It should also be mentioned that (on modern jets) there is a mass sensor in the fuel line leading to the engine, so the fuel flow is also in true kilos, and thus the Fuel Control Unit commands a set mass of fuel to the engine, not volume.
This I did not know Checkboard.
Originally Posted by
Jumbo Driver
Refuelling is metered by volume, which is why the S.G. and temperature are needed to convert your fuel onload into weight for loadsheet purposes.
However, wouldn't it be more sensible if it were billed by weight (mass?), as surely that is the truer measurement of the "energy" being supplied?
JD
Metering by volume is the more accurate method of dispensing fuel due, I imagine, to equipment limitations. It is easier to implement than the alternative - using scales. On a typical fuel bowser, a .00001% error in weight measurement is still a considerable amount. I would think even a moderately stiff wind on the sail area of the tank would affect accuracy during the weigh-in.