AFAIK the files laser drilled in the panel are conical in shape, with narrower holes outside, towards the air. So when clogged by bugs not a great deal, once fluid pressure comes from the other side easily “pumps out” the remainings…
DA42 with Lyco engines is not FIKI (I don’t know why but it isn’t) while all others with factory TKS are FIKI.
From POH: “If OÄM 42-054 is carried out: flight into known or forecast icing conditions. Refer to Supplement S03, latest revision.”
Not sure if posting this will give much that’s new info to this debate, but it was unexpected enough and I handled it so poorly that I feel the need to share.
This is a taken from a flight yesterday from Pontoise LFTP to La Mole LFTZ at FL130 in a PA46-350 (FIKI pneumatic turbo aircraft with a ceiling at FL250).
Conditions were forecasts as benign with occasional embdb CBs at the end of the route; Rocketroute did forecast a high likelihood of icing, but that just means clouds and temps between +5 and -10 in their model. The Jep icing page didn’t show anything.
I was flying in IMC (occasionally between layers) at -5c. There was some light rain on the downlink weather, but nothing showing on the radar, and no activity on the stormscope. I had my anti-icing checklist executed: alt air intake, windshield hot, prop hot, stall warmer and pitot hot (I always have that on) and I was checking my tail, wing and airspeed regularly; disconnecting the AP every 5min as well.
I started to pick up a bit of ice, activated the boots a couple of time and they did their job fairly well.
A couple of minutes later, same again. I’m starting to think about my options: I can climb 3k feet, descending’s not a good idea given the airway base is FL125 and I don’t want to deviate. Hum, can’t be bad given the forecast, can it? I’ll just activate the boots again. I do, they clear most of the stuff I can see, but ais is slow to come back up (activating the boots make you lose some). Oh well, let’s see.
It happens a couple more times over the following 15 minutes, but that isn’t enough to shake me out of my complacency.
Suddenly I hear stuff hitting the windshield, the (unheated) co-pilot side is completely iced-up, the boots are covered with a translucent layer of ice, and I’ve just lost 10kts in the space of 15 seconds… Holy s#it, is that SLD?!?! Full power, A/P disconnect, pitch up, no one on TCAS, boots (the translucent stuff turns solid white but doesn’t go away), check my speed stays above 135 IAS (minimum ice penetration speed), call ATC to tell them what I’m doing and they approve me to FL160 to start with. At that point the noise has stopped and I exit the cloud (the whole thing lasted 30 seconds max.), I can see more high stuff (but definitely not CBs) ahead, I climb to FL160 in the clear and decide to stay VMC whatever. I take a look at the elevator and the outside section of the leading hedge (not boots protected) is basically a 0.5cm thick icicle.
I stay there in the sun at -11c (where did that precip come from? Or was the noise coming from ice getting shed from the prop?), the ice
stays there. I know the layer’s not deep (0C at FL80, the METAR in my current position says few 3000 broken 8000) and I’m soon to be over an area where I can go down to FL060 if need be. My cruise airspeed slowly goes back to normal although I can still see that ice on the elevator and I take the picture below – the stall warner is frozen solid (it was drawing amps and was hot when I touched it after landing), and there’s enough ice on there to cool a few bottles of rosé. The boots were working but had no effect on this.
I told ATC I wanted to stay high until cleared to FL080, which they did eventually; I set up for a reasonably fast 1000fpm descent by slowly bringing power back and going to LOP. The clouds were clearing, and I got rid of the visible ice by the time I reached FL080.
I asked to hold at 4000 ft to make sure all the ice was gone before landing uneventfully at La Mole.
As a matter of habit, I always try to debrief myself after each flight, making a few notes. Here the debrief is simple: I had no reason whatsoever not to ask for an immediate climb the first time I had ice. I was lucky to be in the plane I was in, but I was complacent. Lesson learned.
Have others experienced that kind of ice accumulation?
Thanks for the report.
It looks like what you experienced was nothing but moderate icing. And: moderate icing can happen anywhere, not just if there is CBs, heavy precip or similar on the stormscope or radar. Bottom line: always expect moderate icing in cloud. And: always have a way out of moderate ice. I think it is that simple after all.
By the way, the lower limit of the airway is no factor really (unless there is terrain). These lower limits often have to do with airspace structure, because the airways are designed to keep traffic inside controlled airspace. But if really needs be, you can go into uncontrolled airspace. The most extreme example is Sweden, where almost all airways have a lower limit of FL100, yet you can happily fly IFR below that as well. To a certain degree, the same principle applies in France.
MSA 10k where I was (shortcut between LSE and RETNO). I could have gone west from there if I had decided to go down, though.
I’m glad you think it was moderate icing, do you have any pictures of what heavy looks like on you plane? Loosing 10kts didn’t feel that moderate to me, especially that quickly ;-)
It also depends on the aircraft. The Cirrus easily loses 15 knots in light icing within moments, if the TKS isn’t used.
Thanks for the report, denopa. Very interesting especially that the boots didn’t shift it, and the stall warner was frozen.
The worst I have seen was about 3cm in 5 minutes. The stall speed rose to about 110kt and at full power (TKS prop) I could not go above about 3000ft. The tops were 4000ft (I had just been there – smooth stratus cloud layer). Surface temp was +3C or so so eventually I got rid of it over the sea at 1000ft (near Lydd). Absolutely no fronts, a nice high pressure area, obviously no weather forecast at all let alone any icing forecast. In a PA28, or some type which doesn’t like ice, I would have gone straight down with that much ice left to accumulate.
I guess you went through a buildup or two which are especially wet near their tops – as is any cloud actually, I think.
Icing forecasts are IMHO completely worthless. Any solid IMC between 0C and -15C will eventually ice you up, and -5C (or -3C to -8C perhaps) will do it fastest.
So any flight in IMC should be done below the +1C level, or above the -15C level. VMC on top is best of all of course because you have all the nice options 
Back to the original post, would you dare performing an IFR approach, in solid IMC with negative temps, in a SEP with TKS ?
Dealing with departure:
I don’t agree with that, without various qualifiers. For example in the departure or arrival phases you have no option but to transit through icing conditions. A turbo just means you can climb through the stuff faster, but if like today right where I am now
you have the full 8000ft of the stuff, you are looking at ~8 minutes of exposure.
I guess TKS would be better than turbo in that case. Peter, would have you taken off in your example, if you had full-TKS ?
Dealing with FIKI:
I have flown the TKS version of the SR22 and the FIKI approved version. The backup pump, indication of how much and for how long there is TKS left, the wing-lights to monitor (=see) your wings and the front windscreen sprayer(s). It gave me a dispatch rate in the last few winters of close to 100%.
Does that mean that dispatch rate would be less with non-FIKI TKS ?
[ quotes fixed – Peter ]
@EDNY visitors
Will you inquire Airplus during the show, to learn about their price tag / strategy, in the $ raising context ?
Peter, would have you taken off in your example, if you had full-TKS ?
Which example? The one where I got the ice near Lydd?
In that case nobody would have forecast any ice (although as I often say, IMC between 0C and -15C…..) but had I known it would be that bad the answer is Yes. Full TKS is extremely effective. It should be, given how much mess it makes all over the aircraft
But I had earlier climbed up all the way through that cloud and got only ~ 5mm of ice, which had little effect on speed; maybe 5kt.
