other expenses such as semi-annual surface treatments, overhaul of the occasional devective valve (there are three), and the added costs of the bigger air pumps. One other issue I have is the periodic need to clean the ends of the drip tubes that feed alcohol to the props. If you had electric props, they need periodic brush replacement and AFaik that's about a kilobuck for both props.

I have no idea as to TKS maintenance costs as I've never owned such a system.

 

[Bones]

Ice...yuk. I think it all depends really. Here are some of the things I have learned at Flight Safety and through the school or hard knocks that I keep in mind:

Mind you most of my ice experience is in a King Air and Lear...and it really does depend on what you are flying but you can scale these things down to different specific scenarios.

1. You CAN try and climb out of the ice. But most airplanes espeically ones for "known ice" have a min icing speed. If your aircraft doesn't have one you might consider setting your own limitaiton on this airspeed...perhaps VX or something less considering your AOA. Keep in mind that if you are icing up the inside of a freezer and you get to your min icing speed while trying to climb out of the tops...if it doesn't work and you don't get on top..you might have to go right back down through all of that ice agian and get another frosty load. Uguly.

2. The Tops...where are the tops and how do you know what they are...pirep? How close are you really to the tops. Over and over I have been suprised with the amount of ice I pick up in the last 200ft climbing out of the tops. I seem to Always get a splattering of ice when cruising in the tops of most clouds if conditions are right. So be wary and stay out of the tops would be my advice and something I try to fly by. If ATC assigns me an altitude that puts me just 50ft into the Tops I ask for something else..keep going down or if I can go up ...go up.

3. I have gotten some of my worst ice in the summer going through a build up. Avoid, those; sometimes you won't have a choice due to ATC but minmize your time in there. You can get a nasty coat of ice in a hurry that can stick with you till your approach if conditions are right.

4. Ice can be VERY Localized. Sometime just picking a new heading 45deg off of what your flying for a minute will get you out. Use all your tools...take a turn and a climb, or a turn and a desecnt. Ask for Reports, many pilots will and should always report icing conditions.

5. Remember you not only have ice on wings and prop but also the tail-plane which is a whole other aerodynamic subject that can have very nasty consequences. B/c of this many folks prefer to hand fly the airplane in icing conditions to get a "Feel" for what the aircraft is doing. Such as weight of controls and responsiveness. It would be a shame to have the aircraft loaded up with ice and then depart flight or the AP kick off and you are left trying to fly an ice cream sandwhich.

6. If all else fails descend to a warm altitude or out of conditions.

Everyone has their own checklist for ice and their own ideas about ice. I would AVOID it at all costs. Even if you are Known Ice equipped. Would not be fun to be tryign to get a load of ice off and then have something else go wrong and have an emergeny with a load of ice. Those pesky Sim Instrutors love to pile that kind of stuff on.

Those are just a few of the basics I try to fly by, and things that work for me. Hope they may help someone.

 

[John J]

Eric;

Thank you for your post. I have picked up ice a number of times and your points are well taken. I picked some of the worst in the summer flying in and out of some buildups that ATC would not let me dodge. Fortunately the time in them was short.

John J

 

[Henning]

That makes sense, Brian, but wouldn't it be better to descend and try to get the ice to melt off? While its drier up there, it's also colder, so I can't see the ice melting.

I'm not trying to challenge conventions here, just trying to get a good grasp on why.

Two things, as you go higher, it's both colder and drier. This means typically first off you'll eventually quit accumulating ice, and secondly, the ice you do have will sublimate off rather than melt. Please note the emphasis on the word typically. Then there is not so typical, super cooled ice droplets, heavy accumulations... You have to take every icing situation individually and seriously. There are times like when you are picking up heavy icing that you don't want to climb to avoid building ice too heavily on the bottom of the wing, or giving up any airspeed.

 

[Doug R]

I agree with Eric...he makes some very valid points. Worst Ice I ever picked up in my life was in a King Air 350 on a missed approach GPS RWY36 to an ILS 18 bad vis dropped to 200 and a 1/2.Wind shift/shear at 4,000. Temp went from +7C to 0 in an instant at 4,000. It was amazing how much ice I picked up in just a short time. If I had been in an aircraft not equiped to handle that amount of ice it would have been over...ugly indeed. Just like thunderstorms ice is nothing to play with....it can kill you only once. In the winter be careful of the low level jet aloft ...nice warm air...usually around 5 to 7 thousand then decending for the approach with freezing temps on the ground ....could make for a long day. Eric and I we can blast up through ice fairly quick and usually don't get into serious ice until in the approach mode of the flight. Toughest flying out there in my opinion is 10k and below. Just give ice a huge amount of respect.

 

[Henning]

On the plus side for TKS:

Usage cost of $10-20/hr (when you need it you won't care).

When you need it, it's the best freakin bargain in aviation, and it pretty much is a pay as you go deal with no boot replacement (not saying these systems are going to be maint and problem free). Stay out of ice, and it doesn't cost.

 

[Dave Siciliano]

Doug:


Can you shed more light on this? Convective activity? Inversion? Frontal system. Seems like a real dramatic chage. Obviously, not stable air.

Best,

Dave

 

[Henning]

Doug:


Can you shed more light on this? Convective activity? Inversion? Frontal system. Seems like a real dramatic chage. Obviously, not stable air.

Best,

Dave

Just as there is more than one type of ice, there is more than one atmospheric pattern that will cause it. When you have an inversion with convection you can run into the real bad supercooled rain drops, this just get the hell out of ASAP whether your K-ICE or not.

Stable stratus clouds with no inversion can still give you some icing, but it's typically a light rime ice, and you can typically climb through it in 1000'-1500' of the altitude you encounter it. If you're gonna fly winter IFR, you'll eventually have to deal with it one way or another.