The metric system is much simpler and less likely to lead to confusion, we would be better off adopting it in its entirety than continuing with the present mishmash.
A Russian pilot orders his fuel in kilograms, the tank quantities are given in kgs, he uses kgs on the load sheet and engine fuel flow indicates kg/hr. SIMPLE
A western pilot could easily, depending on the type of aircraft and country he was in, order his fuel in litres, have tanks in USgal, use kgs on the loadsheet and have fuel flow indicated in pounds per hour. GLIMI GLIDER