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Old 17th September 2024 | 16:03
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vilas
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From: Wanderlust
Originally Posted by Grlazos
The following is from the text:
At FL 300 +30 Minutes ( which is 44 minutes of EET ) you will switch OFF the X Feed and apply the gravity fuel feeding procedure . You can stay at FL 390 and the left tank will be on gravity. Which is in the middle of the paragraph and the way he writes it down, I think that he assumes 2 engine running at this point too.




Ok, so I will make another scenario from the beginning to tell me if now I have it correct in my mind. You climb and at FL200 you have the LO PR on the left hand side again. In a ceo 320 your gravity ceiling is FL150. So you put your xfeed on, eng mode sel..ign, tk pump 1+2 off (the left ones). And on the right hand side we have 2000 kg. When the right hand engine has 100kg, you jump into the gravity fuel feeding, which states. If no fuel leak and with one engine running (fed by gravity):
fuel xfeed on, bank angle 1 wing down, rudder trim use. So the right hand engine will go off in a matter of minutes if not seconds and then you have only one engine left which is fed by gravity. correct?


Yes, I get the whole explanation, my question is something else? You need to have pumps working constantly for the deaeration to happen? Or if they even work for 1 minute and they give the initial force the whole process continue automatically because it only needs a trigger action.


PS: I am not allowed to use links, so I deleted them.
Fuel pumps have nothing to do with deaeration. Air will keep bubbling as atmospheric pressure keeps dropping. But pumps keep supplying fuel under pressure despite that. You need fuel pumps all the time atleast in one main tank which if required can provide fuel to other side via cross feed. If both tanks pump fail below 30000 then go to 15000ft. If you stayed above 30000ft for 30mts before pumps failed then you can stay there.
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