Fuel on the 737


I have been flying the 737-800/900 for a while. I have noticed that the fuel economy is very good. I have a question why when I load the aircraft with 2 hours of fuel I am able to fly 2 hours and 45 minutes though? On other aircraft I have flown it does not happen as well as with these aircraft. Is there any particular reason?


Maybe a super strong wind helping you?


I fly everywhere with it and it does not matter whether its a tail wind or headwind. it is always able to fly longer than the amount of fuel I give it. I am doing a KMIA-KEWR with it and loaded 2 hours and 55 minutes of fuel and been flying 1 hour and 38 minutes and still have 1 hour and 50 minutes worth of fuel left. There is only a crosswind.


The fuel estimations are not fully accurate. There a many other factors such as wind,other weight,cruising height,climb rate ect.


I noticed it too. Many aircraft have inaccuracies. The one that bugs me the most is the 777-200ER and LR. In IF the ER has a longer range than the LR, but not in real life. I told the devs, but they said I needed actual data. But because the LR is basically the same thing as the ER except with a bigger fuel tank and drag reducing wingtips, physics should prove that the LR has a longer range. The E175 is also highly inaccurate, it can only fly 2/3s the distance it can in real life.


I like to make the flight plan on SimBrief because of this; there they give the right amount of the combustivel to be used.


@Kate_Russell You are going to travel faster the lower the altitude you are at. Maybe that is why.


No, he had 2 hours of fuel, wind affects distance not fuel time


The throttle percentage contributes the most from what i have seen


Yeah, no. Quite the opposite ;)


Noticed that too. Flew today in the 737, fuel for 2:50 and I flew for 4:10 ish with like 2% reserves. Not even at economy cruise speed


The fuel consumption that you see is the baseline. As your weight decreases the less thrust you will need to use at altitude thus resulting in less thrust needed to maintain that speed. Less thrust power less fuel being used.


The T7 consumption model is already based from real life figures. Try changing the way you fly the bird. I have been able to do super long flight with the LR.

Same for the E175, the data was sent by an actual pilot.


It just looks like it although it’s not true


A333 preflight fuel calcs are way off usually also. As the weight burns off, the throttle input drops, turning the 737s into fuel sippers.


Not sure where you learned this. If you stay on your flight plan, the wind would hardly impact the distance you have to cover, if at all.
Wind does effect fuel time because if you have strong headwinds, your engines need more power to maintain their cruise speed, and more power requires more fuel, which will be burnt faster. If you have a strong tailwind your engines require less power to maintain your cruise speed, which means less fuel is used and your fuel will last longer.

Correct me if I’m wrong :)


Indeed, the B77L does have longer range than the B77W in IF, as it does in real life. Substantially more range.

Simbrief does a great job calculating the block fuel required given the weather forecasts and regulations. I almost always land with all of my alternate, contingency and final reserve fuel still onboard, and I factor in 5 minutes of taxi at each airport unless I can see it’s really busy then I’ll increase that.


Incorrect all the winds will do is affect your GS. Weight and altitude are what will affect your fuel flow. Winds have a negligible effect. Remember it this way. GS is mostly affected by winds. IAS (which is where IF is using to determine thrust settings) is affected more by altitude


Your gonna travel faster the higher you’re at!


The fuel tanks are only carrying fuel and the bottom of the fuselage… plus the winglets on the wingtips won’t make the high pressure air from below the wing swirl to the top of the wing where the low pressure area is which is reduced drag and better fuel efficiency. It’s basically eliminating wing tip vortex. During takeoff and drag during flight. Coming from a aviation maintenance technician/pilot point of view.