Abstract: A system for bleeding air from a compressor of an aircraft engine, the system comprises a bleed off valve and a plenum for receiving bleed air from the compressor via the bleed off valve. The plenum has a first outlet for discharging the bleed air from the plenum into the atmosphere, and a second outlet fluidly connected to the compressor for reinjecting a portion of the bleed air into an air intake portion of the compressor. A backflow valve is provided for selectively closing the first outlet of the plenum. The backflow valve has an actuator operable to displace a closure from a closed position to an open position upon a fluid pressure inside the plenum reaching a pressure threshold.

Abstract: A valve assembly for an aircraft engine includes a base defining an air opening configured to receive airflow therethrough in a flow direction from an upstream side to a downstream side, a stopper extending from the downstream side of the base adjacent the air opening, and a flapper plate pivotably mounted to the base about a pivot axis. The flapper plate is pivotable relative to the base and the stopper between a closed position and a fully open position. In the fully open position, a downstream surface of the flapper plate abuts the stopper. In the closed position, the flapper plate obstructs the air opening. A deflector extends from an upstream surface of the flapper plate and projects into the airflow when the flapper plate is located in the fully open position.

Abstract: A system for feeding pre-cooled air to an aircraft environmental control system (ECS) comprises an aircraft engine including a compressor section having a bleed port, and an engine oil circuit including an oil cooler for cooling engine oil. The system further includes an air pre-cooler including an air passage in heat exchange relationship with a coolant passage. The air passage has an air inlet fluidly connected to the bleed port of the compressor section and an air outlet fluidly connected to an inlet of the ECS. The coolant passage has a coolant inlet fluidly connected to an oil outlet of the oil cooler and a coolant outlet fluidly connected to the engine oil circuit at a location upstream of the oil cooler.

Abstract: A method is provided for operating an aircraft engine in a fire-induced emergency state. The engine is housed in a nacelle defining a nacelle bypass duct having a first outlet fluidly connected to an inlet of the engine and a second outlet fluidly connected to an environment external to the nacelle. An indication of a fire of the aircraft engine is received. In response to receiving the indication, an emergency shutdown sequence of the engine is initiated. In response to the initiating the emergency shutdown sequence, a volume of air entering the inlet of the aircraft engine is increased by restricting air flow through the second outlet of the nacelle bypass duct. The volume of air entering the inlet is used to drive a rotor of the engine. The rotor is used to drive an oil pump to circulate oil through a main oil conduit of the engine.

Abstract: A method is provided for operating an aircraft engine in a fire-induced emergency shutdown state. An indication of a fire in a fire zone of the aircraft engine is received. In response to the receiving the indication of the fire in the fire zone of the aircraft engine, an emergency shutdown sequence of the aircraft engine is initiated. In response to the initiating the emergency shutdown sequence of the aircraft engine, an auxiliary oil pump positioned outside of the fire zone of the aircraft engine and distinct from a main oil pump of the aircraft engine is activated. Once activated, the auxiliary oil pump circulates oil through a main oil conduit of the aircraft engine.

Abstract: An aircraft engine has an exhaust duct receiving an engine gas flow and a heat exchanger duct having a wall extending from an inlet receiving a cooling air flow to an outlet connected to the exhaust duct. A heat exchanger is disposed in the heat exchanger duct between the inlet and outlet. A diverted airflow pathway in the heat exchanger duct includes first and second plates extending inwardly in the heat exchanger duct from first and second positions on an inner surface of the wall to plate distal ends, the plate distal ends extending past one another in a direction transverse to the wall. A valve in the wall selectively fluidly connects the heat exchanger duct to an evacuation location and is movable between closed and open positions during operating and shutdown conditions of the engine to fluidly disconnect and connect the heat exchanger duct to the evacuation location.

Abstract: An aircraft engine reservoir system includes a reservoir inner chamber containing a flammable fluid. A chamber inlet is fluidly connectable to a flammable fluid source pressurizing the fluid. The chamber includes an outlet. An air source operates at a pressure that is lower that a flammable fluid pressure during an engine operational condition. A valve selectively fluidly connecting the chamber to the air source is movable between a closed position, in which the chamber flammable fluid pressure acting on the valve exceeds the air source pressure acting on the valve such that the valve blocks the air from entering the chamber, and an open position, in which the chamber flammable fluid pressure acting on the valve is lower than the air source pressure acting on the valve such that the valve allows the air to flow into the chamber and evacuate the flammable fluid from the chamber through the outlet.

Abstract: An aircraft engine comprises an exhaust duct receiving an engine gas flow at a first pressure during an operating condition and at a second, lower pressure at shutdown. A heat exchanger duct connected to the exhaust duct has a heat exchanger disposed therein. A cover in the heat exchanger duct includes a closure movable between open and closed positions to fluidly connect or disconnect the heat exchanger duct to the exhaust duct. A biasing member disposed in the exhaust duct, exposed to the gas flow, and operatively connected to the closure biases the closure toward the closed position with a biasing force. First and second forces opposing the biasing force are generated on the biasing member by the gas flow at the first and second pressures, the first being greater than the second. The biasing force is greater than the second force and less than the first force.

