1. Trailblazer

    Trailblazer Moderator Staff Member

  2. Trailspotter

    Trailspotter Senior Member

  3. Trailblazer

    Trailblazer Moderator Staff Member

  4. M Bornong

    M Bornong Senior Member

    When it's from one wing, isn't that likely a pressure relief release? I think there was a similar discussion some time ago.
  5. Trailblazer

    Trailblazer Moderator Staff Member

    Don't we have a 747 pilot here? @TWCobra
  6. Trailspotter

    Trailspotter Senior Member

    Well, the duration of the video is 34 sec and there is neither the beginning, nor the end of the dumping fuel. Wouldn't this be a bit long for a pressure relief release?
  7. Mick West

    Mick West Administrator Staff Member

    747 Fuel dumping from the main tanks is done with pumps. Possibly it was the result of a pump malfunction. The fuel from the other wing tanks could still be dumped via the center wing tank.

    Some details on on the system here:
    Last edited: Jul 11, 2016
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  8. deirdre

    deirdre Moderator Staff Member

    i think he could have shared the video from really anytime. I'm not finding any indication that he himself took it (he's in Quebec)

    i did find this October 31 2015, although i dont see airfrance colors on the tail.
    having trouble finding original pic source too.
    Last edited: Jul 11, 2016
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  9. TEEJ

    TEEJ Senior Member

  10. Trailspotter

    Trailspotter Senior Member

    The dark paint the tail edge is compatible with the Cathay Pacific livery, the closest by the date incident in the above list (#2) http://avherald.com/h?article=48e91a91&opt=1 :
    Screen Shot 2016-07-11 at 17.55.55.
    [Broken External Image]:http://c8.alamy.com/comp/BN26W4/cat...rcraft-taking-off-heathrow-airport-BN26W4.jpg
    As one of the engines was thought to have been damaged and on fire, it is possible that fuel dump was carried out on the other side only. Perhaps, there could be a matching image found in the Indian sources.
  11. Trailspotter

    Trailspotter Senior Member

    It looks like the Aviation Herald list of known incidents is incomplete. The Air France incident appears a more likely candidate, given the fact that the Facebook thread is mostly in French.
    The tail paint also is compatible with the Air France livery. I found another photo of this fuel dump:
    [​IMG]F-GITI by alexis boidron, on Flickr


    Also, there is a dailymotion video of this fuel dump:
    Screen Shot 2016-07-11 at 20.53.50.

    Last edited: Jul 11, 2016
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  12. deirdre

    deirdre Moderator Staff Member

    nice. i was looking like crazy for another video. and youre right, i cant see any tail colors in that video either, must be a sun issue.

    he's actually in Quebec according to one of his posts. Luckily i didnt think of that initially so i googled "airfrance fuel dump" :)
  13. TWCobra

    TWCobra Senior Member


    Fuel dumps on aircraft like the 747-400 are generally done symmetrically, in that the drill is to set the fuel remaining value that you want and open both wing jettison valves. This initiates the pump sequence. You want the fuel out of the big centre wing tank first, followed by the fuel in the larger inboard wing tanks. The system will do this automatically.

    Once the centre tank is empty and the system senses an imbalance between the two inboard tanks (main 2 and 3), it shuts down the pumps in the tank with the lower value until balance is restored.

    I thought that this would be the answer here but the schematic reveals a fuel cross flow manifold in the system that should still have fuel coming out of both jettison valves in this situation. It is pictured just above the STAB tank.

    So the only real answer here as far as I can see is that one of the jettison valves failed to open.
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  14. Mick West

    Mick West Administrator Staff Member

    I agree, that seems to be the only plausible explanation. No matter what other valves or pumps operate it's all going to the Jettison/Fueling manifold. Then if either of the jettison nozzle valves are open it will come out. There's no other way of making it come out of just one side.


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  15. Trailblazer

    Trailblazer Moderator Staff Member

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