Fuel disagree

[Hardy Heinlin]

Hi Jean-philippe,

I can't reproduce such large disagreements when I fly long routes myself. I've been trying it on Mac and Windows, with and without networked clients.

I'm still trying to find out what might be special on your system.

What Instructor page is typically displayed when you're flying a route? Is it the Aerodynamics page or Service page? (These pages provide fuel edit controls.)

Can you confirm your add-ons cannot accidentally influence any fuel quantity related Q vars?


Regards,

|-|ardy

[JP59]

Thanks again for investigating this Hardy. Please note that I am not the only PSX user who has this problem. Two other guys on this thread reported also. My PSX server computer displays the pedestal layout because I didn't finish my hardware pedestal. I never let service or aerodynamics page displayed long time. My "home made" add-ons do not deal with fuel related variables at all.

Regards,

[Hardy Heinlin]

Some questions to all who have this problem:

When it happens, ...

... are you running a network?

... are your frame rates on the server lower than 20 fps?

... can you fix it by activating the jettison system for a second?

... can you fix it by entering the totalizer value into PERF INIT 2L, and then deleting 2L?


Thanks,

|-|ardy

[Peter Lang]

... are you running a network?
... are your frame rates on the server lower than 20 fps?
... can you fix it by activating the jettison system for a second?

1. Yes
2. No (72 fixed and shown) Server is sec. EICAS in my case
3. Will have to check

4. also will have to check


from SEAZ to LEMD ("onbord "route) after 8 hours of flight time more than 10 tons disagree. When disagree then sensed fuel is always more than calculated. So now I will have more than 25 tons left in LEMD vs to the ~ 12 tons from the calculation.

Another item:
It happened already twice that after refuelling (from the service panel) was finished a rapid defuelling occured. I only could stop it by setting the value again in the aerodynamics panel.   after checking defuelling panel and resetting malfunctions (which were not set before, just to be sure)

All on RB engines.

Regards

Peter

[Hardy Heinlin]

Another item:
It happened already twice that after refuelling (from the service panel) was finished a rapid defuelling occured. I only could stop it by setting the value again in the aerodynamics panel.

What do you mean by "rapid defuelling"? Which values decreased at what rate? There are 3 types of values:

1. True values (Instructor Service page)
2. FQIS totalizer values (EICAS)
3. Calculated values (CALC values in FMC, added by fuel flow)

When refueling is completed, the totalizer values keep increasing for some minutes because the fuel level sensor systems (intentionally) lag behind the physical levels.


Regards,

|-|ardy


P.S.: I just noticed this disagree problem too, for the first time. It just occured at random, after 3 hours; it was a sudden change, not gradual at all. It can be fixed by trick #3 or #4 (until I fix it in the code).

[Peter Lang]

What do you mean by "rapid defuelling"? Which values decreased at what rate? There are 3 types of values:

1. True values (Instructor Service page)
2. FQIS totalizer values (EICAS)
3. Calculated values (CALC values in FMC, added by fuel flow)

When refueling is completed, the totalizer values keep increasing for some minutes because the fuel level sensor systems (intentionally) lag behind the physical levels.

I know that after the fuel sheet pops up it takes a while until the sensed fuel reaches the selected value. This is shown in the EISAS and sec. EICAS / FUEL page. Service page shows selected values, when fuel sheet pops up. This is ok.

But some minutes later I noticed at the EICAS and sec. EICAS / FUEL page, that there are already 1 to 2 tons missing. The only fuel consumption I had came from the APU. Looking at the values it seems, that the defuelling is as nearly at the same speed as the refuelling.

I will check the values in the Service page and CDU next time.

Regards

Peter

[JP59]

P.S.: I just noticed this disagree problem too, for the first time. It just occured at random, after 3 hours; it was a sudden change, not gradual at all. It can be fixed by trick #3 or #4 (until I fix it in the code).

On my side, it is never a sudden change. Always a slow gradual change which looks like to be at the same rate every time. And never random : I have this problem at every flight. Did you try to continue the flight with the SITU I gave you ? Load the SITU "Before reaching cruise altitude" and let the computer run for some hours. Don't you notice the disagree ? In my case I had the FMC message after 2h25 of flight.

