Corrosion in fuel cap adapter

[Sabremech]

I'm modding my fuel caps to a new all aluminum assembly via FAA 337 field approval. Is there a need for this option on other older Mooney's. If so, I may go farther than just doing it on my airplane. Here's some photos of my solution.

David

[carusoam]

1) It may make sense to go one step further and start with an inspection panel with no hole in it already...

-or-

2) use a piece of polished stainless outer ring to be scratch resistant to the fuel nozzle... for the nozzles that don't have a nice rubber cushion at the contact point.... or that's what you did already..?  Bravo!

Just thinking out loud,

-a-

[Sabremech]

30 minutes ago, carusoam said:

1) It may make sense to go one step further and start with an inspection panel with no hole in it already...

-or-

2) use a piece of polished stainless outer ring to be scratch resistant to the fuel nozzle... for the nozzles that don't have a nice rubber cushion at the contact point.... or that's what you did already..?  Bravo!

Just thinking out loud,

-a-

1) Huh? Why reinvent the wheel and make it a much costlier project?

2) Stainless is not scratch resistant and that still leaves the issue of dissimilar metals. 

[thinwing]

Also isn't that machined to provide a flush mount to wing surface...replacing it inspection panel would create a "lip"....regardless your local FSDO must be very different from mine to even consider a field approval

[thinwing]

Oh I see your in Wisconsin..your FSDO inspectors must be members of EAA!

[carusoam]

When I had to do this for my M20C... 

1) I may be errantly thinking... the whole panel didn't need to come out. Just the mild steel Fuel neck had to go... speaking of dissimilar metal...

2) my current challenge is the paint chips around the fuel caps... so, not really a scratch resistance issue as I typed, but a paint chip resistance may be an improvement.

3) the real problem that my C had was somebody had replaced the parts with a plastic cap and rotated fuel neck to match the cap, from a race car supply shop.  Mooney caps didn't properly fit The re-rotated fuel neck.  MS didn't exist yet, so problem solving was a bit of a challenge... the race car cap supplier wouldn't talk to me after I mentioned 'for my airplane'...

I have re-learned a lot in the past few years...

Best regards,

-a-

Edited June 4, 2017 by carusoam

[Sabremech]

31 minutes ago, thinwing said:

Also isn't that machined to provide a flush mount to wing surface...replacing it inspection panel would create a "lip"....regardless your local FSDO must be very different from mine to even consider a field approval

I had to cut 2 pieces of aluminum to fit this cap assembly in the original mounting hole. It is flush or a little below flush when the cap assembly is secured to the panel. 

Here's couple of photos to hopefully explain this better. I don't quite understand the difficulty of field approvals in other FSDO's. I do know that everything I've done has been run through the engineers at ACO for an ACO assist field approval. I'm just working within the regulations and rules. 

 

[thinwing]

I don't either but your setup looks very good

[Guest]

2 hours ago, Sabremech said:

I'm modding my fuel caps to a new all aluminum assembly via FAA 337 field approval. Is there a need for this option on other older Mooney's. If so, I may go farther than just doing it on my airplane. Here's some photos of my solution.

David

That would make a really nice STC for installation during a tank reseal.

Clarence

[smwash02]

I don't have issue with corrosion, but it's the shaw gas caps that are becoming incredibly rare.

I had one that wouldn't seal properly because the metal block on top had worn too much. I replaced gaskets, readjusted the spring, etc. It was too far gone. Ended up buying a few on eBay for $30-40 instead the $500 someone wanted. Now I have a few that fit the bill.

A more standard fuel opening would be nice.

[carusoam]

Nice work, David.

That is also a great photo for anyone with a 65C that can't figure out where the rust particles are coming from while checking the tanks for water...

The factory hid a piece of mild steal in there, it rusts and sluffs off pieces.  The pieces fall to the bottom of the tank and stick in the fuel sample drain. Drip, drip, drip....

The rust particles also make their way to the strainer and stick in the pull ring drain.  More drip, drip, drip...

My final straw was the mild steal Fuel neck finally rusted all the way through. Rain water would enter each time it rained.  One day it wasn't drops, more like a quart had gotten in...

So if you are seeing rust particles in the bottom of your fuel cup.  Looks like David has come up with a solution that will,solve that problem too.

Best regards,

-a-

Edited June 5, 2017 by carusoam

[Guest]

It also makes the filler port Jet A nozzle proof.

