好處:
It is possible to have an aircraft certified with a reduced MTOW, lower than the structural maximum, to take advantage of lower MTOW-based fees, such as insurance premiums, landing fees and air traffic control fees are MTOW based.
https://en.wikipedia.org/wiki/Maximum_takeoff_weight
方法就唔係個個一樣,例如A220最近個MTOW Increase:
This performance increase is achieved by taking credit of existing structural and systems margins as well as existing fuel volume capacity.
A321XLR個MTOW就要加強個landing gear
JAL 啲A350 MTOW 217t (from 280t) and Trent-XWB-75 (from 84klbf) 好似都係software de-rate
售後改MTOW我估都係靠software