"BOTH" fuel selector without interconnecting L and R tanks

[Jetfever]

So what do you not like about tanks being connected? Only problem I see is if you are parked on a hill and one tank could drain into the other in which case I would turn the fuel off. I like the Both position since I like short hops with not a lot of fuel on board. I am not the best at remembering to switch tanks.

Let me be perfectly clear:

I am NOT a Nay Sayer!!!!

I have NOTHING against adding a both position to the Piper fuel valve.

I have only been trying to make pilots "aware the fuel system operation is DIFFERENT" when changing to the Both and Off position. The quote above suggesting that selecting the OFF position would prevent the higher tank draining to the lower is a perfect example of a VERY COMMON misunderstanding of the "new" fuel system.

Sincerely, Steve

[Tp109]

Anybody made the change without replumbing the right down and back up under the panel, and not like the both position?


I too am a bit afraid of not having my reserve in the left side. I think it would be nice to not need to switch tanks while flying, but I typically fly right down to 5 gallons in the left side after draining the right. With both I guess I would have to fuel up earlier because I would wind up with 2.5 gallons aside and not gonna fly like that. I never top off after every flight because I have never found water in my plane. I fly less than an hour a lot and stick the tank so I know zactly how much gas I have.

Back to the question, anyone went both ways and than afterwords wished they wouldn't have?

[Tp109]

Thinking about that, could takoff in both fly til half tanks and switch to right til it gets quiet and than switch to left to land.

[PACERGUY]

Think of the fuel selector as a 13 year old boy! Put it on Right and DONT MOLEST IT until the engine coughs. Than go to left tank. Now you have 18 gal to land, pretty simple.
DENNY

[Tp109]

Treat an airplane like you would a woman, touch her slow and gentle, works well 90% of the time..

[Steve Pierce]

Thinking about that, could takoff in both fly til half tanks and switch to right til it gets quiet and than switch to left to land.

That is what I did with the Dakota Cub Super 20 when we got into some crazy headwinds and I was not too familiar with the sight gauges. Switched from both to right and lookd at my watch, when it quit I knew about what I had in the left.

[CamTom12]

I have a "both." I typically fly R-L-R-L... sometimes I cruise in both until half tanks, then start switching sides.

Personal preference. Having a "both" does not require that you use it.


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[dgapilot]

With all the discussion on the Allen valve, nobody even thought to mention that it could be installed using an Engineering Approval on an 8110-3 as the approved data for the 337. That said, the talk about AC 20-62E, you must remember that ACs are only ADVISORY in nature, and the installer is the person making the airworthiness determination. Back when these airplanes were built, the regulatory structure was much different, and the vendor items were much like the Commercial Parts that are discussed in the AC. They didn't identify them as such because there was no Part 21, and there wasn't even a PMA rule similar to what is in Part 21. Airplanes used all sorts of automotive and standard parts like the Model A fuel gage in the PA-15/17 and Aeronca Champ and Chief. If you have the original vendor part number, go for it. There is no problem installing that. If the original vendor part was modified, then you need the data to make the modification, and it becomes an Owner Produced Part and is still eligible for installation - the key is that it still needs to meet the original Type Design. With the fuel valve, the original valve body doesn't appear to be available, so you can't take and modify it to the drawing. That still doesn't prevent you from finding a substitute and getting it approved. The Major Repair and Alteration Job Aid allows substitution of fuel system parts with Engineering approval. Any DER that has Engine Installation authorization and Major Alteration authorization can do it. Just ask. Yes, it will cost a couple $$, but it wouldn't be bad if he figured he could sell several copies of the same approval and spread the development cost out.

[Steve Pierce]

I wonder if it would be cost effective to get an 8110-3 for the Allen valve vs buying the Dakota valve?

[dgapilot]

I'm thinking an hour or two to write up a report, another half hour to fill out the 8110-3. First time through would be about $250, replicate it for about $50 each for follow on. If I knew I could sell at least 10 over a couple years, I'd eat the up front cost and sell the approvals for $50 each. That's what I charge for my J3 battery installation approval for.

Not sure if I'm breaking any rules here, if so, my apologies and please remove this post.