A fuel circuit of an aircraft engine including a fuel tank; an engine fuel system including a low-pressure pump and a high-pressure pump, and a fuel recirculating pipeline connected to the engine fuel system; and a fuel recirculating valve arranged so as to switch between an open position and a closed position according to the pressure differential of the low-pressure pump, the valve being able to obstruct the fuel recirculating pipeline in the closed position, and to bring the fuel recirculating pipeline into communication with the fuel tank in the open position.

A method of and a system for operating a fuel pump management system of an aircraft. The method comprises receiving, from a fuel gauge, an electronic reading of a level of fuel fluid contained in a fuel tank; and analysing the electronic reading of the level of the fuel fluid, the analysing comprising upon determining that the level of fuel fluid is equal or below a predetermined fuel level threshold, causing a fuel pump in communication with the fuel tank to be shut down.

A method of and a system for operating a fuel pump management system of an aircraft. The method comprises receiving, from a fuel gauge, an electronic reading of a level of fuel fluid contained in a fuel tank; and analysing the electronic reading of the level of the fuel fluid, the analysing comprising upon determining that the level of fuel fluid is equal or below a predetermined fuel level threshold, causing a fuel pump in communication with the fuel tank to be shut down.

A method for improving inflight fuel efficiency of an aircraft includes sensing aircraft fuel weight in the aircraft fuel tanks and reading the fuel weight by a flight management system during aircraft flight; calculating a current center of gravity position from the fuel weight; calculating an aircraft longitudinal trim drag factor from the current center of gravity; and adjusting a fuel burn prediction utilizing the longitudinal trim drag factor. A system for improving aircraft inflight fuel efficiency includes a flight management system programmed to calculate a current center of gravity position from a current aircraft fuel weight, calculate a longitudinal trim drag factor from the current center of gravity, adjust a fuel burn prediction, and display in the flight deck an adjusted fuel burn prediction for each leg of aircraft flight, which is used to adjust aircraft performance automatically by the flight control system or by the pilot.

An airplane is provided. The airplane includes a fuel gauging and quantity estimation system with an improved estimation accuracy. The fuel gauging and quantity estimation system operates by detecting an environment of a tank comprising a liquid and selecting one or more liquid gauging algorithms based on the environment. The fuel gauging and quantity estimation system further operates by receiving sensor data characterizing the liquid of the tank and utilizing the sensor data and the one or more liquid gauging algorithms to determine a property of the liquid.

A system includes display equipment and a processor coupled to the display equipment. The processor is configured to cause the display equipment to display an electronic checklist associated with an aircraft. The processor is configured determine whether the electronic checklist includes a checklist item associated with a particular control page of a plurality of control pages. The processor is configured to, based on determining that the electronic checklist includes the checklist item associated with the particular control page, cause the display equipment to display the particular control page that includes a control element that is selectable to cause a control command to be sent to one or more components.

A combination of a fuel tank assembly and a tool for opening an outlet of the fuel tank assembly. The assembly includes a tank for storing a liquid hydrocarbon; and an operator-openable valve arrangement configured to move between a closed flow condition in which flow through the valve arrangement is prevented and an open flow condition in which liquid is allowed to drain out of the tank. The tool is connectable to the valve arrangement, such that in a connected condition of the tool and the arrangement a liquid flow path exists between the interior and the exterior of the tank. The liquid flow path is at least partly defined by a conduit in the tool. A filter, in the flow path, includes a water-permeable member configured to enable water to pass through the water-permeable member and substantially prevent passage of liquid hydrocarbon.

An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.

An aircraft fuel tank system including a fuel tank compartment for containing liquid fuel and having a float-activated valve arranged to become positively buoyant when immersed in liquid fuel so that the float moves up to a raised position which causes the valve to close and prevent liquid fuel from flowing out of the fuel tank compartment through the valve. The float is also arranged to move down to a lowered position in response to a level of the liquid fuel in the fuel tank compartment dropping, the movement of the float to the lowered position causing the valve to open and permit liquid fuel to flow out of the fuel tank compartment through the valve. A pressure-activated valve may be used as an alternative to the float-activated valve.

A method and apparatus of control of fuel in a fuel tank including use of pneumatics employing a non-reactive gas. The aircraft fuel tank is handled and monitored by a pneumatic apparatus using oxygen depleted air from air separation module or auxiliary power unit of the aircraft. Electrical discharge from electrical apparatus is obviated.