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TKS ice protection for a TB20

Very interesting a Peter, thanks for sharing.

Forever learning
EGTB

Nearly there Peter. I bet you’re desperate to get airborne again.
Sorry if it seems lazy not to reread all the thread but is this going to be just for your safety level and personal limits or does it get certified for known Icing?
Kind regards Pete

United Kingdom

The TB20/21 TKS is not “FIKI” (due to only one alternator and no heated stall warner, etc) but “FIKI” is a purely US term which maps only onto US weather services. It has no practical meaning here in Europe, in terms of aviation regulation (i.e. whether a criminal offence is created by a departure into specified wx conditions). In terms of ice protection the system should be as effective as any other TKS system.

Yes it will be great to fly again. Next week hopefully. We just need to run the system and check for leaks on the various pipe couplings in the belly areas. The project has slowed down because my A&P has not been able to work on it 7 days a week like he did initially. I did all I could to help, which was of some value. One day I will write it up properly but I doubt it will encourage anyone to replicate it, because you need some damn careful people to do the installation.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

The TB20/21 TKS is not “FIKI” (due to only one alternator and no heated stall warner, etc) but “FIKI” is a purely US term which maps only onto US weather services. It has no practical meaning here in Europe, in terms of aviation regulation (i.e. whether a criminal offence is created by a departure into specified wx conditions). In terms of ice protection the system should be as effective as any other TKS system.

I used to fly a TB20 with factory installed TKS, which was approved for flight into icing conditions by the DGAC. The setup appears identical to yours (single alternator etc.). I never actually flew it in more than light icing, but in those conditions it worked well and according to the POH it should be expected to handle moderate icing.

ESKC (Uppsala/Sundbro), Sweden

Yes; a G-reg (e.g.) TB20 is approved for flight in specified icing conditions.

I imagine this is true for all EASA-reg ones but I really don’t know. AIUI, CAV have not sold any TB TKS systems for at least 10 years and indeed many of the parts I received for this one were ~15 years old stock (the pump unit and some other bits were brand new). So most flying examples will be with national-CAA POH supplements.

The clear feeling I get is that CAV are pretty busy installing TKS systems in their US facility, while their “European sole agent”, Airplus at EDNY, has done their arrogant best to wreck any significant penetration of the European market in the last decade or two. Airplus is the only company in Europe which gets the trade (installer) discount, too!

Administrator
Shoreham EGKA, United Kingdom

Wow, Peter! I am impressed! Well done!

I wonder how many industries would be able to survive when built in a way that such overwhelming level of effort and workmanship is required to perform maintenance items (this not only happens on TKS installs but also a lot of other aircraft maintenance items).

Can you imagine having a business around doing this kind of work and having to charge so many man-weeks of specialised and skilled labour perhaps…once a year? Even if the german guys were doing a good job of looking after customers I dont think they would be doing one install a month (and even if so then it would be on different types!) …the market is just not there.

When you are charging way more than the price of the [used] airframe (sans engine) for such installations, (and you can’t really charge less and survive) , you are talking of an impossible business.

I think we are very lucky that we are still getting support on our out-of-production aircraft, and you were very lucky that the OEM would put together a kit for you at such a “low” price 10 years after they sold the last one.

Antonio
LESB, Spain

Indeed Antonio…

It looks like CAV does a lot of defence business and is thus structured to make money out of these oddball products and you could order something they have not made for 30 years and they would get the drawings out, blow the dust off them, and make it. That is how it works when you sell to govt/military. Or they will sell you a 30 year old stock item – I got a fair few of those (well not quite 30 years old but well on on the way) whose condition might be questionable

I think all the titanium panels came straight out of their stock, about 15 years old, and only the pump unit and a few other bits were manufactured fresh. That is just as well since the seals are quite strictly lifed and an old pump assembly would need a complete overhaul in order to be airworthy.

