An aircraft turboprop engine has at least a low-pressure body and a high-pressure body. The low-pressure body drives a propeller by a gearbox. The turboprop engine also includes means for supplying air to an air-conditioning circuit of an aircraft cabin, wherein the means for supplying air has at least one compressor of which the rotor is coupled to the low-pressure body. The compressor has an air inlet connected to means for bleeding air from an air inlet duct of the turboprop engine.

Fuel used as a coolant in an aircraft can be thermally conditioned for active thermal management of the airframe and engine. The fuel can be thermally conditioned using the residual cooling capacity of a power and thermal module (PTM), providing flexibility of thermal system design, or via a compact engine-mounted turbo cooler, to maximize system efficiency. The fuel can be stored in a thermal reserve tank to provide a missionized heat sink capable serviceable for periodic high heat flux equipment. The cooling and provision of cooled fuel to aircraft components can be intelligently controlled to provide efficient cooling and effectively unlimited ground hold times.

An aircraft turboprop engine includes at least a low-pressure body and a high-pressure body. The low-pressure body drives a propeller by means of a gearbox. The turboprop engine also includes means for supplying air to an air-conditioning circuit of an aircraft cabin, wherein the supply means has at least one compressor borne by the gearbox and of which the rotor is coupled to the low-pressure body by means of the gearbox.

A method of operating a gas turbine engine compressor. The engine comprises a compressor having an environmental control system bleed port having an outlet in fluid communication with an aircraft environmental control system air duct, and an air turbine starter configured to rotate a compressor shaft of the gas turbine engine. The air turbine starter has an inlet in fluid communication with the environmental control system air duct via an air turbine valve. The method comprises determining a surge margin of the compressor, and where the surge margin of the compressor is determined to be below a predetermined minimum surge margin, opening the air turbine valve to supply air to the air turbine.

An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.

Pressurized air systems for aircraft and related methods are described herein. An example pressurized air system includes a compressor having a compressor inlet and a compressor outlet. The compressor inlet receives air from a first air source and the compressor outlet supplies pressurized air to an environmental control system (ECS). The pressurized air system includes a turbine having a turbine inlet to receive air from a second air source, a first overrunning clutch operatively coupled between an output shaft of an accessory gearbox and the compressor, the accessory gearbox operatively coupled to a drive shaft extending from an engine of the aircraft, and a second overrunning clutch operatively coupled between the compressor and the turbine. The first and second overrunning clutches enable the accessory gearbox to drive the compressor during a first mode of operation and enable the turbine to drive the compressor during a second mode of operation.

Fuel used as a coolant in an aircraft can be thermally conditioned for active thermal management of the airframe and engine. The fuel can be thermally conditioned using the residual cooling capacity of a power and thermal module (PTM), providing flexibility of thermal system design, or via a compact engine-mounted turbo cooler, to maximize system efficiency. The fuel can be stored in a thermal reserve tank to provide a missionized heat sink capable serviceable for periodic high heat flux equipment. The cooling and provision of cooled fuel to aircraft components can be intelligently controlled to provide efficient cooling and effectively unlimited ground hold times.

An aircraft propulsion system includes a gas turbine engine; an environmental control system (ECS); and a bleed flowpath from the gas turbine engine through the ECS. A turbine is along the bleed flowpath and a propulsion fan is mechanically coupled to the turbine to be driven by the turbine.

A fuel and bleed controller is provided. The fuel and bleed controller includes a processor and a memory. The memory stores program instructions thereon. The program instructions are executable by the processor to cause the fuel and bleed controller to send status requests to systems of the aircraft. The systems comprise a bleed system and bleed user controllers. The program instructions are further executable by the processor to cause the fuel and bleed controller to receive status responses from the systems of the aircraft and determine fuel requirements based on the status responses in advance of operational needs by the systems of the aircraft. The program instructions are further executable by the processor to cause the fuel and bleed controller to control engines of the aircraft based on the fuel requirements.

An aircraft cabin blower system is described having a hydraulic circuit comprising a first hydraulic device and a second hydraulic device. The first hydraulic device is mechanically coupled to a cabin blower compressor and the second hydraulic device is arranged in use to be mechanically coupled to a spool of a gas turbine engine. The first hydraulic device is capable of performing as a hydraulic motor and the second hydraulic device is capable of performing as a hydraulic pump. When, in use, the system is operating in a cabin blower configuration, a driving force supplied by the spool of the gas turbine causes the second hydraulic device to pump liquid provided in the hydraulic circuit and thereby to drive the first hydraulic device, which in turn rotates the cabin blower compressor.