Clarence

[Piloto]

Same new caps used on new Mooneys and Long Range Tanks

[Sabremech]

12 hours ago, Piloto said:

Same new caps used on new Mooneys and Long Range Tanks

Curious if anyone has this cap assembly and can post the illustrated parts catalog page and reference? That could make the process much easier to install. 

Thanks,

David

[Piloto]

3 minutes ago, Sabremech said:

Curious if anyone has this cap assembly and can post the illustrated parts catalog page and reference? That could make the process much easier to install. 

Thanks,

David

Check Aircraft Spruce: http://www.aircraftspruce.com/catalog/appages/aerofuelcaps.php?clickkey=3008203

 

[Sabremech]

8 hours ago, Piloto said:

Check Aircraft Spruce: http://www.aircraftspruce.com/catalog/appages/aerofuelcaps.php?clickkey=3008203

 

Hi Piloto,

Spruce is where I purchased mine from. If I could get documentation that shows Mooney uses these caps, an STC may not be necessary.

Thanks,

[Andy95W]

Owner produced or supplied part?  

I don't like using that too much, but this fuel cap doesn't seem to much different than, say, a prop cable from McFarlane.

I would be less comfortable with this method on a customer's airplane.

[Sabremech]

2 hours ago, Andy95W said:

Owner produced or supplied part?  

I don't like using that too much, but this fuel cap doesn't seem to much different than, say, a prop cable from McFarlane.

I would be less comfortable with this method on a customer's airplane.

This is a hard one as the FAA considers it part of the fuel system. If Mooney is using this type cap assembly in the new airplanes, it will make it easier to get through a simple STC. Still will take time to get through approval process. Not sure I'll go through the process unless there's a true need for them.

 

[jetdriven]

On 6/4/2017 at 1:00 PM, Sabremech said:

I had to cut 2 pieces of aluminum to fit this cap assembly in the original mounting hole. It is flush or a little below flush when the cap assembly is secured to the panel. 

Here's couple of photos to hopefully explain this better. I don't quite understand the difficulty of field approvals in other FSDO's. I do know that everything I've done has been run through the engineers at ACO for an ACO assist field approval. I'm just working within the regulations and rules. 

 

A lot of FSDO are in CYa mode, and have effectively said "no field approvals". 

[Sabremech]

What I'm finding out is that the FSDO is going through the engineers at ACO and doing ACO assist field approvals. As long as the ACO has no objections, the FSDO seems more than willing to sign block 3. 

David

[Andy95W]

David, I think you and I are in the same ACO.  We get basically the same decision from our FSDO (Detroit).

I'm not complaining. I've dealt with difficult FSDOs before.

[MB65E]

David, I have the same cap installed in a few airplanes in the hangar. They have a Cork seal on the installs I'm working with. If able, I'd make sure they are sealed with a better material. They do have a clever locking ring that is cut so you can lip out the backing plate to change the gasket with out loosing the plate in the tank. I guess pulling the inspection panel might be just as easy. I was working with carbon tanks. 

Looks great!!

-Matt

 

 

[Sabremech]

9 hours ago, MB65E said:

David, I have the same cap installed in a few airplanes in the hangar. They have a Cork seal on the installs I'm working with. If able, I'd make sure they are sealed with a better material. They do have a clever locking ring that is cut so you can lip out the backing plate to change the gasket with out loosing the plate in the tank. I guess pulling the inspection panel might be just as easy. I was working with carbon tanks. 

Looks great!!

-Matt

 

 

I used a very light coat of PR sealant on the cork gasket when I installed mine. I also sealed around the edge of the adapter and panel on top. I think if I do proceed with getting this certified as an option for others, I'll install the sealed nut plates for the adapter so the panel doesn't need to be removed for a gasket change if it happens to leak. 

I didn't do the nutplates on mine as I just need to get mine flying again! Down to long! 

David

[Sabremech]

I heard back from the FAA last week and they confirmed for me that this is a major alteration. Fill out a 337 and send it to OKC. If anyone else is interested in doing this in the future, let me know and I can share my 337 as well as provide the spacers at a minimal cost.

Thanks,

David

Edited June 27, 2017 by Sabremech

[jetdriven]

Why do they want a 337 for a minor alteration?   The very title of it is major repair and alteration. So by definition it wouldn't apply, no?