The invention provides an aircraft fuel system comprising a fuel storage facility for storing fuel and ullage, a separate ullage storage facility for storing ullage, and a transfer arrangement for transferring ullage between the fuel storage facility and the ullage storage facility, wherein the transfer arrangement is capable of controlling the transfer of ullage based on a pressure input to the transfer arrangement. The invention also provides an aircraft with such a fuel system and a method of operating an aircraft.

The invention provides an aircraft fuel system comprising a fuel storage facility for storing fuel and ullage, a separate ullage storage facility for storing ullage, and a transfer arrangement for transferring ullage between the fuel storage facility and the ullage storage facility, wherein the transfer arrangement is capable of controlling the transfer of ullage based on a pressure input to the transfer arrangement. The invention also provides an aircraft with such a fuel system and a method of operating an aircraft.

A fuel extraction system for extracting a gaseous fuel from a fuel tank. The fuel extraction system includes a conveying device which is configured to convey gaseous fuel and to bring it from a first pressure level to a second pressure level, a first line which is configured to connect the conveying device fluidically to the interior of the fuel tank, a buffer tank which is configured to store the fuel at the second pressure level, and which has a first outlet and a second outlet, at least one valve with a pneumatic actuating device, and a second line which is connected to the first outlet of the buffer tank and is configured to conduct a part of the fuel at the second pressure level to the pneumatic actuating device of the at least one valve. Furthermore, a fuel tank apparatus and a fuel cell system are described.

A fuel extraction system for extracting a gaseous fuel from a fuel tank. The fuel extraction system includes a conveying device which is configured to convey gaseous fuel and to bring it from a first pressure level to a second pressure level, a first line which is configured to connect the conveying device fluidically to the interior of the fuel tank, a buffer tank which is configured to store the fuel at the second pressure level, and which has a first outlet and a second outlet, at least one valve with a pneumatic actuating device, and a second line which is connected to the first outlet of the buffer tank and is configured to conduct a part of the fuel at the second pressure level to the pneumatic actuating device of the at least one valve. Furthermore, a fuel tank apparatus and a fuel cell system are described.

An oil reservoir assembly includes a tank, a return passage, a pressurization valve, a first passage, and a vent valve. The tank includes a canister, a fill port, an first oil outlet, an second air outlet, and an inlet. The inlet is disposed in the canister and is connected to a restrictor. The return passage is connected to the inlet of the tank and to a scavenge pump. The pressurization valve is fluidly connected to the second air outlet of the tank. The first passage is connected to the pressurization valve and to an accessory gearbox of the engine. The vent valve is disposed in the return passage and includes a body, a channel extending through the body, an inlet orifice, and an outlet orifice. The inlet orifice is disposed in an end of the body. The outlet orifice is fluidly connected to the inlet orifice via the channel.

An oil reservoir assembly includes a tank, a return passage, a pressurization valve, a first passage, and a vent valve. The tank includes a canister, a fill port, an first oil outlet, an second air outlet, and an inlet. The inlet is disposed in the canister and is connected to a restrictor. The return passage is connected to the inlet of the tank and to a scavenge pump. The pressurization valve is fluidly connected to the second air outlet of the tank. The first passage is connected to the pressurization valve and to an accessory gearbox of the engine. The vent valve is disposed in the return passage and includes a body, a channel extending through the body, an inlet orifice, and an outlet orifice. The inlet orifice is disposed in an end of the body. The outlet orifice is fluidly connected to the inlet orifice via the channel.

Fuel tank inerting systems and methods for aircraft are described. The systems and methods include controlling of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve, to control a state of a fuel tank inerting system. The states of the fuel tank inerting system include an OFF state, a CIRCULATE state, a PRIME state, a CATWARM state, an ON state, a DEPRESSURIZE state, and a COOLDOWN state, wherein the states are determined in part by a prior state and/or a position/actuation of a given element of the system.

Fuel tank inerting systems and methods for aircraft are described. The systems and methods include controlling of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve, to control a state of a fuel tank inerting system. The states of the fuel tank inerting system include an OFF state, a CIRCULATE state, a PRIME state, a CATWARM state, an ON state, a DEPRESSURIZE state, and a COOLDOWN state, wherein the states are determined in part by a prior state and/or a position/actuation of a given element of the system.

An oil reservoir assembly includes a tank, a return passage, a pressurization valve, a first passage, and a vent valve. The tank includes a canister, a fill port, an first oil outlet, an second air outlet, and an inlet. The inlet is disposed in the canister and is connected to a restrictor. The return passage is connected to the inlet of the tank and to a scavenge pump. The pressurization valve is fluidly connected to the second air outlet of the tank. The first passage is connected to the pressurization valve and to an accessory gearbox of the engine. The vent valve is disposed in the return passage and includes a body, a channel extending through the body, an inlet orifice, and an outlet orifice. The inlet orifice is disposed in an end of the body. The outlet orifice is fluidly connected to the inlet orifice via the channel.

An oil reservoir assembly includes a tank, a return passage, a pressurization valve, a first passage, and a vent valve. The tank includes a canister, a fill port, an first oil outlet, an second air outlet, and an inlet. The inlet is disposed in the canister and is connected to a restrictor. The return passage is connected to the inlet of the tank and to a scavenge pump. The pressurization valve is fluidly connected to the second air outlet of the tank. The first passage is connected to the pressurization valve and to an accessory gearbox of the engine. The vent valve is disposed in the return passage and includes a body, a channel extending through the body, an inlet orifice, and an outlet orifice. The inlet orifice is disposed in an end of the body. The outlet orifice is fluidly connected to the inlet orifice via the channel.