TKS weirdness; level meter shows fluctuating indications

[dkkim73]

Hi All, 

The new Acclaim is home as of last week. Some interesting weather on the way up, great training with Sam from Mooney Pros. Getting some reps in now and working out some kinks. Really impressive machine! 

The TKS system was worked on at Mooney, overhauled tail proportioning unit and 2nd windshield pump. All checked out as expected at the end (including a low pressure light in warmer conditions, but they instrumented pressure sensors and talked to a former CAV engineer to verify all was as expected). 

System worked fine on the way up (was needed several times). The flow looked good and the level indications over time were as expected. 

One the last flight last week we used it down to 2.2, and I asked the FBO to add 4 gals. I found out a couple days ago that a lot came out the belly and they "saved some of it". It is unclear how much was retained in the aircraft, sounds like ~2 gals. I carefully added a jug, I think about 1.5gal (not labeled) and got only a tiny few drops. Tested the system on ground and the flow looked good, no leaks. It read 4.4 when I was done, so I figured they'd just filled it too fast, and let it sit for a day.

When I went in today to check on several things, the meter read over 6 (I think like 6.4, which is more than nominaly full). I'd spoken to an A&P (Michael at Mooney) and he said the meters can be unreliable, but the way to know for sure is to fill until it comes out the belly tube. Stressed that it should be added slowly as there are vents and a standpipe that can overflow even if it's not full. 

So... I took another jug, and added I think about 1.3 gal or so, starting slowly. Everything was fine over about 3-5 min, until the last cup or so, when suddenly fluid started coming out of the belly. It ran for a while, over 10 min, actually put out over a gallon. So I thought perhaps it was already nearly full. 

Oddly, I watched the indicator during this time and saw it go down into the 5's, then 4's, 3's. I let it sit with the master off for a bit, rocked the plane on the wheels a bit (in case something might be stuck) and then when I turned on the master it was at 1.9 (!!). 

So, I'm not sure what is going on. Simplest explanation is a nearly full tank and a bad sender.

I *think* given the dynamics a leak from the bottom of the tank is unlikely, but it's funny to have the level keep falling like that. Perhaps there is a long way for the fluid to go between the drain hole and the overflow vents/pipe in the tank? 

Figured I'd see if anyone had encountered similar behavior before. Also, how easy is it for a (handy but non A&P) lay owner to remove panels to look at all this? 

Thanks,

David

 

[BravoWhiskey]

I have a similar issue.  I think my float has a leak in it and is allowing fluid inside.  If I fill it all the way the meter starts to go down, when about half full it seems to be accurate.  
 

it will also change during long climbs and slowly correct when back at level flight.

Edited February 22 by BravoWhiskey

[GeeBee]

Welcome to TKS! After a while you get pretty good at knowing when the tank is full by the rate at which the filler accepts fluid. You don't want to fill it until the vent tube on the belly starts flowing because once it gets going, it creates a siphon action that dumps out a lot of fluid and creates a less than full tank. When I service my fluid, I usually put one of those oil drain pan/tank you purchase at an auto supply store under it just in case. I use it for only TKS so if some does dump out, I can recover it un-contaminated. I also use a Flo Tool  funnel with a screen in it to protect the system from particle contamination and it has a valve on the bottom to regulate the flow in. Finally it has a removable lid so I can cap the top, close the bottom valve and stow it in the airplane. 

The gauge has two readings. On the ground and in the air. On the ground is lower than in the air. I find my in the air, the most accurate. I have tried numerous times to make the gauge more accurate and you can get close but it never really holds. For me, there is only two dispatch conditions. Full or empty. I say this because who wants to dispatch into possible icing conditions with less than a full tank? Equally so, on a summer CAVU day who needs fluid that weighs 9lb/gallon?

[Fly Boomer]

9 minutes ago, GeeBee said:

I also use a Flo Tool  funnel with a screen in it to protect the system from particle contamination and it has a valve on the bottom to regulate the flow in. Finally it has a removable lid so I can cap the top, close the bottom valve and stow it in the airplane. 

Went to the Flo Tool website, but couldn't find a funnel with screen, valve, and lid.  Can you post a link?  Thanks.

[GeeBee]

I bought it at WalMart but can't find it now. I will look at it today when I go to the airport and find a model number.

[Fly Boomer]

10 minutes ago, GeeBee said:

I bought it at WalMart but can't find it now. I will look at it today when I go to the airport and find a model number.

Thanks.  Sounds like a useful tool.

