Reserve Fuel

[savage]

Hi,

How is the Fuel calculations done in FSP? Last time I heard if I'm not mistaken, it's based on averages... It's SEVERELY screwed up I'm
sorry

Can a option be added to disable the penalty?

I'm flying the PMDG 744 on a long haul now. FMC reports 23.4 tons at landing for Feul - which is MORE than sufficient. FSP Reports
Remaining Fuel Allow: -13h30 flight time (by the time I got to paste the report (maybe 15 minutes tops), an additional -40 minutes!!!.
Nevermind my one hour reserve... And no, I'm NOT kidding

Flight Distance: 1,639 Nm Fuel Used: -73663 lbs
Time Airborne: 03h10:28 Fuel Remaining: 329004 lbs
Flight Time (block): 03h18:36 Fuel Consumption: -23205 lbs/hour (until now)
Time on Ground: 00h08:34 Remaining fuel allow: -14h10:40 flight time
Average Speed: 516.16 kt With one hour reserve: -15h10:40 flight time
Max. Altitude: FL 280 (fuel stats based on current number)

I am now just over 3 hours in my flight, I've kept a close eye on this... The flight time for allowable fuel just gets more and more in the
negative. But I *KNOW* I have enough fuel on board.

This, really sucks... And no, no fuel was added or removed during flight. And yes, the Allowable Fuel / Reserve Fuel in FSP is almost
always wrong for me at least.... Any plane, any settings...

--
Chris

[ste9889]

ive thought this for a while, im not sure what can be done though
All The Best
Ste

[Covoxer]

If you have negative number of fuel used, than it definitely was added after you loaded your plane with FsP payload editor.
Maybe you were taxiing near by the refueling station in the departure airport?
Such things happend, so that MSFS refuels you to 100%.
Anyway, used fuel in FsP is calculated as fuel in load FsP dialog minus current fuel. If it's negative, that you have currently more than you
have loaded with FsP.
So...

[savage]

Urgh. Still sucks though.

I still call for a option to disable it... I'm at -313Hrs Feul Remaining now... Don't even want to think what the penalties are going to be.
Besides, this is a LONG HAUL flight already that I'm doing... Flight Time is close to 14hrs. Just how much extra feul could have been
added... -shrugs-

[savage]

LOL Ok, now I *really* rest my case...

7:30 Hours into the flight... Report reads:

Flight Distance: 3,893 Nm Fuel Used: 56877 lbs
Time Airborne: 07h26:42 Fuel Remaining: 198462 lbs
Flight Time (block): 07h34:50 Fuel Consumption: 7639 lbs/hour (until now)
Time on Ground: 00h08:34 Remaining fuel allow: 25h58:39 flight time
Average Speed: 522.68 kt With one hour reserve: 24h58:39 flight time
Max. Altitude: FL 320 (fuel stats based on current number)

So in 7 Hours, I go From 0 to -14Hours, and from -14 Hours to +25Hours!!! I'd like to see a 744 fly for 25 Hours non stop . Dan, I'm sorry
mate, you need to look at this code... A 53 Hour jump in a Fuel Estimation, is simply wrong...

[DanSteph]

Hello,

FsP simply get the fuel value from Fs9 and make a rough calculation
each nn seconds Fuel at start-current fuel=fuel used time/fuel used= comsumption

If you had negative value as said john this is because fuel was added after FsP started
hence the "start fuel" value was obviously wrong.

Sorry no code in world can correct this, to get the total fuel used you must of course
get the start fuel value, if you add fuel after FsP started the value is wrong.

Solution:
Add fuel before starting FsP or use only FsP to add fuel and take care to not pass
over the "F" station of Fs9.

Hope it answer ?

Dan

[Covoxer]

Wait, there's a different problem hrere!!!
There's states in FsP report that you currently have 329004 lbs of fuel!!!
I bet it's the max fuel 744 can get.
And your MFC says that the's only about 45000LBS (23tons).
So, it looks like FsP gets not current fuel but max fuel capacity instead!
Obvious bug, but I have suspicion that it can be a PMDG bug since they had to mess the whole fuel handling sheme of FS to implemend
advanced functions.
Does anyone else have the same issue with PMDG747-400???
'Cause I don't get it on other aircraft models.

[jboweruk]

Seem to remember I had it on a plane once, but blowed if I can remember which one, and certainly not QoTS as she wasn't even out then.

[savage]

Thing is, this happens regularly to me (and I've been flying for well over 2yrs now - I doubt I'm loading my fuel incorrectly, I've never
crashed due to the lack of fuel before)... Often, I land (not only the queen) my plane with excess of 15+ Klbs of fuel - only a fraction of
them are 'over' the 45 minute reserve. I bet with most heavies, you can fly well over 45 minutes on 15 Klbs of feul.... I'm not going after
accuracy here, it's merely making a point, so excuse me if 15 Klbs is not a 100% spot on value, I'm sure that the point does come across
however.

If it can't be corrected, atleast give the option to disable it. Whether it's FSP or FS9, it still doesn't justify penalising the pilot for it. If that
makes sense. The fact remains that in many circumstances, you DO have more than enough fuel at landing, and FSP doesn't recognise
that - due to whatever reason. There's also the fact that the reserve fuel is actually ALLOWED to be used during certain circumstaances
(like waiting for landing at a busy field for example) - but that's a completely different story - or topic.

There's issues in FSP that is allowed to be disabled that has far less impact as far as convience and penalties go - yet, this has been
over looked for so long...

