De-Icing for light singles.

[pumper_bob]

With the cold weather looming, i was wondering why a cheap, light weight de-icing system hasnt appeared on the extras list for light singles? Take the TB21 or the Saratoga for example. Very capable aircraft complete with airways nav avionics. Yet put a couple of clouds in the sky below freezing level and your grounded! So does anyone know why the manufacturers havnt developed a system for these aircraft? I am thinking in terms of an electric element fitted to the leading edge, similar to the windscreen defrost system on my car, which can clear solid ice in a matter of seconds in the morning and only has a 20 amp fuse, so cant be too power hungry can it? I am not an expert in these fields, so does any one know why pnuematic boots and alcohol systems seem to dominate the de-icing system of choice? I would have thought electric would have been lighter and more effective, obviously i am missing something?

[S-Works]

I suspect it is more to do with making them "aviation grade" rather than anything else. I also suspect that it would require a lot more than 20amps to deice an airframe especically when can be looking at outside tems in the -40c region.

Despite a lack of icing systems there are not many days that actually cause icing problems. A guy in the US teaches the FA IR year round in a non iced single and has never had to cancel yet and his courses go al the way to alaska. a lot of the IR training organisations in the UK do not have de-ice. The twins I did my JAA IR in were de-iced and I never used them in anger. In fact I have only used the de-ice on the senecca once after spending an hour in the icing layer after not getting my filed level. I could have insisted on the climb or taken a descent but the ice was not bad and I wanted to test the systems.

Most of the time it is easy to climb on top of the icing layer and once clear of it the ice will melt quickly. In the winter the ice layer is low but then so are the cloud tops. In the summer it is the other way around and it is easy enough to fly above the cloud or below the freezing layer but above the MSA. Most performance singles will punch through it very quickly.

I get more worried about CB's than ice.

[IO540]

The TB20/TB21 are available with TKS de-ice. The full system costs about £20k; a prop-only de-ice is about £3k. Not cheap but the full system is highly effective - until the TKS fluid runs out...

There are new developments on the electric front. I believe Lancair are doing something with heating the leading edges, and they have a separate 70 amp (at 24V, I assume) alternator to power it.

Electrically heated props have been around for decades but the wings etc have traditionally (on piston and turboprop aircraft) been done by rubber boots. Jets tend to use bleed air to de-ice the leading edges, but if you are going fast enough the aerodynamic heating prevents icing pretty effectively.

The name of the game in IFR flight planning is to get up into VMC and stay there. Nobody wants to sit in freezing IMC for hours. With full TKS you can do it but if you use up more than 50% of your fluid then your flight planning for the return journey gets somewhat compromised. Same with oxygen actually... one can't get refills in Europe, in general. Also, if sitting in IMC you don't get a chance of avoiding vertical cloud development visually.

Nothing in aviation is "cheap" especially if you are talking about IFR. One could do low priced products for the Permit market but they are limited to VFR only so ...

[nouseforaname]

we've got boots on our Cessna, to be honest I think I have used them twice in necessity in about 300hrs in all kinds of imc. Used them yesterday actually when picked up a lot of ice in the decent, if i'd waited another 30seconds I would have been below the icing layer anyway. If the boots stopped working tomorrow I wouldn't be worried about flying the aircraft through a bit of ice.

[scooter boy]

My Mooney ovatiion 2 GX has known ice certification with the TKS system.
Very effective in the winter (and summer) when you are in precipitation.
It is expensive to refil though but you can pick it up (aeroshell compound 07) at some european airports. I have it on "max" for a couple of minutes and then "normal" so long as the ice isn't continuing to build. With no ice on the airframe off it goes.
A Mooney fan working in Birmingham ATC enquired as to whether I had TKS fitted when I crossed their airspace in it yesterday - it makes the Mooney as much of a true year round machine as a light single can be.

Unfortunately living in the UK (where the Wx is frequently pants) we need all the help we can get.

SB

[IO540]

Very effective in the winter (and summer) when you are in precipitation

Not sure you meant to say that, SB ;)

Precipitation above 0C is just fine; precipitation below 0C is freezing rain which is potentially quite nasty and I am not sure TKS would cope with it too well.

Also, with the full TKS system, isn't there a "standby" setting which you are supposed to use when flying below 0C? This is to prevent the tiny holes getting blocked up. With a prop-only TKS this isn't much of an issue because the dispenser tubes are about 3mm diameter.

[Flying Farmer]

To quote IO540

" precipitation below 0C is freezing rain which is potentially quite nasty and I am not sure TKS would cope with it too well."

I dont know if that is strictly correct precipitation can take many forms.It can be hail, rain, freezing rain, sleet or snow.

