Just prop deice... why?
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Just prop deice... why?
Anyone know the advantage of JUST having prop de-ice, say on a TB20...
I know it is better than nothing when you enter icing conditions inadvertently... but you are not certified for flight in icing conditions which you would be with a full TKS system and certification.
So with a prop deice you would have to stay well clear of icing conditions anyway, and if you enter icing then yes, your propulsion system might stay alive, but what use would that be when your airframe ices up...
Who decided on fitment of a prop de-ice only, and for what reasons?
I guess this gives you no benefit in dispatch capability, but eases the mind when operating in marginal conditions... any thoughts?
I know it is better than nothing when you enter icing conditions inadvertently... but you are not certified for flight in icing conditions which you would be with a full TKS system and certification.
So with a prop deice you would have to stay well clear of icing conditions anyway, and if you enter icing then yes, your propulsion system might stay alive, but what use would that be when your airframe ices up...
Who decided on fitment of a prop de-ice only, and for what reasons?
I guess this gives you no benefit in dispatch capability, but eases the mind when operating in marginal conditions... any thoughts?
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I have this and it is excellent.
The idea is that no matter what else collects ice, you will have power. This is obviously important. Depending on the aircraft, it can take a LOT of ice before you lose significant lift but it will take very little ice on the prop to seriously clobber the ability to climb, especially if you are already at say FL100+.
You need power to climb, and climbing is one of the escape routes (depending on what the TAT happens to be; if it was say -2C and there is 5000ft of safe air below then I obviously wouldn't climb). If you get serious prop imbalance (due to ice) then you may have to reduce power and you are stuffed; the only way is down.
As for despatch capability, and known ice certification, the whole subject of what constitutes "known ice" (particularly in the UK where "icing in cloud" appears on every F215) has the potential for a very long thread indeed....
The general idea with flight into potential icing is that you must always have an escape route. A deiced prop gives you more options in that department.
The idea is that no matter what else collects ice, you will have power. This is obviously important. Depending on the aircraft, it can take a LOT of ice before you lose significant lift but it will take very little ice on the prop to seriously clobber the ability to climb, especially if you are already at say FL100+.
You need power to climb, and climbing is one of the escape routes (depending on what the TAT happens to be; if it was say -2C and there is 5000ft of safe air below then I obviously wouldn't climb). If you get serious prop imbalance (due to ice) then you may have to reduce power and you are stuffed; the only way is down.
As for despatch capability, and known ice certification, the whole subject of what constitutes "known ice" (particularly in the UK where "icing in cloud" appears on every F215) has the potential for a very long thread indeed....
The general idea with flight into potential icing is that you must always have an escape route. A deiced prop gives you more options in that department.
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Wow, great post, just what I was looking for!
What is "a LOT of ice" before you lose significant lift, if I may ask?
Most I had was half a centimeter on the leading edge, with no noticeable performance degradation. That was incidentally the point when I was very happy to switch on the de-ice function of the TKS...
What is "a LOT of ice" before you lose significant lift, if I may ask?
Most I had was half a centimeter on the leading edge, with no noticeable performance degradation. That was incidentally the point when I was very happy to switch on the de-ice function of the TKS...
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The answer must depend on the aerofoil.
On a TB20 I've had up to about 8mm of mixed clear+rime and there was no noticeable IAS drop.
You need to switch on TKS before entering IMC when the temp is below zero, otherwise the orifices can clog up with ice. I would guess this could play havoc with a prop if some blades got it and not others. This is less of a problem with the prop TKS (the full TKS system has tiny holes on the leading aerofoil edges). I always switch the prop TKS to max (never use the low flow option) when in IMC below zero.
Prop TKS also keeps the front window ice free; works brilliantly and is operational in about 1 minute from switching it on.
Of all the "uncertified" (and therefore supposedly useless) gadgets one can get for a plane, prop TKS is one of the best. It's also relatively cheap, 1/10 of the cost of full TKS. Others are perhaps a Shadin flowmeter (linked to the GPS) and an EDM700.
On a TB20 I've had up to about 8mm of mixed clear+rime and there was no noticeable IAS drop.
You need to switch on TKS before entering IMC when the temp is below zero, otherwise the orifices can clog up with ice. I would guess this could play havoc with a prop if some blades got it and not others. This is less of a problem with the prop TKS (the full TKS system has tiny holes on the leading aerofoil edges). I always switch the prop TKS to max (never use the low flow option) when in IMC below zero.