Regards,

[Hardy Heinlin]

Peter, did you see this effect in that older version which had that APU FF bug?

JP, yes, I tried your situs, I even completed the flight to Shanghai and my disagreement did not rise along the entire flight (on the Mac).

Anyway, temporary solution:
When it happens, enter the totalizer value in PERF INIT 2L, then delete 2L. The CALC value is wrong, the totalizer value is good.

[JP59]

JP, yes, I tried your situs, I even completed the flight to Shanghai and my disagreement did not rise along the entire flight (on the Mac).

Very strange... I use windows on all my network if it can help.

Anyway, temporary solution:
When it happens, enter the totalizer value in PERF INIT 2L, then delete 2L. The CALC value is wrong, the totalizer value is good.

When I do this the CALC value is well reset to the TOT value, but the drift continues and the disagree message comes back after about 2 hours.

[Peter Lang]

Hi Hardy,

just had the following trouble:

After Landing in LEMD during rollout I had fire warnings on engine 2 and 3. Both EICAS blanked and lights went off. After starting the APU I and haviong Power again I saw Hyd fluid of all 4 engines are empty.
I resetted the malfunctions in the General page and watched Hyd fluid refill. Then starting engines in the Instructor / Service Page again and taxi to the gate. After engine shut down I had the same rapid defuelling rate as seen before. From about 27 tons it came to 19 tons until I stopped it in the Malfunctions / General page again.
The values could be seen decreasing on both EICAS pages and the Instructor / Service page. CDU I forgot to look.
Before I switched to ground power and switched off the APU I checked the defuelling panel to stop it, but all was ok and nothing helped.
....

During writing this I noticed the fuel quantity was down from ~19 tons from where I stopped it to 5.3 tons. Hyd fluid empty again. I checked the malfunctions again and found that a lot of malfunctions where triggered in the /Bleed, /Fuel and /Hyd pages, even all malfuntions were set to off in the / General page. How can this be? And if, shouldn't there be EICAS warnigs about low Hyd fluid before. Or low pressure, or high temperature warnings?
BTW the landing was quite normal: touch down rate - 169 / -197 and wings level

Is there a key I could have hit to trigger the malfunctions even if they are set to off in the Malfunctions / General page? Will check the manual for this, but maybe you are faster :-)

Regarding the fuel disagree: the same here. It starts after 2 + hours in the flight and is a steady slow gradual change.


No, I noticed this in version 10.0.2. Not before.



Regards
Peter

[Hardy Heinlin]

Hi Peter,

what are you settings on the Malfunctions/General page under "Allow random failures within a flight phase"?

When the sliders are up, you may get various malfunctions, including fires and fuel leaks. That's intentional.


Cheers,

|-|ardy

[Peter Lang]

When it happens, enter the totalizer value in PERF INIT 2L, then delete 2L. The CALC value is wrong, the totalizer value is good.

I'm not sure about this. When I made my flight planning from SAEZ to LEMD with www.simbrief.com I had a total remaining fuel calculated for LEMD of about 12 tons. This value varied during the flight from 12 to 15 tons in the PROGRESS page.

Somewhere between 8 and 9 hours flight time the fuel dísagree was more than 10 tons and I selected "totalizer" in the PROGRESS 2/3 page.
From this point the remaining fuel in the PROGRESS page raised steadily to finally ~27 tons remaing fuel in LEMD.

And... during writing this, fuel tanks are complete empty, and Hyd fluid is gone again. I just see various malfunctions triggered again..  :shock:

Regards
Peter

[Peter Lang]

what are you settings on the Malfunctions/General page under "Allow random failures within a flight phase"?

Hi Hardy,

all 3 sliders are set to "no failures"

This is what confuses me completely. And thats why I asked if there are keys strokes which I could have hit unintentionally to trigger the malfunctions...

Regards

Peter

[Hardy Heinlin]

Hyd fluid of all 4 engines are empty

Do you mean oil quantity?

Aside from the malfunction settings, you can also get malfunctions as a consequence of weather or wrong crew work or bad landings etc.

Is there anybody on your network triggering malfunctions from somewhere else on this planet?

Can you send me some situs?

