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TKS quantity indicating 0.0?


Rick Junkin

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My TKS quantity indication was a bit erratic and now indicates 0.0. There is at least 3 gallons in the tank, as I ran it on my last flight starting with about 3 gallons, and added another gallon tonight to see if the quantity indication would change. No luck.

Has anyone else seen this? My guess is that its a simple fix of a fluid level sensor that's gone bad, but nothing with the CAV system ever seems to be simple. And I don't have any documentation or drawings for how the system is put together or installed, or how to get to the fluid level sensor. Any ideas?

I'll be calling CAV tomorrow, but thought I could prepare for the conversation with some knowledge from MooneySpace. None of my searches turned up anything that resembles my indication problem. Thanks for any ideas or experience.

Cheers,
Rick

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They have a really cheap quantity indicating sensor.  I had the exact same problem and got p.o.'ed and pulled the sender out to see what was wrong.  Found the float was the problem.  It's been enough years now I don't remember if there was a hole in it or if it wasn't attached to the sensor arm properly.  Edit; I seem to remember the float had TKS fluid in it and I drained it and resealed it.  Seems it was a hole and I used a special Locktite product (Hysol) I was using for fuel tank sealer on my Lancair wings.  I could get you a bit of it if you find that's the issue.

At any rate I was able to repair it, got my A&P's blessing to sign it off, and reinstalled the original sender with no cost other than my labor time and it's work fine since.  I DO REMEMBER if I had replaced it with new, the problem would have resurfaced later.   

I recommend you pull it and inspect it before getting a bunch of money in it.  One recollection; it was a real bitch separating the sender from the tank.  I had to use a very thin scraper and worked at it for probably an hour to separate it without damaging it.  It is sealed on there pretty good.

Tom

Edited by Yooper Rocketman
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22 minutes ago, Yooper Rocketman said:

 I recommend you pull it and inspect it before getting a bunch of money in it.  One recollection; it was a real bitch separating the sender from the tank.  I had to use a very thin scraper and worked at it for probably an hour to separate it without damaging it.  It is sealed on there pretty good.

Thanks Tom! I'll use a timer to track quantity until I'm ready to take this project on, and then I'll look at hitting you up on your offer of repair material. "Hour Projects" are sort of a hobby of mine, usually days at a time on each. I'll still give CAV a call tomorrow, my guess based on your experience with separating the sender is that they will recommend that I replace the whole tank.

Cheers,
Rick

Edited by Junkman
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2 hours ago, carusoam said:

Sounds like something Cies could help with... @fuellevel as a long term type of development thing....

Sewing seeds for the future...

Best regards,

-a-

Thanks Anthony. The CAV system on my airplane (very early adopter, not FIKI) is STC'd, wondering if changing out the sender would be an issue? Not opposed to hangar fairy maintenance, just want to be aware of what I might be doing to resale if I go that route.

Cheers,
Rick

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3 hours ago, StevenL757 said:

Rick, second Tom's comments.  I had the same issue and corrected it exactly as Tom indicated.  Let know how you make out.

Steve

Will do. It indicated 1.1 yesterday... flying in the morning, I'll see what it indicates and turn it on to see what happens. I don't deal well with lack of precision... HAHA!

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Cies has the skills to develop and certify float based liquid level indicators for airplanes...

It is quite a bit of work on their part to get all the details in place.  They have done it so many times for various shapes and sizes of tanks and float combinations it is well within their wheel house to get it right...

They have been doing Mooney fuel tanks only recently after years of being an OEM supplier for other airframes...

It will be interesting if Scott @fuellevel can get back to us with any insight to having done this in fiki tanks.

There are a lot of cirri with Cies gauges in their fuel tanks.  No reason to not have them in their fiki tanks as well... especially as the existing float has(?) a significant failure challenge. This is a type of technical challenge that sales engineers generally like to hear about...

Not much sense in having a hangar fairy work on the project.  But there are some that can identify that the float has actually leaked and sank...

