Abstract: A fuel pumping apparatus, particularly useful for gas turbine engines, includes a dual element positive displacement fuel pump having a centrifugal type boost stage and, downstream, at least two parallel gear type elements. A controllable means for unlocking at least one of the elements includes a bypass line which provides a flow path to the inlet of the fuel pump from the pressurizing chamber of the gear elements which is used to urge end bearings of the gear elements into contact with the revolving gears thereby enabling the gears to pump fluid. Disposed in the bypass line is slide valve to open up the bypass line and unload and render the unloadable gear element inoperative. Control is provided by a Full Authority Digital Electronic Control and its associated Hydromechanical Unit which uses the fuel as a hydraulic fluid to actuate the slide valve.