[Danb]

10 hours ago, dkkim73 said:

Hi All, 

The new Acclaim is home as of last week. Some interesting weather on the way up, great training with Sam from Mooney Pros. Getting some reps in now and working out some kinks. Really impressive machine! 

The TKS system was worked on at Mooney, overhauled tail proportioning unit and 2nd windshield pump. All checked out as expected at the end (including a low pressure light in warmer conditions, but they instrumented pressure sensors and talked to a former CAV engineer to verify all was as expected). 

System worked fine on the way up (was needed several times). The flow looked good and the level indications over time were as expected. 

One the last flight last week we used it down to 2.2, and I asked the FBO to add 4 gals. I found out a couple days ago that a lot came out the belly and they "saved some of it". It is unclear how much was retained in the aircraft, sounds like ~2 gals. I carefully added a jug, I think about 1.5gal (not labeled) and got only a tiny few drops. Tested the system on ground and the flow looked good, no leaks. It read 4.4 when I was done, so I figured they'd just filled it too fast, and let it sit for a day.

When I went in today to check on several things, the meter read over 6 (I think like 6.4, which is more than nominaly full). I'd spoken to an A&P (Michael at Mooney) and he said the meters can be unreliable, but the way to know for sure is to fill until it comes out the belly tube. Stressed that it should be added slowly as there are vents and a standpipe that can overflow even if it's not full. 

So... I took another jug, and added I think about 1.3 gal or so, starting slowly. Everything was fine over about 3-5 min, until the last cup or so, when suddenly fluid started coming out of the belly. It ran for a while, over 10 min, actually put out over a gallon. So I thought perhaps it was already nearly full. 

Oddly, I watched the indicator during this time and saw it go down into the 5's, then 4's, 3's. I let it sit with the master off for a bit, rocked the plane on the wheels a bit (in case something might be stuck) and then when I turned on the master it was at 1.9 (!!). 

So, I'm not sure what is going on. Simplest explanation is a nearly full tank and a bad sender.

I *think* given the dynamics a leak from the bottom of the tank is unlikely, but it's funny to have the level keep falling like that. Perhaps there is a long way for the fluid to go between the drain hole and the overflow vents/pipe in the tank? 

Figured I'd see if anyone had encountered similar behavior before. Also, how easy is it for a (handy but non A&P) lay owner to remove panels to look at all this? 

Thanks,

David

 

Hey great news on your new arrival, Sam had issues with my TKS also on my ferry flight. Anyway I’d contact Jason @CAV he helped me recently regarding a leak which I fixed over the weekend. CAV is awesome 

Jason Jennings….J.jennings@cav-systems.com

direct te. 913-738-5397

good luck welcome to the Acclaim club.

Dan

[dkkim73]

Thank you all for the quick and helpful responses, and the ref. to CAV systems. "Welcome to TKS!" indeed  I will say it's a thing of beauty to observe in flight with icing...

A siphon effect would explain the weird "overshoot" behavior, as would a stuck or leaky float. 

Do you all think re-using the leaked TKS fluid is a reasonable idea? (mentioned above, and by one of the line guys... a filter was mentioned above, and I bought some paint filters for filling) I'm wondering if it picked up particulates while draing along the belly pan. The surfaces pores are pretty small, but there is an upstream filter in the system, so maybe's it OK. 

Thanks,

David

 

 

[GeeBee]

4 hours ago, dkkim73 said:

Thank you all for the quick and helpful responses, and the ref. to CAV systems. "Welcome to TKS!" indeed  I will say it's a thing of beauty to observe in flight with icing...

A siphon effect would explain the weird "overshoot" behavior, as would a stuck or leaky float. 

Do you all think re-using the leaked TKS fluid is a reasonable idea? (mentioned above, and by one of the line guys... a filter was mentioned above, and I bought some paint filters for filling) I'm wondering if it picked up particulates while draing along the belly pan. The surfaces pores are pretty small, but there is an upstream filter in the system, so maybe's it OK. 

Thanks,

David

 

 

As long as it leaks into a clean container. 

Here is the funnel by the way. Cut the tube to about 6 inches to fit in the fill

https://www.oreillyauto.com/detail/c/flotool/tools---equipment/oil---lube-tools/funnels/9227a0a2bf37/hopkins-flotool-clear-black-blue-plastic-funnel/hop5/10704

 

Here is what I use to collect TKS spilled fluid from the vent. It is only used for that event.

https://www.oreillyauto.com/detail/c/flotool/hopkins-flotool-drain-pan/hop5/42004/v/a/5340/automotive-truck-2002-ford-f-250-super-duty?q=oil+change+pan&pos=3

 

[Fly Boomer]

44 minutes ago, GeeBee said:

As long as it leaks into a clean container. 

