According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

There is described a shaft shear event detection method. The method comprises obtaining a demodulated waveform of a shaft oscillation wave superimposed on a shaft rotational speed signal, comparing the amplitude to an amplitude threshold, detecting oscillation when the amplitude threshold is exceeded for a plurality of samples, and detecting a shaft shear when oscillation continues for a predetermined time limit.

A system for monitoring the axial position of a rotating shaft includes a phonic wheel mounted coaxially to the shaft for rotation with a circumferential row of teeth. The system includes a sensor configured to detect the passage of the teeth by generating an alternating measurement signal. First and second portions of the teeth alternate around the row and contribute respective first and second components to the alternating measurement signal. The first portion of teeth vary in height in an axial direction of the wheel such that the relative height of the first and second portions varies with axial distance across the phonic wheel, and the sensor is positioned relative to the phonic wheel such that axial displacement of the shaft causes the signal to vary the first component's amplitude relative to the second component's amplitude due to the height variation, to monitor the axial position of the shaft.

A gas turbine engine for an aircraft that includes a nacelle, a fan, an engine core, a bypass duct extending between the engine core and the nacelle and guiding a bypass airflow through the bypass duct, and at least one non-structural strut extending in the radial direction within the bypass duct, wherein the non-structural strut includes an outside wall acting as a heat exchanger, and wherein the outside wall includes first transport means configured to transport in the outside wall at least one fluid to be cooled. It is provided that the non-structural strut further includes second transport means configured to transport a fluid to be heated, wherein the first transport means and the second transport means are configured such that the fluid to be heated is heated by the at least one fluid to be cooled and the at least one fluid to be cooled is cooled both by the bypass airflow and the fluid to be heated.

A method is provided involving a turbine engine. During this method, data is received indicative of twist of a shaft of the turbine engine. The data is monitored over time to identity one or more reversal events while the turbine engine is operating, where each of the reversal events corresponds to a reversal in a value sign of the data. Shaft shear is identified in the shaft based on occurrence of N number of the reversal events.

A gas turbine engine, includes: an engine core including a turbine, compressor, and shaft system connecting the turbine to the compressor, and forming a torque path therebetween. The shaft system is axially located by a thrust bearing located forward of the turbine, and the engine is configured, in the event of a shaft break which divides the shaft system into a front portion located by the thrust bearing and a rear portion unlocated by the thrust bearing, the rear portion is free to move axially rearwardly under a gas load. The engine further includes a shaft break detector having a forward speed sensor configured to measure a rotational speed of the front portion of the shaft system, and a rear microwave sensor configured to measure a rotational speed of the rear portion of the shaft system, wherein a shaft break can be detected based on differences in the measured speeds.

A gas turbine engine, includes: an engine core including a turbine, compressor, and shaft system connecting the turbine to the compressor, and forming a torque path therebetween. The shaft system is axially located by a thrust bearing located forward of the turbine, and the engine is configured, in the event of a shaft break which divides the shaft system into a front portion located by the thrust bearing and a rear portion unlocated by the thrust bearing, the rear portion is free to move axially rearwardly under a gas load. The engine further includes a shaft break detector having a forward speed sensor configured to measure a rotational speed of the front portion of the shaft system, and a rear microwave sensor configured to measure a rotational speed of the rear portion of the shaft system, wherein a shaft break can be detected based on differences in the measured speeds.

A method of controlling a gas turbine engine includes the steps of: detecting a shaft break event in a shaft connecting a compressor of the gas turbine engine to a turbine of the gas turbine engine; and in response to this detection, activating a shaft break mitigation system which introduces a fluid into a gas flow of the gas turbine engine downstream of the turbine, or increases an amount of a fluid being provided into the gas flow of the gas turbine engine downstream of the turbine, whereby the fluid reduces an effective area of a nozzle for the gas flow so as to reduce the mass flow rate of the gas flow through the turbine.

A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes a full authority digital engine control (FADEC) that controls operation of the gas turbine engine in a full-power mode and controls operation of the core turning motor to drive rotation of the engine core using a reduced power draw when the FADEC is partially depowered in a low-power bowed rotor prevention mode.