An aircraft signal computer system includes a plurality of modular signal computer units and a liquid cooling device for cooling the modular signal computer units. The liquid cooling device includes a coolant line, which is connectable to a central liquid cooling system of an aircraft in order to supply a liquid coolant medium at a desired low temperature to the liquid cooling device. The coolant line of the liquid cooling device is in thermal surface contact with the modular signal computer units in order to dissipate heat from the modular signal computer units. A heat-emitting component of the modular signal computer units may be in thermal contact with a coolant bath or an internal heat conductor for removing heat energy.