Prop TKS also keeps the front window ice free; works brilliantly and is operational in about 1 minute from switching it on.
Of all the "uncertified" (and therefore supposedly useless) gadgets one can get for a plane, prop TKS is one of the best. It's also relatively cheap, 1/10 of the cost of full TKS. Others are perhaps a Shadin flowmeter (linked to the GPS) and an EDM700.
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IO,
8mm and no difference! Are you sure it was ice. A dose of rime on the leading edge will cause most machines to suffer and I speak from experience. A cavalier attitude tempts others to ignore most sensible advice which must be stay well clear of icing conditions. Might I suggest that pilots consider the possibility of icing conditions before they depart. A matter I touched on in the recent debate about the JAA/IR. I presume you are not such a qualified pilot.
8mm and no difference! Are you sure it was ice. A dose of rime on the leading edge will cause most machines to suffer and I speak from experience. A cavalier attitude tempts others to ignore most sensible advice which must be stay well clear of icing conditions. Might I suggest that pilots consider the possibility of icing conditions before they depart. A matter I touched on in the recent debate about the JAA/IR. I presume you are not such a qualified pilot.
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I was trying to provide a useful answer to a question, BP, and I did say any "data" like this is aerofoil specific.
On the legal issues, and personal attitude to risk, one can pontificate for ever, without increasing anybody's knowledge. Something online forums (fora?) are excellent at.
It was white with clear bits, rough looking, came from apparently nowhere and was getting thicker. It might have been frozen Dulux emulsion, I suppose, but I've seen it quite often. Also, it always seems to melt when the TAT passes through 0C into positive. And yes I have an IR, though it is only the sort which comes free if you collect 25 vouchers from fag packets (the same one which perhaps 95% of the world's entire population of private IR pilots fly with).
On the legal issues, and personal attitude to risk, one can pontificate for ever, without increasing anybody's knowledge. Something online forums (fora?) are excellent at.
It was white with clear bits, rough looking, came from apparently nowhere and was getting thicker. It might have been frozen Dulux emulsion, I suppose, but I've seen it quite often. Also, it always seems to melt when the TAT passes through 0C into positive. And yes I have an IR, though it is only the sort which comes free if you collect 25 vouchers from fag packets (the same one which perhaps 95% of the world's entire population of private IR pilots fly with).
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You might consider the JAA/IR. It will improve your understanding of IFR flying. If the full course is too onerous and I appreciate this may be the case for most private pilots then why not consider the Met theory material.
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I was pulling your leg, BP, about the Dulux emulsion.
With your JAA IR, you should know it all, while regrettably refraining from posting something that is useful to read.
Anyway, there are two ways to approach flight into potential icing
(1) Never fly into potential IMC (i.e. IFR) at a level where the OAT is forecast below zero, unless the plane is certified for known ice (and what exactly does that mean - think about that one, not just legally but more to the point practically)
(2) Understand a bit about one's aircraft's capability, understand where 3D weather data can be obtained from, examine the data carefully, and plan the flight with appropriate escape routes (usually a descent into warmer air, while remaining above the MSA).
Option (1) grounds all non-KI planes for some 6 months of each year in N Europe, for IFR (airways) flight.
It's amazing how many JAA IR holders sit around internet forums, having absorbed all that knowledge and having sat all those exams, yet seem so economical with their time when it comes to passing on that fountain of knowledge onto others.
If you had written some technical stuff on how different aerofoils are affected by ice (for example) that would be something else.
Anyway, any more than 5mm of ice (or whatever the white stuff was?) I would be executing my Plan B.
With your JAA IR, you should know it all, while regrettably refraining from posting something that is useful to read.
Anyway, there are two ways to approach flight into potential icing
(1) Never fly into potential IMC (i.e. IFR) at a level where the OAT is forecast below zero, unless the plane is certified for known ice (and what exactly does that mean - think about that one, not just legally but more to the point practically)
(2) Understand a bit about one's aircraft's capability, understand where 3D weather data can be obtained from, examine the data carefully, and plan the flight with appropriate escape routes (usually a descent into warmer air, while remaining above the MSA).
