Abstract: A method of operating an aircraft air conditioning system is includes delivering cabin air to a lower recirculation heat exchanger included in a lower cooling zone to generate lower cooled recirculated cabin air and delivering the cabin air to an upper recirculation heat exchanger included in an upper cooling zone to generate upper cooled recirculation air. The method further comprising generating power via a power system, and invoking, via the controller, a recirculation ground maintenance mode to command the power system to deliver power to one or both of the lower cooling zone and the upper cooling zone so as to output one or both of the lower cooled recirculated cabin air and the upper cooled recirculated cabin to an aircraft cabin.

Abstract: 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.

Abstract: A heat exchanger includes a first end opposite a second end, a first side opposite a second side, a first layer, and a second layer. The first side and the second side extend from the first end to the second end. The first layer includes an inlet at the first end and an outlet at the second end of the heat exchanger. The second layer includes a first passage at the first end of the heat exchanger and extending from the first side to the second side and a second passage adjacent to the first passage. The second passage extends from the first side to the second side. The second layer further includes a third passage extending from the second end toward the second passage. The first passage is fluidically connected to the third passage proximate the second end and the third passage is fluidically connected to the second passage.

Abstract: Fuel tank inerting systems are described. The systems include a fuel tank, a catalytic reactor arranged to receive a reactant mixture comprising a first reactant and a second reactant to generate an inert gas to be supplied to the fuel tank to fill an ullage space of the fuel tank, a condenser heat exchanger arranged between the catalytic reactor and the fuel tank and configured to cool an output from the catalytic reactor, and a fan assembly arranged within an inerting system flow path upstream of the catalytic reactor, wherein the fan assembly is arranged within a gas flow having a temperature of at least 185° C.

Abstract: 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.

Abstract: A method of monitoring an air cycle machine including driving a rotary shaft of an air cycle machine, disconnecting a driving source to allow the rotary shaft to slow the rotary shaft, and monitoring a shutdown cycle of the rotary shaft.

Abstract: A method of monitoring aircraft including removing a conical collector through a cabin exhaust valve of the aircraft wherein ambient cabin air has been driven from the cabin over a reagent fluid within the conical collector in order to collect a representative sample of the cabin air within the reagent fluid.

Abstract: A heat exchanger includes a first end opposite a second end, a first side opposite a second side, a first layer, and a second layer. The first side and the second side extend from the first end to the second end. The first layer includes an inlet at the first end and an outlet at the second end of the heat exchanger. The second layer includes a first passage at the first end of the heat exchanger and extending from the first side to the second side and a second passage adjacent to the first passage. The second passage extends from the first side to the second side. The second layer further includes a third passage extending from the second end toward the second passage. The first passage is fluidically connected to the third passage proximate the second end and the third passage is fluidically connected to the second passage.

Abstract: An environmental control system includes an airflow source, and an air cycle machine in flow communication with the airflow source, and through which an airflow from the airflow source is directed. The air cycle machine includes a compressor and a turbine. A liquid load heat exchanger is located in flow communication with the turbine such that airflow downstream of the turbine exchanges thermal energy with a liquid flow at the liquid load heat exchanger to cool the liquid flow. A liquid load reheater is located upstream of the turbine and upstream of the liquid load heat exchanger. The liquid load reheater is configured such that a thermal energy exchange between the airflow prior to the airflow entering the turbine and the liquid flow prior to the liquid flow entering the liquid load heat exchanger occurs at the liquid load reheater.

Abstract: Fuel tank inerting systems are described. The systems include a fuel tank, a catalytic reactor arranged to receive a reactant mixture comprising a first reactant and a second reactant to generate an inert gas to be supplied to the fuel tank to fill an ullage space of the fuel tank, a condenser heat exchanger arranged between the catalytic reactor and the fuel tank and configured to cool an output from the catalytic reactor, and a fan assembly arranged within an inerting system flow path upstream of the catalytic reactor, wherein the fan assembly is arranged within a gas flow having a temperature of at least 185° C.

Abstract: A method of monitoring an air cycle machine including driving a rotary shaft of an air cycle machine, disconnecting a driving source to allow the rotary shaft to slow the rotary shaft, and monitoring a shutdown cycle of the rotary shaft.

Abstract: An ozone converter includes an outer housing having an inlet and an outlet and a core disposed within the outer housing, the core including a central passageway formed therein and passing thorough the core. The converter also includes an ozone control assembly that allows air to pass through the central passageway in an closed mode and prevents flow thorough the central passageway in an open mode, the assembly including cover flaps that cover a portion of the core in the closed mode and that do not cover the core in the open mode.

Abstract: A water extractor includes an outer duct with an inlet and an outlet, and an inner duct with an inlet and an outlet. The inner duct is positioned in the outer duct. The water extractor further includes a gap between the inner duct and the outer duct. The gap is tapered between a first position and a second position.

Abstract: An environmental control system includes a turbo-compressor assembly and a ram air system. The turbo-compressor assembly includes a first turbine, a first compressor, and a first heat exchanger. The first heat exchanger has a first heat exchanger first side in fluid communication a first turbine outlet, a first heat exchanger second side, a first heat exchanger inlet in fluid communication a first compressor outlet, and a first heat exchanger outlet. The ram air system has a first ram air inlet in fluid communication with the first heat exchanger second side, and a second heat exchanger in fluid communication with the first ram air inlet.

Abstract: A water extractor includes an outer duct with an inlet and an outlet, and an inner duct with an inlet and an outlet. The inner duct is positioned in the outer duct. The water extractor further includes a gap between the inner duct and the outer duct. The gap is tapered between a first position and a second position.

Abstract: An environmental control system includes an airflow source, and an air cycle machine in flow communication with the airflow source, and through which an airflow from the airflow source is directed. The air cycle machine includes a compressor and a turbine. A liquid load heat exchanger is located in flow communication with the turbine such that airflow downstream of the turbine exchanges thermal energy with a liquid flow at the liquid load heat exchanger to cool the liquid flow. A liquid load reheater is located upstream of the turbine and upstream of the liquid load heat exchanger. The liquid load reheater is configured such that a thermal energy exchange between the airflow prior to the airflow entering the turbine and the liquid flow prior to the liquid flow entering the liquid load heat exchanger occurs at the liquid load reheater.

Abstract: An environmental control system includes two environmental control system components with a duct extending between them. There is a drain in the duct including an orifice through the duct, a plenum in serial fluid communication with the orifice; and an orifice device removably connected to the duct, the orifice device including a second orifice in serial fluid communication with the plenum and the first orifice.

Abstract: A water extractor includes an outer duct with an inlet and an outlet, and an inner duct with an inlet and an outlet. The inner duct is positioned in the outer duct. The water extractor further includes a gap between the inner duct and the outer duct. The gap is tapered between a first position and a second position.

Abstract: A water extractor includes an outer duct with an inlet and an outlet, and an inner duct with an inlet and an outlet. The inner duct is positioned in the outer duct. The water extractor further includes a gap between the inner duct and the outer duct. The gap is tapered between a first position and a second position.

Abstract: An ozone converter includes an outer housing having an inlet and an outlet and a core disposed within the outer housing, the core including a central passageway formed therein and passing thorough the core. The converter also includes an ozone control assembly that allows air to pass through the central passageway in an closed mode and prevents flow thorough the central passageway in an open mode, the assembly including cover flaps that cover a portion of the core in the closed mode and that do not cover the core in the open mode.