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Can I add a fuel tank to my airplane

Lemos

Active Member
I was debating adding a 10-15 gallon fuel tank to my plane. However, I am not sure I can. Yes my airplane is experimental but it has an airworthiness certificate. My limits say that a minor change has no appreciable effects on w&b, structural strength, reliability, operational characteristics, or other characteristics affecting airworthiness. It goes on to say changes that aren’t minor need FAA approval, and an airworthiness review and authorization.

Adding fuel might affect the reliability of the fuel system, and certainly would affect the operational characteristics. Therefore I think this isn’t a minor change and requires FAA approval and an airworthiness review. Is this correct?
 
I think you are correct. But it most likely is not that hard. You’ll probably be put back into phase 1 for five hours of testing.
 
I was debating adding a 10-15 gallon fuel tank to my plane. However, I am not sure I can. Yes my airplane is experimental but it has an airworthiness certificate. My limits say that a minor change has no appreciable effects on w&b, structural strength, reliability, operational characteristics, or other characteristics affecting airworthiness. It goes on to say changes that aren’t minor need FAA approval, and an airworthiness review and authorization.

Adding fuel might affect the reliability of the fuel system, and certainly would affect the operational characteristics. Therefore I think this isn’t a minor change and requires FAA approval and an airworthiness review. Is this correct?

Make an appointment with your local FSDO to get the airworthiness certificate and operating limitations re-issued. Your new oplims will require that you notify the FSDO of your intention to put the airplane into phase 1 after a major change and get their approval of your proposed test flight area. They won't need to re-inspect the airplane. It may be possible for a DAR to issue the certificate and oplims. It's worth checking with a local DAR.

Ed Holyoke
 
First, read your OPLIMS. There should be a paragraph that tells you exactly what to do for a major change. Pretty simple actually the gist of which is contacting the FSDO and putting your RV-10 back in a minimum 5-hour Phase 1. Again this is all spelled out in your OPLIMs. Second, unless something has changed drastically over the past few years, unless you are changing a fixed pitch prop to CS or installing a different type of engine, which is not the case, you don't need to re-accomplish and submit a 8130-6 for a new airworthiness certificate, you won't need new OPLIMs, and you don't necessary need to ever go to the FSDO in person as it can be done over the phone and by e-mail.
 
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I'll let the Legal Eagle's help you figure out what needs to be done with the FAA.

I flew my -10 for 100 hours, give or take, before deciding that 60 gallons was not enough for a true IFR mission. Alternate + Reserve fuel can really eat into stock tank range. I added 15 gallons a side, one bay outboard of the main tanks. They automatically transferred into the mains, keeping the Primary fuel system stock. I then emailed the local FSDO, put the airplane back into Phase 1 and did a 5 hour flyoff. Probably one of the best mods I ever did as far as aircraft usability.

Now, your -14. Couple of ways you can add fuel, easily.
1. Hotel Whiskey ER tanks. They will give you 6 gallons a side. Quite popular, keeps the fuel in the wings, overall probably the best option.
2. Use Smoke System Helper RV-14 behind the seat tanks. 4.8 gallons a tank, two will fit. Downsides, only 9.5 gallons, fuel is in the cockpit (really not a fan), if you spill when filling up.. well, you already know.
3. Cut the leading edge or a section of it off and replace with additional tanks. Not for the faint of heart. However, the capacity can be whatever you want it to be, only limited by the wingspan.

As I said, I added 15 a side on my -10 bringing total up to 90 gallons. For a 540 @ 14gph it was perfect for 3.5 hours + Alternate + Reserve. I have seen -10's with up to 120 gallons, but I think that was for simplicity of tank construction. I'm fairly sure they just built another set of main tanks and mounted them up.

As Mark attempted to point out, Aerobatics with fuel in the Aux tanks (wing) is probably not a wise move. You would think that it goes without saying, but I guess not! ;-)
 
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