# How is Fuel Burn calculated specifically?

Hey everyone. I’m doing a bit of research, and I wanted to see if anyone would have an answer.

Before you go down to to reply: this is not a topic about how to calculate how much fuel I need for a trip.

How is specific fuel burn calculated? Is there a formula?

I would imagine it goes something like: weight/thrust-headwind/N1

What factors are taken in to consideration? How much does air pressure (by changing altitude) affect fuel burn. And climbing?

Thanks!

-Pie

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Searched this up on Google. This post shows(I think) what you’re looking for

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As far as I know it is very hard to calculate this. You need to take in loads of variables such as weather (wind mostly) , aircraft , load , exact flightplan. Furthermore you need to include taxi fuel , emergency fuel ect.

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That’s a tad long. But what exactly are you trying to do? Know the precise fuel burn at exactly 23487 feet with an 86 percent N1 and a 50 knot headwind and a load of 86 percent? I mean exact fuel burn is only good for that precise moment under the exact environmental circumstances and I’m not sure what formula you’re looking for if you specifically don’t care about flight planning as you stipulated.

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Thats exactly what I need it for :) thanks.

Alrighty then. Sweet. :)

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