we can perform one at the side of the Aircraft via the Visijar located on the Bowser, never been asked to perform one in the 2 years i"ve been Fuelling though.
Refuelling big aircraft, B777 sized, I always ask for the SG. All the dispensers at ARN can measure it on the truck, and we can watch them do it. I find the SG changes often, it not only depends on temp, but which refinery the fuel comes from. We get fuel from different refineries and see the SG change often.
But on small aircraft, my company uses a standard SG of 0.8 all the time. When fuelling an A319 with 6000 litres, the difference from mid-summer to mid-winter is only around 200kg, so why bother? And I can calculate litres x 0.8 without a calculator!
Many large aircraft, B744 and B777 for two, will show you the uplift SG on the fuel maint page on the EICAS. They get this from the densitomitor in the tanks.
Be careful when you do a stick check.
Fuel gauges are very accurate. Sticks are not. Use the sticks to roughly check the gauges. To accurately stick check takes a lot of time.
And if you are stick checking an A320, call an expert. To convert the stick reading to the tank qty is an art.