A liquid fuel system for an aircraft engine includes a first fuel supply conduit hydraulically connected to a fuel source, a second fuel supply conduit hydraulically connected to the engine, a fuel return conduit hydraulically connected to the second fuel supply conduit, and a fuel pump. The fuel pump has a main inlet hydraulically connected to the first fuel supply conduit, an outlet hydraulically connected to the second fuel supply conduit, and an intermediate inlet hydraulically connected to the fuel return conduit. The intermediate inlet is located between the main inlet and the outlet and in use has a pressure between the main inlet pressure and the outlet pressure. A method of supplying a liquid fuel to an aircraft engine is also described.

A liquid fuel system for an aircraft engine includes a first fuel supply conduit hydraulically connected to a fuel source, a second fuel supply conduit hydraulically connected to the engine, a fuel return conduit hydraulically connected to the second fuel supply conduit, and a fuel pump. The fuel pump has a main inlet hydraulically connected to the first fuel supply conduit, an outlet hydraulically connected to the second fuel supply conduit, and an intermediate inlet hydraulically connected to the fuel return conduit. The intermediate inlet is located between the main inlet and the outlet and in use has a pressure between the main inlet pressure and the outlet pressure. A method of supplying a liquid fuel to an aircraft engine is also described.

A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine includes feeding un-heated fuel from a fuel tank to the gas turbine engine, by using an ejector pump to draw the fuel from the fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine. Fuel from the main fuel line is bled and directed to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump. The bleed fuel flow is then passed through a hydrophobic fuel screen located upstream of the motive flow pump.

A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine includes feeding un-heated fuel from a fuel tank to the gas turbine engine, by using an ejector pump to draw the fuel from the fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine. Fuel from the main fuel line is bled and directed to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump. The bleed fuel flow is then passed through a hydrophobic fuel screen located upstream of the motive flow pump.

There is described a method of operating a multi-engine system of an helicopter. The multi-engine system has a first turboshaft engine having a first shaft, a second turboshaft engine having a second shaft, a gearbox having a clutch system, and a range of rotation speeds defined as a placarded zone. The method generally has rotating the first shaft at a flight rotation speed when clutched and rotating the second shaft at a first idle rotation speed when unclutched, the first idle rotation speed above the placarded zone; decreasing a rotation speed of the first shaft from the flight rotation speed to a given rotation speed within the placarded zone; decreasing a rotation speed of the second shaft to the given rotation speed; clutching the second shaft; and decreasing the rotation speeds of the first and second shafts to a second idle rotation speed below the placarded zone.

In an aircraft, a fuel return valve (FRV) controls a flow of fuel, used to cool an oil feeding a propulsion engine and an oil of an integrated drive generator (IDG). A first sensor supplies measurements of the oil temperature at an output port of the IDG and a second sensor supplies measurements of oil temperature of the propulsion engine. An FRV operation monitoring system: determines, for each flight of the aircraft, an oil temperature maximum at an output port of the IDG and/or a maximum oil temperature of the propulsion engine; assesses a trend of one and/or the other of the oil temperature maxima over several flights; and generates an alarm when the trend of one and/or the other of the oil temperature maxima shows that a predetermined threshold has been exceeded.

In an aircraft, a fuel return valve (FRV) controls a flow of fuel, used to cool an oil feeding a propulsion engine and an oil of an integrated drive generator (IDG). A first sensor supplies measurements of the oil temperature at an output port of the IDG and a second sensor supplies measurements of oil temperature of the propulsion engine. An FRV operation monitoring system: determines, for each flight of the aircraft, an oil temperature maximum at an output port of the IDG and/or a maximum oil temperature of the propulsion engine; assesses a trend of one and/or the other of the oil temperature maxima over several flights; and generates an alarm when the trend of one and/or the other of the oil temperature maxima shows that a predetermined threshold has been exceeded.

Embodiments of a flow system are provided. The flow system includes a flow source device configured to receive fluid from a first flow line and output fluid on a second flow line. An output is in fluid communication with the flow source device on the second flow line. An actuation system is in fluid communication with the second flow line through a third flow line. A flow meter measures a flow rate in the second flow line without bypassing any fluid to the first flow line. A controller is in communication with the flow source device and the flow meter. The controller adjusts the flow source device to achieve a desired flow rate at the output based on a condition of the flow source device and the flow rate measured by the flow meter.

A fuel supply system for a turbine engine that provides a modulated thrust control malfunction accommodation (TCMA) is disclosed. An example fuel supply system includes a fuel supply line to supply fuel to a combustion engine, a fuel metering valve coupled to the fuel supply line, the fuel metering valve to control a flow of fuel through the fuel supply line to the combustion engine, a throttle valve coupled to the fuel supply line downstream of the fuel metering valve, the throttle valve to bleed off fuel supplied to the combustion engine based on a pressure difference across the fuel metering valve, and a controllable servo coupled to the throttle valve, the controllable servo to control the throttle valve based on a sensor output indicative of the pressure difference.

A fuel supply system for a turbine engine that provides a modulated thrust control malfunction accommodation (TCMA) is disclosed. An example fuel supply system includes a fuel supply line to supply fuel to a combustion engine, a fuel metering valve coupled to the fuel supply line, the fuel metering valve to control a flow of fuel through the fuel supply line to the combustion engine, a throttle valve coupled to the fuel supply line downstream of the fuel metering valve, the throttle valve to bleed off fuel supplied to the combustion engine based on a pressure difference across the fuel metering valve, and a controllable servo coupled to the throttle valve, the controllable servo to control the throttle valve based on a sensor output indicative of the pressure difference.