Nacelle Tanks on 310J

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    I am looking at an aircraft 310J with nacelle tanks on both sides, not wing locker tanks. I have not had access to the logs, but I am not aware of nacelle tanks as even options on J models. The total fuel is 170 gallons with normal mains and 15 gallon aux tanks + nacelle tanks.

    Are there STCs for 310J aux fuel that I should be aware of? Has anyone heard of factory stock 310 nacelle tanks? Could a set of wings from a later model 310 be swapped onto a 310J fuselage?

    This is a Canadian Registry aircraft- what is the process of re-registration in the U.S. if the tanks are STC and not documented (i.e. missing paperwork).


    Hi, Mike…

    You aren’t clear as to the difference between “nacelle tanks” and “wing locker tanks”. In any event, the wing locker tanks are not eligible for installation in the “J” model under the approved configurations listed in the Type Certificate Data Sheet (only eligible on “L” models and later). The only configurations approved for the “J” are the main tanks (51 gallons each) and the optional auxiliary tanks (15.5 gallons each). I can’t find any U.S. STC that permits the installation of wing locker tanks in your airplane.

    The possibility exists that the wing locker tanks were installed in your Canadian-registered aircraft under the provision of an STC approved by Transport Canada, making it perfectly legal for operation. If you plan to register the airplane in the U.S. and apply for a U.S. airworthiness certificate, the Bilateral Airworthiness Agreement between the U.S. and Canada allow for U.S. acceptance of the Canadian STC.

    If, however, you don’t have any approved data for the installation of the additional fuel tanks, then they won’t be acceptable for certification in the U.S.. A U.S. Designated Engineering Representative would be able to approve the installation if the data supported the airworthiness of the installation, but you’d have to provide all of the engineering drawings for installation and other analysis. The DER could reverse engineer the installation, but now you’re getting into a major project and expense.

    Without approval for the installation, the aircraft would have to be returned to its originally-certificated configuration, meaning that all remnants of the unapproved fuel system would need to be removed including the tanks, pumps, fuel lines, electrical installations, quantity indicators, etc.

    Hope that this helps.

    Brian Ingraham


    I had a 67 320E with dual nacelle tanks. They had there own gauge and transfer switch. They were great to have and fairly easy to maintain. They had a simple electric pump in each flap well.


    Your talking about wing locker tanks. They are a bonus for sure. Dont even think about wing replacement. That would be the beginning of the end of that 310. I had them on a 64 model that allowed me that extra hour enroute and really helped out.
    Keepem flying. 😀



    Out of curiosity, what tanks did you have in your 64 model that gave you an extra hour in flight (so 20-25 gallons?) and what approval was there for the installation?



    As an update to my original post/question, I was able to talk to a pretty knowledgeable Cessna support engineer, and an even more knowledgeable expert at O&N Aircraft. Apparently the wing locker tanks were offered as a retrofit STC back to 310 I models by Air America Inc in Pittsburg KS under STC SA2872SA.

    I have not been able to get to the logbook entry doing the install, and there is a possibility this is a factory install as the 310J Owner Manual describes the “Wing Locker Tanks” as a Optional Equipment Item, even though the 3A10 TCDS does not mention wing locker tanks until the L model 310.

    These tanks have been installed for years and according to O&N Aircraft, were popular mods in the 70’s and 80’s. O&N still offers a similar wing locker tank under a different STC. but not for I, J or K models.

    So I am still looking for the complete data trail to support the installation as a Conformance Check.

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