40odd2 ---
Lemain,
So, do you know where we can get a fuel pump that dispenses in kgs?
Only asking 'cos we've been told more than once that it's Gallons or Litres only - which is why, in the door pocket of the aircraft there's a laminated card with the Kgs to Litres conversion on it to make sure that we put the right amount in. Then, at the end of each month when the Senior Pilot does the QA checks on the tech logs, one of the items to be checked is that the litres vs kgs figures do actually reconcile and add up to a "normal" average fuel consumption.
The kg/litres debacle has its history in charging for fuel, not flying. Higher temps in the tank farm lower the SG of the fuel so you get more litres for a given kg. It doesn't matter much for very small a/c like the 135, or light aviation but over a time, the difference is huge for the heavies. The last time I had involvement in pump metering was nearly 20 years ago, though I keep an eye on the technology, just for interest. I believe that all pump meters that dispense direct to a/c are of a volumetric design. If you want to convert to mass then you have to measure the temperature, look up the fuel characteristics being dispensed and calculate the mass. I can't think of any reason why the industry should burden pilots with the task of running two units of measurement alongside each other, some 20% apart in magnitude (SG = 0.81). Can anyone else offer an explanation other than for the convenience of bean-counters?