Hello all, I love using simbrief to plan flights and using the integrated function for aircraft that enable you to do so. I’m still relatively new and am having some issues when it comes to using the PMDG 737-800 preset on the dispatch tab. Everything works great except for fuel. I always receive the right amount of fuel for a flight but the fuel burn calculation is never even close to accurate. Almost every flight I do I have to add 6,000-8000lbs of extra fuel and even then sometimes I’ll land with 6,000lbs onboard. I know the fuel amount simbrief gives me is correct but for some reason the aircraft burns fuel super fast. I feel like I’ve tried everything from making sure both the aircraft and dispatch are using pounds and not KG, making sure the aircraft actually has the right amount loaded, using live weather and time, etc. I even used default weather and added a tailwind but I never have the right fuel burn. I know it’s not supposed to be spot on but being 8000lbs + off the mark is definitely not right. I use LNAV and VNAV but still never have any luck. Does anyone know what might be causing this? Any help is appreciated.
Hi, I actually don’t know what to suggest. The PMDG 737 normally matches quite close to SimBrief.
The best suggestion might be to also post this in PMDG’s support forum, if you haven’t already. They might be able to provide some better guidance.
Best regards,
Hello.
I’m not exactly sure why this happens but the reason why the PMDG T7 burns so much fuel during long hauls is the discrepancy between SAT temperature and TAT.
Now, idk how much of a discrepency is allowed between these two temperatures, but I am currently at crz FL360. SAT is simbrief accurate at -50C but the aircraft is displaying the TAT at -19C. I’m no expert, but it seems to me the difference between those two numbers is way too much.
The only way I have been able to combat this issue is to add more fuel before takeoff. Again, not sure whether it’s a problem with live weather data or the PMDG aircraft.
Hi, TAT (Total Air Temperature) increases with airspeed. At cruise, a TAT of -19 sounds about right for a SAT of -50.
This image I found online shows where the SAT can be found on the FMS PROG page:
That being said, I know I have seen other reports of incorrect air temperatures causing fuel burn discrepancies in the sim. If you haven’t already, you might also want to post this in the PMDG forums. Perhaps they know of a way to correct this issue.
Best regards,
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