Throttling up during takeoff - is it "phased"?
I fly commercial fairly often. I've noticed often that when we taxi onto the runway and get into position then throttle up for takeoff, rather than just going straight up to full right then and there, the pilot usually throttles up to a certain RPM, then some more after a couple seconds, then eventually hits it to full throttle as we are rolling along a few yards ahead. Kind of like in "phases".
Just curious as a non-pilot: is there an official term for this? Is it basically just to check that the engines don't have issues when throttling up and to make it easier to throttle back quickly if something goes wrong and takeoff has to be aborted?