Tie Down Fuel Tank Question

[Echo]

26 minutes ago, Kelpro999 said:

Plumbers tape (Teflon) doesn’t fair well with straight threads as it won’t capture and compress the tape. The oe threads are 5/16-18, then after they get worn or damaged, the holes get re-threaded to 3/8-16 and larger tie down rings go in. If yours are 3/8, Heli-coil back to 5/15” (Lasar bolt size) kind of works but not perfect then use fuel tank access panel sealant on the lasar bolt threads, between the jack points ,tie eyes and wing skin.

 All this seems kind of strange having fuel above the tie down eye since the poh says to remove tie down eyes before flight.

Thanks.  But remember, regarding strange, that the OEM tank does not use the bay that the Monroy STC uses.  Hope I don't have to heli-coil.

[Jsno]

To do it right you need to open the tank and use fuel tank sealant on the inside where the tie down comes through.  Better to do it right the first time than right after many times.

[Shadrach]

56 minutes ago, Jsno said:

To do it right you need to open the tank and use fuel tank sealant on the inside where the tie down comes through.  Better to do it right the first time than right after many times.

If indeed the tie down boss is located in part of an extended wet wing compartment, then the above recommendation is likely the only way to ensure a good seal. 
 

I wonder if the bolt could be shortened enough to avoid breaching the tank while still retaining adequate thread engagement to secure the aircraft.

[Echo]

10 minutes ago, Shadrach said:

If indeed the tie down boss is located in part of an extended wet wing compartment, then the above recommendation is likely the only way to ensure a good seal. 
 

I wonder if the bolt could be shortened enough to avoid breaching the tank while still retaining adequate thread engagement to secure the aircraft.

I am not certain bolt extends beyondthe threaded angle.  I will see what Paul says.  I want it sealed properly.  Hopefully I don't need to shorten the length.

[Echo]

Paul said there is a block off of the area with the extended tank conversion.  Just screw in the bolt.  Thanks everyone.  Scott

[Fly Boomer]

21 hours ago, Echo said:

I have extended tanks that apparently compromise the Tie down (as it enters the extended tank).  Anyone else experience this?  I have purchased Laser jack/tiedown and want to install them, but I don't want massive tank leaks.  I appreciate suggested methods to safely and properly install the Laser tie down/jack points.

I have Monroy tanks and, when I swap my tie-down rings with jack points, no fuel comes out.  I would look for leaked fuel inside the wing that has found its way to a convenient hole.

[Shadrach]

So this whole thing was a goat rope based on the previous owner’s ignorance?
I feel silly for entertaining the premise that an STC would be approved in such a way.

[Echo]

1 hour ago, Shadrach said:

So this whole thing was a goat rope based on the previous owner’s ignorance?
I feel silly for entertaining the premise that an STC would be approved in such a way.

Sadly I think that is correct OR the tank that has an STC did not adhere to STC?  Sorry I brought this up Ross.  Scott

[Shadrach]

1 hour ago, Echo said:

Sadly I think that is correct OR the tank that has an STC did not adhere to STC?  Sorry I brought this up Ross.  Scott

No apologies. I would’ve done the same. Imagine if you threaded in your new tiedowns only to find that you compromised your long range tanks.

[Kelpro999]

14 hours ago, Echo said:

regarding strange

Have you read the STC? Wondering if there’s something related to removing the eye? I get that not many remove it but it’s part of preflight as outlined in the POH

edit: I should have read other responses before commenting 

Edited January 2, 2024 by Kelpro999

[A64Pilot]

If it’s been years since the tie downs have been installed. It may be prudent to clean out the threads with a tap because they could be rusted.

I put a little bit of anti-seize on mine because I don’t remove them, never understood that requirement. My guess is the flight testing was done with them removed and the FAA brought that up?

However the bright side is if it didn’t have tie downs it’s very likely it lived in a hangar.

I get a kick out of the sales ads that say always hangared, then list the covers the airplane comes with or the pictures show it tied down.

If I ever sell mine my first pic will be the hangar  I’ll say something like always hangared, really.

[LANCECASPER]

4 hours ago, A64Pilot said:

If it’s been years since the tie downs have been installed. It may be prudent to clean out the threads with a tap because they could be rusted.

I put a little bit of anti-seize on mine because I don’t remove them, never understood that requirement. My guess is the flight testing was done with them removed and the FAA brought that up?

How do you put it on jacks for a gear swing?

[A64Pilot]

28 minutes ago, LANCECASPER said:

How do you put it on jacks for a gear swing?

I have the Lazar ones that have the built in jack point

[Echo]

Success.  There were bolts installed in jack points, but the combo SS Laser Jackpoints/Tie Downs threaded just fine.  The tanks ARE wet as there was no fuel showing on visural, but pilot side tank DID run fuel when I unscrewed bolts.  I put fuel sealant on the bolt threads, but might of been compromised with install on pilot side.  The jackpoints showed ZERO sign of fuel seepage through threads without any sealant applied.  Glad to have dedicated tie down and jack point functional in my Mooney.