Can you find out whats wrong:)
Thread Starter
Join Date: Feb 2007
Location: Istanbul
Age: 41
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
I still don't know why...
It was really surprising for us , when we see it.
Besides EFOB kept increasing while we got close to the destination.
On final approach it was 3.9T, but we landed with 2.8T
But On the return flight everything was normal
I asked some of the captains in the fleet and one of them said he had expereinced it 2 years ago for once. So its like rare and a misterious situation
May be one of the guys in the forum happend to have this as well and have an explanation...
It was really surprising for us , when we see it.
Besides EFOB kept increasing while we got close to the destination.
On final approach it was 3.9T, but we landed with 2.8T
But On the return flight everything was normal
I asked some of the captains in the fleet and one of them said he had expereinced it 2 years ago for once. So its like rare and a misterious situation
May be one of the guys in the forum happend to have this as well and have an explanation...
Join Date: Nov 2007
Location: RH base 36R
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
I'm not familiar with this FMS and aircraft, but in this picture FOB appears to be determined by fuelflow (/FF) only. Should it not normally be determined by both fuelflow and the measured fuel quantity (/FF+FQ)?
Still a funny indication.
Still a funny indication.
The FOB indication is only being based on fuel flow (FF after the FOB) whereas it is normally a composite of fuel flow and fuel quantity sensor information (FF+FQ), looks like FQ was deselected for some reason. Does that have something to do with it?
Originally Posted by FCOM DSC.22_20.50.10
[3R] FOBThis field displays the fuel on board, which is computed:
- With information from the fuel flow and fuel quantity sensor (FF + FQ), or
- From FF only (enter/FF to deselect FQ), or
- From FQ only (enter/FQ to deselect FF).
The pilot can modify this number.
- With information from the fuel flow and fuel quantity sensor (FF + FQ), or
- From FF only (enter/FF to deselect FQ), or
- From FQ only (enter/FQ to deselect FF).
The pilot can modify this number.
Join Date: Nov 2007
Location: RH base 36R
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
What does the color blue mean on this FMS? Data entered by pilot? In that case, the FOB would indeed have been modified by the pilot here to a value below the actual FOB.
Next it's just a matter of taking a picture before the FMS has realized what has just happened, and has not yet recalculated the EFOB at destination...
Next CLR the FOB-line, all's back to normal and you have a nice picture for PPRUNE... correct?
Next it's just a matter of taking a picture before the FMS has realized what has just happened, and has not yet recalculated the EFOB at destination...
Next CLR the FOB-line, all's back to normal and you have a nice picture for PPRUNE... correct?
Thread Starter
Join Date: Feb 2007
Location: Istanbul
Age: 41
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
Moodyblue you created a good conspiracy theory 
But no, the pic is what we saw.
And Eventhough FOB is blue , you can not enter a made up FOB value.Its not alowed.
Probably its blue because you can deselect FF or FQ i dont know.
Like the FCOM says may be someone or something deselected FQ but it was not us for sure ,
Checkboard i wonder how you can put in a FF value? i havent done it or seen it before.
I'll try it in the next flight
But no, the pic is what we saw.
And Eventhough FOB is blue , you can not enter a made up FOB value.Its not alowed.
Probably its blue because you can deselect FF or FQ i dont know.
Like the FCOM says may be someone or something deselected FQ but it was not us for sure ,
Checkboard i wonder how you can put in a FF value? i havent done it or seen it before.
I'll try it in the next flight
Join Date: Nov 2007
Location: RH base 36R
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
I'm not familiar with the Airbus FMS. I am familiar with the MD-11 FMS, and it is somewhat similar. It too has the /FF+FQ format, which can be replaced by /FF or /FQ.
The FMS Guide says: "The flight crew ... may reinitialize UFOB by entering a new value (thereby deselecting the fuel quantitiy sensor)" with UFOB being Usable Fuel On Board.
So on the MD-11 it is possible to enter a value in the UFOB-field, and the resulting display would be xx.x/FF, just as in your picture.
Maybe the same goes for the Airbus?
But then, if neither you nor the guy/girl next to you entered this into the FMS how did it get there? And even then the question remains, why does the aircraft think it will land with more fuel than it thinks it has on board?
I give up.
Another good case against pilotless aircraft I guess.
The FMS Guide says: "The flight crew ... may reinitialize UFOB by entering a new value (thereby deselecting the fuel quantitiy sensor)" with UFOB being Usable Fuel On Board.
So on the MD-11 it is possible to enter a value in the UFOB-field, and the resulting display would be xx.x/FF, just as in your picture.
Maybe the same goes for the Airbus?
But then, if neither you nor the guy/girl next to you entered this into the FMS how did it get there? And even then the question remains, why does the aircraft think it will land with more fuel than it thinks it has on board?
I give up.
Another good case against pilotless aircraft I guess.
Join Date: Mar 2008
Location: Above the Transition Level
Posts: 160
Likes: 0
Received 0 Likes
on
0 Posts
I believe there is an oeb on this.
Adding a random waypont to the flightplan then delete it forces it to recalculate the fuel and should bring it right.
Adding a random waypont to the flightplan then delete it forces it to recalculate the fuel and should bring it right.
Thread Starter
Join Date: Feb 2007
Location: Istanbul
Age: 41
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
ElitPilot i remember that , Very very long time ago when we got no prediction about time or fuel at all, we had added a waypoint and deleted it, afterwards it worked.But i didnt remeber that during the flight.
May be you are right it might have worked if we had done that.
But i still wonder the reason , /FF still looks suspicios.
I looked up the FCOM but couldnt find any details about it.
id like to know what difference it makes if we deselect FF or FQ ,
i have less knowledge about that
and would appreciate if anybody share his knowledge..
May be you are right it might have worked if we had done that.
But i still wonder the reason , /FF still looks suspicios.
I looked up the FCOM but couldnt find any details about it.
id like to know what difference it makes if we deselect FF or FQ ,
i have less knowledge about that
and would appreciate if anybody share his knowledge..
Last edited by Okivan; 29th Aug 2012 at 17:19.
Join Date: Sep 2006
Location: any town as retired.
Posts: 2,182
Likes: 0
Received 0 Likes
on
0 Posts
Just a guess not Bus driver
The FF indicates that the fuel flow has been entered manually, or by the system as an over-ride for faulty sensors.
This must have been well before the pic taken, thus suggesting a significant change in FF to deviate from the destiation fuel, predicted by the FP, vs the "computed fuel remaining.
This must have been well before the pic taken, thus suggesting a significant change in FF to deviate from the destiation fuel, predicted by the FP, vs the "computed fuel remaining.