A flow combiner is provided for a gas turbine engine. The flow combiner includes an outlet duct, a compressor bleed inlet duct coupled to the outlet duct, and a ventilation inlet duct coupled to the outlet duct. The compressor bleed inlet duct is configured to receive a bleed flow from a compressor of the gas turbine engine. The ventilation inlet duct is configured to receive a ventilation flow from an enclosure surrounding the gas turbine engine. The bleed flow and the ventilation flow are combined as an outlet flow through the outlet duct.

A bleed air supply system has a sensor monitoring the system, an operating condition monitor detecting an operating condition value of the aircraft (other than the bleed air supply system), and independent monitoring modules evaluating a part of the bleed air supply system. The monitoring modules each have an individual monitoring function and individual activation and deactivation parameters based on sensor data and the operating condition value. The method includes: detecting the condition of the bleed air supply system via sensor data and the operating condition value; activating a monitoring module, which has activation parameters met by the sensor data and the operating condition value; monitoring the condition of the bleed air supply system by the activated monitoring module by a monitoring function of the activated monitoring module; and deactivating the activated monitoring module, deactivation parameters of which are met by the sensor data and the operating condition value.

A bleed air supply system has a sensor monitoring the system, an operating condition monitor detecting an operating condition value of the aircraft (other than the bleed air supply system), and independent monitoring modules evaluating a part of the bleed air supply system. The monitoring modules each have an individual monitoring function and individual activation and deactivation parameters based on sensor data and the operating condition value. The method includes: detecting the condition of the bleed air supply system via sensor data and the operating condition value; activating a monitoring module, which has activation parameters met by the sensor data and the operating condition value; monitoring the condition of the bleed air supply system by the activated monitoring module by a monitoring function of the activated monitoring module; and deactivating the activated monitoring module, deactivation parameters of which are met by the sensor data and the operating condition value.

A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor including a circumferential array of blades, a low pressure compressor section including a low pressure compressor section inlet with a low pressure compressor section inlet annulus area and a low pressure turbine section. The low pressure turbine section includes a maximum gas path radius, the blades include a maximum radius, and a ratio of the maximum gas path radius to the maximum radius of the blades is equal to or greater than 0.35, and is less than 0.55.

A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor including a circumferential array of blades, a low pressure compressor section including a low pressure compressor section inlet with a low pressure compressor section inlet annulus area and a low pressure turbine section. The low pressure turbine section includes a maximum gas path radius, the blades include a maximum radius, and a ratio of the maximum gas path radius to the maximum radius of the blades is equal to or greater than 0.35, and is less than 0.55.

A method of operating a multi-engine system of an aircraft having first and second engines includes accumulating compressed air in a pressure vessel external to the engines, and operating the first and second engines asymmetrically, by controlling the first engine to operate in an active operating condition providing sufficient power and/or rotor speed for demands of the aircraft, and controlling the second engine to operate in a standby operating condition wherein the second engine produces less power output than the first engine. In response to a power demand request, the second engine is accelerated out of the standby operating condition by introducing therein compressed air from the pressure vessel at a location upstream of a combustor of the second engine.

A method of operating a multi-engine system of an aircraft having first and second engines includes accumulating compressed air in a pressure vessel external to the engines, and operating the first and second engines asymmetrically, by controlling the first engine to operate in an active operating condition providing sufficient power and/or rotor speed for demands of the aircraft, and controlling the second engine to operate in a standby operating condition wherein the second engine produces less power output than the first engine. In response to a power demand request, the second engine is accelerated out of the standby operating condition by introducing therein compressed air from the pressure vessel at a location upstream of a combustor of the second engine.

An orifice pack is provided for delivering pressurized air to a compressor bleed valve of a gas turbine engine. The orifice pack has a diffusion chamber in serial flow communication with a tapering passage and a first outlet passage for venting a first portion of the pressurized air from the diffusion chamber. A second outlet passage branches off from the diffusion chamber at an axial location between the inlet and the tapering passage. The second outlet passage is fluidly connected to the compressor bleed valve for directing a second portion of the pressurized air from the diffusion chamber to the compressor bleed valve.

An environmental control system for an aircraft includes a higher pressure tap associated with a higher compression location in a main compressor section. The higher pressure tap leads into a turbine section of a turbocompressor such that air in the higher pressure tap drives the turbine section to in turn drive a compressor section of the turbocompressor. A combined outlet receives airflow from a turbine outlet and a compressor outlet intermixing airflow and passing the mixed airflow downstream to be delivered to an aircraft system. A buffer air outlet communicates airflow to an engine buffer air system.

An environmental control system for an aircraft includes a higher pressure tap associated with a higher compression location in a main compressor section. The higher pressure tap leads into a turbine section of a turbocompressor such that air in the higher pressure tap drives the turbine section to in turn drive a compressor section of the turbocompressor. A combined outlet receives airflow from a turbine outlet and a compressor outlet intermixing airflow and passing the mixed airflow downstream to be delivered to an aircraft system. A buffer air outlet communicates airflow to an engine buffer air system.