Wrong fuel calculation?

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dkreiskott
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Joined: Thu Dec 15, 2022 11:11 am
Location: Germany \ near EDDL
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Wrong fuel calculation?

Post by dkreiskott »

Hello Jean Luc,

As I was just looking into the tanks of the A320, I found an error in the fuel displays.
The total amount displayed and the amount in the individual tanks do not match. The amount filled up is also not calculated correctly.
To me, that looks like a calculation error?

Here is an example:
The amount of fuel according to the simulator letter is: 4,274 kg, which is transmitted to the simulator.

Image

This results in 2,137.05 kg per tank in the simulator. This value is therefore correct.

Image

The total amount is shown in the display with FOB 4270. This results in a difference of only -4kg.

Image

For the individual tanks (left/right), only 2,130 is then shown. This results in a difference of -14kg
Apart from the fact that both displays show different values.

Image

It would be nice if you could take a look at the calculation.
Regards
Dieter

A320 cockpit Prepar3d v5.4 with full voice control for ATC and ground crew
Developer of EWD Overlay and Home Cockpit Builder
jeehell
Site Admin
Posts: 414
Joined: Thu Nov 03, 2022 10:14 am

Re: Wrong fuel calculation?

Post by jeehell »

Geez, do you realize that the accuracy of the FOB and each tank is +/-10 kg, which means that depending on rounding what you see is therefore correct?
2134 is rounded down to 2130
2134+2134=4268 rounded up to 4270
Regards,
Jean Luc
dkreiskott
Posts: 211
Joined: Thu Dec 15, 2022 11:11 am
Location: Germany \ near EDDL
Contact:

Re: Wrong fuel calculation?

Post by dkreiskott »

Okay, but 2137, 05 is rounded not 2130. And 2137,05 is the Real fuel per tank. So the Resultat can be 2137 or 2140. I don't understand your answer.
Regards
Dieter

A320 cockpit Prepar3d v5.4 with full voice control for ATC and ground crew
Developer of EWD Overlay and Home Cockpit Builder
jeehell
Site Admin
Posts: 414
Joined: Thu Nov 03, 2022 10:14 am

Re: Wrong fuel calculation?

Post by jeehell »

The rounding are probably always "round down" then. Which gives you this result. I don't recall exactly what was put there. And I will not change it because there is no issues in any case.
Regards,
Jean Luc
Aron
Posts: 17
Joined: Wed Jul 10, 2024 5:55 am

Re: Wrong fuel calculation?

Post by Aron »

I really don't see a reason for change anything here, nevertheless I observed what the real 320 is doing after reading the post.

It seems to round on 10th on each tank and adds the rounded values together. As in one tank the value changes, the sum changes in the exact same moment.

Just for info! This is such a minor issue, I don’t even find words for this, no offence!
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