An airplane is provided. The airplane includes a first medium at a first pressure, a second medium at a second pressure, a third medium at a third pressure; and an air conditioning system. The air conditioning system includes a compressor, a first heat exchanger configured to transfer heat from the first medium to the third medium, a second heat exchanger configured to reject heat from the first medium, a third heat exchanger configured to reject heat from the second medium, a first turbine configured to receive the first medium, and a second turbine configured to receive the second medium.

An airplane is provided. The airplane includes a first medium at a first pressure, a second medium at a second pressure, a third medium at a third pressure; and an air conditioning system. The air conditioning system includes a compressor, a first heat exchanger configured to transfer heat from the first medium to the third medium, a second heat exchanger configured to reject heat from the first medium, a third heat exchanger configured to reject heat from the second medium, a first turbine configured to receive the first medium, and a second turbine configured to receive the second medium.

An air cycle machine is provided. The air cycle machine can be included an environmental control system of an aircraft. The air cycle machine can include a turbine comprising a plurality of inlet gas flow paths, a compressor driven by the turbine from a shaft, and a fan driven by the turbine from the shaft.

An air cycle machine is provided. The air cycle machine can be included an environmental control system of an aircraft. The air cycle machine can include a turbine comprising a plurality of inlet gas flow paths, a compressor driven by the turbine from a shaft, and a fan driven by the turbine from the shaft.

An airplane is provided. The airplane includes a pressurized medium, a turbine, and a valve. The turbine includes at least one nozzle. The valve is located upstream of the turbine. The valve provides the pressurized medium to the at least one nozzle of the turbine according to an operational mode.

An airplane is provided. The airplane includes a pressurized medium, a turbine, and a valve. The turbine includes at least one nozzle. The valve is located upstream of the turbine. The valve provides the pressurized medium to the at least one nozzle of the turbine according to an operational mode.

A differential pressure sensor system for use in an aircraft comprises a differential pressure sensor for determining a differential pressure between a pressurizable aircraft cabin and an aircraft environment, the differential pressure sensor having a first port connectable to the pressurizable aircraft cabin via a first line and a second port connectable to the aircraft environment via a second line. A shut-off device of the differential pressure sensor system is arranged in the second line which is switchable between an open position in which it opens the second line, such that a pressure prevailing in the aircraft environment acts on the second port of the differential pressure sensor, and a shut-off position in which it closes the second line, such that the second port of the differential pressure sensor is shut off from the pressure prevailing in the aircraft environment.

A differential pressure sensor system for use in an aircraft comprises a differential pressure sensor for determining a differential pressure between a pressurizable aircraft cabin and an aircraft environment, the differential pressure sensor having a first port connectable to the pressurizable aircraft cabin via a first line and a second port connectable to the aircraft environment via a second line. A shut-off device of the differential pressure sensor system is arranged in the second line which is switchable between an open position in which it opens the second line, such that a pressure prevailing in the aircraft environment acts on the second port of the differential pressure sensor, and a shut-off position in which it closes the second line, such that the second port of the differential pressure sensor is shut off from the pressure prevailing in the aircraft environment.

An apparatus is disclosed that includes an aircraft or repurposed aircraft or fuselage having a cabin capable of pressurization, a way to pressurize the cabin whether by built in machinery or external apparatus, a way to deliver oxygen to a plurality of persons in the cabin, a source of hyperbaric oxygen, a pressure gauge or regulator configured to measure or regulate a pressure of the hyperbaric oxygen or the aircraft, a plurality of face or head coverings configured to provide the hyperbaric oxygen to persons or patients in need thereof, and an optional exhaust system configured to remove gas(es) from the face or head coverings without releasing the gas(es) into the cabin. Each of the face or head coverings includes a gas inlet, a gas outlet, and one or more seals adapted to contain oxygen in the face or head covering at a pressure greater than 1 atm. A related kit and a related method of treating persons with hyperbaric oxygen are also disclosed.

A cockpit pressurization and oxygen warning system includes a cabin pressure input and an aircraft pressure input. A pilot interface includes a first visual indicator having a first recognizable characteristic disposed in a first position that is made visually perceptible when a first signal is asserted and a second visual indicator having a second recognizable characteristic esthetically different from the first recognizable characteristic and disposed in a second position different from the first position that is made visually perceptible when a second signal is asserted. A control circuit that is responsive to the cabin pressure input and the aircraft pressure input determines an acceptable range for the cabin altitude that corresponds to the aircraft altitude. The control circuit asserts the first signal when the cabin altitude is within the acceptable range and asserts the second signal when the cabin altitude is not within the acceptable range.