A method of controlling variable extraction flow in a 
combustion turbine engine, wherein extraction flow comprises a supply of 
compressed air extracted from the compressor and supplied to the 
turbine through extraction conduits, and wherein the extraction conduits includes a variable extraction orifice, the method comprising the steps of: measuring a plurality of 
turbine engine operating parameters; monitoring, by a 
control unit, the measured operating parameters of the 
combustion turbine engine; setting the variable extraction orifices to a setting that allows an approximate 
maximum level of extraction flow; calculating, by the 
control unit, at least one calculated operating parameter based upon model-based control and the measured operating parameters, including at least a current turbine 
inlet temperature and a maximum turbine 
inlet temperature; and manipulating the setting for the supply of fuel to the 
combustor such that an increased and / or 
maximum level of engine output is determined by comparing the values for the current turbine 
inlet temperature and the maximum turbine inlet temperature.