A refueling system may include an inlet tube that fluidly connects to a container containing gaseous hydrogen, a cryocooler including a cold tip and a cold head, the cold tip driven to a hydrogen liquefaction temperature by the cold head, a condensation chamber fluidly connected to the inlet tube to receive the gaseous hydrogen and thermally connected to the cryocooler cold tip, a catalyst disposed in the condensation chamber and that conducts ortho-to-para hydrogen conversion. The cryocooler cold tip absorbs a resulting exothermic reaction. The refueling system may also include a funnel fluidly connected to the condensation chamber and that receives liquid hydrogen from the condensation of the gaseous hydrogen, and a coupling mechanism fluidly connected to the funnel to receive the liquid hydrogen and having a nozzle downwardly movable to fluidly connect from above to an upwards facing tank inlet of a vehicle.

An aircraft is disclosed including a fuel tank, and a refuelling system configured to feed fuel into the fuel tank. The refuelling system includes a sensor. The sensor is configured to measure a composition of fuel in the refuelling system before it is fed into the fuel tank, and the sensor is further configured to generate an output based on the measured composition.

Heat exchangers are adjacent to electric driving units. Electric blowers of electric blower units rotate at rotational speed corresponding to amounts of heat generation of the electric driving units and suck air (ventilation air and outboard air). The sucked-in air passes through the heat exchangers that are adjacent to the electric driving units.

Heat exchangers are adjacent to electric driving units. Electric blowers of electric blower units rotate at rotational speed corresponding to amounts of heat generation of the electric driving units and suck air (ventilation air and outboard air). The sucked-in air passes through the heat exchangers that are adjacent to the electric driving units.

A fuelling method is described which comprises the steps of dispensing an initial quantity of fuel to a fuel tank, waiting for a predetermined settling period for the fuel dispensed to the fuel tank to homogenise and settle, after the predetermined settling period has elapsed, taking a fuel quantity reading using a fuel gauge associated with the fuel tank, calculating a differential volume of fuel between the fuel gauge reading and a desired final fuel quantity, and dispensing to the fuel tank a volume of fuel substantially equivalent to the differential volume using a dispensing apparatus including a fuel volume meter.

A fuel distribution system for an aircraft having wing and fuselage fuel tanks. The system includes sensors for indicating the level of fuel in each tank and at least one selectively controllable pump for moving fuel between the fuselage tank and one or more wing tanks. A controller is configured to monitor sensed fuel levels in the wing and fuselage tanks and selectively control the pump to shift fuel between the fuselage tank and the one or more wing tanks to maintain the aircraft's longitudinal center of gravity within preselected limits.

A liquid tank system comprises a main liquid tank, an outlet communicating between a fluid circuit and the main liquid tank, an inlet communicating between the fluid circuit and the main liquid tank, and an auxiliary cavity. First vent passage and second vent passage(s) communicate between the main liquid tank and the auxiliary cavity and allows liquid and gas to flow from the main liquid tank to the auxiliary cavity. The second vent passage has a flow control device regulating flow through the second vent passage and having a set point at which it allows liquid and gas to flow from the main liquid tank to the auxiliary cavity only when a pressure in the main liquid tank is beyond a threshold. The liquid tank system has an attitude envelope in which the liquid tank system is configured such that, in use, the flow control device blocks flow through the second vent passage when an end of the first vent passage in the main liquid tank is above a liquid level, and the flow control device allows gas and/or fluid flow through the second vent passage when main fluid tank pressure is above the threshold and the end of the first vent passage in the main liquid tank is below the liquid level.

A liquid tank system comprises a main liquid tank, an outlet communicating between a fluid circuit and the main liquid tank, an inlet communicating between the fluid circuit and the main liquid tank, and an auxiliary cavity. First vent passage and second vent passage(s) communicate between the main liquid tank and the auxiliary cavity and allows liquid and gas to flow from the main liquid tank to the auxiliary cavity. The second vent passage has a flow control device regulating flow through the second vent passage and having a set point at which it allows liquid and gas to flow from the main liquid tank to the auxiliary cavity only when a pressure in the main liquid tank is beyond a threshold. The liquid tank system has an attitude envelope in which the liquid tank system is configured such that, in use, the flow control device blocks flow through the second vent passage when an end of the first vent passage in the main liquid tank is above a liquid level, and the flow control device allows gas and/or fluid flow through the second vent passage when main fluid tank pressure is above the threshold and the end of the first vent passage in the main liquid tank is below the liquid level.

A method for detecting a failure in a fuel return valve of an aircraft engine fuel circuit, the fuel circuit including a fuel tank, an engine fuel system connected to the fuel tank capable of delivering a flow of fuel to the engine depending on a speed of the engine, a fuel return pipe connected between the engine fuel system and the fuel tank, a fuel return valve arranged to switch between an open and closed position, the valve being capable of blocking the fuel return pipe in the closed position, and of bringing the fuel return pipe into communication with the fuel tank in the open position, the method including measuring a pressure of the flow of fuel from the fuel tank, and if the measured pressure is lower than a predefined threshold, measuring the engine speed.

A method for detecting a failure in a fuel return valve of an aircraft engine fuel circuit, the fuel circuit including a fuel tank, an engine fuel system connected to the fuel tank capable of delivering a flow of fuel to the engine depending on a speed of the engine, a fuel return pipe connected between the engine fuel system and the fuel tank, a fuel return valve arranged to switch between an open and closed position, the valve being capable of blocking the fuel return pipe in the closed position, and of bringing the fuel return pipe into communication with the fuel tank in the open position, the method including measuring a pressure of the flow of fuel from the fuel tank, and if the measured pressure is lower than a predefined threshold, measuring the engine speed.