Option (1) grounds all non-KI planes for some 6 months of each year in N Europe, for IFR (airways) flight.
It's amazing how many JAA IR holders sit around internet forums, having absorbed all that knowledge and having sat all those exams, yet seem so economical with their time when it comes to passing on that fountain of knowledge onto others.
If you had written some technical stuff on how different aerofoils are affected by ice (for example) that would be something else.
Anyway, any more than 5mm of ice (or whatever the white stuff was?) I would be executing my Plan B.
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Buy and read John C. Eckalbar's 'Flying High Performance Singles and Twins'. The final chapter is devoted to icing and there is much else besides that will be of interest.
You can get it from Sporties or one of the other US Pilot Shops if it is not readily available in the UK.
You can get it from Sporties or one of the other US Pilot Shops if it is not readily available in the UK.
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Good to have someone spit out some useful info IO, appreciate it.
How stupid do I look now with my JAA/IR asking silly questions about TKS systems, but when blasting along on a 744 with all that hot air available you just don’t think about prop de-icing. I have also never experienced prop vibration due to ice, and nooo, I am afraid it probably won’t help much when it might happen to have read in some JAA theory course that you should never be there in the first place.
When faced with a variety of equipment on a small aircraft and a trip to fly in cold weather you become very mindful about what is useful and for what reasons, in fact I have just been offered a prop de-iced aircraft to replace my usual aircraft furnished with full TKS, which has just gone tech.
By the way, I would confirm from personal experience that the de-ice function is not really there to get off any accretions that have already formed. Since there is also an anti-ice switch position one would think that one prevents and the other actively REMOVES ice… however I too had the impression that the orifices clogged up and that not much happened until I peeled off the ice by hand after landing.
I would like to think though that the orifices SLOWLY melt free when the de-icing agent is constantly pressed out by the pump.
The full TKS also offers a windscreen sprayer… suppose that one may be left in idle if you say that the prop de-ice does the same job effectively.
Might be what some call a non JAA compliant cavalier attitude, but holding the qualifications, operating suitable equipment and (like IO says) having plan B, tentative exposure to icing might make you a more experienced and therefore safer aviator.
How stupid do I look now with my JAA/IR asking silly questions about TKS systems, but when blasting along on a 744 with all that hot air available you just don’t think about prop de-icing. I have also never experienced prop vibration due to ice, and nooo, I am afraid it probably won’t help much when it might happen to have read in some JAA theory course that you should never be there in the first place.
When faced with a variety of equipment on a small aircraft and a trip to fly in cold weather you become very mindful about what is useful and for what reasons, in fact I have just been offered a prop de-iced aircraft to replace my usual aircraft furnished with full TKS, which has just gone tech.
By the way, I would confirm from personal experience that the de-ice function is not really there to get off any accretions that have already formed. Since there is also an anti-ice switch position one would think that one prevents and the other actively REMOVES ice… however I too had the impression that the orifices clogged up and that not much happened until I peeled off the ice by hand after landing.
I would like to think though that the orifices SLOWLY melt free when the de-icing agent is constantly pressed out by the pump.The full TKS also offers a windscreen sprayer… suppose that one may be left in idle if you say that the prop de-ice does the same job effectively.
Might be what some call a non JAA compliant cavalier attitude, but holding the qualifications, operating suitable equipment and (like IO says) having plan B, tentative exposure to icing might make you a more experienced and therefore safer aviator.
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I have zero personal experience of the full TKS system but I understand from those that have it that the anti-ice position does have a use, in that it prevents the little holes getting clogged up.
I would question the value of the anti-ice position on the prop-only TKS system. There are no "little holes" to clog up; the smallest orifice is about 2mm diameter.
The thing is that none of these systems, known ice certified or not, are 100%. The full TKS is reported as really really excellent under serious icing conditions and much better than rubber boots. I've met pilots who fly in the most northern bits of Europe with it, all year round. But the fluid won't last for ever, so the name of the game remains the same as always: get into VMC, above or below (above is nicer, you get sunshine and a TB has a cr*p heater )
The fluid in the prop-only version doesn't last long; only about an hour I think, but no plane wants to hang in there collecting ice for that long. A TB20 gives you the option (with an IR) of flight planning a flight at say FL160/170 and that should take you above en-route clouds most of the time. Nevertheless, icing remains a real flight planning issue, all around the year, if one has to go up/down through it. You could get a TB21 (cert ceiling 25k) but then you end up with a W&B issue due to the size of the oxygen bottle (work it out; 4 pax, masks not cannulas). If I was doing this properly while working down to a sub-turboprop budget, I would get a TB21 with full TKS.
