Originally Posted by
new_era
Now please tell me, where is the cheating, where is the illegal thing on it.
This is legitimate, as long as you actually replan for 310 and get a load sheet that gives a good landing weight at/below the limit. (Or, in the case of my airline, this isn't shown directly but there's just a takeoff weight that is predicated on that.)
What's illegal is to just say "we'll burn it off in the air" and take off at the higher weight without replanning.
"Cheating," depending on the slang of where you're from, may refer to something that's legitimate but involves a clever work-around an initial obstacle; i.e., it could be either one of the above two actions.