A method for depressurizing a cabin of an aircraft on the ground from the outer side of the aircraft using a depressurizing system including a venting valve which can be actuated between open and closed positions by means of a shutter and which is connected in fluid terms to a vacuum pump and to a pressure tap port of the aircraft which is connected to a protection valve against excess pressure in the cabin. The method includes fluidly connecting the venting valve to the pressure tap port, the shutter being in the open position, moving the shutter to the closed position thereof and activating the vacuum pump to generate a reduced pressure in the region of the pressure tap port.

An environmental control system of an aircraft includes a ram air circuit with a ram air shell having at least one heat exchanger positioned therein, a dehumidification system arranged in fluid communication with the ram air circuit, a compression device arranged in fluid communication with the ram air circuit and the at least one dehumidification system, and an expansion device arranged in fluid communication with the ram air circuit. At least one of the compression device and the expansion device is selectively operable to supplement the ram air within the ram air circuit to meet a demand of the aircraft.

The invention relates to an air system for an aircraft, that includes air consumers; air sources and a network of ducts and associated control valves controlled by a control unit. The air system is characterized in that: the network of ducts and associated valves includes at least one isolation valve, arranged between an air bleed device and an air duct connecting an air conditioning pack and an auxiliary power unit; the control unit is configured to be able to determine an ideal configuration of the control valves according to the identified requirements of each consumer and a degraded configuration that makes it possible to supply air to predetermined air consumers from the available air sources when the ideal configuration is not attainable.

Auxiliary power systems, aircraft including the same, and related methods are disclosed herein. In one embodiment, the aircraft includes an airframe and an auxiliary power system that includes an auxiliary power unit (APU), an APU controller, and a bleed air temperature (BAT) sensor. The APU defines a bleed air outlet and is configured to regulate a BAT of a bleed air flow generated by the auxiliary power unit. The BAT sensor is positioned at a remote BAT location that is outside the bleed air outlet of the APU. In another embodiment, the auxiliary power system includes an APU configured to generate a bleed air flow, an APU controller configured to receive and transmit signals, and a BAT sensor suite configured to measure the BAT of the bleed air flow and to generate a BAT signal that is based, at least in part, on the BAT.

An aircraft air conditioning system includes a lower cooling zone and an upper cooling zone. The lower cooling zone includes a lower recirculation heat exchanger configured to receive cabin air from a cabin and convert the cabin air into lower cooled recirculated cabin air. The upper cooling zone includes an upper recirculation heat exchange configured to receive the cabin air from the cabin and convert the cabin air into upper cooled recirculated cabin air. A power system selectively delivers power to the lower cooling zone and the upper cooling zone. A controller is in signal communication with the power system. The controller determines a target temperature of the cabin and invokes a recirculation ground maintenance mode that commands the power system to deliver power to one or both of the lower cooling zone and the upper cooling zone so that a temperature of the cabin reaches the target temperature.

Aircraft cabin blower systems and methods of operating aircraft cabin blower systems are provided. One aircraft cabin blower system comprises: a cabin blower compressor having a contactless bearing arrangement; a transmission having a transmission output arranged to drive the cabin blower compressor, a first transmission input arranged to receive mechanical power from a gas turbine engine, and a second transmission input; a reversible variator arranged to receive power from the gas turbine engine and to output mechanical power to the second transmission input, the reversible variator operable to output in both forward and reverse directions of rotation; and a controller configured to control an output speed and direction of rotation of the reversible variator.

An example system for determining a performance status of an environmental control system (ECS) in a vehicle includes memory and processing circuitry. The processing circuitry is configured to determine, based on one or more of the aircraft data, the weather data, or the trending data, an estimated compressor exit temperature. The processing circuitry is configured to determine a current residual compressor exit temperature based on the estimated compressor exit temperature and a current compressor exit temperature. The processing circuitry is configured to determine whether a residual condition is met based at least in part on the residual compressor exit temperature and whether a pack condition is met based at least in part on a pack temperature. The processing circuitry is configured to provide an indication of the performance status of the ECS based on at least one of the residual condition or the pack condition being met.

An environmental control system of an aircraft includes a compressing device including a compressor and a turbine configured to receive a flow of first medium sequentially. The compressing device additionally includes a second turbine configured to receive a flow of second medium distinct from the first medium. A dehumidification system is arranged in fluid communication with the turbine and a bypass valve is configured to divert the flow of the first medium output from the compressor around the turbine.

A method of operating an environmental control system of an aircraft includes providing a first medium to the environmental control system including a compressor and a turbine, wherein the first medium is provided to the compressor and the turbine sequentially and extracting work from a second medium provided to a power turbine operably coupled to the compressor to drive the compressor. In a first mode of operation, the first medium to be provided to a downstream load is output from the turbine, in a second mode of operation, at least a portion of the first medium to be provided to a downstream load bypasses the turbine, and in a third mode of operation, at least a portion of the first medium output from the compressor is provided to the power turbine.

An aircraft system includes a turbine engine having a compressor, a combustor having an inlet and an outlet, and a turbine having an inlet portion and an outlet portion. An auxiliary power unit (APU) is operatively connected to the turbine engine. The APU includes a compressor portion, a generator, and a turbine portion. The compressor portion is operatively connected to the turbine portion through the generator. A source of cryogenic fluid is operatively connected to the turbine engine and the APU. A heat exchange member includes an inlet section operatively connected to the source of cryogenic fluid, a first outlet section operatively connected to the turbine engine and a second outlet section operatively connected to the compressor portion.