An air duct arrangement (58) for an aircraft (40). The arrangement (58) comprises an environmental control system (ECS) (50). The ECS (50) comprises an air inlet (60) arranged to ingest a low velocity portion of a boundary layer flow adjacent the aircraft fuselage (44), and to deliver a flow of air to an environmental control system air intake (66). The arrangement (58) further comprises an ejector (70) arranged to receive an ECS exhaust (76), and boundary layer air from an aft region of the aircraft (40), and to exhaust air to the ambient airstream at an aft portion of the aircraft (40).

A gas turbine engine anti-icing system troubleshooting method comprising providing an anti-icing system comprising a bleed air source coupled to a pressure regulating valve set having an upper valve coupled end-to-end in series with a lower valve; and an air pressure sensor coupled to the pressure regulating valve set downstream of the pressure regulating valve set; detecting at least one valve fault; checking the upper valve for the at least one valve fault; checking the lower valve for the at least one valve fault; deactivating at least one of the upper valve and the lower valve; and replacing at least one of the upper valve and lower valve.

A gas turbine engine comprising a compressor, a compressor case surrounding the compressor and a compressor tip injector system is disclosed. The compressor tip injector system comprises a cabin blower system comprising a cabin blower compressor arranged in use to compress air used in a cabin of an aircraft and by the compressor tip injector system. The compressor case comprises one or more injectors of the compressor tip injector system through which in use air from the cabin blower compressor is injected towards blade tip ends of blades of the compressor as they rotate.

Aircraft, air conditioning systems, and air diffusers that may be used to create a quiet, comfortable environment within an aircraft cabin are disclosed. For example, an aircraft cabin air diffuser, which may be used in an air conditioning system and/or an aircraft, may include an inlet section, a neck section downstream of the inlet section, an outlet section downstream of the neck section, and a flow controller within the neck section. The flow controller may be a passive pressure controller (configured to affect air flow through the passive pressure controller in response to an air pressure differential across the passive pressure controller) and/or a vortex inducer (configured to create a vortex of air downstream of the vortex inducer).

A ram air system includes a bay comprising an exterior wall defining an interior volume that at least partially encloses a ram air duct. The ram air duct includes an outlet configured to discharge an exhaust airflow at a first temperature. At least one of the exterior wall and the ram air duct defines an aperture therein providing for flow communication between the bay interior volume and the exhaust airflow such that cooling air flows from the interior volume to form a boundary layer between the exhaust airflow and the exterior wall downstream of the outlet. The boundary layer is at a second temperature that is lower than the first temperature.

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.

Aircraft cargo compartment airflow distribution system and aircraft cargo compartment airflow distribution sub-assemblies configured to modify a primary aircraft compartment airflow distribution assembly and methods are presently disclosed.