Teflon hose question

[Tom Baker]

For those of you who have converted to Teflon or aircraft type fuel hoses this question is for you.

This question is in regards to the outlet side of the fuel pump where it attaches to the splitter. What did you do with the banjo bolt connection? Did you use a banjo to AN adapter, or have a hose made with an integral fitting?

I am replacing a 20 year old Pierburg fuel pump that had integral fuel lines on a certified aircraft, and I am hoping to find a solution for the fuel line outside of Rotax's $600 plus hose.

[Madhatter]

I went to all AN fittings on the fuel lines including the carbs, the only way to go in my opinion. There is good reason to use AN for the last 80+ years.

[FlyingMonkey]

On 8/23/2023 at 5:21 PM, Tom Baker said:

For those of you who have converted to Teflon or aircraft type fuel hoses this question is for you.

This question is in regards to the outlet side of the fuel pump where it attaches to the splitter. What did you do with the banjo bolt connection? Did you use a banjo to AN adapter, or have a hose made with an integral fitting?

I am replacing a 20 year old Pierburg fuel pump that had integral fuel lines on a certified aircraft, and I am hoping to find a solution for the fuel line outside of Rotax's $600 plus hose.

Aircraft Specialty made me fuel lines with integrated stainless banjo fittings.  Steve at AS said they looked at AN fittings for the Rotax and decided in the end there was no real benefit, so they retained the banjo fittings at the fuel distribution block and the carbs.

[Madhatter]

1 hour ago, FlyingMonkey said:

Aircraft Specialty made me fuel lines with integrated stainless banjo fittings.  Steve at AS said they looked at AN fittings for the Rotax and decided in the end there was no real benefit, so they retained the banjo fittings at the fuel distribution block and the carbs.

The benefit is fewer places for fuel leaks and more solid connections. Don't need multiple copper gaskets to seal. Aircraft Specialty provided the fittings for me so I don't get the change in their position. You don't see this setup in certified. 

[Tom Baker]

3 minutes ago, Madhatter said:

The benefit is fewer places for fuel leaks and more solid connections. Don't need multiple copper gaskets to seal. Aircraft Specialty provided the fittings for me so I don't get the change in their position. You don't see this setup in certified. 

The aircraft I am working on is certified, that is the reason for my quandary. 

[FlyingMonkey]

42 minutes ago, Madhatter said:

The benefit is fewer places for fuel leaks and more solid connections. Don't need multiple copper gaskets to seal. Aircraft Specialty provided the fittings for me so I don't get the change in their position. You don't see this setup in certified. 

Maybe they haven't changed their position so much as adjust it on a case-by-case basis.  I know you are very firm on wanting AN fittings everywhere, so maybe they keyed off of that when you spoke to them.  I took a more "whatever you guys recommend" position and they told me the banjo fittings work fine and there were some additional geometry challenges going to AN.

[FlyingMonkey]

39 minutes ago, Tom Baker said:

The aircraft I am working on is certified, that is the reason for my quandary. 

I'd call Steve at AS and have a conversation.  He's very helpful and knowledgeable, and can give you all the pros and cons.

[Anticept]

Quote

 

21.9 Replacement and modification articles.

(3) A standard part (such as a nut or bolt) manufactured in compliance with a government or established industry specification;

 

AC 20-62e expands on this. If you can find an AN to banjo fitting with a AN, AS, NAS, MS, SAE, ASTM, or other major specification attached, you could use something like these:

 

[Garrett Gee]

I went with AN fittings (also used Steve at aircraft specialties).  Got rid of the banjo in favor of an AN 4 way T and the another 3 way T to completely get rid of the banjo fittings and the "manifold".  A.S. had all of these and sent everything needed as a kit with the hoses.  Sent them the old hoses and they near perfectly matched them up accounting for the new AN fittings being a little different than the banjo manifold.  I believe one of the fittings was "non AN" for lack of a better word (didn't have a standard AN number) but did have the AN fitting.  Overall, super impressed and have not had a single problem with the conversion.  Steve was super knowledgeable and helpful.

[Anticept]

Since tom is working on a certified aircraft, everything is super strict on standards compliance, it's much harder to find some parts like this for certified due to the requirements.