Somewhere between 8 and 9 hours flight time the fuel dísagree was more than 10 tons and I selected "totalizer" in the PROGRESS 2/3 page.
From this point the remaining fuel in the PROGRESS page raised steadily to finally ~27 tons remaing fuel in LEMD.

I said the TOT value is good because on my side it agreed with the true values on the Instructor. Whether your FMC prediction is correct or not is yet another story. When there is a leak, the true value decreases faster than the CALC value (which is FF based).


Haha! You got a traffic collision! That kills your hydraulic reservoirs and two engines.

[Peter Lang]

Do you mean oil quantity?

Yes, off course Oil Qty

Aside from the malfunction settings, you can also get malfunctions as a consequence of weather or wrong crew work or bad landings etc.

Weather was ok, wind 300° with 8 kts on RWY32L. No gusts. Landing also. I hope at least. Less than -200 ft/min should be a landing, where you can leave the plane on your own feet :-)
Crew work? Hm..  I also hope so.  FO, disabled, its a one man show.

Is there anybody on your network triggering malfunctions from somewhere else on this planet?

No

Can you send me some situs?

http://www.hoppie.nl/forum/var/Situations.zip
I do not know if they are of any help. They are made just some minutes ago. I will press the EVENT REC button more often when the problem comes up again.

I said the TOT value is good because on my side it agreed with the true values on the Instructor. Whether your FMC prediction is correct or not is yet another story. When there is a leak, the true value decreases faster than the CALC value (which is FF based).

Thats what I say: the sensed fuel was always higher than the calculated fuel. Otherwise I would have suspected a fuel leak and see how I had to handle this.

If the CALC value is FF based and I steadily get more fuel in my tanks than I should, than there must be some refuelling in the air, which would declare the traffic collision.  :lol:

Now we have to find the reason for the defuelling after refuelling on ground before takeoff or why the malfunctions are on while set to off.

Haha! You got a traffic collision! That kills your hydraulic reservoirs and two engines.

Ah.. MS ghost plane. Thats it. Or this guy must have hit me from behind. Ok, I'll go to sleep now.

Peter

[Hardy Heinlin]

From (I can't remember exactly when) some weeks, I have a ... "Fuel disagree - Prog 2".

Beta 5:
• Bug cleared: Time acceleration sometimes skipped fuel tank updates.

http://aerowinx.com/forum/topic.php?id=1951

Could it be that this disagree problem never occured before November 2014?


|-|

[Hardy Heinlin]

I think I found the cause of the problem.

In 10.0.3-beta5 I accidentally inserted a fuel update signaler at a place in my code that PSX clients execute. It should be executed only by the server. The server serves. The clients eat. When the clients serve as well, it's an error, because clients never have the latest fuel data (they get it a few milliseconds later from the server). They have to eat what the server serves.

So, that would explain why during fueling the clients refeed lower quantities into the network from the previous time, and why during engine fuel consumption the clients refeed higher quantities into the network from the previous time. -- The refeed happens across multiple threads at different timings, so that would explain the random effect.


Cheers,

|-|ardy

[JP59]

From (I can't remember exactly when) some weeks, I have a ... "Fuel disagree - Prog 2".

Beta 5:
• Bug cleared: Time acceleration sometimes skipped fuel tank updates.

http://aerowinx.com/forum/topic.php?id=1951

Could it be that this disagree problem never occured before November 2014?


|-|

Hi Hardy,

As I said I do not remember the exact time this problem started, but November 2014 looks like ok. I could be that. I planed to do the return flight ZSPD-LFPG on Saturday. I can try a test beta and report if you want.

[Hardy Heinlin]

Hi,

this one should fix the fuel disagreement:

http://aerowinx.com/forum/topic.php?id=2637

The totalizer value should be slightly higher than the CALC value, but very well within the allowed tolerance. That's intentional. I tested it on the YSSY-KLAX route and all went fine, including the fuel predictions.


Cheers,

|-|ardy

[JP59]

Hello Hardy,

I tested Beta 4 modifications and the CALC/TOTALIZED fuel disagree bug disappeared completely. It wasn't easy to find, but you found and solved it. Congratulations and a big thank to you.

Regards,