Fred J McCall wrote:
So fuel variations of 3% when you are managing your required 10% to bare
minumum is a huge "error" and I suspect they are very careful about that.


To get a 3% swing in fuel volume you would need a preposterous
temperature swing. Coefficient of expansion of kerosene is something
like 0.00099 per degree Celsius, so a 3% change in volume would
require a temperature swing of some 30+ degrees Celsius from
'standard'.

That is why I question the reasoning that fuel has to be calculated
in weight and then converted to volume "because of variations in the
fuel density". There will be some difference but it will be very
small. Important for space flight, but probably not for aviation.