Broken TKS lines, sharing the information

[glenn reynolds]

I fly a fiki ovation and have had four TKS system failures.  I thought it might be helpful if I shared the information with the rest of the team, as I have found few shops that are up to speed on these systems, so I've had to play the role of director of money spending:

1) This is the well documented failure of the stall strip triangle on the leading edge.  There are multiple reports of the glue giving out and I was alerted to this by a fellow pilot and got mine re-attached before it was lost.  recently I've read about using rtv to seal the gaps (which mine has) so I'll do that soon.  this is a tedious repair due to the cleaning involved, exact placement and then cure time required.  

2) failure of the COPPER prop slinger nozzle.  I lost two of these prior to learning several things: CAV now wants an RTV "cone" of vibration dampener of RTV (room temperature Vulcanizing) sealant at the base of the nozzle.  I did this and it has worked perfectly.  Second: they now have a new and improved nozzle made of a metal which has less tendency to vibration work harden.   If your nozzle doesn't have a cone of rtv at the base of the nozzle, why not?  

3) nylon belly tubing failure.  This is more complicated.  it appeared that my nylon supply tubing had shrunk which apparently is normal and so there must be additional length accounted for in the installation.  My installation was lacking this "contraction" length and thus pulled out so I needed a longer replacement section.  Careful reading of the CAV installation paperwork shows that the tubing is connected with what CAV calls an "olive" (the tubing industry calls it a ferrule) and these were missing on my installation.  CAV supplied both ferrules and tubing.  You want a low boy creeper to work under the belly skin!  Next time I'll do this with the plane on jacks.

4) this is the latest:  forward of the firewall my tks tubing was firesleeved from firewall to engine cooling baffle where the tubing transitions to stainless steel tubing across the top of the engine.  I recently replaced all the hoses, firewall forward when I changed the engine and I found the firesleeved TKS hose to be stiff and inflexible.  This was in stark contrast with all the other hoses which seemed to laugh and mock me for throwing them away with there excellent looks and high flexibility.  So a played a little.  As I was flexing my tks line it snapped!  I cut open the firesleeve and found that the TKS line had not been a fuel line material, but rather what looked like Buna with a spring wire reinforcement.  It had leaked, rusted and failed.  I had not detected the leaking  as the firesleeve was very well sealed at both ends.  The forensic evidence indicates that it had been leaking into the fire sleeving for some time.  I assume my propslinger worked solely due my filling the fire sleeve with tks fluid each time I primed.  I know some of you will ask so i address it now:  I forgot to check the hose date code to determine how old the tks hose was, but the bad news is that other evidence indicates that it was only six years old.   It only takes about twenty minutes to remove this hose and see if it is supple or not.  There are two shops who supply custom made teflon, fire sleeved, hoses.  I called both, one was three weeks, the other was three days.  it wasn't expensive, budget around $100 bucks.  You send your old hose and they return it with an identical replacement.  

[milotron]

Great advice here. 1, 2 and 3 have all happened to me. I think my firewall forward hose may be solid though?

CAV sells a complete kit with olives and o rings for redoing the whole hose installation, which helps for having some spare parts around.

[glenn reynolds]

Hard to imagine the firewall line as solid since the engine vibrates so the transition from firewall to engine should be flexible. Check it out on your next oil change

[carusoam]

Great TKS and CAV pireps Glenn!

Thanks for sharing all of the details…

W/ pics!

Best regards,

-a-

[carusoam]

Always invite the good people from @CAV Ice @CAV Ice Protection to stop by…

They are always keeping up with MSer issues…

Go TKS!

Best regards,

-a-

[philip_g]

Haven't had any of those happen on brand c but had an actual panel fail.

[CAV Ice]

@glenn reynolds

This is the first fire sleeve failure I've seen.  Good catch!  

Stall strips should be checked on a regular basis (preflight?).  The sealant used now is PR1221 B1/2 or CS3204 B1/2 (I have instructions on installation and sealing if needed).  This has proven much more effective than the older sealant, which can weather and crack.  Should a stall strip come off make sure the feed tube is secured.  If the feed tube breaks off flush with the panel it would require a panel replacement $$$.

Sorry to hear about the belly tubing.  PM me with the installation information.

Thanks!

[M20F]

A good example of if you are going to get icy make sure to make a a mess on the ground to ensure it works.  If you are in the air ensure you are getting spread before you need it. 

[r0ckst4r]

I also have notice a belly leak.  Can you post some more information on the parts and work required for this?

[glenn reynolds]

You need to remove the belly panels and run the system. My leak was instantly apparent. Then all I needed was a longer replacement tube and fittings for both ends. Super easy repair