Quote from Robini:
Is it possible to go with MTOW (230T) if the flight include following:
MZFW: 173000 kg
Fuel: 45000kg
Logically wouldn't the TOW be 218T? Or can it be 230T? And if it can, HOW?
[Unquote]
Robini, your English is 1000 times better than my Swedish, but I'm sorry to say I still do not fully understand your question. I agree with what bfisk has just posted, so I hope that gives you the information you wanted. Just in case it doesn't, however, I am going to risk insulting you by spelling out what is probably the obvious...
In the way you phrase the question, the only answer is that 173T + 45T = 218T (not 230T). The weight (bfisk correctly calls it the "mass") of an aircraft is, by definition, the actual ZFW plus the current FOB (fuel on board). If the aeroplane is loaded already up to a maximum ZFW of 173T, the ony legal way of increasing the actual TOW to 230T is to load more fuel on board, so that you have 57T FOB at the start of the take-off run. [And you have to prove that the RTOW for all the prevailing conditions is 230T or more.]
All the best for your project,
Chris