B747 Fuel Burn Issues

Several times i would plane a medium range flight (8hrs -10hrs) and attempt to fly the B747. I would always take about 2hrs extra fuel than what is required. But when i reach cruise, it always says that my fuel remaining is way under. My climb out is about 238kts at 2500FPM. I would even take 5hrs over the required and still it would tell me fuel remaining is way under. WHY!!!

Are you utilizing a step climb?

Make sure you’re not climbing up to your final altitude right off the bat.

When you’re in the climb, the fuel remaining will be under your expected time enroute and likely into the early phases of cruise. As you lose weight through the process of fuel burn, fuel efficiency will be better. Last night, I did a flight that said I was going to be an hour short on fuel. But by the time I landed, I ended up having over 3 hrs of fuel to spare.

By utilizing step climbing and planning your weight properly, you won’t have any issues.


In addition to what @DeerCrusher said you should be decreasing your vertical speed as you get to higher altitudes. You should also be at 250kts under FL100 then set thrust to 90% N1 for climb out (yeah not getting as technical as I can here but just stick to that) and then once you are at 319kts below FL280 set AP to hold your speed then continue to adjust your VS to maintain the same thrust setting you were during climb out. This will ensure that you are not forcing the aircraft to increase thrust to maintain a speed you are climbing to fast to achieve.


Here’s another good topic:

The estimated flight time for the 747 is not very accurate. I would recommend you to use Simbrief to calculate your needed fuel. I personally use it and I don’t have/never had any problems regarding fuel.

Is simbrief an app? I’ve been looking to use something to work out my fuel i.e. to add that bit of extra authenticity.

It’s a website for flight planning. This topic explains it pretty well:

It’s also recommended to use Simbrief in combination with fpltoif.com
Here’s the topic:

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Alright, starting to stray off topic now.

The fuel burn in the Infinite Flight Fleet are derived from real world data. With that being said, there’s a slight chance that there are is an issue with the fuel burn specifically and a higher chance that the pilot could reevaluate his decision making skills.

If your aircraft is burning through 85,000lbs of fuel in a matter of minutes (fighters excluded), thennnnnn, we have an issue.