Pressure Checking Fuel Cell

Discussion in 'Sheet Metal' started by Tantrum1, Mar 28, 2019.

  1. Apr 2, 2019 #21

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    8,383
    Likes Received:
    5,375
    Location:
    97FL, Florida, USA
    That was my fingers trying to type Been There Done That.

    Lived at the plant dealing with testing, forced outages, planned major modifications, etc.


    BJC
     
    Pops likes this.
  2. Apr 2, 2019 #22

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    6,482
    Likes Received:
    5,380
    Location:
    USA.
    OK, why didn't I know that? Don't answer :)
    One outage to another , a lot forced outages and some planed. Many a time just get home from a long outage and the phone would ring again for another outage maybe in some other state. Went years without unpacking a suitcase. I was young and enjoyed it.
    Fuel tank-- Fuel cap with tire valve and outlets sealed except one with a balloon.
     
  3. Apr 2, 2019 #23

    TerryM76

    TerryM76

    TerryM76

    Well-Known Member

    Joined:
    Sep 8, 2012
    Messages:
    410
    Likes Received:
    140
    Location:
    Tempe, AZ
    " After a seam or a damaged area is welded, you must clean the tank of any flux or debris that may have fallen into the tank. Water rinsing and acid solutions are commonly used.
    A leak check to ensure the repair is sound follows a welded repair. This can be done by pressurizing the tank with a specified amount of air pressure and using a soapy solution
    on all seams and the repaired area. Bubbles form should air escape. The amount of air pressure used for a leak check is very low. One half to 3.5 psi is common. Use an accurate
    regulator and pressure gauge to prevent overpressurization that could deform or otherwise damage the tank. Tanks ordinarily supported by aircraft structure when installed
    should be similarly supported or reinstalled in the airframe before pressurization. Figure 14-91 shows an aircraft fuel tank being welded and the repaired tank installed in the frame
    of an antique aircraft."

    Refer to FAA Handbook H-8083-31 Vol 2 page 14-51.
     
  4. Apr 2, 2019 #24

    gtae07

    gtae07

    gtae07

    Well-Known Member

    Joined:
    Dec 13, 2012
    Messages:
    1,694
    Likes Received:
    1,014
    Location:
    Georgia
    I connected a water manometer to one of the outlets, capped the others, and put a schrader valve in the drain port. Pumped up with a bicycle pump to get ~3ft of difference in the manometer, and capped the valve. Applied soapy water and let it sit for 48 hours. Found no leaks. We’ll see if that holds in service.

    Be careful doing pressure tests though. Far too many big airplane wings have been blown up through poor pressure testing procedures. I saw the aftermath first hand; imagine a 50ft machined spar ripped down its length like paper :eek:
     
  5. Apr 2, 2019 #25

    Tantrum1

    Tantrum1

    Tantrum1

    Well-Known Member

    Joined:
    Jul 8, 2016
    Messages:
    100
    Likes Received:
    232
    Location:
    Saint John, NB Canada
    Great thanks I appreciate all the great comments. I was able to get the oil tank leak checked, found one tiny pin hole. going to rectify it and by then I will have the fuel tank ready for leak check.
     

Share This Page

arrow_white