I would celebrate that kind of hangar help!

I think... Cies has showed pictures of the various types of float failures they have seen. A couple of floats that were hollow shapes that split on seems filled with the liquid they were trying to measure... blow molding polymer shapes is a low cost method of making float parts.  Doing it with chemical resistant materials makes it a little more challenging...  Not much different than the millions of toilet tank floats in use today... just chemical resistant instead of water resistant...

The Cies floats were made from a simple chemical resistant polymer foam without any seams to fail... brilliant?

Aside from that, Cies's magic is the additional digital accuracy they get from their electronics. The snazzy floats are just indicative of the added skill level their engineers provide...

Their fuel level float system have a pretty high level of accuracy. Extended to the fiki system... would be incredibly nice to know kind of information...  talk to JPI about Fiki fluid gallons left to destination.... If this is a first... I'd like to assign the patent idea to Craig @mooniac58... whose MS skills so deserve it...

Reminder... Send the TKS folks a request for an updated float to make their system work for a longer period of time... a fair request as well... :)

I think automobiles have been using a good technology with fuel pumps in the fuel tank, with the fuel level float/indicator as part of the package...  talk about a tough environment for an electronic device...

PP thoughts only, not a mechanic or sensor guy...

Best regards,

-a-

 

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On 1/25/2018 at 7:18 PM, Junkman said:

My TKS quantity indication was a bit erratic and now indicates 0.0. There is at least 3 gallons in the tank, as I ran it on my last flight starting with about 3 gallons, and added another gallon tonight to see if the quantity indication would change. No luck.

Has anyone else seen this? My guess is that its a simple fix of a fluid level sensor that's gone bad, but nothing with the CAV system ever seems to be simple. And I don't have any documentation or drawings for how the system is put together or installed, or how to get to the fluid level sensor. Any ideas?

I'll be calling CAV tomorrow, but thought I could prepare for the conversation with some knowledge from MooneySpace. None of my searches turned up anything that resembles my indication problem. Thanks for any ideas or experience.

Cheers,
Rick

 Just another thought…There is an overflow tube (cut at an angle) coming through the belly plate just below the back seats. Just beneath the belly plate there is a small hole drilled into the overflow tube to prevent siphoning of the TKS tanks. Over the years some overflowed fluid may have plugged the small hole. You may have drained your tanks through siphoning. Yes, it happened to me.  If your sensor reads zero, turn the system on to see if your panels still wet out-confirming the reading is erroneous.. 

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8 hours ago, carusoam said:

Cies has the skills to develop and certify float based liquid level indicators for airplanes...

It is quite a bit of work on their part to get all the details in place.  They have done it so many times for various shapes and sizes of tanks and float combinations it is well within their wheel house to get it right...

They have been doing Mooney fuel tanks only recently after years of being an OEM supplier for other airframes...

It will be interesting if Scott @fuellevel can get back to us with any insight to having done this in fiki tanks.

There are a lot of cirri with Cies gauges in their fuel tanks.  No reason to not have them in their fiki tanks as well... especially as the existing float has(?) a significant failure challenge. This is a type of technical challenge that sales engineers generally like to hear about...

Aside from that, Cies's magic is the additional digital accuracy they get from their electronics. The snazzy floats are just indicative of the added skill level their engineers provide...

Reminder... Send the TKS folks a request for an updated float to make their system work for a longer period of time... a fair request as well... :)

 

First off, thinking CAV is going to come up with a solution is dreaming.   Their solution to the clamps breaking for the prop spray bars was to continue providing the same $3 clamp, but raising the price to $50 each!!!  This part now becomes an "owner produced part".

A Cies replacement would be awesome!  Coming down to Florida on Friday I used my TKS several times without the quantity indication dropping one tenth of a gallon.  After landing in TN, on my next start up it shows 3 gallons down on the TKS fluid level.  Keep in mind, when I repaired the sender 3-4 years ago, it was reading low or empty because the float was saturated with fluid.  This is a common trait that the gauge will stick showing more fluid during flight while using it and then correct itself after landing, shutdown, and a restart.