Funnily enough, a TB20 with full TKS, G-reg is KI cert while an N-reg one isn't (last time I checked). Clearly, they have different ice in the USA
NASA have a good icing course on their site http://aircrafticing.grc.nasa.gov/courses.html but you've probably seen that one.
This site http://ows.public.sembach.af.mil/ has nice icing region diagrams under Flight Hazards.
This site http://pages.unibas.ch/geo/mcr/3d/meteo/ under Animated Soundings gives some forecasts of cloud tops and temps (skew-t).
This site http://weather.uwyo.edu/upperair/sounding.html under Europe, Skew-T GIF has the actuals but they are usually a bit late to be useful for planning.
This is the standard GFS site http://www.arl.noaa.gov/ready/cmet.html where you can get, among a pile of other stuff, variation of temp (at a given millibar level) with time.
Of course none of this data is CAA compliant; they like you to use the Met Office faxback facility...........
I would question the value of the anti-ice position on the prop-only TKS system. There are no "little holes" to clog up; the smallest orifice is about 2mm diameter.
The thing is that none of these systems, known ice certified or not, are 100%. The full TKS is reported as really really excellent under serious icing conditions and much better than rubber boots. I've met pilots who fly in the most northern bits of Europe with it, all year round. But the fluid won't last for ever, so the name of the game remains the same as always: get into VMC, above or below (above is nicer, you get sunshine and a TB has a cr*p heater
)The fluid in the prop-only version doesn't last long; only about an hour I think, but no plane wants to hang in there collecting ice for that long. A TB20 gives you the option (with an IR) of flight planning a flight at say FL160/170 and that should take you above en-route clouds most of the time. Nevertheless, icing remains a real flight planning issue, all around the year, if one has to go up/down through it. You could get a TB21 (cert ceiling 25k) but then you end up with a W&B issue due to the size of the oxygen bottle
(work it out; 4 pax, masks not cannulas). If I was doing this properly while working down to a sub-turboprop budget, I would get a TB21 with full TKS.Funnily enough, a TB20 with full TKS, G-reg is KI cert while an N-reg one isn't (last time I checked). Clearly, they have different ice in the USA
NASA have a good icing course on their site http://aircrafticing.grc.nasa.gov/courses.html but you've probably seen that one.
This site http://ows.public.sembach.af.mil/ has nice icing region diagrams under Flight Hazards.
This site http://pages.unibas.ch/geo/mcr/3d/meteo/ under Animated Soundings gives some forecasts of cloud tops and temps (skew-t).
This site http://weather.uwyo.edu/upperair/sounding.html under Europe, Skew-T GIF has the actuals but they are usually a bit late to be useful for planning.
This is the standard GFS site http://www.arl.noaa.gov/ready/cmet.html where you can get, among a pile of other stuff, variation of temp (at a given millibar level) with time.
Of course none of this data is CAA compliant; they like you to use the Met Office faxback facility...........
Last edited by IO540; 10th Mar 2006 at 05:00.
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Originally Posted by IO540
Anyway, there are two ways to approach flight into potential icing
(1) Never fly into potential IMC (i.e. IFR) at a level where the OAT is forecast below zero, unless the plane is certified for known ice (and what exactly does that mean - think about that one, not just legally but more to the point practically)
(1) Never fly into potential IMC (i.e. IFR) at a level where the OAT is forecast below zero, unless the plane is certified for known ice (and what exactly does that mean - think about that one, not just legally but more to the point practically)
Last edited by bpilatus; 10th Mar 2006 at 06:16.
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I agree it is getting rather tedious. It wouldn't be quite so bad if you refrained from talking about matters on which you appear to have little knowledge.
Even your last post is not clear. Any pilot (with or without an IR) can file IFR. IFR does not mean entering IMConditions, indeed IFR is possible by the quad rule. Sit back take a deep beath and consider the content of your posts. I have also noted your tendency to get aggresive with those that endeavour to correct your mistakes. It takes me back to my school days.
