TKS level indicates 0.0

Hello, just had my TKS filter changed and drained my tanks and topped off with new TKS fluid. Initially it indicated 3.7 gallon. Today when I went to pick up the airplane I got a TKS level indication of 0.0 on the right tank.
Anyone have any issues with this ? What was the solution ? Thanks in advanced !

I have had the float get stuck down after draining before. When that happened to me I removed the rectangular access panel on the bottom of the wing root fairing and tapped on the TKS sending unit and it popped up.

Not an answer (probably a stuck float as Ross said), but I’m curious how much the TKS filter cost. IIRC, it was >$1,000 when I had mine changed last year. For a filter.

Ross has seen a lot of these so he may be right. But it could also be the sender unit that has gone bad. I think that cost a lot more than a stuck float!

If yours is a non-FIKI aircraft, I would suggest changing it on condition or predicated on actual usage. There is no requirement to change it, and a calendar change interval is going to be defined based on “worst case” usage. If you’re typically using it in a non-FIKI bird mostly to just exercise the system once a month or so, the cumulative couple hours a year is obviously not “worst case” usage.

This filter is a poster boy for RCM. For typical non-FIKI usage (which, after all should be very low if you’re staying legal!) changing it every 4 years is still probably overkill.

Ask to see and examine the TKS filter when you change one out. I’ll bet it’s as clean as a whistle.

Mine is a FIKI G6, but i try to use it as if it were a TKS bird. That is to say, very sparingly: only to get through thin layers and no cruising in icing conditions.

I was aware of Mike Busch’s advice, but I got snookered anyway (and I’m not talking about :8ball:). Hoping I won’t be next time.

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The TKS filter part w o-rings etc was $1092 and the labor was 1.95hrs .

Hi Ross,

That’s what I was hoping. We tried tapping on it and even emptied the TKS tank and then attempted to refill hoping that would free up the float. Unfortunately, that didn’t work.

So, after our attempts to free up a possible stuck float failed, we ended up breaking the seal and taking out the sending unit w float. Turned out the the float had physically broke into a few pieces. Was a small task to get the pieces of the tank with the flexible claw. I’ll send pics tomorrow


Thanks–that’s about what I paid, although the labor might have been a little less. Off to check…

Wow–that’s wild. I’ve occasionally had a stuck float in the fuel tank after doing steep turns. It usually self corrects after a few minutes. I guess this was just a bad part.

Since the minimum quantity of TKS to legally launch into icing conditions is 5 gallons, if one side reads 0 gallons, then you automatically have a non-FIKI bird.

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Yes, but I think you meant to reply to the OP (whose reading was 0 on one side).

So the new TKS sending unit came in. I put in a phone call to the manufacturer CAV to find out if we can order just the float and arm and not the entire sending unit ($1000, given that the float seems to be attached to the sending unit via a simple cotter pin. I’ll let you guys know what I find out when they return my call.
I’m really surprised this was broken/corroded the way it was.

Correction guys. The manufacture of the TKS sender float arm that corroded and broke is not CAV its CIES. I’ll reach out to them and see if the arm and float is something we can order if this happens to others.

The arm is replaceable.

So the team is on this. We have seen corrosion on now 3 TKS sensors from 2012 & 2013. The arm material is 1100 aluminum for its corrosion resistance and flexibility without having stress corrosion cracking from the cold work forming process. At the time we heated the arms in a hot water bath prior to forming. The corrosion we have seen is not stress related (ie not directly in the bends) and entirely a corrosion attack on the material itself. A recent picture from the owner shows that this corrosion extended to the cotter pin (steel) and to the rotor which is 6061 with a mil spec hard coat anodize with teflon impregnation. We have had an independent lab do an in-depth analysis on the corrosion pit points and their caution is on the TKS itself and insuring that it is replenished and of good quality similar to requirements for automotive cooling systems.

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From an owner with a retrofitted TKS sender, thank you @Fuellevel for your work on this.

We really appreciate the transparency and work to rectify this issue. Yet another reason I am happy to fly planes with Cies sensing systems and recommend retrofits to many clients. Now if only other aviation companies took this same initiative…