These gauges suck.

Tom

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22 hours ago, L. Trotter said:

 Just another thought…There is an overflow tube (cut at an angle) coming through the belly plate just below the back seats. Just beneath the belly plate there is a small hole drilled into the overflow tube to prevent siphoning of the TKS tanks. Over the years some overflowed fluid may have plugged the small hole. You may have drained your tanks through siphoning. Yes, it happened to me.  If your sensor reads zero, turn the system on to see if your panels still wet out-confirming the reading is erroneous.. 

Today the system indicated as much as 2.1 gallons, as little as 0.0 gallons. I ran the system and all panels wetted out  just fine. The erratic nature of the reported quantity is a bit puzzling.

I didn't make my call to CAV last week. Hope to get to it tomorrow, work permitting. I'll report back with what they recommend.

Cheers,
Rick

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On 1/28/2018 at 6:26 AM, Yooper Rocketman said:

First off, thinking CAV is going to come up with a solution is dreaming.   Their solution to the clamps breaking for the prop spray bars was to continue providing the same $3 clamp, but raising the price to $50 each!!!  This part now becomes an "owner produced part".

A Cies replacement would be awesome!  Coming down to Florida on Friday I used my TKS several times without the quantity indication dropping one tenth of a gallon.  After landing in TN, on my next start up it shows 3 gallons down on the TKS fluid level.  Keep in mind, when I repaired the sender 3-4 years ago, it was reading low or empty because the float was saturated with fluid.  This is a common trait that the gauge will stick showing more fluid during flight while using it and then correct itself after landing, shutdown, and a restart.

These gauges suck.

Tom

I just spent 60K installing a full FIKI TKS system. The result.....A totally non functioning system. To be fair, CAV did not do the installation. One of their two "certified" shops did. Mooney (my first choice) was to busy to install. Among other things the 2 main problems are 1. The tanks siphon them selves dry (as mentioned previously) 2. Quantity sensor (reads anywhere from 0 to 7.4 gal) even when the tank is bone dry. When full, no difference.

I am taking the plan to CAV in 3 wks for them to trouble shoot and revise the new installation. Sounds like the sensor issue has not changed. I will bring up this thread and discuss the deteriorating product quality/reliability. I'm hoping to get a functioning system before winter is up.

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On 1/28/2018 at 11:46 PM, milotron said:

Have you checked for wiring issues? From the drawings I have, it looks like a 3 wire resistive sensor. Maybe a grounded conductor or an open circuit somewhere, especially given that it is somewhat intermittent.

 

iain

Thanks for the suggestion, I honestly haven't done any troubleshooting yet. My next action is to syphon the tank and then put in a known quantity. I don't have any illusions about that fixing the problem, but it will give me a baseline quantity to use timing for monitoring how much I have left in the tank. Its icing season here in Missouri, and I turn on the system every time I turn on the pitot heat. When we get to weather where I don't want to have the TKS available, I'll start the troubleshooting.

Cheers,
Rick

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@fuellevel

Scott, you must have been up early this morning!

How many senders would it take to fully instrument a Fiki Long Body Mooney, six?

  • Two for each fuel tank.  Four total...
  • one for Each TKS tank. Two total...

For the TKS tanks...

is it just a swap of the sender to the original TKS instrument on the panel?

Or are people using a JPI (or other) to collect, record, and display tank levels?

Is this an STC extension, or would New paperwork be required to make usable?

Available today? Or a long wait from now?

Reported possible challenges...

  • Float sticking, or not floating... leads to not knowing how much is left.
  • TKS fluid getting siphoned out... leads to fluid exhaustion in flight.
  • a combination of missing fluid and poor instrumentation can be pretty bad...

 

PP thoughts only, Asking for my MS friends with a TKS system....

Best regards,

-a-

 

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