A LIQUID FUEL SUPPLY SYSTEM FOR AN AIRCRAFT GAS TURBINE ENGINE HAS A CENTRIFUGAL PUMP ARRANGED TO SUPPLY FUEL TO REHEAT BURNERS AT A RATE WHICH IS REGULATED BY A FIRST FLOW CONTROL MEANS, AND ARRANGED ALSO TO SUPPLY LIQUID FUEL FOR OPERATING AN AUXILIARY POWER SERVICE WHICH INCLUDES A SECOND FLOW CONTROL MEANS CONTROLLING A VARIABLE AREA DISCHARGE NOZZLE OF THE ENGINE. THE CENTRIFUGRAL PUMP HAS A TURBINE DRIVE TO WHICH THE SUPPLY OF COMPRESSED AIR IS REGULATED BY A VALVE IN RESPONSE TO THE TOTAL FLOW DEMAND OF THE FIRST AND SECOND FLOW CONTROL MEANS.