The present invention relates to a method of controlling the production of a liquefied natural gas product stream (31) obtained by removing heat from natural gas by indirect heat exchange with an expanded heavy mixed refrigerant and an expanded light mixed refrigerant. The method comprises executing a control loop comprising maintaining the flow rate of the liquefied natural gas product stream (31) at a dependent set point and maintaining the flow rates of the heavy mixed refrigerant (60a) and the light mixed refrigerant (65) at operator manipulated set points (80, 81). The method further comprises executing an override control loop comprising: determining an override set point (95′) for the flow rate of the liquefied natural gas and computing an override set point (80′) for the flow rate of the heavy mixed refrigerant and an override set point (81′) to reduce residual available power of the electric motor.