With a hour of flight time remaining, things SEEMS to finally start getting back to normal for me (almost):

Flight Distance: 5,225 Nm Fuel Used: 187616 lbs
Time Airborne: 12h38:17 Fuel Remaining: 67724 lbs
Flight Time (block): 12h46:25 Fuel Consumption: 14845 lbs/hour (until now)
Time on Ground: 00h08:34 Remaining fuel allow: 04h33:43 flight time
Average Speed: 413.22 kt With one hour reserve: 03h33:43 flight time
Max. Altitude: FL 370 (fuel stats based on current number)

FMC reports now a 26.4 Klbs load at landing - the above seems fairly correct to me from the top of my head, based on consumption and
usage according to the plane... I'll make a bet however, after I landed, I'm going to be short - or JUST have enough fuel to make the report
happy.

Also yes, my Queen was fully loaded 100% max fuel at engine start. Flying from FACT to YSSY without a full fuel load is well, close to
impossible - just as it is on just about any 14hr flight. This is also why it's strange for me, even *if* I did magically get a re-feul for
passing to close to a refueling station, just how much fuel could it have added considering that I started on a 100% load.... At most, it
could have replaced my taxi fuel, which, IMHO - should be insignificat...

Thanks,
Chris

[DanSteph]

notice the shorter the time the lower the precision of comsumption is
if it's calculated with very small number you may have irrealist comsumption
as time pass the comsumption calculus is more and more precise.

Perhaps you looked the report at the very start ?

Dan

[SaVas]

Did you load fuel in both the PMDG fuel load editor and FsP?

[savage]

Dan - First report posted was 3hrs in flight. All the others also have the time stipulated in the postings (Time Airborne I believe)... I do
know that the fuel stats changes drastically at the end of the flight - especially during decent when the engines are mostly idle. Hence,
what I said in my last post. It's going to be interesting for me at least, what the final verdict on this one is going to be when I'm on the
blocks with PAX unboarding. My gut tells me, I will be short.

Latest Report:

Flight Distance: 5,538 Nm Fuel Used: 207899 lbs
Time Airborne: 13h32:56 Fuel Remaining: 47441 lbs
Flight Time (block): 13h41:04 Fuel Consumption: 15344 lbs/hour (until now)
Time on Ground: 00h08:34 Remaining fuel allow: 03h05:30 flight time
Average Speed: 408.54 kt With one hour reserve: 02h05:30 flight time
Max. Altitude: FL 370 (fuel stats based on current number)

A hour (about) later than the previous report, Fuel Allowed -1.5 Hours already....

SaVaS: I have my payload disabled in FSP. I use the PMDG Loader for my weights (ZFW in this case, 535.1 Klbs), fuel load was 100%,
and I believe I was at 109% MTOW due to the heavy fuel load.

[SaVas]

Im sure there is a work around for this as there are quite a few that use the 747 PMDG with FsP.

I have the 747 since release but dont use it in FsP as Im still trying to learn its systems...

But the PMDG 747 is a VERY complex add-on, that is built around its own systems and algorithms/settings (mainly fuel and payloads)
instead of the ones in FS9, and as such, add-ons like FsP which base most of its information on what FS9 provides, might run into some
various issues.

Have you looked on the PMDG forums at AvSim?

I have read from several people there that use FsP, and they might have some idea what you can do to fix it.

[savage]

I understand that. And I take my hat off to PMDG for developing such a complex aircraft, but at the same time want to kill them for not
allowing a generic way to access data from the aircraft - this is hampering some FS9 development I am doing myself as well, and I send
of emails to PMDG about this and other issues I'm having quite often. The Queen for example also have a inaccurate V/S and Altitute
indicators according to FSUIPC - something I just contacted them about today and still wait feedback on.

That aside, I mainly fly only the PMDG744 (Soon the 744F - Can't wait ), and sometimes, the PSS Airbus A320 and A340. As I did say in
my posts previously however, whilst not as significantly huge, I still also get irragularities with the Fuel Allowed. It's not only with the
queen....

That aside, about to start my decent and it looks like the fuel will at least hold this time.

Flight Distance: 5,755 Nm Fuel Used: 221561 lbs
Time Airborne: 14h10:24 Fuel Remaining: 33779 lbs
Flight Time (block): 14h18:32 Fuel Consumption: 15632 lbs/hour (until now)
Time on Ground: 00h08:34 Remaining fuel allow: 02h09:39 flight time
Average Speed: 405.86 kt With one hour reserve: 01h09:39 flight time
Max. Altitude: FL 370 (fuel stats based on current number)

I do understand the possible complexity at working out these values and doing the predictions... But if there are problems with them (and
I'm sure I'm not the only one), at least give a option to disable the penalty.....

Dan perhaps more complex, but would it not be better to rather come up with a avg rate of fuel burn, rather than taking the hard values out
of FS9? If we take start-current fuel=fuel used time/fuel used= comsumption for example:

Why not, say, every 5 minutes do: (start fuel - current fuel) / time = fuel burn rate And then, use the rate to determine the values based on
averages. So 2 hours into the flight you will have 2hrs * rate = fuel used. I think the value should be better presented than the fuel start -
fuel current scenario, as the average SHOULD 'evenly' increase or decrease, whether you had a accidental refuel or not.

Appart from that, some hard coded 'fail safe' values would be good as well - perhaps in the payloads. If you land with more than x Klbs
fuel, then FSP automatically assumes you have enough fuel for 45 minutes... THAT is a very safe way to solve this IMHO.

Will have to play with the maths to see if it adds up, it's just an idea...

[DeCarvalho]

But isnt there a comand capable of overwritting the 45 min. reserve at landing?....i want to disable that penalty!!!