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Greg Goodavish

Fuel Planning of MD-11

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Just to make sure I got this right, the FMC calculates the fuel needed for the trip, correct? If so, is it best to use the load manager with zero fuel in the aircraft, until the FMC calculates it, and then load the fuel needed per the FMC via the drop down PMDG Fuel menu?

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Just to make sure I got this right, the FMC calculates the fuel needed for the trip, correct? If so, is it best to use the load manager with zero fuel in the aircraft, until the FMC calculates it, and then load the fuel needed per the FMC via the drop down PMDG Fuel menu?
If you set up the FMC with zero fuel in the aircraft, the FMC is going to tell you "INSUFFICIENT FUEL", and all of your weight and balance (Center Of Gravity) and V-speed calculations will be completely inaccurate.I'm all ears for a good way to calc the fuel needed for a trip. Here is a rough guide I use, which may or may not be good:20,000 lbs fuel burn per hourIf I do that, I can be sure of having enough fuel because really in most typical loads at a decent cruise altitude, I have found my actual fuel consumption to be more like 18,000-19,000 lbs per hour.

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Correct, the FMS is the best calculator available; however, you don't need to start with no fuel. I start with a notional amount, then when I look and the Weight & Fuel page (INIT pg 2) I start adjusting with the pmdg options menu. Of course, there is no wrong way to do this.

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Just to make sure I got this right, the FMC calculates the fuel needed for the trip, correct? If so, is it best to use the load manager with zero fuel in the aircraft, until the FMC calculates it, and then load the fuel needed per the FMC via the drop down PMDG Fuel menu?
Calculating fuel with the FMC isn't as easy as it sounds. Why... because the amount of fuel on board also affects the amount of fuel burned. If you enter a BLOCK fuel figure of 0, the FMC will calculate the other fuel figues based on the aircraft at this weight. Once you start adding fuel, more fuel is required to get you there. Therefore, if using the FMC you need to play around with different BLOCK fuel values until you come up with a figure that gives you a positive EXTRA value and one which isn't excessive.Regards,Martin Neep

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True, there is some iteration involved but I've found my number in less than maybe three tries everytime. I shoot for 45 min reserve or whatever I deem prudent then use the weight surplus as a guide to trim. Seldom takes longer than a minute, which is a lot quicker than the stubby pencil method.

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True, there is some iteration involved but I've found my number in less than maybe three tries everytime. I shoot for 45 min reserve or whatever I deem prudent then use the weight surplus as a guide to trim. Seldom takes longer than a minute, which is a lot quicker than the stubby pencil method.
Dan don't you kind of estimate a ballpark figure of your fuel burn? Like 20,000 lbs/hour? Do you see anything wrong with that?

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If you enter a BLOCK fuel figure of 0, the FMC will calculate the other fuel figues based on the aircraft at this weight.
You definitely don't want to start with 0, that would add a lot of unnecessary iterations steps as you describe. Why not start with some value that you can almost calculate in your head based on the typical fuel burn per hour and approximate duration of the flight.

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Dan don't you kind of estimate a ballpark figure of your fuel burn? Like 20,000 lbs/hour? Do you see anything wrong with that?
For a longer flight, sure. However, add a little for a shorter flight. KMEM-KJFK was about two hours and 55,000 if I recall, but I've slept twice since that flight.

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Correct, the FMS is the best calculator available; however, you don't need to start with no fuel. I start with a notional amount, then when I look and the Weight & Fuel page (INIT pg 2) I start adjusting with the pmdg options menu. Of course, there is no wrong way to do this.
Is there documentation such as what the airlines has that shows how to plan for a sufficient amount of fuel. Where does the MD 11 operators such as FEDEX get their fuel consumption information? This data has to exist. I am surprised that PMDG has not made this information available as there is a wealth of other performance information in the MD 11 manuals? Any help would be appreciated.ThanksDon

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I am surprised that PMDG has not made this information available as there is a wealth of other performance information in the MD 11 manuals?
If you had searched the forum for fuel planning or planner, you wouldn't be surprised: these documents are not available to us.

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well if PMDG had provided a Manuel like they did for 747x I guess this wouldn't be discussed right now.But instead of a Manuel,if you gather required information about MD 11 you could do the planning as realistically as possible.Fist you need to know flight plan fuel, the fuel you need to keep her on route,say you'll fly between KLAX and JFK, you'll need to find out the total length in NM.IF it's 2500NM, this number would encounter to the fuel you need(its in fact the trip time) of course altitude also effects it.then comes the MIN LANDING FUEL the fuel you have to have at the time of arrival, plus ALTERNATE Fuel and then Contingency fuel ( unexpected weather or holds) so far;MİN.LAN.FuelALT. fuelCon.fuel+ flight plan fuel + taxi fuel then add your ZFW(MD 11 weight+Pax weight+cargo) that should give you the gross take off weight .the only thing you may not now is the trip length that you can figure out by MSFS'S default flight planning file the plan you want open the nav log it will tell you the total length, it will also tell you how much fuel needed but don't believe that its not accuratesleep.gifsleep.gif

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The flight planning software FSBuild has performance profiles for both engine variants.If you adjust the BOW to match the PMDG model you get reasonable figures that are only off by a 2-3 tons.I recommend it if you are looking for a fast and easy to use method that is reasonably accurate.

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I'm not to sure if it is okay to post links to other products but hey ho. VRoute Pro has a fantastic fuel planner specificity implemented for the PMDG MD-11 and all other PMDG products for that matter. Not only that but this is all incorporated into a flight planner where you can export all the data into your PMDG flightplans folder. It really is a fantastic add on that has saved me hours of time.

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Dan don't you kind of estimate a ballpark figure of your fuel burn? Like 20,000 lbs/hour? Do you see anything wrong with that?
Thats what i do i start with 10,000kg (roughly 20,000 Lbs) and allow that for the 1st hour of flight then about 7,000 p/h after that. Im usually spot on with enough reserve on arrival. You can then tweak with fuel mngr and the FMC depending on weight etc to get the final figure.Correct me anyone but would be fair saying to allow 10,000kg for 1st hour then about 7,000 for any hour after that?

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