I use the FMC.

That is what I have been doing as well, and to tremendous results. The FMC on the NGX is no joke, it really is darn accurate, especially when you enter the winds in and the ISA deviation.

ISA deviation.

Can you elaborate on this please? Where do you insert this in the FMC and how do you calculate it? Thanks!

hey guys! thanks so much for all ur input! ill buy fs build and see what i can do! Cheers! :) Andrew

Can you elaborate on this please? Where do you insert this in the FMC and how do you calculate it? Thanks!

It is in the init page when doing pre-flight. Same page where you enter the ZFW, the fuel, the Crz Alt. One the left side you can either enter a TOC temperature and let the FMS calculate the ISA deviation, or enter the ISA yourself. You can also enter an ISA deviation, as well as arrival QNH, and up to three winds aloft in the descent forecast page to help calculate a better TOD and descent path.

It is in the init page when doing pre-flight. Same page where you enter the ZFW, the fuel, the Crz Alt. One the left side you can either enter a TOC temperature and let the FMS calculate the ISA deviation, or enter the ISA yourself. You can also enter an ISA deviation, as well as arrival QNH, and up to three winds aloft in the descent forecast page to help calculate a better TOD and descent path.

Will have to take a better look at this... Thanks Scott!

I think "pen and paper" is usually the most accurate (freeware) way to calculate your fuel. :)

Can you elaborate on this please? Where do you insert this in the FMC and how do you calculate it? Thanks!

On Init 1 page.To calculate your ISA deviation, here's a good rule of thumb, which will also help you with your Take off performance when setting up your Flex Temperatures for your engines..It's simple (I'm using celsius here, but I think that's the unit the FMC uses anyways):- Consider a 2ºC temperature decrease for each 1000' feet above Sea Level for your departing airfield.- Exemple: Guarulhos (SBGR): Field Elevation 2500' ASL, so for every 1000' we consider a 2ºC temp loss, so ISA Temp for SBGR is 10ºC.- Then you check your actual OAT, that's visible at the upper DU, or at your Metar report.. Let's use 25ºC for this case.. So, ISA OAT is supposed to be 10º, but actual OAT is 25ºC, so you're 15ºC above ISA..And there's your ISA Dev. right there.. Cheers

Um just trial and error with the FMC PROG page?

Um just trial and error with the FMC PROG page?

I'd take that would be on the ground. Would hate to have a pilot learning on the job... But that's just me.

On Init 1 page.To calculate your ISA deviation, here's a good rule of thumb, which will also help you with your Take off performance when setting up your Flex Temperatures for your engines..It's simple (I'm using celsius here, but I think that's the unit the FMC uses anyways):- Consider a 2ºC temperature decrease for each 1000' feet above Sea Level for your departing airfield.- Exemple: Guarulhos (SBGR): Field Elevation 2500' ASL, so for every 1000' we consider a 2ºC temp loss, so ISA Temp for SBGR is 10ºC.- Then you check your actual OAT, that's visible at the upper DU, or at your Metar report.. Let's use 25ºC for this case.. So, ISA OAT is supposed to be 10º, but actual OAT is 25ºC, so you're 15ºC above ISA..And there's your ISA Dev. right there.. Cheers

Thanks Jeff!!!

On Init 1 page.To calculate your ISA deviation, here's a good rule of thumb, which will also help you with your Take off performance when setting up your Flex Temperatures for your engines..It's simple (I'm using celsius here, but I think that's the unit the FMC uses anyways):- Consider a 2ºC temperature decrease for each 1000' feet above Sea Level for your departing airfield.- Exemple: Guarulhos (SBGR): Field Elevation 2500' ASL, so for every 1000' we consider a 2ºC temp loss, so ISA Temp for SBGR is 10ºC.- Then you check your actual OAT, that's visible at the upper DU, or at your Metar report.. Let's use 25ºC for this case.. So, ISA OAT is supposed to be 10º, but actual OAT is 25ºC, so you're 15ºC above ISA..And there's your ISA Dev. right there.. Cheers

You're neglecting the fact that the air might not cool at the standard rate. You have to know the temperature at altitude (Through ActiveSky or various RW weather services), and compare that with the ISA at that altitude. The difference is ISA deviation. Or, you could just input the temperature at altitude into the T/C OAT line, and let the FMC calculate the deviation.

As I said, it's just a simple way to find the deviation. I wasn't 'neglecting' the air cooling rate. But using the standard rate is always a safe/conservative method.In the end, though, you don't even need to input those data in the FMC, since all it does is improving the systems estimates/predictions regarding the fuel.If you just let it 'as is', your flight will still be spot on, and being these a virtual environment, saving 300kg's of fuel isn't that important, since we're not buying our carburant, it's free!:)But, yes, It's always better, if we're trying to emulate real world operations, to have all the weather background prior to our flight. Cheers.

FSbuild is best for accurate fuel planning, TOPCAT admittedly from a few sources is known to not be as accurate as it dose not take into effect winds allot and is also can calculate taxi, alternatives, hold time etc. Most my 747/MD11 and now 737-800 flights planned with FSbuild have been within a few 100lb at the planned fuel along on route. I just use TOPCAT for loading of the aircraft and takeoff planned in regards to CG% MTOW etc

I agree regarding FSBuild. Very accurate fuel calculations.

I'd take that would be on the ground. Would hate to have a pilot learning on the job... But that's just me.

Eh? This is a computer game, what you on about? Also you'd want to do your fuel calc on the ground right? So you know when you take off you're gonna be able to land at your destination...