A method detects a failure in a fuel return valve of an aircraft engine fuel circuit. A fuel system is connected to a fuel tank of the circuit and includes a high-pressure pump delivering a flow rate to an actuating cylinder, a cutoff valve capable of feeding the actuating cylinder disposed in a feed pipe of the engine; a fuel return pipe; a fuel return valve arranged to switch between an open position and a closed position. The method includes starting the engine at an engine speed; increasing the engine speed until a flow rate reaches a predefined value sufficient for opening the cutoff valve; measuring the position of the actuating cylinder and an engine speed corresponding to the opening of said cutoff valve.

A method detects a failure in a fuel return valve of an aircraft engine fuel circuit. A fuel system is connected to a fuel tank of the circuit and includes a high-pressure pump delivering a flow rate to an actuating cylinder, a cutoff valve capable of feeding the actuating cylinder disposed in a feed pipe of the engine; a fuel return pipe; a fuel return valve arranged to switch between an open position and a closed position. The method includes starting the engine at an engine speed; increasing the engine speed until a flow rate reaches a predefined value sufficient for opening the cutoff valve; measuring the position of the actuating cylinder and an engine speed corresponding to the opening of said cutoff valve.

Methods and apparatus for cryogenic fuel bayonet transfers are disclosed. A disclosed example fuel transfer system includes a fuel tank. The example fuel transfer system also includes a bayonet receptacle extending into an internal volume of the fuel tank, where the bayonet receptacle is to receive a fuel transfer bayonet to fill the fuel tank with fuel and a fuel discharge bayonet to discharge the fuel.

Methods and apparatus for cryogenic fuel bayonet transfers are disclosed. A disclosed example fuel transfer system includes a fuel tank. The example fuel transfer system also includes a bayonet receptacle extending into an internal volume of the fuel tank, where the bayonet receptacle is to receive a fuel transfer bayonet to fill the fuel tank with fuel and a fuel discharge bayonet to discharge the fuel.

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.

The disclosure provides composite polymer compositions comprising a polyaryl ether ketone base polymer, a conductive filler, a dispersing and processing additive, and optionally a dielectric filler. The composite polymers exhibit retained or improved strength, increased toughness, and significantly increased elongation at break compared to the base polymer. The composite polymer may be used in lightweight, non-metallic fuel conveyance systems in aircraft.

The disclosure provides composite polymer compositions comprising a polyaryl ether ketone base polymer, a conductive filler, a dispersing and processing additive, and optionally a dielectric filler. The composite polymers exhibit retained or improved strength, increased toughness, and significantly increased elongation at break compared to the base polymer. The composite polymer may be used in lightweight, non-metallic fuel conveyance systems in aircraft.

A system comprises a non-transitory machine readable storage medium storing instructions and a database identifying a plurality of assets and a state of each asset. The instructions configure a processor for receiving updates to a distributed electronic ledger managed by plural peer processors. Each update includes an event or change affecting one of the assets. The peer processors verify portions of the ledger describing each event or change. At least one of the updates has not yet been recorded in the ledger at a time of the receiving. The processor computes a state of each asset, based on the updates, receives a request for a state of one of the assets; and responds to the request, reflecting each event and change affecting that asset. The response is performed without waiting for the peer processors to verify an update that has not yet been recorded in the ledger.

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.