To be fair to them, it is hard for a “far away” company to appoint a good agent in Europe. I have had that problem in my business too. Europe is often painted as one country (especially the EU) but in reality it is nothing like it and you need an agent in each of the principal countries. Even in aviation which is the most international of all! You need an agent in each of UK, France, Germany to cover the major “high end GA” activity areas. This is a major effort and you have little information on how the agent is doing his job, since few customers will be motivated enough to complain to the principal. Especially on pricing, where the agent gets a trade discount and likely sticks a good % on top of the list price and inflates the installation fee.

Otherwise I think the market would be there. People spend 40k on avionics…

But you need a good installer because this job is full of tricks. You also need a fully heated hangar (+20C at least) otherwise half the installation time will be spent waiting for the panel glue to go off. You could attach the panels early but that is not IAW the IM because you can’t do the system test as prescribed.

Overall I would say CAV are a really good company. We’ve had good support from them during the installation.

I am eager to find out what the speed loss will be. Nobody I have ever met seems to have the slightest idea of the factors influencing this – or they work in the aero business and don’t want to say. The change to the leading edges seems to be very slight and there are so many different aerofoils in GA use anyway… Losses up to 7kt have been reported however. We took great care to do the blending fillets well; currently some bits have a ~0.7mm depression (caused by natural slumping of the sealant) which we will re-do. I wonder if some of the losses were due to out of trim aircraft e.g. it is possible to attach the elevator panels at slightly different angles which will then “twist” the whole aircraft in flight, requiring aileron trim tab correction, with a load of resulting drag.

Administrator
Shoreham EGKA, United Kingdom

I agree. Having the infrastructure to keep those drawings, some parts, the capability to source or manufacture the others, and put together a kit like that after so long and even support a one-off installation only speaks of a good company. I however dont think a dealer per country can survive on such a small market.

Our airplane has no deice other than a hot-prop and pitot+stall warning heaters…(and a turbocharger, but I dont want to thread-divert that much). Even before purchasing I was looking at TKS because it was advertised as less draggy than boots, but I figured there was 3-5 knots loss anyway. My concern was not so much the speed as the range and efficiency (although let’s face it: we all like speed). And yes, TKS’d airframes commandedonly a $5k-15k premium.Then there’s also the useful load loss. We ended up buying the lightest, cleanest airframe of the type I could find and guess what: cruise is over 10ktas faster than book when other owners are reporting P210’s are 10 kts slower than book. Put boots, air conditioning, dual multi-bladed tcas antennas and assymmetry-creating accessories causing trim drag and you lose at least 10 kts or the equivalent of 15 percent power. Clearly all those things we put on the airframe add up and even a clean install like yours has an impact. Having said that, my guess is your clean install with thinned edges, re-filled fillets and so on could be half as draggy as a rough careless install. Standing by to hear your flight reports…you have as much before-data as anyone so your after-data should be trustworthy.

I keep thinking of a future with TKS for myself but my wife hates flying in weather and the turbo does help a lot to stay out of ice…so my short-term future is TKS-less, but hearing from you about CAV makes me think again…

Antonio
LESB, Spain



The stuff does make quite a mess, because it doesn’t dry. One can remove it with water, or better still with IPA. It probably does come off eventually with the airflow – like my prop TKS did before. And flying in (non freezing) IMC at the end of a flight is going to remove it fairly well.

We found one curious thing: one of the three propeller TKS feed tubes was blocked! That explains occassional vibration when using the prop TKS. One blade was icing up. It was probably like that for a year… I reckon insects climb into the tubes, just like they climb into static vents, pitot tubes, etc. Except the prop TKS tubes do not have covers when on the ground.

I keep thinking of a future with TKS for myself but my wife hates flying in weather

I don’t see myself doing convective wx just because I have TKS – because there are other hazards then. It will be used mainly for going up or down through stratified cloud which is all too common, and if it is say 10,000ft thick then you can be sure of icing conditions at some point.

Administrator
Shoreham EGKA, United Kingdom

Peter, I assume this is quite a cost vis-a-vis the value of the airframe. Did you go through an exercise to decide to upgrade vs change aircraft?

Obviously, like all these things, all that matters is that you are happy with it but I guess it is an upgrade done on the basis you are keeping the TB20 for some time.

EGTK Oxford
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