B747-400 Fuel Burn

Does anyone know how much fuel is needed when flying the B744? I put 2 hours more fuel than my flight time and still didn’t have enough fuel to get to my destination! I use Flightradar24, so I’m climbing at actual vertical speeds and cruising at proper altitudes. She’s the Queen, however she certainly is a gas hog! No wonder airlines are retiring her for more fuel efficient birds. :(

2 Likes

(post withdrawn by author, will be automatically deleted in 24 hours unless flagged)

(post withdrawn by author, will be automatically deleted in 24 hours unless flagged)

Try this site:
Fuelplanner

Type your departure and arrival ICAO and choose the aircraft you’re using. (This is including the extra fuel)


Otherwise, check Simbrief:


and step climbing for a long haul flight:

5 Likes

Try this one

2 Likes

I suppose you are step climbing, which is great if you are. You should be able to fly for about 2hrs, remember you burn a decent chunk of fuel during takeoff and climb more than what you do on cruise so that may be why you ran short of the 2h mark when you had put in 2hrs worth of fuel?

And also wind has a effect on your estimated time you have fuel left for which is displayed at the bottom as you probs know, that indication of for how long you have fuel left will change over time as you fly and headwinds can be a major drawback since you’ll need to put in more thrust to keep your speed and still go through the winds that are pushing you back.

Lastly, the B747-400 cruises at M0.86 to be exact, so be sure that you’re not flying too slow making the engines give in more power since you’re too heavy and too slow and in the end you’ll not be flying for 2hrs although your fuel indicator may have shown that you would make it for 2h.

Another factor could be that your simply too heavy and too high. I know you said “cruising at proper altitudes”, so imma leave height away, but weight is still important, the heavier you are the juice you’re gonna use at certain altitudes.

It’d be nice if you could give us specs on your weight, initial altitude and speed, thank you :)

I was simulating Qantas 28 from Santiago to Sydney. Flight time is 14 hours, so I put in 16 hours of fuel. Unfortunately I don’t remember initial weight, altitude, and speed. If I had to guess I’d say initial cruise at FL290. Speed might have been M0.85 and I probably had cargo set to heavy with 371 passengers.

Oh, sorry i misread your original post, okay so you were not able to make it to Sydney although you put in 2h extra fuel?

Headwinds could be the cause… If you’re crossing the Pacific heading west it’ll take you longer than if you were going since there can be some heavy headwinds in that direction.

1 Like

Something to remember is that when you are heavier, your engines will need to produce more thrust to keep your heavy aircraft moving. More thrust means a higher fuel burn which means less time flying.

With that said, it’s ok to be an hour short on fuel needed to make it to your destination on such a long flight as what you’ve stated. As you’re flying a long, the fuel you burn is reducing the overall weight of the aircraft. As a result, less thrust is needed and a lesser fuel flow will be observed.

  • Heavy aircraft = High fuel flow (shorter time to fly)
  • Light aircraft = low fuel flow (longer time to fly)
3 Likes

I ran out of fuel at New Zealand! So you’re saying on a 14 hour flight, I should only put in 13 hours of fuel?

Basically what he is saying is that as your plane is very heavy early in the flight, you’ll burn more fuel than what you would at the end, final 2 or 3 hours of your flight. Since you’re heavier early on your engines need to give in more power to keep stay airborne.

Btw, did you step climb properly? Cuz i’ve done longer flights with the 747 without and issues, whatever the case may be, something in your planning might’ve gone a tad bit off the charts…

Yes, I did a steep climb. Again, I simulated the actual vertical speed using FlightRadar24. I’ve ran out of fuel twice now while flying the B744. So obviously there is something I’m not doing right. I just have to figure out what it is that I need to correct. So far, I’m not sure…

Nope. I’m saying, if you put in 15 hrs of fuel for a 14 hr flight, you’ll be fine. Once you hit your first cruise altitude it may say, 13hr 30mins to destination and your fuel remaining may say 12hrs 30mins.

Your first thought is, “Oh. I messed up. I won’t have enough fuel.” But if you were to let this flight go all the way to your destination, you’ll find that you’ll infact “make fuel” and you may end up with 3 hrs of fuel to spare when you thought you were going to be short by an hour.

The fuel burn on the 747 is correct. There isn’t an issue unless you’re draining the tanks in 5hrs. If you’re draining the tanks in a few hours then this might be something worth looking into.

4 Likes

Well try what @DeerCrusher suggested, that exact method is what i use every time i fly the 747 and it works wonders and has ever since the very beginning :)

Anouther vote for using Simbrief here. First time I tried a long haul flight I also thought I was going to run out of fuel and I quit as well. However I always use simbrief now and follow the waypoints, speed and fuel and don’t have an issue now.

Good luck and happy landings.

1 Like

I guess I’ll try Simbrief and see what they suggest for amount of fuel.

1 Like

Hi everyone. Just wanted to let you know Simbrief suggested full fuel tanks (estimated flight time 18:46 for a 14:46 flight time). I made it from SFO to SYD with 42,000lbs of fuel remaining. The gas hog Queen herself needed 4 hours more fuel than the flight time! Wow.

2 Likes

@Adam_Reid

Very glad you made it. A couple quick thoughts:

  1. If you carry more fuel than needed, you will burn fuel at a higher rate during the flight, which likely contributed to landing with only 4 hours of fuel remaining.

  2. Simbrief fuel burn rates are generic and often don’t match the IF models perfectly. You can, however, adjust the fuel factor (Found under Advanced Aircraft Options) to get it to match the IF model. It can be a bit of an iterative process (need to check the Avg FF in the upper right corner of the paperwork preview against the Weight and Balance screen in IF), but once you have it aligned it helps with the planning process.

Use this @Adam_Reid: http://fuelplanner.com/
It’s accurate and adds extra fuel

All 747 models in IF pitch up a ton in flight and you can’t do anything about it except cruise lower. On a long haul start FL300-320. And make sure you are .85-.88 else your fuel burn will skyrocket. It’s a fact that these models burn a lot, just pack extra