Even your last post is not clear. Any pilot (with or without an IR) can file IFR. IFR does not mean entering IMConditions, indeed IFR is possible by the quad rule. Sit back take a deep beath and consider the content of your posts. I have also noted your tendency to get aggresive with those that endeavour to correct your mistakes. It takes me back to my school days.
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I would generally endorse IO540s views on the usefulness of TKS prop-deice. The value is entirely associated with keeping your powerplant useful at a time when other parts of the aircraft may (however inadvertantly) be picking up lots of ice. It amounts to an imperfect get-out-of-jail card, rather than a mechanism for flying into icing conditions deliberately.
It does also have the additional benefit (on a TB20) of keeping much of the windshield ice free, as well as a few feet of the leading edge on both sides.
Where my experience departs from that of IO540 is when he talks about the ability of the TB20 to carry ice. My experience has been that the TB's performance tails of quite quickly with ice, with a measurable drop in IAS. The quid-pro-quo is that being relatively thin-winged, the rate at which ice acretes is somewhat slower than in types with a thicker wing section. Swings and roundabouts.
bpilatus - your language skills continue to improve, I see
It does also have the additional benefit (on a TB20) of keeping much of the windshield ice free, as well as a few feet of the leading edge on both sides.
Where my experience departs from that of IO540 is when he talks about the ability of the TB20 to carry ice. My experience has been that the TB's performance tails of quite quickly with ice, with a measurable drop in IAS. The quid-pro-quo is that being relatively thin-winged, the rate at which ice acretes is somewhat slower than in types with a thicker wing section. Swings and roundabouts.
bpilatus - your language skills continue to improve, I see
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And as any IR pilot worth his salt will know rime gathers quickest on the smaller diameters, OAT probe, tail/ fin leading edges and main wing leading edges, particularly thin winged types.
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I often fly IFR in IMC at levels below the airways with a UK IMC rating without the benefit of any de-ice equipment. Freezing level at the flight planning stage and the OAT guage in flight are both considered rather important.
Returning to my home field for an IFR rejoin at (typically) 3000 feet I am often requested to 'climb 4000'. If the OAT is ner to freezing at 3000 feet I politely request 'wish to remain below 3000 due icing' and have never had a problem.
Without getting into another debate about the wisdom of flying in IMC without a radar service (I have long ago decided that I subscribe to the big clouds theory) do any more exzperienced forumites have any opinions on this? I would be especially interested to hear an ATC view.
Returning to my home field for an IFR rejoin at (typically) 3000 feet I am often requested to 'climb 4000'. If the OAT is ner to freezing at 3000 feet I politely request 'wish to remain below 3000 due icing' and have never had a problem.
Without getting into another debate about the wisdom of flying in IMC without a radar service (I have long ago decided that I subscribe to the big clouds theory) do any more exzperienced forumites have any opinions on this? I would be especially interested to hear an ATC view.
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Originally Posted by IO540
As for despatch capability, and known ice certification, the whole subject of what constitutes "known ice" (particularly in the UK where "icing in cloud" appears on every F215) has the potential for a very long thread indeed....
, "forecast ice" means "known ice". If the forecastsays "icing in cloud", then using an FAA IR you may not enter any cloud in the plane you are describing.
The general idea with flight into potential icing is that you must always have an escape route. A deiced prop gives you more options in that department.
You can attempt to reinterpret this how you like, and I am sure you will as you are going to do what you want to do anyway, but Federal case law is very clear. Forecast icing or potential icing = known icing. You may be in the UK but the Feds can still pull your certificate. They did in the following cases.
Administrator vs Bowen
Administrator vs Irmisch
Administrator vs Groszer
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bpilatus - True for rime ice, but although generalising is dangerous, rime is not the sort of ice to strike terror into the heart of a pilot at first sight. Rime normally provides escape time...
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Originally Posted by 2Donkeys
Where my experience departs from that of IO540 is when he talks about the ability of the TB20 to carry ice. My experience has been that the TB's performance tails of quite quickly with ice, with a measurable drop in IAS. The quid-pro-quo is that being relatively thin-winged, the rate at which ice acretes is somewhat slower than in types with a thicker wing section. Swings and roundabouts.
bpilatus - your language skills continue to improve, I see
bpilatus - your language skills continue to improve, I see
2D, you sound like an experienced pilot, I presume you have some knowledge of the TB20.