In the real world fuel temp will start at roughly ambient temp of your originating airport and slowly drop during climb and cruise. I don’t know if that starting temp value is saved with panel states or not. I haven’t tested it to see.
One thing that may or may not be related to the various “Insufficient Fuel” warnings people are receiving may have to do with fuel density. This is discussed briefly in the PMDG online documentation but the effect of changing values isn’t entirely obvious. Fuel density can be edited/changed on the FUEL page of the FMC menus (MENU → FS ACTIONS → FUEL, if I recall correctly). Increasing the density a bit means the same weight of fuel takes up less space and leaves more room in the tanks. Conversely, reducing density means the same weight of fuel takes up more space in the tanks.
I do not know how the real aircaft measures fuel flow. I do know from engineering experience that true mass-flow rate gauges are very, very difficult to create and are not terribly accurate. Volumetric flow rate is much more accurately measured. This is then usually converted to mass-flow rate by density calculations. So if the fuel density is inaccurate, the estimated mass flow displayed for the fuel usage will be wrong.
The issue I’m experiencing is that fuel leaves the tank faster than the “FF” Fuel Flow on the Engine synoptic pages, when using Time Compression / Simrate increase.
I suggest this as a test:
Plan a flight
Climb to stable cruise with Time Compression off
Mark the Time, Fuel on Board (FOB), and Fuel Flow (FF) values
FF is x1000 per side per hour
After an hour of flight, check FOB and see if it makes sense
Example I had FOB = 63.9 and FF = 7.5 per side (15 burn per hour)
… But when using Time Compression / Simrate x 4, fuel was leaving tanks at 20 per hour, 5 unaccounted for by FF.
I really meant to include this, sorry.
Entirely at 1x rate, no time compression at all.
2 hours later and I’m still in-flight (Lima Peru to Atlanta Georgia), and the insufficient fuel warning is still present, but Prog page estimates 22.3 thousand pounds at arrival.
You need to consider that having the “Insufficient Fuel Warning” does not mean that you will see Zero fuel at destination in the PROG page.
This warning is triggered when the estimated fuel at the destination goes below the Reserve Fuel set in the Performance page. Did you put that value manually or directly imported from SimBrief?
Arriving with 22.3 Klbs is not a bad number (I did a quick SB plan with your route and is showing me Reserve Fuel ~ 19 Klbs). This value of course will depend on many factors.
That message pops up whenever the aircraft thinks you’ll be cutting into your reserves? What did you enter in the FMC during your pre-flight for reserve fuel?
You raise a good point. For the 777, I do not use any Fuel Factor in Simbrief (P00), and I accepted SimBrief’s defaults. Since this was the first occurrence of this warning, I never had a reason beforehand to change it, or the Fuel Factor.
About 12,000 pounds of the loaded fuel is for the alternate airport, KBNA, if that helps.
There are other considerations for the Reserve fuel and I also keep all as Default/Auto and P00.
What value do you have in your FMC performance page for Reserves? and what does the SB plan shows? You can see it in the Briefing page and is called FINRES + ALTN
Looks like you may have used the wrong value in the FMC, higher than what SB estimated and thats why you are getting the warning.
22.8; so that is likely the answer: the reserves should have been higher.
Why, after dozens of flights in the 777 (including several transatlantic, both directions) the SimBrief calc for necessary reserves should be off, I have no idea (winds seem very reasonable in-flight). But that seems to be the root cause.
I don’t want to hijack this thread any further, and thank you everyone for helping me debug. It seems clear that this is NOT related to the ongoing XBox temperature issue.
Am I wrong to have hope the extra liveries added to the operations manager on PC might make their way into marketplace in todays update…? The EVA Air etc.
Just flew my full first gate to gate flight using VNAV on XBox. It’s been a lot of fun to learn all the details of how the plane works and the YouTube tutorials people have posted have been a huge help (combined with the guides of course).
Still a lot to learn but this last flight shows how amazing study planes can work on the console.
Hope there is a few more to add before releasing not sure how many more packs we will see? But would love to see Air NZ and LATAM. Southern hemisphere is a vast place and Brazil world update is coming
I didn’t have time for a true long flight (been testing out KEWR to EGLL), but I flew from KEWR to KORD.
I’ve also recently flown the 737 using VNAV between KEWR and KBOS. Using the SimBrief info would help but get me stuck until I actually started understanding what all of it meant and which actions I needed to take to get VNAV working. Still learning on both but it’s been a fun and interesting journey.
While developing additional liveries may I suggest one for Pakistan International Airlines(PIA) being launch customer for 777 series.PIA started with B-777 LR followed by 200ER and finally 300 ERs.
