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A380 Useable Fuel Capacity

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  • Evan
    replied
    Originally posted by MCM View Post
    Evan,

    The wing tanks can definately contain some fuel on takeoff.

    Have you read the flight manual yet?
    No, I don't think it is in the public domain yet. I can't find it anyway. Do you have it? I'm interested to know what the real answer is.

    Leave a comment:


  • MCM
    replied
    Evan,

    The wing tanks can definately contain some fuel on takeoff.

    Have you read the flight manual yet?

    Leave a comment:


  • Evan
    replied
    Originally posted by MCM View Post
    Are you sure that restriction (no filling of outer tanks) actually applies? I've only had a cursory look, but to me it appears that while for a standard load the wing tanks are not filled (until after takeoff when the transfer takes place), you can fill them on the ground if all the other tanks are already full, which means that the usable fuel is indeed the full amount.

    Maybe that is a direction to investigate.
    Going by what the engineer stated, I interpret that to mean the outer tanks are fueled, then emptied before take-off by transferring them to the trim tank. So, if you consider the trim tank as only a transfer tank, you are fueling all the main tanks initially, and using the trim tank to redistribute the fuel load.

    Deducting the trim tank entirely, I get 300,840 liters, so that's not right. So perhaps the trim tank can be partially fueled, and/or perhaps the outer tanks can be partially filled at take-off (apparently they can be half-filled on landing).

    One thing I just noticed: The Flight Deck and Systems Briefing for Pilots lists the outer tank capacity at 10,520 ltrs, while Mr Ogilvie stated that they can hold only 9,524 ltrs. Perhaps the design changed somewhat between 2005 and 2007???

    Leave a comment:


  • Guest's Avatar
    Guest replied
    Originally posted by MCM View Post
    G'day Wilco,

    Yeah we use the same system for uplift verification as you do - in litres for us antipodeans. I'd get confused using gallons . I was just trying to point out to Evan that we use weight, not volumetric capacity, for most uses.
    Ah ok, guess I somewhat missunderstood you here. sorry 'bout that.

    Gallons confuse me as well, but there are charts and calculators to get it right

    wilco737

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  • MCM
    replied
    G'day Wilco,

    Yeah we use the same system for uplift verification as you do - in litres for us antipodeans. I'd get confused using gallons . I was just trying to point out to Evan that we use weight, not volumetric capacity, for most uses.

    Evan,

    Are you sure that restriction (no filling of outer tanks) actually applies? I've only had a cursory look, but to me it appears that while for a standard load the wing tanks are not filled (until after takeoff when the transfer takes place), you can fill them on the ground if all the other tanks are already full, which means that the usable fuel is indeed the full amount.

    Maybe that is a direction to investigate.

    Leave a comment:


  • Guest's Avatar
    Guest replied
    Originally posted by Evan View Post
    If you read the quote in the first post, the problem was with wing droop on those enormous wings being beyond acceptable limits for take-off due to the weight of the fuel in the outer tanks, so the fuel is placed in the trim tanks for take-off, then transferred slowly through the flight to the outer tanks to give a more efficient aft center of gravity.
    I read that post. I just checked for the possible usable fuel load. I didn't check if that is possible to carry or not. But it could be. Although it is hard to believe that one build an airplane with 285 tons of fuel capacity and you cannot carry it? Strange in my opinion. But on the other hand I guess you never need that much fuel. With 285 tons and an average fuel flow of 14 tons per hour, you have an endurance of 20+ hours...

    Originally posted by MCM View Post
    Evan,

    I'm not sure it matters very much. Useable fuel in litres is not a figure pilots use.

    Pilots deal (for operational purposes) in weight of fuel.

    I can tell you how much (in weight at a standard s.g) a 747 can carry, but I have no idea of the actual volume of the tanks.
    We use weight, that is correct. But when fueling is finished we get a recepit from the fuel truck driver which only states the litres (or gallons) and the density and then we can double check if enough fuel is on board.

    wilco737

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  • Evan
    replied
    Unless this beast uses much more taxi fuel than I think...

