A cooling system (700, 800, 900, 1000) for an aircraft comprising: a first cooling circuit (702, 802, 1002) having a first evaporator (706, 806, 918, 1016) and a second evaporator (708, 808, 916, 1018); and a second cooling circuit (704, 804, 1004) having a third evaporator (712, 812, 918, 1020) and a fourth evaporator (714, 814, 916, 1022); wherein: two of the evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a first side (720, 820) of the aircraft, and the other two of the four evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a second side (722, 822) of the aircraft opposite the first side (720, 820); characterized in that one of the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) each includes a first set of valves (942, 944, 950) arranged to direct refrigerant through a first cooling sub-circuit, a second cooling sub-circuit, or both the first and second cooling sub-circuits, wherein the first cooling sub-circuit includes a first expansion valve (910, 1010), and the second cooling sub-circuit includes at least a first turbine that is rotationally coupled to a first compressor via a first shaft; the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) reject heat, via a heat exchanger (904, 1004), from their respective cooling circuit (702, 704, 802, 804, 1002, 1004) to air passing into an engine of the aircraft; and a controller configured to operate the first set of valves (942, 944, 950) to direct the refrigerant through the first cooling sub-circuit, the second cooling sub-circuit, or both the first and second cooling sub-circuits based on whether a pressure of the refrigerant in at least one of the first and second evaporators (706, 806, 918, 1016; 708, 808, 916, 1018) is above or below a critical pressure of the refrigerant. a first cooling circuit (702, 802, 1002) having a first evaporator (706, 806, 918, 1016) and a second evaporator (708, 808, 916, 1018); and a second cooling circuit (704, 804, 1004) having a third evaporator (712, 812, 918, 1020) and a fourth evaporator (714, 814, 916, 1022); wherein: two of the evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a first side (720, 820) of the aircraft, and the other two of the four evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a second side (722, 822) of the aircraft opposite the first side (720, 820); characterized in that one of the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) each includes a first set of valves (942, 944, 950) arranged to direct refrigerant through a first cooling sub-circuit, a second cooling sub-circuit, or both the first and second cooling sub-circuits, wherein the first cooling sub-circuit includes a first expansion valve (910, 1010), and the second cooling sub-circuit includes at least a first turbine that is rotationally coupled to a first compressor via a first shaft; the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) reject heat, via a heat exchanger (904, 1004), from their respective cooling circuit (702, 704, 802, 804, 1002, 1004) to air passing into an engine of the aircraft; and a controller configured to operate the first set of valves (942, 944, 950) to direct the refrigerant through the first cooling sub-circuit, the second cooling sub-circuit, or both the first and second cooling sub-circuits based on whether a pressure of the refrigerant in at least one of the first and second evaporators (706, 806, 918, 1016; 708, 808, 916, 1018) is above or below a critical pressure of the refrigerant. two of the evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a first side (720, 820) of the aircraft, and the other two of the four evaporators (706, 708, 712, 714, 806, 808, 812, 814, 916, 918, 1016, 1018, 1020, 1022) are installed on a second side (722, 822) of the aircraft opposite the first side (720, 820); characterized in that one of the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) each includes a first set of valves (942, 944, 950) arranged to direct refrigerant through a first cooling sub-circuit, a second cooling sub-circuit, or both the first and second cooling sub-circuits, wherein the first cooling sub-circuit includes a first expansion valve (910, 1010), and the second cooling sub-circuit includes at least a first turbine that is rotationally coupled to a first compressor via a first shaft; the first and second cooling circuits (702, 704, 802, 804, 1002, 1004) reject heat, via a heat exchanger (904, 1004), from their respective cooling circuit (702, 704, 802, 804, 1002, 1004) to air passing into an engine of the aircraft; and a controller configured to operate the first set of valves (942, 944, 950) to direct the refrigerant through the first cooling sub-circuit, the second cooling sub-circuit, or both the first and second cooling sub-circuits based on whether a pressure of the refrigerant in at least one of the first and second evaporators (706, 806, 918, 1016; 708, 808, 916, 1018) is above or below a critical pressure of the refrigerant.