An apparatus (10) for fuelling an aircraft, in particular during performing a tank leakage test on the aircraft, comprises a fuel supply line (14) for supplying fuel to an aircraft tank system (12), at least one pressure sensor (26) for sensing a pressure within the aircraft tank system (12) and for providing a signal indicative of the pressure within the aircraft tank system (12), an electronic control unit (ECU) for processing the signal of the pressure sensor (26) and for generating an emergency shut-off signal, if the pressure within the aircraft tank system (12) exceeds a first predetermined level, and an emergency shut-off device (24) which is controlled by the electronic control unit (ECU) and which is adapted to interrupt the supply of fuel to the aircraft tank system (12) in response to the emergency shut-off signal from the electronic control unit (ECU).