Here is the funnel by the way. Cut the tube to about 6 inches to fit in the fill

https://www.oreillyauto.com/detail/c/flotool/tools---equipment/oil---lube-tools/funnels/9227a0a2bf37/hopkins-flotool-clear-black-blue-plastic-funnel/hop5/10704

 

Here is what I use to collect TKS spilled fluid from the vent. It is only used for that event.

https://www.oreillyauto.com/detail/c/flotool/hopkins-flotool-drain-pan/hop5/42004/v/a/5340/automotive-truck-2002-ford-f-250-super-duty?q=oil+change+pan&pos=3

 

And that funnel has caps on both ends that allow you to keep it in the airplane with TKS fluid in it?

[Fritz1]

I would take the rear belly pan off, just a couple of quarter turn fasteners and see if anything is leaking, then take the plug off from the back of the command unit in the instrument panel and spray the contacts with contact cleaner, plug it back in and unplug it a couple of times to make sure the plug is correctly inserted and there is no corrosion going on that distorts the fill level signal.

[GeeBee]

39 minutes ago, Fly Boomer said:

And that funnel has caps on both ends that allow you to keep it in the airplane with TKS fluid in it?

It has caps at both ends so you can put it away in your airplane "wet" after using it. No need to wipe it out.

[exM20K]

I have no issues filling old 1 gallon jugs (and some new ones from Grainger) from my 55 gallon drum.  It’s pretty simple to pour the 1 gallon jugs into the TKS fill.

-dan

[Fly Boomer]

50 minutes ago, exM20K said:

I have no issues filling old 1 gallon jugs (and some new ones from Grainger) from my 55 gallon drum.  It’s pretty simple to pour the 1 gallon jugs into the TKS fill.

-dan

So you don't use a funnel at all?

[exM20K]

6 minutes ago, Fly Boomer said:

So you don't use a funnel at all?

Nope.  Airplane fill cap holds the door open.  Easy peasey. At least inside the hangar….

-dan

[Bolter]

6 minutes ago, Fly Boomer said:

So you don't use a funnel at all?

I find that I can fill with 1 gallon jugs without spilling a drop, without a funnel.  Just slow and careful.  I buy the 1 gallon jugs from Davies, and I suspect the shape of the jug at the cap will affect how easy this is to do.  It is one reason I buy the Davies jugs.  It costs more per gallon compared to a drum, but there is a convenience to always being ready to dispense, or bring extra with me.  

[dkkim73]

FWIW I flew the plane today (engine test runs, unrelated) and it read 5.3. Go figure. 

@GeeBee Thank you for the specific recs and fluid-saving tips. Just ordered those locally. 

@Danb I got a super-quick response from Jason Jennings. He said "I would also recommend inspecting the tanks (under the rear seats) to ensure that a vent hole is drilled in them. This should be located at the highest portion somewhere on the tank." and provided a troubleshooting sheet for the electricals (uploaded). 

@Fritz1 Belly pan. How difficult is it in general for a non-aircraft mechanic to get into things? You mention 1/4-turn fasteners, I'm thinking similar to the upper cowling. Is that all there is to it? I haven't disassembled anything yet. Does anyone know if removing the rear seats is very involved? Ie. does a person have to remove torqued-down rail bolts, etc, or is it simpler than that? 

For the command unit, can you simply reach behind, or unscrew it from the front? (trying to figure out if any panel disassembly would be required). 

Thank you all,

David

Fluid Quantity Indications.pdf

[Danb]

I’d get a helper to help remove the belly, I did last week when wonton TKS, just unlock  fasteners, let it drop on you loosen the antenna cables and set it aside, while it’s off a couple coats of wax or ceramic is easy. Reverse don’t forget to fasten antennas. Most of the removal is simple, get a copy of maintenance and parts manual BTW I’m 75, a CPA not very mechanically inclined but do what I can within my pay grade.

 

D

[GeeBee]

I drop the belly panels all the time. The forward panel requires you to loosen the screws on the boot cowl. Makes it easier to re~insert the forward edge. Other than those they are all cam-locks. Easy peesy. I use a creeper and let the panel drop onto me, that way they don’t get scratched. 

 

[CAV Ice]

@dkkim73 in reference to the control panel, it depends on what style is installed in the aircraft. If you are able to email me some pictures of yours, I can advise on the easiest way to access it for testing. 

