Yesterday, I flew on FS2004 TDS B737MAX8 with Southwest 737 MAX 8 flight, SWA #660, from DAL to MCO on May 10.
We took a long detour route to avoid thunderstorms over Alabama, Georgia, and northern Florida.
Dispatch released the flight with a planned fuel burn of 12,500 lbs.
However, when I arrived, I checked how much fuel I had left and calculated the actual fuel burn—it was 17,579 lbs, with 4,800 lbs remaining in the reserve tanks.
SimBrief didn’t calculate the correct fuel amount for the longer route—it assumed a direct DAL-MCO flight.
But I had already selected the route:
DAL ELD LGC MCN WADEB HATMA VPLJA MUNKZ MCO
You can check FlightAware or Flightradar24 to see the actual flight path.
Why didn’t SimBrief correctly calculate the fuel burn for the route I selected?
A burn of 12,500 lbs sounds right for a 2h30 flight. A burn of 17,500 is much too high for the 737 MAX.
SimBrief did account for your longer route. When choosing the more direct route, it gives a burn of only 10,600 lbs and 2h10 in the air.
Best guess is that the add-on in question is burning too much fuel. Or there was a bug in the sim that caused your fuel burn to be much higher than normal. In any case, SimBrief’s calculations look correct.
I notice you often fly the 737 MAX. If all of your previous flights have planned the correct amount of fuel, then this flight was probably an outlier (maybe a sim bug). Perhaps your next flight will be fine.
Well, I assume that the attitude doesn’t affect the fuel amount when you change levels from FL370 to FL300, then to FL260 during the descent to MCO. Maybe the fuel calculation assumes you’re flying at FL370 all the way from departure to arrival. But I guess flying at a lower altitude burns more fuel the longer you stay at that lower altitude. I started descending from FL370 at 1:32, reached FL300 at 1:57, and FL260 at 2:12 en route to MCO.
I can’t change altitude in the SimBrief editor, so it’s harder for me to get an accurate fuel amount to load the right amount of fuel. Oh well, maybe Navigraph will add a new feature to allow altitude changes in the future.
Just to follow up, there is actually a way to specify custom altitude changes by typing them directly into the route. For example, ABC J1 DEF/F240 J2 XYZ would trigger a step down to FL240 at DEF waypoint.
You can include as many altitude changes as you’d like using this method. Also refer to the User Guide - Route Formats section for more details.