Abstract: In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine's speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine's power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine's speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a rate lower than the maximum permissible rate.

Abstract: In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine's speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine's power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine's speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a rate lower than the maximum permissible rate.

Abstract: In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine's speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine's power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine's speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a rate lower than the maximum permissible rate.

Abstract: In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine’s speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine’s power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine’s power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine’s speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine’s power output is increased at a rate lower than the maximum permissible rate.

Abstract: Systems and methods for operating an engine of a rotorcraft are described herein. An engine parameter indicative of torque of the engine is obtained. A decrease of the torque of the engine is detected. At least one rotorcraft parameter indicative of at least one command to control the rotorcraft is obtained and evaluated to determine whether one of an autorotation mode and a powered flight mode of the rotorcraft has been commanded. When the powered flight mode of the rotorcraft has been commanded and the decrease of the torque has been detected, a shaft shear of the engine is detected and a signal indicative of the shaft shear is transmitted. When the autorotation mode of the rotorcraft has been commanded and the decrease of the torque has been detected, detection of the shaft shear is disabled during operation in the autorotation mode.

Abstract: A system and a method for fault detection for a liquid level sensing device are provided. The liquid level sensing device comprising a plurality of switches arranged to measure variance in a liquid level. A sensing signal comprising a plurality of measurements indicative of the liquid level is received from the liquid level sensing device. Each measurement is obtained in response to one or more of the plurality of switches being in a given position at a given liquid level. It is determined, based on the sensing signal, whether the liquid level changed according to one or more expected change patterns. A fault signal is output in response to determining that the liquid level changed according to an abnormal change pattern.

Abstract: Systems and methods for operating an engine of a rotorcraft are described herein. An engine parameter indicative of torque of the engine is obtained. A decrease of the torque of the engine is detected. At least one rotorcraft parameter indicative of at least one command to control the rotorcraft is obtained and evaluated to determine whether one of an autorotation mode and a powered flight mode of the rotorcraft has been commanded. When the powered flight mode of the rotorcraft has been commanded and the decrease of the torque has been detected, a shaft shear of the engine is detected and a signal indicative of the shaft shear is transmitted. When the autorotation mode of the rotorcraft has been commanded and the decrease of the torque has been detected, detection of the shaft shear is disabled during operation in the autorotation mode.

Abstract: A braking system for the low pressure spool of a gas turbine engine includes a braking assembly connected to the low pressure spool and reversibly configurable between an actuated state and an unactuated state. The braking assembly in the unactuated state allows rotation of the low pressure spool without interference. The braking assembly in the actuated state applies a force opposing the rotation of the low pressure spool. A method of controlling the speed of rotation of a low pressure spool and a method of controlling the speed of rotation of low and high pressure spools are also discussed.

Abstract: A system and a method for fault detection for a liquid level sensing device are provided. The liquid level sensing device comprising a plurality of switches arranged to measure variance in a liquid level. A sensing signal comprising a plurality of measurements indicative of the liquid level is received from the liquid level sensing device. Each measurement is obtained in response to one or more of the plurality of switches being in a given position at a given liquid level. It is determined, based on the sensing signal, whether the liquid level changed according to one or more expected change patterns. A fault signal is output in response to determining that the liquid level changed according to an abnormal change pattern.

Abstract: A braking system for the low pressure spool of a gas turbine engine includes a braking assembly connected to the low pressure spool and reversibly configurable between an actuated state and an unactuated state. The braking assembly in the unactuated state allows rotation of the low pressure spool without interference. The braking assembly in the actuated state applies a force opposing the rotation of the low pressure spool. A method of controlling the speed of rotation of a low pressure spool and a method of controlling the speed of rotation of low and high pressure spools are also discussed.

Abstract: A blade root retaining system for attachment of a turbine blade to a turbine disc of a gas turbine engine comprises a blade root having at least one projection on each of opposite sides thereof, the projection extending from a leading edge to a trailing edge of the blade in an axial direction toward a longitudinal axis of the gas turbine engine. The blade root is received in an attachment slot defined through a periphery of the turbine disc. The attachment slot is configured in shape and direction for retaining the blade root.

Abstract: A blade root retaining system for attachment of a turbine blade to a turbine disc of a gas turbine engine comprises a blade root having at least one projection on each of opposite sides thereof, the projection extending from a leading edge to a trailing edge of the blade in a axial direction toward a longitudinal axis of the gas turbine engine. The blade root is received in an attachment slot defined through a periphery of the turbine disc. The attachment slot is configured in shape and direction for retaining the blade root.

Abstract: A dimple for use on a heat transfer surface exposed to a flowing gas, for use for example in a gas turbine engine, the dimple having an aspherical shape.