[Fritz1]

in my Bravo the TKS command unit is low in the panel on the pilot side, the plug in the rear is accessible by reaching up in the pilot footwell. My plug was loose once after avionics work, inserting it fixed the erroneous level reading. The float in the tank tends to get sticky, so it may not count down the fluid level running the TKS system on the ground, with the engine running the float tends to come loose and the fluid level gets displayed correctly.

The bottoms of the rear seats just lift out, to remove the backrests you have to pull a pin out of the seat rail. However to get to the to of the TKS tank you have to remove a large plastic shell under the seats, you may want to hire an A&P to help, preferably one who has worked on a Mooney before.

My aircraft was bought new by a gentlemen from Bozeman and maintained by Arlins. I am in Bozeman 2-3x per year, am there right now, Bravo sitting on ramp snowed in, and like Arlins shop, you might give them a try with maintenance. All avionics work was done by Airtronics in Billings, no avionics shop in Bozeman.

Bozeman flights from the east coast in winter are only doable for me with the TKS system, so I think you bought the right stuff for your location.

[dkkim73]

So, on Friday I went to the airport and looked at a few things (shared hangar so can't really leave anything apart): 

Dropped aft belly panel, thanks @GeeBee for the info. A bit dirtier and more grunt than I thought, but only because I didn't have jacks (not much clearance) and should've worn real work clothes . I didn't see anything obviously disconnected. I presume the TKS lines are the opaque poly-ish lines with the abrasion wrap in the following pics (I took a bunch but only include 1 or 2 as I didn't see anything obviously wrong, I think the black cylinder is the main TKS filter?). 

Looks like the TKS drain line comes from plastic "domes" that presumably are part of the TKS tank system (see pic), so I guess that allays my worries about collecting and reusing fluid that has run all over the inside of the belly... 

The whole belly was damper than I expected; I saw "sweat" everywhere. There was a film of something slippery (oil, protectant, not sure) that made it hard to figure out what might've been TKS fluid. But I think it was likely condensation (the line guy was away so I didn't have a history of exactly the plane was inside or outside, and it was cold in the hangar, too). 

So... I took a crack at the back seats. The seats and plastic pan came off reasonably well, with some carefully prodding and inspection. The left side had labels saying "TKS tank no drill" or something like that. I peeled back a couple of aluminum panels (with aluminum tape) and looked underneath. I believe that revealed the blank tops of tanks through lightening/inspection holes: 

 

 

I didn't see any vent holes, but really couldn't appreciate the entire outline of the tank, it's profile in level flight (plane nose-up in standard ground configuration), etc, to define the highest point. So I figured I'd get a lot more information before attempting to place any vent holes. But at least I could get a sense of the overall access. I didn't see where the sender unit would be accessed, and most of the tank was covered. 

Next, tried @Fritz1's suggestion of looking at the control box. Things were reachable from below, but the harnesses were zip-tied in place so I just settled for inspecting the connectors and hitting all sides with contact cleaner followed by canned air. The connectors did not appear obviously mis-seated though I will say the sender plug (3 wires in 6 pins) was looser in design than I would have thought. Powering on showed a reasonable-ish level. 

So, what to do? 

I figure I might try a slow empirical full fill when the drain pan and funnel (recommended above) get in, assuming I'd overfilled and created a siphon, and observe the indicated levels in use. Have some A&P work coming up so might ask him to dig further. 

Although I did not really reveal much in the above looks, I figured it might be worth posting what I saw and seeing if anyone else had further thoughts. 

Thanks,

David

[Fritz1]

Might just be stuck float, empty and refill tank, see what that does, after that maybe take sender connector off, spray with contact cleaner and reinsert a couple of times to get rid of potential corrosion. While belly pan is off good idea to wipe off all TKS fluid, spray all rod ends with triflo, I put a small rubber seal strip in front of the front belly panel under the cowl boot to stop TKS fluid from splashing into the belly, run the system on the ground, look for dead spots in the wing panels, best indication of dead spot is drip pattern on the ground, squeeze TKS fluid into dead spot with sponge, tail hardly ever has dead spots, gets much more fluid per foot due to tighter radius

 

[Danb]

David as Fritz mentions I’d dry off all the damp spots most likely TKS fluid not condensation it’s a PIA to find it all mine was drenched from the 5\16 tubing coming apart. Good idea spraying the rod ends, wish I thought of that before putting it back together. 
D

[GeeBee]

As I said, I would not worry about what the tank levels show. There are really only two levels for me for dispatch. Full and empty. Full because I want to dispatch with a full tank into icing conditions because you don't know how much you will need. You can make a good wag of how much remains by time you run the system. Empty because in non-icing conditions where you need the payload, you want it all out. Beyond that is IMHO a waste of time and technology.