Dual fuel pump system for an aircraft

An aircraft engine system for an aircraft, the aircraft engine system comprising:

• a compressor section including a number of compressor stages;
• a turbine section;
• a combustor fluidically connected to the compressor section and the turbine section;
• and
• a dual fuel pump system comprising:
• a primary run-dry fuel pump comprising multiple stages, each of the stages configured to produce fuel pressure between a pump stage inlet and a pump stage outlet, and at least one of the stages operable in a run-dry mode;
• a secondary run-dry fuel pump operable in the run-dry mode, wherein the secondary run-dry fuel pump is mechanically driven by an accessory gearbox of an engine of the aircraft;
• an electric motor operably coupled to the primary run-dry fuel pump and configured to drive rotation of the stages of the primary run-dry fuel pump;
• and
• a controller configured to pressurize fuel using a single stage of the primary run-dry fuel pump in a first engine power setting range between start and cruise and pressurize fuel using the secondary run-dry fuel pump to provide pressurized fuel to an actuation system of the aircraft while the single stage of the primary run-dry fuel pump is driven to pump fuel at the engine power setting below the first engine power setting range.

A method of controlling a dual fuel pump system of an aircraft, the method comprising:

• pressurizing fuel using a single stage of a primary run-dry fuel pump of the dual fuel pump system in a first engine power setting range between start and cruise, wherein the primary run-dry fuel pump comprises multiple stages driven by an electric motor;
• pressurizing fuel using at least two stages of the primary run-dry fuel pump at a second engine power setting range between climb and takeoff;
• pressurizing fuel using the single stage of the primary run-dry fuel pump at an engine power setting below the first engine power setting range;
• and
• pressurizing fuel using a secondary run-dry fuel pump of the dual fuel pump system to provide pressurized fuel to an actuation system of the aircraft while the single stage of the primary run-dry fuel pump is driven to pump fuel at the engine power setting below the first engine power setting range, wherein the secondary run-dry fuel pump is operably coupled to an accessory gearbox driven by an engine of the aircraft.