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  • Evan
    replied
    Originally posted by MCM View Post
    Evan,

    I'm not sure it matters very much. Useable fuel in litres is not a figure pilots use.

    Pilots deal (for operational purposes) in weight of fuel.

    I can tell you how much (in weight at a standard s.g) a 747 can carry, but I have no idea of the actual volume of the tanks.
    Ok, understood, but the same Airbus Flight Deck and Systems Briefing for Pilots chart lists the total useable fuel at 561,660 lbs, which is the equivalent of 324,540 liters, which cannot be possible if those outer tanks need to be light on takeoff.

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  • MCM
    replied
    Evan,

    I'm not sure it matters very much. Useable fuel in litres is not a figure pilots use.

    Pilots deal (for operational purposes) in weight of fuel.

    I can tell you how much (in weight at a standard s.g) a 747 can carry, but I have no idea of the actual volume of the tanks.

    Leave a comment:


  • Evan
    replied
    Originally posted by WILCO737 View Post
    I dont know if it can take off with that fuel load. I just checked for the possible tank capacity.
    But how stupid would it be to have that capacity but because of the design it ia not possible?!
    If you read the quote in the first post, the problem was with wing droop on those enormous wings being beyond acceptable limits for take-off due to the weight of the fuel in the outer tanks, so the fuel is placed in the trim tanks for take-off, then transferred slowly through the flight to the outer tanks to give a more efficient aft center of gravity.

    The thing I find interesting though, is that the Airbus A380-800 Flight Deck and Systems Briefing for Pilots (an informational document not to be used as an official reference) seems to have incorrect data for Total Useable Fuel, adding up all the tank volumes without taking this into consideration.

    It does describe the Load Alleviation (LA) Transfers as follows:

    The following load alleviation transfers occur in flight:
    • After Takeoff:
    • Transfer to the outer tanks, until the outer tanks are full.
    • Before Landing:
    • Transfer from the trim tank, until the trim tank is empty
    • Transfer from the outer tanks, until the outer tanks are half empty.

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  • MCM
    replied
    285 tons of fuel is incredible... Loooong flight...
    Not when you burn as much per hour as it does

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  • Guest's Avatar
    Guest replied
    Originally posted by Evan View Post
    Are you sure they can actually take-off with that much fuel (based on Mr. Ogilvie's remarks about wing design at the top of the thread)? Or is that just the collective volume of the tanks?
    I dont know if it can take off with that fuel load. I just checked for the possible tank capacity.
    But how stupid would it be to have that capacity but because of the design it ia not possible?!
    I cannotcomment on that as I havent heard of it. 285 tons of fuel is incredible... Loooong flight...

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  • Evan
    replied
    Originally posted by WILCO737 View Post
    LH A380s have a tank capacity of: 323,546 or 258,837 kgs.

    wilco737
    Are you sure they can actually take-off with that much fuel (based on Mr. Ogilvie's remarks about wing design at the top of the thread)? Or is that just the collective volume of the tanks?

    Leave a comment:


  • Guest's Avatar
    Guest replied
    LH A380s have a tank capacity of: 323,546 or 258,837 kgs.

    wilco737

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  • Evan
    replied
    Originally posted by brianw999 View Post
    Best person to ask this question of would be Frank Ogilvie don't you think ?
    Brian, it would appear that Mr. Ogilvie has already given his answer. That was in 2005, however, and perhaps before the final production design. The Airbus website lists fuel capacity at 310,000 Litres, which sounds more reasonable. So now we have three different figures from three different Airbus sources. Kind of strange, isn't it?

    Adding to the confusion, Wikipedia says 323,546 Liters. I think this was also calculated by adding up all the tank capacities, which you can't actually do if you expect to leave the ground.

    So, again, what's the right figure?

    Leave a comment:

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