We had an event a couple years ago in a C404, Breacon northbound underneath the airway. Light icing was forcast that day with tops around 10000ft. The rime ice that developed in just a few minutes over the whole of the aircraft was incredible. As we tried to climb out of the icing layer the unbooted wing section just inboard of the engine nacelle had 30 or so mms of ice built up on it, the engines were suffering impact icing, the ice shed from the props was making a terrible din against the fueselage. Added to this was a buffeting from the airframe which felt very unusual.

I imagine it would have rated as a severe icing encounter and hope never ever to have to face it again. It made me all the more determined to get on to turbines ASAP. :}

[High Wing Drifter]

Take the TB21 or the Saratoga for example. Very capable aircraft complete with airways nav avionics. Yet put a couple of clouds in the sky below freezing level and your grounded!
Talking to a couple of the charter pilots at my school, I get the impression that despite the Seneca's certification for moderate icing, it is not a pleasant experience and is generally avoided as if it wasn't capable of dealing with that type of icing. As far as light aircraft are concerned, I remain to be convinced that de-ice equipment is much practical use for serious situations such as moderate icing. I suspect much simpler and more robust systems like prop and window heat provide the get out of jail without the notion that you can get into jail first.

[S-Works]

Talking to a couple of the charter pilots at my school, I get the impression that despite the Seneca's certification for moderate icing, it is not a pleasant experience and is generally avoided as if it wasn't capable of dealing with that type of icing. As far as light aircraft are concerned, I remain to be convinced that de-ice equipment is much practical use for serious situations such as moderate icing. I suspect much simpler and more robust systems like prop and window heat provide the get out of jail without the notion that you can get into jail first.

The Seneca is fine in ice, at least as fine as any light aircraft can be.

[AC-DC]

"I am thinking in terms of an electric element fitted to the leading edge,"

There are 2 companies in the US that have developed such a thing. One company already certified it (for the Diamond) and the other one is a one-man bend who came up with a very cheap and lightweight system (that seems to work) but I don't know what stops him from completing the project.

[Maxflyer]

the other one is a one-man bend

You'd better check with Bose-X if this is okay with regard to decompression versus flying!

[IanSeager]

"I am thinking in terms of an electric element fitted to the leading edge,"

There are 2 companies in the US that have developed such a thing. One company already certified it (for the Diamond) and the other one is a one-man bend who came up with a very cheap and lightweight system (that seems to work) but I don't know what stops him from completing the project.

I am only aware of one system (EVADE) and it has been certified on the Columbia, not the Diamond.

Ian

[scooter boy]

Very effective in the winter (and summer) when you are in precipitation

Not sure you meant to say that, SB ;)

Precipitation above 0C is just fine; precipitation below 0C is freezing rain which is potentially quite nasty and I am not sure TKS would cope with it too well.

Also, with the full TKS system, isn't there a "standby" setting which you are supposed to use when flying below 0C? This is to prevent the tiny holes getting blocked up. With a prop-only TKS this isn't much of an issue because the dispenser tubes are about 3mm diameter.



In my experience of crossing frontal systems (usually when flying in cloud within airways where the tops are well above my max ceiling) precip is inevitable as are turbulence and icing (when the conditions are right). The TKS prevents significant buildup and the Mooney system covers the whole airframe from prop (slinger ring and heated boots at blade roots) to windshield (2 separate pumps) leading edges of wings and empennage.

Ice accumulation can be brutally rapid when crossing fronts. The landing light area of my leading edge (the only non-TKS part) can sometimes have several centimetres of ice stuck to it.

Significant precip is not usually of long duration and the deicing has never failed to take care of it. It really is a great system - lots of redundancy.

The system operates in 2 modes, normal and max - max initially to prime the system and the normal once the ice has been shed. The holes do not block if the system is off and you pick up a little glaciation - since the system is under pressure the fluid is forced out under the ice causing it to be shed.
I do not switch the TKS on until I see ice. Sometimes this can happen at +3C in lightish precip, sometimes there is no accumulation at -2C in more significant precip. Really depends on whether the ice wants to stick or not. If it is 0C and I am in rain I do not waste the fluid unless the airframe is accumulating ice. I may need the TKS later and as there is a limited supply I prefer to use it in short bursts.

Don't get me wrong, I think that the best place for ice is in a martini and I do not seek out icing conditions. The TKS helps get you through sections of air where life would become uncomfortable without it, places where venturing without deicing would be extremely risky.

SB

[pumper_bob]

AC/DC
do you have a link or web address for either of the systems you mention? Sounds something like what i was thinking! As far as ice build up goes, i did an experiment with my instructor in a Traumahawk. We entered cloud, a big cumulus one well below freezing and the ice built up very quickly. Although decending lost it all pretty quick. I suppose my main worry is if you are in freezing conditions and dont have the height to loose, what options do you have then? Its better to be on the ground wishing you were up there, than being up there wishing you were on the ground!

[Jinkster]

Just to let you know - flew at FL80 yesterday in a C152 in IMC and caught icing - leading edge, windscreen and tires

All good fun - descent and it melted

Ground temp approx: 13C

Jinkster :ok: