TKS ice protection for a TB20

I didn’t go through any real exercise of looking at options, no. I doubt I would have spent 200k upgrading the TB20 (if I had 200k to spend and there was something one could spend it on) but this upgrade was reasonable because

• I like the plane – have about 2k airborne hours in it so know it well

• it does the job I need

• the plane has given me 16 years of amazingly reliable service, with a virtually 100% uptime (I recall losing a few hours before a 2015 trip to Lausanne due to a faulty flow totaliser, and I would not have flown a much longer trip without the totaliser) and I simply do not know anybody else who has had such a high level of reliability in the SEP/MEP arena, though there must be some… AOG is massive in light GA, with ~ 30% cancelling fly-ins due to (a claimed) tech issue

• I know the plane well maintenance-wise and I am able to keep it running in the present and pretty standard difficult situation (e.g. not allowed to do any work in the hangar) which might not be possible with another type, especially if it involved having to deal with some dodgy outfits

• there are very few TB20 GTs for sale, and even fewer with TKS

• I wanted the opportunity to do my best on the loss of performance, which some owners have reported at 7kt (which I would consider outrageous and hope I don’t get that too)

• the internals are as-new so it will go for many more years

• it has just had a new engine

• apart from discretionary updates and the infamous SB569, my maintenance costs are very low; a fraction of what the average syndicate around a C152 spends

• I have no dealer relationship to maintain so I am free to post my views on Socata on EuroGA

• the smallest logical upgrade would be a Jetprop which would be too big a piece for me to swallow, as well as being unsuitable for getting good photos and being generally unsuitable for local flights

• I got what might be an unusual opportunity to buy the TKS kit directly from the manufacturer instead of being forced to go to their expensive and disinterested “agent” in Germany, which would have been a really nasty option because there is no practical way to keep an eye on the job while it is progressing (there are some flights to EDNY, in the winter, admittedly) and you know what happens when you don’t keep an eye on a job…

I don’t think the cost is excessive, looking at prices paid for some TB20s in a very good condition and with good equipment AND then you are still buying a potential can of worms. So a large factor is how much you value aircraft availability and reliability. If you fly say 150hrs a year and go places with it, these become important.

The installation downtime of 2 months was mostly with heavy rain banging on the hangar roof, almost every day. Most satisfying

Not sure if there is any more interest in this topic so this is just a quick update. Today was the first post-TKS flight and it doesn’t look like there is any performance loss, in cruise or rate of climb. Stall behaviour is slightly modified in that if you go deep into the buffet zone it eventually does a fairly rapid break which I don’t think it did before. But the speeds for stall warner onset and buffet onsets (both clean and full flaps) are not different.

The fuel totaliser transducer turned out to be dead when we started up. I am not sure when it failed but it didn’t get noticed until takeoff (reading 0.0) so we aborted the takeoff, because it could be some huge fuel leak etc etc. Luckily I have a simulator box (described here) which generates 29.5 USG/hr so isolated it down to the sensor pretty quickly. I would not do a long trip without the totaliser but “the Alps” etc is OK. New one is in order – $300 last time one failed (2015).

This meant the engine operating point had to be set according to the EDM700 (peak EGT is about 12 GPH, and I normally fly 11.5 GPH at low level) and I was readily getting 140kt which is at the top end of what I ever saw before! To slow the plane down to the more usual 138kt I had to go quite a long way LOP.

So it doesn’t look like I am getting anything like the 5kt-7kt loss which most others have reported.

The only difference I noticed is that when you push the plane deep into the buffet it does eventually do quite an interesting break, which I think it didn’t do before. You would need to be completely asleep to get this far however.

Clean
Stall warner 75kt
Buffet onset 68kt

Full flap
Stall warner 60kt
Buffet onset 55kt

We were loaded as follows (MTOW 1400kg)

The TB panels were not flush

so needed a lot of forming, with a wooden clamp we constructed. It took me 1-2 days to do just that part, on the 8 panels (the 9th is the VS panel which fitted as it came).

Yes a loss of 7kt (IAS or TAS) is a great deal of engine HP going down the drain somewhere…

The high altitude performance is something that will be interesting. I have lots of experience of that in the TB20, up to FL210.