FOB in minutes

SimBrief Dispatch
1

I’ve noticed there is the ability to specify the FOB value in minutes in addition to weight, which I guess is done for consistency with the rest of the interface.

At first glance it doesn’t seem very usable though, as the resulting “endurance” is somewhat far from the requested value, for example EGLL KJFK requesting 555 minutes (9 hours, 15 minutes) I got an “endurance” of 8 hours, 17 minutes:

TRIP       56430  07.05               .....  .....

CONT 5%     2822  00.21               .....  .....

ALTN        5174  00.39  KIAD         .....  .....  ....

FINAL RES   3664  00.30               .....  .....

EROPS          0  00.00               .....  .....

EXTRA        313  00.03               .....  .....

PLNTOF     68403  08.17               .....  ..... SIX EIGHT FOUR  

DIFF       .....  .....

PLNTOF     .....  .....  (CORRECTED)

EXTRA     ......  .....  POSS   9027L .....  .....

TOF       ......  .....               .....  .....

TAXI        ....           998/00.20  .....

Not sure if this can be made to work better (or if it’s even useful); maybe FOB only makes sense as a weight instead?

Regards,

Tim

2

Hi Tim, not sure there’s an easy fix for this. The endurance is basically the sum of the different fuel types (trip, alternate, reserve, etc). This seems to be in line with most flight planning software, but since all of these fuels are calculated using different cruise profiles and under different conditions, it isn’t easy to make them match.

I’ve noted this to look into further down the road.

Cheers,

3

Makes sense. I guess I was kind of suggesting a fix/workaround would be to not allow entering FOB in minutes, but it’s not exactly essential.

Regards,

Tim

4

I’ve been mostly using OFP formats where the exact fuel at destination is not indicated. I’ve recently tested a few OFP formats including e.g. UAL18 which indicates REMF in weight and time.

And thus I just noticed that FOD suffers from the same inaccuracies as FOB, when you request a time in minutes, the resulting remaining “endurance” at destination is off by at least several minutes.

My understanding is that having a minimum of e.g. 75 minutes of fuel at destination is not uncommon; I wonder if real-world software is perhaps more accurate than simbrief here when it comes to computing the extra fuel required to reach said minimum (note: when requesting a minimum FOD in terms of weight, the result is exact, but I guess that’s much easier to compute)?

Regards,

Tim

5

Oh man, this was way more complicated to fix than I even thought.

Please check again to make sure I didn’t break anything, but I think time-based FOB/FOD should work properly now.

Best regards,

1 Like
6

Negligible rounding errors notwithstanding, seems to work very well indeed. And FOB/FOD in terms of weight is still accurate.

Will keep an eye out for regressions but so far it seems like you nailed it.

Regards,

Tim

1 Like
7

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