Abstract: An aircraft engine comprises an exhaust duct receiving an engine gas flow at a first pressure during an operating condition and at a second, lower pressure at shutdown. A heat exchanger duct connected to the exhaust duct has a heat exchanger disposed therein. A cover in the heat exchanger duct includes a closure movable between open and closed positions to fluidly connect or disconnect the heat exchanger duct to the exhaust duct. A biasing member disposed in the exhaust duct, exposed to the gas flow, and operatively connected to the closure biases the closure toward the closed position with a biasing force. First and second forces opposing the biasing force are generated on the biasing member by the gas flow at the first and second pressures, the first being greater than the second. The biasing force is greater than the second force and less than the first force.

Abstract: An aircraft engine, has: an oil system, a component containing a baseline volume of oil during normal operation greater than a maximum volume of the oil for compliance with fire resistance requirements, the oil system having: an oil circuit, a de-priming port fluidly connected to a fluid source at a pressure sufficient to overcome a pressure drop through the component to drain the component to a volume of oil less than the maximum volume of the oil for compliance with the fire resistance requirements, and a valve connected to the de-priming port, the valve having a closed configuration preventing the fluid from entering the oil circuit and an open configuration permitting the fluid to enter the oil circuit via the de-priming port and through the valve, the valve movable from the closed configuration to the open configuration in response to the component being subjected to a fire event.

Abstract: An aircraft engine has an exhaust duct receiving an engine gas flow and a heat exchanger duct having a wall extending from an inlet receiving a cooling air flow to an outlet connected to the exhaust duct. A heat exchanger is disposed in the heat exchanger duct between the inlet and outlet. A diverted airflow pathway in the heat exchanger duct includes first and second plates extending inwardly in the heat exchanger duct from first and second positions on an inner surface of the wall to plate distal ends, the plate distal ends extending past one another in a direction transverse to the wall. A valve in the wall selectively fluidly connects the heat exchanger duct to an evacuation location and is movable between closed and open positions during operating and shutdown conditions of the engine to fluidly disconnect and connect the heat exchanger duct to the evacuation location.

Abstract: An aircraft engine reservoir system includes a reservoir inner chamber containing a flammable fluid. A chamber inlet is fluidly connectable to a flammable fluid source pressurizing the fluid. The chamber includes an outlet. An air source operates at a pressure that is lower that a flammable fluid pressure during an engine operational condition. A valve selectively fluidly connecting the chamber to the air source is movable between a closed position, in which the chamber flammable fluid pressure acting on the valve exceeds the air source pressure acting on the valve such that the valve blocks the air from entering the chamber, and an open position, in which the chamber flammable fluid pressure acting on the valve is lower than the air source pressure acting on the valve such that the valve allows the air to flow into the chamber and evacuate the flammable fluid from the chamber through the outlet.

Abstract: An aircraft engine, has: an oil system, a component containing a baseline volume of oil during normal operation greater than a maximum volume of the oil for compliance with fire resistance requirements, the oil system having: an oil circuit, a de-priming port fluidly connected to a fluid source at a pressure sufficient to overcome a pressure drop through the component to drain the component to a volume of oil less than the maximum volume of the oil for compliance with the fire resistance requirements, and a valve connected to the de-priming port, the valve having a closed configuration preventing the fluid from entering the oil circuit and an open configuration permitting the fluid to enter the oil circuit via the de-priming port and through the valve, the valve movable from the closed configuration to the open configuration in response to the component being subjected to a fire event.

Abstract: A cover system selectively allows a gas flow through a heat exchanger duct upstream of an exhaust duct in an aircraft engine. A fluid is at a first pressure during an engine operating condition and a second pressure lower than the first during shutdown. A plate extends across the heat exchanger duct with aperture(s) extending therethrough. A closure is movable between an open position with gas flowing through the apertures into the exhaust duct, and a closed position with the closure closing the apertures. A biasing member operatively connected to the closure closes the closure with a biasing force. During the engine operating condition, the first pressure creates a first force acting against and greater than the biasing force to urge the closure open. At shutdown, the second pressure creates a second force acting against and lower than the biasing force, the biasing force biasing the closure closed.

Abstract: A gas turbine engine according to a first embodiment, having a case; a core within the case; an exhaust nozzle that is fluidly coupled to the case; a duct having a duct outlet that is fluidly coupled to the exhaust nozzle and a duct body extending from the duct outlet to a duct inlet; an air/oil cooler having an airflow outlet disposed at the duct inlet and a cooler body extending from the airflow outlet to an airflow inlet; and an airflow control baffle disposed at one of: the duct inlet; the duct outlet; and the airflow inlet of the cooler, wherein the airflow control baffle is configured to open when oil temperature in the engine is above a first threshold and close when the oil temperature is below a second threshold that is lower than the first threshold.

Abstract: An aircraft engine includes a core gas path through which a core gas flow flows, an exhaust duct receiving the core gas flow, an air-cooled heat exchanger disposed in a heat exchanger duct having an air inlet providing cooling air to the air-cooled heat exchanger and an air outlet in fluid communication with the exhaust duct, and a cover disposed in the heat exchanger duct downstream of the air-cooled heat exchanger. The cover is movable between an open position, in which the cover allows the cooling air to flow through the air outlet into the exhaust duct, and a closed position, in which the cover substantially blocks the air outlet. The cover is operable to move from the open position to the closed position at a predetermined temperature of the cover.