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ArjenVdv

Fuel planning

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Hello,Since I'm using the NGX, I'm always using a small program called 737NG fuel planner to plan fuel. Unfortunately it's always calculating in LBS, and as I'm dutch, I prefer using KGS.What I'm always curious about, how do real pilots calculate fuel? There must be some formulas? And how do you guys plan fuel?I partly know how to do it. You use ZFW, cruising altitude, trip distance. And in the end you add, minimum landing fuel, holding fuel, alternate fuel, taxi fuel, etc.Thanks in advance,


Arjen Vandervelde

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In real life the fuel is calculated by flight planners not pilots. ( I think.) I think there was another fuel planner but I dont remeber the name. Google it.


Dmitriy Kotov

If it is not IFR conditions it is not fun.

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The NGX's Fuel Planner is very nice and simple to use.You can change from LBS to KILOS if you wish. The really nice thing about it is it will give you the ZFW and you can line select that on the Perf Init page of the CDU.


Frederic Steiner.

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The NGX's Fuel Planner is very nice and simple to use.You can change from LBS to KILOS if you wish. The really nice thing about it is it will give you the ZFW and you can line select that on the Perf Init page of the CDU.
Then we're probably talking about another fuel planner. Could you please tell me where you got it?

Arjen Vandervelde

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Then we're probably talking about another fuel planner. Could you please tell me where you got it?
It is part of the NGX !! It is in the FS Actions section of the CDU.It has a Fuel and a Payload section.Both of them will give you the ZFW and CG.

Frederic Steiner.

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It is part of the NGX !! It is in the FS Actions section of the CDU.It has a Fuel and a Payload section.Both of them will give you the ZFW and CG.
I know, I know, I'm not that silly not to nice that fuel and payload section :( It's indeed showing ZFW and CG, but it isn't making any fuel recommendations is it?

Arjen Vandervelde

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I know, I know, I'm not that silly not to nice that fuel and payload section tongue.png It's indeed showing ZFW and CG, but it isn't making any fuel recommendations is it?
I understand what you are saying ! ZFW, Cost Index etc comes from Dispatch in the real world. There are fuel calculation tables in the Boeing docs that come with the NGX. I just use the presets like 1/2 2/3 etc depending on the flight plan.But if you want to get very specific you will have to do some reading. I think the program Topcat does fuel calculations.

Frederic Steiner.

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I understand what you are saying ! ZFW, Cost Index etc comes from Dispatch in the real world. There are fuel calculation tables in the Boeing docs that come with the NGX. I just use the presets like 1/2 2/3 etc depending on the flight plan.But if you want to get very specific you will have to do some reading. I think the program Topcat does fuel calculations.
Ok thank you, I'll check that one out. :(

Arjen Vandervelde

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Firstly you must carry enough fuel for your destination plus fixed and variable reserves here in Oz we use 30 min fixed and 10% variable reserve the 10% is calculated on your flight fuel portion. Then add any weather holding and alternate holding fuel if required. Then payload is worked out from your max brake release weight given for that departureaerodrome. Bear in mind you cannot land at your destination unless you have burned fueldown to below your max landing weight also. Fuel reqd is normally the following added.Flight fuel10% variable fuel(based on flight fuel)30min fixed reserveStart / taxi fuelAllow for following fuel if reqdHoldingAlternate Remember you must plan to land with your reserves in tact.


Steve F
Offshore Helicopter Pilot ME-IFR AW139  / Sikorsky S92

SpecsWin 106th Gen Intel Core 6700 liquid cooledIntel 100 chipset4 processor 8 way multi16GB DDR4512 GB Intel pro SSD2TB 7200 rpmSata 3 HD
Nvidia GTX 1060

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Firstly you must carry enough fuel for your destination plus fixed and variable reserves here in Oz we use 45 min fixed and 10% variable reserve the 10% is calculated on your flight fuel portion.
Are you sure? That sounds like an awful lot. Anyhow these numbers sound familiar, but certainly for props and definitely not jets. For props we have indeed 45'/10%, for jets we however have 30 min FR and 5% contingency, but only if you have no enroute alternates. If you however do, then it's even only 3%. But then again, not down under here (too bad actually!). Big%20Grin.gif EMV posted some guidance as how to use the FMC to get an estimate in some other thread (can't find right now but a search for his recent posts might help), quite interesting. Not only because the FMC has some pretty darn accurate numbers. Otherwise someone else just recently presented another very simple method, that doesn't incorporate a thousand variables and might be alright for a start. Take your flight time and estimate your trip fuel with ~2500 kg/hr (if you like, estimate your flight time by dividing your total DTG with some arbitrary TAS of 450 knots or the like). Add 5% contingency. Add 1800 kgs for alternate and FR (that was just the example he was making). Add extra if you think you need. That's your TOF. Add 200 kg for start up and taxi and you have release fuel.Very simple method, not exactly super accurate and will most certainly fail at extreme conditions, but it has worked for a number of my recent flights surprisingly well. For probably way better planning you might want to check out PFPX which we hope will be release later this year. sig.gif

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Sorry Badderjet, i just edited my post to clarify, you are correct 30 mins for jet i just am used to my prop figures and blurted it out!.. the standard for our Civil aviation advisory publications(CAAP) here by CASA is IFR FIXED WING JET AND PROP 30 MINS FIXED RESERVE10% VARIABLE Piston eng here is 45min and 15%


Steve F
Offshore Helicopter Pilot ME-IFR AW139  / Sikorsky S92

SpecsWin 106th Gen Intel Core 6700 liquid cooledIntel 100 chipset4 processor 8 way multi16GB DDR4512 GB Intel pro SSD2TB 7200 rpmSata 3 HD
Nvidia GTX 1060

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There's a perfectly good way in the tutorial although I found a flaw in it. Enter ithe route the the cdu and perform weight init and execute. Now goto the PROG page of the cdu and subtract the amount shown at the destination to the amount on the aircraft (fuel on board) and then add 5000lbs for extra. Fuel on board - fuel at destination + 5000lbsNow here's the thing when using this method. You need to already have more fuel than required for the trip before using the calculation above and also you'll have to run through the weight init page again. Also it's best to enter winds aloft data to get an even more accurate fuel load. I've also been using the default FsBuild 738 profile for planning fuel and it's pretty darn accurate.


Gavin Price

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