An aircraft cooling system evaporator arrangement has at least two mutually independent coolant circuits, at least two evaporation devices arranged to be hydraulically parallel for enabling an exchange of heat between the coolant and a refrigerant, at least two supply lines for supplying refrigerant to the evaporation devices, and at least two discharge lines for discharging refrigerant from the evaporation devices. A different one of the evaporation devices, a different one of the supply lines and a different one of the discharge lines are assigned to each of the coolant circuits, and the supply lines are hydraulically separate from each other as are the discharge lines. At least one refrigerant sensor monitors a refrigerant state of each of the discharge lines and an expansion valve is driven in accordance with the refrigerant sensors to control streams of refrigerant through the supply lines.